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USMLE Step 2 (Subject) / Cardiology (Lesson)

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• Long QT syndrome Long QT syndrome (LQTS) is a congenital or acquired heart condition in which the QT interval (i.e., ventricular depolarization and repolarization) is prolonged. Congenital LQTS:- Arises from mutations in genes that code for ion channels within myocytes- Jervell and Lange-Nielsen syndrome → Associated with congenital deafness→ Autosomal recessive- Romano-Ward syndrome → No associated deafness→ Autosomal dominant Acquired LQTS:- Antiarrhythmics: especially class IA and class III antiarrhythmics- Psychiatric medications: especially tricyclic antidepressants and haloperidol- Antibiotics (e.g., macrolides, fluoroquinolones)- Antihistamines (e.g., diphenhydramine)- Antiemetics (e.g., ondansetron, granisetron)- Opioids- Electrolyte imbalances (e.g., hypokalemia, hypomagnesemia, hypocalcemia)- Endocrine disorders (e.g., hypothyroidism) Clinical features:- Palpitations- Dizziness- Syncope- Cardiac arrest Diagnostics:- Prolonged QTc interval: Males: > 440 ms; Females: > 460 ms- Genetic testing Treatment:- Avoid activities that stress the heart- Avoid cold temperatures (e.g., swimming, diving, skiing)- Congenital LQTS→ First line: beta blockers (e.g., propranolol)→ Left cardiac sympathetic denervation (stellectomy): patients not responsive to beta blockers→ High-risk patients: implantable cardioverter defibrillator (ICD)- Acquired LQTS: treat cause (remove offending drug, fix electrolyte imbalances, etc.)
• Gallop heart sounds Third heart sound (S3)- Heard during rapid filling of ventricles in diastole- Turbulent blood flow to the ventricles due to increased volume- Normal: Children, young adults, pregnancy- Abnormal: Age > 40, heart failure, dilated cardiomyopathy, mitral regurgitation Forth heart sound (S4)- Heard immediately after atrial contraction phase as blood is forced into a stiff ventricle- Normal: Healthy older adults- Abnormal: Younger adults, children; ventricular hypertrophy (e.g., hypertension, aortic stenosis, cor pulmonale); acute myocardial infarction
• Poor prognostic factors in systolic heart failure Clinical:- Higher NYHA funcitonal class- Resting tachycardia- Presence of S3 gallop- Elevated jugular venous pressure- Low blood pressure (< 100/60 mmHg)- Moderate to severe mitral regurgitation- Low maximal oxygen consumption (peak VO2) Laboratory:- Hyponatremia- Elevated pro-BNP levels- Renal insufficiency ECG:- QRS duration > 120 msec- Left bundle branch block pattern Echocardiography:- Severe LV dysfunction- Concomitant diastolic dysfunction- Reduced right ventricular function- Pulmonary hypertension Associated conditions:- Anemia- Atrial fibrillation- Diabetes mellitus
• Cholesterol crystal embolism Risk factors:- Comorbid conditions: Hypercholesterolemia, hypertension, type 2 diabetes mellitus- Cardiac catheterization or vascular procedure Clinical features:- Dermatologic: Livedo reticularis, ulcers, gangrene, blue toe syndrome- Renal: Acute kidney injury- CNS: Stroke, amaurosis fugax- Ocular: Hollenhorst plaques- GI: Intestinal ischemia, pancreatitis Diagnostics:- Lab findings: ↑ creatinine, eosinophilia, hypocomplementemia- Urinalysis: Typically benign with few cells or casts, may have eosinophiluria- Skin or renal biopsy: Biconvex, needle-shaped clefts within occluded vessels Treatment:- Symptomatic- Termination of anticoagulant therapy, initiate statin therapy
• Hypertension workup 1. Urinalysis for occult hematuria and urine protein/creatinine ratio 2. Chemistry panel: Serum Na+, K+, and Ca2+ 3. TSH 4. Stratification of cardiovascular risk: fasting blood glucose, lipid profile (HDL, LDL, and triglycerides levels) 5. Baseline ECG (to evaluate for coronary artery disease or left ventricular hypertrophy)
• Non-pharmacologic modifications for hypertension Weight loss: Reduce BMI < 25 kg/m2- ↓ 5-20 mmHg per 10-kg loss DASH diet: Diet high in fruits & vegetables & low in saturated fat & total fat- ↓ 8-14 mmHg Exercise: 30 minutes/day for 5-6 days/week- ↓ 4-9 mmHg Dietary sodium: < 3 g/day- ↓ 2-8 mmHg Alcohol intake: 2 drinks/day inmen & 1 drink/day in women- ↓ 2-4 mmHg
• Cardiac myxoma Epidemiology:- Most common primary cardiac neoplasm (usually benign)- Most common location: Left atrium (80%)- F > M- Peak incidence: 40-60 years Clinical featuers:- General: Weight loss, fever, pallor, clubbing of the fingers- Auscultatory findings→ Mid-diastolic rumbling murmur over the apex→ "Tumor plop"- Dyspnea, lightheadedness, syncope- Embolization of tumor fragments (eg, stroke) Diagnostics:- Echocardiography Treatment: Surgical resection
• Stress tests Exercise ECG test:- Mechanism: ↑ HR, ↑ BP- Best for: Patients able to reach target HR (tHR = 85% of 220-age) Pharmacologic stress test with adenosine or dipyridamole:- Mechanism: Nonselective adenosine agonist; Dilates coronary arteries without ↑ HR or BP- Best for: LBBB, pacemaker, patients unable to reach tHR Dobutamine stress echocardiography:- Mechanism: B1 agonist; ↑ HR ± BP- Best for: Reactive airway disease- Patients unable to reach tHR Nuclear stress test:- Perfusion with thallium- The reversibility (normal perfusion at rest, compromised with stress) identifies salvageable tissue Patients with new-onset chest pain, ST segment depression, hypotension or arrhythmias should undergo cardiac catheterization!
