USMLE Step 3 (Fach) / Cardiovascular (Lektion)

First Aid Step 3

Diese Lektion wurde von estoffel erstellt.

Lektion lernen

zurück  |  weiter 2 / 2

• Multifocal atrial tachycardia Etiology- Exacerbation of pulmonary disease (eg, COPD)- Electrolyte disturbance (eg, hypokalemia)- Catecholamine surge (eg, sepsis) Clinical findings- Typically asymptomatic- Rapid, irregular pulse- ECG: >3 P-wave forms & atrial rate >100/min Treatment- Correct underlying disturbance- AV nodal blockade (eg, verapamil) if persistent
• Use of fibrinolytic therapy Reperfusion in patients with STEMI and onset of symptoms within 12 hours of presentation with qualifying ECG findings if PCI is not available within 90 minutes of first medical contact
• Cautious use of nitroglycerin - Inferior wall MI and RV infarction - Hypotension (SBP less than 90 mmHg), bradycardia (less than 50/min), tachycardia  - Recent phosphodiesterase inhibitor use
• Hypertensive crises Hypertensive crisis (acute severe hypertension): an acute increase in systolic blood pressure > 180 mm Hg and/or diastolic blood pressure > 120 mm Hg   Hypertensive urgency: hypertensive crisis without symptoms and with no signs of organ damage Hypertensive emergency: hypertensive crisis with signs of end-organ damage, mainly in the cardiovascular, central nervous, and renal systems Hypertensive urgency- Asymptomatic or nonspecific symptoms- Although commonly associated with high blood pressure, isolated findings of nonspecific headache, dizziness, or epistaxis do not constitute end-organ damage.  Hypertensive emergency- Cardiac:→ Heart failure exacerbation, pulmonary edema: dyspnea, crackles on examination→ Myocardial infarction: chest pain, diaphoresis→ Aortic dissection: chest pain, asymmetric pulses- Neurologic:→ Hypertensive encephalopathy: headache, vomiting, confusion, seizure, blurry vision, papilledema→ Ischemic or hemorrhagic stroke: focal neurological deficits, altered mental status- Renal:→ Acute renal failure: azotemia and/or oliguria, edema- Ophthalmic:→ Acute hypertensive retinopathy: blurry vision, decrease in visual acuity, retinal flame hemorrhages, papilledema→ Microangiopathic hemolytic anemia: fatigue, pallor Diagnostics:- CBC: signs of microangiopathic hemolytic anemia- BMP: altered electrolytes and/or elevated creatinine and urea, which suggest kidney failure- BNP: elevated in heart failure- Troponin: elevated in myocardial ischemia- Urinalysis: signs of glomerular injury (e.g., proteinuria, hematuria)- ECG: left ventricular hypertrophy, signs of cardiac ischemia (e.g., ST depressions or elevations)- Chest x-ray: cardiomegaly, pulmonary edema- Additional evaluation to consider:→ Urine pregnancy test  → Toxicology screen  → CT chest with IV contrast if chest pain is concerning for aortic dissection  → Consider TTE if clinical features suggest pulmonary edema → Consider CT head if neurological symptoms are present. Treatment:- Hypertensive urgency → Outpatient treatment is recommended.→ Move patient to a quiet room for 30 minutes.→ Reinstitute or increase the dosage of existing oral antihypertensive therapy.Hypertensive urgency is usually caused by nonadherence to antihypertensive therapy. Aggressive intravenous antihypertensive therapy is not required.- Hypertensive emergency → ICU admission and immediate initiation of intravenous antihypertensive therapy → Reduce BP by max. 25% within the first hour to prevent coronary insufficiency and to ensure adequate cerebral perfusion pressure.→ Reduce BP to ∼ 160/100-110 mm Hg over the next 2-6 hours.→ Reduce BP to patients baseline over 24-48 hours. Intravenous antihypertensives- Calcium channel blocker: Nicardipine, Clevidipine- Nitric-oxide dependent vasodilators: Sodium nitroprusside, Nitroglycerin- Direct arterial vasodilators: hydralazine- Selective beta-1 antagonist: esmolol- Nonselective beta blocker with alpha-1 antagonism: labetalol- Nonselective alpha antagonist: phentolamine- D1 agonist: fenoldopam- ACE inhibitor: enalaprilatBecause prolonged use of sodium nitroprussidecarries a risk of cyanide toxicity, it should be limited in dose and duration of use.
• Stages in the development of heart failure Stage AHigh risk for heart failure, but without structural heart disease or symptoms of heart failure (patients with risk factors for diabetes or hypertension, patients exposed to cardiotoxic drugs) Stage BStructural heart disease, but without signs or symptoms of heart failure (patients with prior myocardial infarction or valvular heart disease with left ventricular enlargement or low ejection fraction) Stage CStructural heart disease with prior or current symptoms of heart failure Stage DHeart failure symptoms at rest or refractory end-stage heart failure