• Joint National Committee recommendations for treating hypertension Age ≥ 60:- Initiate: ≥150/>90 mmHg- Goal blood pressure: < 150/90 mmHg Age < 60, chronic kidney disease, diabetes- Initiate: ≥140/> 90 mmHg- Goal blood pressure: < 140/90 mmHg Blacks: Thiazide diuretic or CCB alone or in combination(ACE-I/ARB are not first-line!) Other ethnicities: Thiazide diuretic, ACEI, ARB, CCB alone or in combination All ethnicities with chronic kidney disease: ACEI or ARB alone or in combination with other drug classes
• Surgical indications for severe chronic mitral valve regurgitation Primary MR:- Surgery if LVEF 30%-60% (regardless of symptoms)- Consider surgery if successful valve repair is highly likely:→ Symtomatic & LVEF < 30%→ Asymptomatic & LVEF > 60% Secondary MR: Medical management, valve surgery rarely indicated
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• Second-degree AV block Mobitz type I- Usually AV node- ECG: Progressive prolonged PR interval leads to a nonconducted P wave ("group beating")- Exercise or atropin: Improves type I AV block- Vagal maneuvers: Worsens type I AV block Mobitz type II:- Below the level of AV node (eg, bundle of His)- ECG: PR interval remains constant with intermittent nonconducted P waves- Exercise or atropin: Worsens type II AV block- Vagal maneuvers: Paradoxically improves type II AV block- Indicaton for pacemaker
• Chronic aortic regurgitation Etiology:- Congenital bicuspid aortic valve- Postinflammatory (e.g., rheumatic heart disease, endocarditis)- Aortic root dilation (e.g., Marfan syndrome, syphilis) Pathophysiology:- Backflow from aorta into LV → ↑ LV end-diastolic volume- LV initially compensates with eccentric hypertrophy → ↑ SV & CO- Eventual LV dysfunction → ↓ SV & CO → heart failure Clinical findings:- Diastolic decrescendo murmur- Widened pulse pressure (↑ SBP & ↓ DBP)- Rapid rise-rapid fall ("water-hammer") pulsation- Abrupt carotid distension & collapse, "pistol-shot" femoral pulses
• Sick sinus syndrome Etiology:- Degeneration and fibrosis of the sinoatrial node and surrounding myocardium- Medications (e.g., β-blockers, digoxin, non-dihydropyridine calcium channel blockers) Clinical features:- Bradycardia→ Fatigue, dyspnea, dizziness, syncope- Bradycardia-tachycardia syndrome→ Atrial arrhythmias (e.g., atrial fibrillation)→ Palpitations ECG findings:- Sinus bradycardia- Sinus pauses (delayed P waves)- Sinoatrial nodal exit block (dropped P waves) Exercise stress testing: shows an inadequate increasing heart rate during physical activity (chronotropic incompetence) Treatment:- Pacemaker- ± Rate-control mediation (if tachyarrhythmias)
• Left ventricular aneurysm Etiology: Scar tissue deposition following transmural MI Clinical features:- Several months following MI- Heart failure & angina- Ventricular arrhythmia (e.g., ventricular tachycardia)- Systemic embolization (e.g., stroke) Diagnosis:- ECG: Persistent ST elevation, deep Q waves- Echocardiograph: Thin and dyskinetic myocardial wall
• Conditions associated with atrial fibrillation Cardiac:- Hypertensive heart disease (most common)- Coronary artery disease- Rheumatic/Valvular heart disease- Congestive heart failure- Hypertrophic cardiomyopathy- Congenital heart disease (eg, ASD)- Post cardiac surgery Pulmonary:- Obstructive sleep apnea- Pulmonary embolism- COPD- Acute hypoxia (eg, pneumonia) Miscellaneous:- Obesity- Endocrine (eg, hyperthyroidism, diabetes)- Alcohol abuse- Drugs (eg, amphetamines, cocaine, theophylline)
• Valve replacement in aortic stenosis Severe AS criteria:- Aortic jet velocity ≥ 4.0 m/sec OR- Mean transvalvular pressure gradient ≥ 40 mmHg- Valve area usually ≤ 1.0 cm2 but not required Indications for valve replacement: Severe AS & ≥ 1 of the following- Onset of symptoms (eg, angina, syncope)- Left ventricular ejection fraction < 50%- Undergoing other cardiac surgery (eg, CABG) Bovine valves (organic)- < 10 years duration- No anticoagulation needed Mechanical valves:- 10-20 years duration- Anticoagulation needed (warfarin; goal INR 2.5-3.5)
• Treatment of chronic stable angina Beta blockers:- First-line therapy- ↓ Myocardial contractility & heart rate Nondihydropyridine CCBs:- Alternative to beta blocker- ↓ Myocardial contractility & heart rate Dihydropyridine CCBs:- Added to beta blocker when needed- Coronary artery vasodilation- ↓ Afterload by systemic vasodilation Nitrates:- Long-acting added for persistent angina- ↓ Preload by dilation of capacitance veins Ranolazine:- Alternative therapy for refractory angina- ↓ Myocardial calcium influx
• Mechanical complications of acute myocardial infarction Right ventricular failure:- Acute- RCA- Hypotension, clear lungs, Kussmaul sign- Echo: Hypokinetic RV Papillary muscle rupture:- Acute or within 3-5 days- RCA- Severe pulmonary edema- New holosystolic murmur- Echo: Severe mitral regurgitation with flail leaflet Interventricular septum rupture:- Acute or within 3-5 days- LAD (apical septal) or RCA (basal septal)- New holosystolic murmur, biventricular failure, shock- Echo: Left-to-right ventricular shunt, ↑ in O2 level from RA to RV Free wall rupture:- Within 5 days to 2 weeks- LAD- Chest pain, shock, distant heart sounds- Echo: Pericardial efffusion with tamponade Left ventricular aneurysm:- Up to several months- LAD- Subacute heart failure, stable angina- Echo: Thin & dyskinetic myocardial wall
• Supravalvular aortic stenosis Second most common form of aortic stenosis. Congenital left ventricular outflow tract obstruction due to narrowing of the ascending aorta. Clinical features:- Systolic mumur- Best heard at the first right intercostal space (higher than valvular AS murmur)- Unequal carotid pulses- Differential blood pressure in the upper extremities (high-pressure jet in ascending aorta)- Palpable thrill in the suprasternal notch Complications:- Left ventricular hypertrophy- Coronary artery stenosis (associated anomaly)→ Myocardial ischemia 
• Cardiac catheterization A procedure used in the diagnosis and treatment of cardiovascular conditions. Coronary angiography/ventriculography:- Contrast-enhanced radiological analysis of the heart cavities (ventriculography) or coronary arteries (coronary angiography).- Indications:→ Coronary artery disease: to assess the exact location and extent of coronary vessel narrowing before possible PCI/surgery→ Patients with unstable angina→ High-risk patients (those with signs of ischemia during stress ECG) Percutaneous coronary intervention (PCI)/percutaneous transluminal coronary angioplasty (PTCA):- A therapeutic procedure carried out during cardiac catheterization in which a blocked coronary vessel is opened and appropriate blood flow is restored. A balloon catheter is used to dilate the narrowed section, with/without the placement of a stent to keep it patent.- Indications:→ Acute and chronic occlusion of coronary arteries→ Myocardial infarction (primary revascularization or primary PCI)→ Occlusion of bypass grafts and stents- Types of stents:→ Bare metal stent (BMS): bare-surfaced, metallic stent that provides a mechanical framework to keep the artery open. After placement, endothelial cells begin to cover the bare surface of the stent (stent endothelialization) → the exposure time of the foreign, thrombogenic material is limited → reduced risk of stent thrombosis → shorter period of post-placement anticoagulation needed (clopidogrel x 1 month). Thus, bare metal stents are better suited to patients who are not compliant with long-term oral medications and/or those who may need to undergo a surgery in the near future.→ Drug-eluting stent (DES): stents that are coated with antiproliferative substances (immunosuppressant drugs, cytostatic drugs) that prevent excessive intimal hyperplasiaThis reduces the risk of in-stent restenosis. However, it requires that post-placement anticoagulation be used for longer, because the stent undergoes slower endothelialization (clopidogrel x 12 months). It is therefore avoided in patients who may require a surgery soon. Used in patients with a high risk of restenosis (e.g., diabetics, previous restenosis).
• Catheterization - Complications Superficial hematoma formation- ± Mass- No bruit Retroperitoneal hematoma: - Most common cause of unexpected mortality after cardiac catheterization- Often asymptomatic- Suprainguinal tenderness and fullness- Sudden flank or back pain with hemodynamic instability- Prompt diagnosis is a priority: CT with contrast of the abdomen and pelvis in hemodynamically stable patients or sonography in unstable patients- Treatment: surgery Pseudoaneurysms: - Bulging, pulsatile mass- Systolic bruit- Strongest risk factor: Inadequate post-procedural arterial compression Arteriovenous fistula:- No mass- Continuous bruit Cardiac:- Myocardial infarction- Arrhythmias can be induced by catheter introduction into the right or left ventricle.- Spontaneous coronary artery dissection (SCAD) in the artery affected by acute coronary occlusion- Injury to coronary vasculature by the catheter (e.g., dissection of coronary artery wall)
• Acute decompensated heart failure Clinical features:- Rapid exacerbation of symptoms of HF - Pulmonary edema with:→ Acute, severe dyspnea and orthopnea, worse when supine→ Cough (occasionally with frothing, blood-tinged sputum)→ Cyanosis→ Auscultation of the lungs: rales accompanied by wheezing→ Flash pulmonary edema: rapid, life-threatening accumulation of fluid associated with the risk of acute respiratory distress - Weakness, fatigue, and cold, clammy skin Diagnostics:- X-ray findings in pulmonary congestion→ Prominent pulmonary vessels and perihilar pulmonary edema (butterfly or “bat's-wings” appearance of the hilar shadow) → Kerley B lines: visible horizontal interlobular septa caused by pulmonary edema→ Basilar edema→ Bilateral pleural effusions Treatment:- Sufficient oxygenation - Assisted ventilation as needed (e.g., CPAP)- Aggressive diuresis (e.g., IV furosemide) to reduce volume overload- Vasodilators: (e.g., IV nitroglycerine) can be considered as adjunct treatment in patients without hypotension- Hemodynamic stabilization: inotropes (e.g., dobutamine) in case of systolic dysfunction- Opiates (e.g., IV morphine) may be considered in patients with anxiety- Hemodialysis if volume overload is symptomatic (pulmonary edema, pleural effusion, ascites) and resistant to treatment