• TIMI score for unstable angina/NSTEMI Method for calculating the risk of mortality in patients with unstable angina or NSTEMI   Can be used to determine recommended therapeutic regimen and timing for revascularization Interpretation:- An increasing score is associated with a higher risk of mortality, new or recurrent myocardial infarction, and need for urgent revascularization (e.g., progression of unstable angina to STEMI)- Risk score ≥ 3: Early angiography recommended- Consider addition of glycoprotein IIb/IIIa inhibitor and treatment with enoxaparin (rather than UFH) 1 point each:- Age ≥ 65 years- Three or more CAD risk factors (e.g., premature family history, DM, smoking, HTN, hyperlipidemia, PAD, abdominal aortic aneurysm)- Known CAD (prior stenosis > 50%)- Two or more episodes of severe angina in the last < 24 hours- ASA use in the last 7 days- ST deviation (≥ 0.5 mm)- Elevated cardiac biomarkers
• Mitral valve repair – Indications - Symptomatic patients with left ventricular ejection fraction greater than 30% - Asymptomatic patients with left ventricular dysfunction (left ventricular ejection fraction of 30%-60% and/or left ventricular end-systolic diameter ≥ 40 mm) - Patients undergoing another cardiac surgical procedure
• Aortic regurgitation – Surgery indications - Symptomatic patients with acute severe AR   - Asymptomatic patients with:→ Chronic severe AR and EF < 50%→ Left ventricular systolic diameter > 50 mm Surgical procedure: aortic valve replacement (occasionally valve reconstruction is possible) and long-term anticoagulation therapy for mechanical valve
• Right bundle branch block - Widened QRS complex (>120 ms) - RSR′ pattern in lead V1 - Wide negative S wave in leads I, V5, and V6. 
• Statin therapy – Indications - Patients with LDL cholesterol elevated ≥ 190 mg/dL - Patients with a clinical atherosclerotic cardiovascular disease (includes coronary artery disease (CAD), stroke, and peripheral arterial disease) - Patients aged 40-75 with diabetes and LDL levels of 70–189 mg/dL - Patients aged 40-75 with an estimated 10-year ASCVD risk ≥ 7.5% and LDL levels 70-189 mg/dL
• Pre-operative cardiac risk - Patients with low risk (<1% risk for perioperative MACE) may proceed to surgery without preoperative cardiac stress testing - Patients with elevated risk (≥1% risk for perioperative MACE) should undergo assessment of functional capacity. Metabolic equivalents (METs) are used to represent the patient's functional capacity based on the intensity of activity able to be performed. - If the patient's functional capacity exceeds 4 METs, the patient may proceed to surgery without further testing. - Cardiac stress testing should generally be reserved for patients at elevated risk for MACE with a functional capacity less than 4 METs, but only if the results of the test will change perioperative management
• Supraventricular arrhythmias - Atrioventricular reentry tachycardia (AVRT) - AV nodal reentry tachycardia (AVNRT)   - Paroxysmal atrial tachycardia (PAT) - Paroxysmal junctional tachycardia (PJT)
• Atrial flutter Atria contract at an approx. rate of 300 beats/minute, resulting in typical ventricular rates of 150, 100, or 75 beats/min (2:1, 3:1, or 4:1 conduction, respectively). - Rhythm is irregular but can appear regular at high ventricular rates. Management:- Cardioversion (pharmacologic or electrical)- Cardiac ablation Systemic thromboembolism acutely increases with the delivery of these therapies. Therefore, in patients with new atrial flutter/fibrillation of duration > 48 hours, ≥ 3 weeks of anticoagulation is needed prior to cardioversion or cardiac ablation.
• Statin-induced myopathy Timing: - Can occur any time during the course of treatment- Most commonly seen in the first few months Labs:- CK to more than 10x the normal is diagnostic- AST/ALT >5 ULN - More susceptible in patients taking medications that inhibit CYP3A4E.g., cyclosporine, HIV protease inhibitors, gemfibrozil, macrolide antibiotics
• Indications for an implantable cardioverter-defibrillator placement Primary prevention:- Prior MI with LVEF ≤ 30%- NYHA class II or III symptoms & LVEF ≤ 35% Secondary prevention:- Prior VF or unstable VT without reversible cause- Prior sustained VT with underlying cardiomyopathy
• Indications for cardiac resynchronization therapy (CRT) LVEF ≤ 35% and sinus rhythm with one of the following:- QRS duration >150 ms and NYHA class III or IV symptoms on optimal medical therapy (class IA)- QRS duration >120 ms but < 150 ms & NYHA class III or IV on optimal medical therapy (optional)- NYHA class I or II symptoms on optimal medical therapy undergoing pacemaker or ICD implantation with anticipated frequent ventricular pacing LVEF ≤ 30%, QRS >150 ms with LBBB, & NYHA class I or II symptoms on optimal medical therapy
• Surgical indications for severe chronic mitral regurgitation Primary MR:- Surgery if LVEF 30-60% (regardless of symptoms)- Consider surgery if successful valve repair is likely:→ Symptomatic & LVEF < 30%→ Asymptomatic & LVEF > 60% Secondary MR: Medical management

zurück  |  weiter 2 / 2