• High-output heart failure Heart failure secondary to conditions associated with a high-output state, in which cardiac output is elevated to meet the demands of peripheral tissue oxygenation. Etiology: conditions that lead to an increased cardiac demand (high-output state)- Anemia- Systemic arteriovenous fistulas- Sepsis- Hyperthyroidism- Physiological causes: pregnancy, fever, exercise Clinical features:- Symptoms of low-output HF; particularly tachycardia, tachypnea, low blood pressure, and jugular distention with an audible hum over the internal jugular vein- Pulsatile tinnitus- Bounding peripheral pulses- Laterally displaced apical heart beat- Midsystolic murmur, S3 gallop (indicates rapid ventricular filling) Diagnostics:- Primarily a clinical diagnosis- X-ray and echocardiography: cardiomegaly Therapy:- Manage heart failure: symptom relief, hemodynamic stabilization- Treat underlying condition
• Orthostatic hypotension Pathophysiology: Standing up/postural change → insufficient counterregulation due to autonomic dysfunction (e.g. decreased baroreceptor sensitivity in the elderly) → reduced cerebral perfusion Sympathotonic orthostatic hypotension:- When standing up: ↓ systolic blood pressure despite excessive sympathotonic counter regulation (significant heart rate increase) → reduced cerebral perfusion- Hypovolemia (dehydration, hemorrhage, use of diuretics such as thiazides),- Medications (vasodilators such as alpha-blockers, and ganglionic blocking agents)- Prolonged bed rest Asympathotonic orthostatic hypotension:- When standing up: ↓ systolic blood pressure without sympathotonic counterregulation (steady or even reduced heart rate) → reduced cerebral perfusion- Diabetic autonomic neuropathies- Parkinson's autonomic dysfunction Diagnosis:- Patient is asked to stand after being in supine position for at least 5 minutes → Blood pressure is measured each minute for at least 3 minutes.→ If systolic BP decreases by ≥ 20 mm Hg and the diastolic BP decreases by ≥ 10 mm Hg, or the heart rate increases by 20 bpm, or BP < 90 mm Hg → orthostatic hypotension→ Coinciding bradycardia → vasodepressor syncope Treatment:- Sufficient intake of sodium and fluids- Compression stockings- Adjust medications (e.g., diuretics)- Fludrocortisone if unable to manage episodes with nonpharmacological interventions
• Hypertension Clinical features.- Headaches, esp. early morning or waking headache- Dizziness, tinnitus, blurred vision- Flushed appearance- Epistaxis- Chest discomfort, palpitations; strong, bounding pulse on palpation- Nervousness- Fatigue, sleep disturbances Diagnostics:- Hypertension is diagnosed if the average blood pressure of ≥ 2 readings obtained on ≥ 2 separate visits is elevated- Stratification of cardiovascular risk: fasting blood glucose, lipid profile (HDL, LDL, and triglycerides levels)- CBC, renal function tests, serum Na+, K+, and Ca2+, urinalysis, TSH- Electrocardiogram (ECG) Nonpharmacological treatment:- DASH diet: most effective- Exercise- Daily sodium intake < 1500 mg/day- High potassium intake - Smoking cessation Pharmacologic treatment:- Non-black population (including those with diabetes): thiazides, CCB, ACE-I, or ARB- African American population: thiazides or CCB (do not use ACE-I)
• Secondary hypertension Definition:- Hypertension before the age of 35 OR- Any hypertension that is refractory to 3 medications Etiology:- Primary hyperaldosteronism (Conn syndrome) - Primary hyperparathyroidism- Pheochromocytoma- Hypercortisolism (Cushing syndrome)- Hyperthyroidism- Acromegaly- Congenital adrenal hyperplasia- Renovascular hypertension (e.g., due to renal artery stenosis) - Polycystic kidney disease (ADPKD)- Renal failure (renal parenchymal hypertension)- Glomerulonephritis- Systemic lupus erythematodes- Renal tumors- Coarctation of the aorta- Obstructive sleep apnea- Medication: sympathomimetic drugs, corticosteroids, NSAIDs, oral contraceptives- Recreational drug use: amphetamines, cocaine, phencyclidine
• Fibromuscular dysplasia A disease that primarily affects young to middle-aged women and is characterized by the proliferation of connective tissue and muscle fibers within the arterial vessel walls. Epidemiology: - Age of onset: typically 30-50 years, but can manifest at any age- Sex: ♀ > ♂ (8:1) Pathophysiology:- Formation of saccular aneurysms → aneurysmal rupture- Arterial dissection → arterial occlusion- Formation of intravascular thrombi → embolization- Renal artery stenosis → ↓ renal perfusion → compensatory activation of the renin–angiotensin–aldosterone system → secondary hypertension Clinical features:- Secondary hypertension- Abdominal bruit- Symptoms of chronic kidney disease- Flank or abdominal pain- Headache, neck pain, pulsatile tinnitus- TIA, amaurosis fugax, stroke, Horner's syndrome- Cervical bruit Diagnostics:- Best initial tests for renal FMD: duplex ultrasonography and/or CT angiography - Best initial tests for cerebrovascular FMD: CT angiography- Gold standard: digital subtraction angiography (DSA) → “String of beads” sign Treatment:- Renal artery FMD: Percutaneous transluminal renal angioplasty- Cerebrovascular FMD: Antiplatelet drugs (e.g., aspirin) for stroke prophylaxis is recommended for all patients.
• Ventricular tachycardia Initial therapy:- If patient is hemodynamically unstable (hypotension, loss of consciousness): → VT with pulse → cardioversion→ VT without pulse → defibrillation- If patient is hemodynamically stable: Antiarrhythmics (typically lidocaine, procainamide, amiodarone)
• Idioventricular rhythm Rhythm without atrial activity. Only the ventricles contract, only the venticles have electrical activity. Treatment:- Avoid atropin- Just pace
• Peripartum cardiomyopathy Uncommon cause of dilated cardiomyopathy that develops during the last month of pregnancy or within 5 months following delivery. Clinical features:- Progressive dyspnea on exertion- Lower extremity edema- S3- Mitral regurgitation Diagnosis:- LV systolic dysfunction with LV ejection fraction < 45%
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• Pseudoaneurysm Leaking artery leads to a hematoma between the vessel and the surrounding tissue. A persistent communication between the vessel and the hematoma remains. Etiology: - Trauma (e.g., deceleration injury, gunshot) - Iatrogenic (e.g., after vascular puncture or cardiovascular surgery) Pathophysiology: - Perforation of the vascular wall causing bleeding into the surrounding tissue→ Formation of an extravascular (pulsatile) hematoma→ Surrounding structures delimit the expansion of the hematoma→ Organization of the hematoma→ Formation of a false vascular wall and false aneurysm- Typical deceleration injury → contained aortic injury of the thoracic aorta (typical location: distal to the left subclavian artery) Clinical features: - Painful and pulsatile mass at the site of trauma- Buzzing sensation- Bruit on auscultation Treatment:- Ultrasound-guided thrombin injection (e.g., to treat iatrogenic postcatheterization pseudoaneurysms that are symptomatic)- Surgical management→ Surgical decompression and resection is necessary in patients with a compressing pseudoaneurysm that causes critical limb ischemia and severe neurological deficits. All pseudoaneurysms at the site of a vascular anastomosis should be repaired surgically.
• Coarctation of the aorta Epidemiology:- Sex: ♂ > ♀- Usually associated with bicuspid aortic valve, VSD, and/or PDA Etiology:- Associated with Turner syndrome Infantile form: Preductal coarctationAdult form: Postductal coartctation Clinical features:- Newborns: Asymptomatic if PDA is present or aortic narrowing is only mild- Cyanosis in lower extremities (differential cyanosis)- Weak femoral pulses (brachial-femoral delay)- In severe stenosis: shock and multi-organ failure, when ductus arteriosus closes- Childhood: Chest pain, cold feet, and lower-extremity claudication on physical exertion- ↑ BP in upper extremities and ↓ BP in lower extremities- Systolic ejection murmur over left paravertebral region and/or continuous murmur below left clavicula and between the shoulder blades - Palpation of strong displaced apical impulse to the left- Adults: Hypertension, variability in blood pressure in the upper and lower extremities, headache, epistaxis, tinnitus, claudication of the lower extremities with exertion Diagnostics:- Best initial test: upper and lower extremity blood pressure measurement and search for brachial-femoral delay- Pulse oximetry: ↓ SpO2- Echocardiography with doppler (confirmatory test): location and extent of stenosis; concurrent anomalies- X-ray: → Cardiomegaly and ↑ pulmonary vascular markings→ “Figure of 3” sign→ Rib notching (on inferior border of the ribs): finding of chronic disease, commonly observed in children aged > 5 years.- Genetic testing for Turner syndrome Treatment:- Initial management: infusion of PGE1 (alprostadil)- Surgery: Should be performed as soon as possible in critical cases.→ Techniques: surgical correction or balloon angioplasty- Follow-up and monitor for restenosis, aortic aneurysm and aortic dissection
• Tetralogy of Fallot Simultaneous occurrence of the following four defects:1. Right ventricular outflow obstruction due to pulmonary valve stenosis2. Right ventricular hypertrophy3. Ventricular septal defect 4. Overriding aorta  Epidemiology: Most common cause of cyanotic CHD (∼ 4/10,000 live births in the US) Etiology:- Typically sporadic; sometimes associated with genetic defects (e.g., Down syndrome)- Associated with other cardiac anomalies in ∼ 40% of patients Clinical features:- Mild cyanosis- Tet spells: Intermittent hypercyanotic, hypoxic episodes with a peak incidence 2-4 months after birth- Associated with psychological and physical stress (e.g., crying, feeding, defecation)- Untreated young children tend to squat- Harsh systolic murmur that is best heard over Erb's point and left upper sternal border Diagnostics:- Pulse oximetry: ↓ SpO2- Hyperoxia test: to distinguish cardiac from pulmonary causes of cyanosis- ECG: right axis with right heart hypertrophy; P pulmonale with increasing age- Echocardiography: detection of the main features of TOF, quantification of right ventricular outflow tract pressure gradient - Chest x-ray: absent pulmonary artery segment, decreased pulmonary vasculature, small “boot-shaped” heart  Treatment:- Severe RVOT: IV prostaglandin (PGE1) until surgery- Acute hypoxia (tet spells): → Administer oxygen→ Knee to chest position, squatting→ IV morphine for sedation and fluids→ If above measures fail: IV beta blockers- Surgery: performed within the first year of life, if possible → VSD repair: patch closure of the ventricular septal defect; ensuring correct aortal positioning above the left ventricle→ Enlargement of the RVOT: resection of the obstructive infundibular musculature
• Acute rheumatic fever Epidemiology:- Peak incidence: 5-15 years- Developing countries: the most common cause of cardiovascular disease in children and adolescents  Diagnostics: Jones criteriaTwo major OR one major plus two minor criteria are required for diagnosis.Major criteria:- Arthritis (migratory polyarthritis involving primarily the large joints)- Carditis (pancarditis, including valvulitis)- Sydenham chorea (CNS involvement)- Subcutaneous nodules- Erythema marginatumMinor criteria:- Arthralgia- Fever- ↑ Acute phase reactants (ESR, CRP)- Prolonged PR interval on electrocardiogramAdditional findings- Normochromic, normocytic anemia of chronic inflammation- Leukocytosis- ↑ Antistreptolysin O titer (ASO): antibodies against metabolites of GAS- Positive rapid streptococcal antigen test or throat culture for GAS- Echocardiogram (may show mitral or aortic regurgitation) Treatment:- Bedrest (especially important in patients with carditis)- Drug of choice: oral penicillin V- Alternatives: Amoxicillin; Benzathine IM (in patients unable to complete oral therapy); Cephalosporins (in penicillin hypersensitivity without anaphylaxis); Macrolides (in patients with severe hypersensitivity to beta-lactam antibiotics)- Syndeham chorea: 2-week course of prednisone followed by a steroid taper Cardiac involvement is the most important prognostic factor. Secondary prevention:- Antibiotic prophylaxis to prevent recurrence- Drug of choice: IM penicillin G benzathine administered every 28 days- Immediately follows antibiotic treatment of acute rheumatic fever- Duration depends on risk and severity of original episode→ Rheumatic fever without carditis: 5 years or until the patient is age 21 (whichever is longer)→ Rheumatic fever with carditis: 10 years or until the patient is age 21 (whichever is longer)→ Rheumatic fever with carditis and permanent valvular heart defects: 10 years or until age 40 (whichever is longer)
• Atrial septal defect Etiology:- Down syndrome- Fetal alchohol syndrome- Holt-Oram syndrome (Autosomal dominant disorder, which is also called hand-heart syndrome because affected children present with an ASD, a first degree heart block, and abnormalities of the upper limbs, e.g., absent radial bones). Clinical features:- Small defects: usually asymptomatic- Palpitations- ASDs typically manifest with advancing age1. Wide and fixed splitting of S2: Resulting from delayed closure of the pulmonic valve 2. Mid-systolic or ejection murmur over the left upper sternal border: Resulting from increased flow across the pulmonic valve3. Mid-diastolic mumble: Resulting from increased flow across the tricuspid valve Diagnostics:- Echocardiography (confirmatory test): to visualize the defect, its extent, and shunt volume- ECG: vertical or right axis, P pulmonale, right bundle branch block (complete or incomplete), signs of right heart hypertrophy, PR prolongation- Chest x-ray: enlarged right atrium, ventricle, and pulmonary arch; increased pulmonary vasculature Treatment:- In childhood, spontaneous closure may occur.- Patch repair: Surgical or via percutaneous transcatheter procedure
• Patent ductus arteriosus Epidemiology:- Sex: ♀ > ♂ (2:1) Etiology:- In 90% of cases, PDAs occur as isolated defects; in 10% of patients, PDAs occur with other congenital heart defects.- Premature infants- Infants born at high altitude- Maternal rubella infection during pregnancy- Maternal prostaglandin administration- Trisomies (Down, Patau, and/or Edwards syndrome)  Clinical features:- Small PDA: asymptomatic with normal findings on physical examination - Nonspecific symptoms (e.g., failure to thrive) and symptoms of heart failure in infancy - Heaving, laterally displaced apical impulse- Bounding peripheral pulses, wide pulse pressure (pulsus celer et altus)- Loud continuous murmur (“machinery” murmur); best heard in the left infraclavicular region Diagnostics:- Echocardiography (confirmatory test): → Shows left cardiac enlargement (in larger PDAs)→ Doppler: assesses degree of shunt and pulmonary artery pressure→ Color Doppler: demonstrates blood flow from the aorta into the pulmonary artery- ECG: normal in small PDA; left axis deviation due to LVH in large PDA- Chest x-ray: prominent pulmonary artery and aortic knob along upper left heart border; increased pulmonary markings  Treatment:- Observation: Regular evaluation in patients with a small PDA- Elective ductal closure: Symptomatic PDAs, left heart enlargement or mild to moderate pulmonary hypertension- Pharmacologic closure (in premature infants): Infusion of indomethacin or ibuprofen - In infants > 5 kg: percutaneous catheter occlusion or surgical ligation - Administer prostaglandin (PGE1) if the PDA is needed for survival (e.g., in transposition of the grand vessels, tetralogy of Fallot, hypoplastic left heart).
• Tricuspid valve atresia Absent or rudimentary tricuspid valve, resulting in no blood flow between the right atrium and the right ventricle Epidemiology:- Third most common cyanotic heart defect- Almost always accompanied by ASD, VSD, and right ventricular hypoplasia Pathophysiology- Functional univentricular heart; the right ventricle is usually hypoplastic → dilatation of left atrium and ventricle due to volume overload- Circulation depends on the patency of the ductus arteriosus and ASD. Clinical features:- Central cyanosis occurring within days after birth- Auscultation: if a concurrent VSD is present → rough holosystolic murmur over lower left sternal border Diagnostics- Echocardiography: (confirmatory test) absent tricuspid valve, atrial septal defect, and RV hypoplasia- Pulse oximetry: ↓ SpO2- Chest x-ray: decreased pulmonary markings- ECG: left axis deviation due to LVH; tall P waves (right atrial enlargement); minimal R waves in precordial leads Treatment:- Initially: infusion of prostaglandin (PGE1)- Definitive treatment: three-staged surgical procedure to separate the pulmonary and systemic circulation
• Transposition of the great vessels Epidemiology:- Accounts for ∼ 20 % of all cyanotic CHD- Often associated with VSD, left ventricular outlet obstruction, and abnormal valves and coronary arteries Etiology:- Infants born to diabetic mothers- Maternal alcohol consumption/poor nutrition- Maternal age > 40 years- Rubella infection or other viral illness- Genetic syndromes: DiGeorge syndrome, Down syndrome, Edward syndrome, Patau syndrome Clinical features:- Postnatal cyanosis (not affected by exertion or supplemental oxygen)- Tachypnea- Single loud S2- If concurrent VSD is present: systolic murmur at the left sternal border Diagnostics:- Echocardiography (confirmatory test): demonstrates transposition of the great arteries and shunts- Pulse oximetry: ↓ SpO2- X-ray→ Heart with an “egg on a string” appearance→ ↑ Pulmonary vascular markings Treatment:- Initially: infusion of prostaglandin (PGE1) to prevent closure of the PDA- Definite repair: surgical correction within the first two weeks of life with arterial switch procedure- Balloon atrial septostomy: if surgery cannot be performed or if hypoxia is severe despite IV PGE1 administration prior to surgery
• Ventricular septal defect Epidemiology:- The most common congenital heart defect (4/1000 live births) Etiology:- Genetic syndromes: Down syndrome, Edward syndrome, Patau syndrome- Fetal alcohol syndrome- Intrauterine infection (e.g., TORCH) Clinical features:- Small defects: usually asymptomatic- Cardiac failure in the first 2-3 months of life- Hyperdynamic precordium - Harsh holosystolic murmur over the left lower sternal border; typically louder in small defects- Becomes louder with maneuvers that increase left ventricular afterload (e.g., handgrip) because of increased left-to-right shunting- Mid-diastolic murmur: due to increased flow across the mitral valve secondary to the left-to-right shunt- Systolic thrill- Loud pulmonic S2 (if pulmonary hypertension develops) Diagnostics:- Doppler echocardiography: confirms diagnosis- ECG: signs of right heart hypertrophy- Chest x-ray: Enhanced pulmonary vascular markings; Left atrial and ventricular enlargement Treatment:- Small VSDs: rarely require surgical interventions → small to moderate defects often heal spontaneously; follow-up echocardiography recommended- Surgical (patch) repair in children < 1 year of age with signs of pulmonary hypertension and older children who did not improve with medical therapy- Heart-lung transplant or lung transplant with concurrent VSD repair if Eisenmenger's reaction has occurred
• Patent foramen ovale Persistence of the foramen ovale beyond 1 year of age Epidemiology:- Prevalence: 25-30% of the general population Pathophysiology- The foramen ovale in the atrial septum does not close after birth. → mild left-to-right shunt- A shunt reversal may be induced by certain maneuvers that induce an increase in right atrial pressure (e.g., Valsalva maneuver, coughing). Clinical findings:- Patients are usually asymptomatic until complications occur  Diagnostics:- Often an incidental finding- If ischemic stroke occurs, specific work-up for suspected PFO is needed: → Contrast echocardiography (best initial and confirmatory test): shunt identification; assess structure and function of the heart Complications:- Paradoxical embolism- Systemic embolisms (e.g., renal infarction)- Stroke Treatment- Asymptomatic PFO: The majority of cases do not require any treatment.- Ischemic infarction in patients with confirmed PFO: medical therapy with antiplatelet agents or anticoagulation and surgical or percutaneous closure of the defect
• Functional murmur Etiology:- Non-cardiac or peripheral cause: due to increased blood flow across normal aortic and/or pulmonary valves (ejection murmur)- Most commonly occurs in infants and children but also in individuals without cardiac conditions (particularly thin or pregnant individuals) due to e.g., hyperdynamic circulation- Cardiac conditions and structural abnormalities (e.g., valvular defects) must be ruled out. Intensity: Soft (< 3/6 without a thrill) Timing: Most commonly mid-systolic or continuous murmur Position change: Position-dependent; murmur varies in intensity or disappears Cervical venous hum: common benign auscultation finding in children- Caused by turbulent flow in internal jugular veins- Continuous murmur best heard at the infraclavicular and supraclavicular regions; more common on the right side- Becomes softer or disappears with flexion of the head, compression of the jugular vein, or in supine positionStill murmur
• Abdominal aortic aneurysm rupture Risk factors: large diameter, rapid expansion, and smoking Clinical features:- Impending rupture or contained leak→ Throbbing abdominal or low back pain radiating to the flank, buttocks, legs, or groin→ Grey turner sign (ecchymosis of the affected flank area)→ Cullen sign (periumbilical ecchymosis)- Manifested rupture:→ Hypovolemic shock (in case of a free, non-covered rupture)→ Sudden onset of severe tearing back or abdominal pain with radiation to the flank, buttocks, legs, or groin→ Painful pulsatile mass→ Nausea, vomiting→ Syncope→ Hematuria Diagnosis: ultrasound, contrast CT → extravasation of contrast agent Treatment: open emergency surgery (gold standard) - Surgery should not be delayed for any confirmatory imaging Prognosis: high mortality rate (∼ 90% if AAA rupture occurs outside of the hospital)
• Cardiac injury Possible injuries:- Cardiac contusion: Clinical features depend on the extent of the injury.→ Cardiac arrhythmia (palpitations, dizziness, syncope)→ Hypotension and tachycardia that do not respond to fluid resuscitation- Myocardial rupture: hypotension, muffled heart sounds→ Most patients die before reaching the hospital.- Septal or valvular injury- Acute coronary syndrome Diagnostics- Best initial test: ultrasound (FAST)- ECG and echocardiography Treatment:- Cardiac monitoring- Cardiac rupture: immediate surgery
• Ventricular premature beats Ventricular premature beats (VPBs) are extra, abnormal heartbeats caused by ectopic foci within the ventricles. Etiology: - Idiopathic- Cardiovascular disease (e.g., CAD, myocarditis)- Electrolyte imbalances (e.g., hypokalemia, hypomagnesemia)- Side effect of certain drugs (e.g., digoxin, psychiatric medications)- Caffeine, alcohol Clinical features: - Most patients are asymptomatic.- Skipped beat- If frequent VPBs, possibly → lightheadedness, dizziness, palpitations, irregular heart beat Diagnostics:- QRS duration ≥ 120 ms with a block-like QRS morphology- VPBs are often followed by a compensatory pause- May be random or adhere to a specific pattern, including:- Single VPBs; Couplet: two VPBs in a row; Triplet: three VPBs in a row- Bigeminy: one extrasystole after every single sinus beat- Trigeminy: one extrasystole after every two sinus beats Treatment:- Most patients do not require any treatment- Treat any underlying disease (e.g., CAD, myocarditis)- Symptomatic: Escalate dose of beta blockers (eg, metoprolol) or calcium channel blockers 
• Supraventricular premature beats Supraventricular premature beats are atrial contractions triggered by ectopic foci rather than the sinoatrial node. Etiology:- Idiopathic- Potential triggers: smoking, alcohol, coffee - Cardiovascular disease or electrolyte imbalances (e.g., hypokalemia) Clinical features:- Usually asymptomatic- Palpitations Diagnostics:- ECG: identify supraventricular premature beats (SPBs) → P-wave abnormalities or absent P waves → Altered PR interval in the premature beats (compared to the normal beats) → QRS complex may be normal, aberrant (widened), or absent → No full compensatory pause- Echocardiography: to rule out structural heart disease and evaluate cardiac structure and function if SPBs are identified on ECG or Holter monitor Treatment - Treatment is not required in asymptomatic individuals without underlying structural heart defects.- Symptomatic patients → Reduce potential triggers like caffeine, alcohol, stress and smoking.→ Beta blockers or catheter ablation in patients with persistent symptoms
• Carotid artery dissection Etiology:- Trauma; spontaneous occurrence- Underlying contributors: HTN, smoking, CTD Clinical features:- Unilateral head & neck pain, transient vision loss- Ipsilateral partial Horner syndrome→ Ptosis & miosis without anhidrosis- Signs of cerebral ischemia (e.g., focal weakness) Diagnosis: Neurovascular imaging (e.g., CT angiography) Treatment:- Thrombolysis (if ≤ 4.5 hours after symptom onset)- Antiplatelet therapy (e.g., aspirin) ± anticoagulation
• Cardiac glycoside poisoning Etiology:- Digoxin overdose (iatrogenic, by nonadherence to prescribed dosages or by ingestion of plants containing cardiac glycosides) - Ouabain poisoining - Hypokalemia - Renal failure- Treatment with verapamil, diltiazem, amiodarone, and/or quinidine - Volume depletion (e.g., treatment with diuretics) Clinical features:- Nausea/vomiting, diarrhea, abdominal pain, and anorexia- Blurry vision with a yellow tint and halos, disorientation, weakness Diagnostics: - ECG: potentially severe cardiac arrhythmias→ Premature ventricular beats→ T-wave inversion or flattening→ Downsloping ST segment depression (“scooped” ST segments)→ ↓ QT interval→ ↑ PR interval→ Atrial tachycardia with AV block- Serum digoxin concentration (ideally, measure 6 hours after ingestion)- Serum electrolyte levels: hyperkalemia - Creatinine and blood urea nitrogen to evaluate renal function Treatment:- Digoxin-specific antibody fragments  - Atropine for symptomatic bradycardia- Slowly normalize serum K+ levels- Mg2+- Class IB antiarrhythmics- Temporary cardiac pacing
• Cholesterol embolization syndrome Definition: embolization of cholesterol released from atherosclerotic plaques or common vessel wall deposits Etiology:- Usually after vascular interventions (like PCI) or during anticoagulanttherapy- Can occur spontaneously in patients with atherosclerosis after plaque rupture Clinical features:- Severe peripheral, muscular, or visceral embolisms- Acute renal failure - Skin involvement (purpura, necroses, livedo reticularis)- Gastrointestinal involvement (e.g., ischemia, pancreatitis)- CNS symptoms (transient ischemic attack, stroke) Histopathology:- Amorphous, eosinophilic material in the vessel lumen- Spindle-shaped vacuoles (“cholesterol clefts”)  Treatment:- Symptomatic treatment- Termination of anticoagulant therapy, initiate statin therapy 
• Pulmonary hypertension Chronically elevated mean pulmonary arterial pressure ≥ 25 mm Hg (normal: 10–14 mm Hg) Group 1: Pulmonary arterial hypertension (PAH)- Idiopathic- Hereditary (e.g., BMPR2 mutation)- Drug-induced: amphetamines, cocaineGroup 2: Left heart disease (e.g. valvular heart diseases, left-to-right shunt)Group 3: Chronic lung diseases and/or hypoxemia- COPD, emphysema- Obstructive sleep apnea- Interstitial lung diseaseGroup 4: Chronic thromboembolic occlusion of the pulmonary vessels Group 5: Unclear multifactorial mechanisms Clinical features:- Fatigue- Dyspnea and/or syncope on exertion (due to an inadequate increase in cardiac output during exercise because of increased pulmonary vascular resistance)- Chest pain - Loud and palpable second heart sound (often split)- Parasternal heave - Nail clubbing- Jugular vein distention - Symptoms of right heart failure Diagnostics:- Doppler echocardiography (best initial test)- Right heart catheterization (confirmatory test)- Electrocardiography: right axis deviation due to right ventricular hypertrophy- Chest x-ray: Pronounced central pulmonary arteries, right heart hypertrophy (prominent right heart border) Treatment:- Diuretics - Physical exercise - Oxygen therapy - Pulmonary vasodilator therapy:→ Calcium channel blockers→ Long-acting prostacyclin analogs (e.g., iloprost)→ Endothelin receptor antagonists (e.g., bosentan) → Phosphodiesterase 5 inhibitors (e.g., sildenafil; see PDE-inhibitors)- Patients who are refractory to medical treatment: Atrial septostomy (right-to-left shunt) or heart-lung/bilateral lung transplantation
• Postmyocardial infarction syndrome (Dressler syndrome) Pericarditis occurring 2–10 weeks post-MI without an infective cause - Thought to be due to circulating antibodies against cardiac muscle cells (autoimmune etiology) Clinical features:- Signs of acute pericarditis: pleuritic chest pain, dry cough , friction rub- Fever Laboratory findings: leukocytosis, ↑ serum troponin levelsECG: diffuse ST elevations Treatment: aspirin, NSAIDs, acetaminophen  Complications (rare): hemopericardium, pericardial tamponade

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