Cardiac Disorders and Clinical Management
Core conditions
ACS follows plaque rupture and thrombosis. Women, older adults, and people with diabetes often present with dyspnea, fatigue, or nausea rather than classic pain. Immediate actions: aspirin 162–325 mg chewed, a P2Y12 inhibitor, anticoagulant, nitroglycerin unless SBP <90, suspected right ventricular infarction, or recent PDE-5 inhibitor, beta-blocker when not in cardiogenic shock, high-intensity statin, and reperfusion - primary PCI (door-to-balloon ≤90 min) or fibrinolysis when PCI is unavailable.
Heart failure is classified by ejection fraction: HFrEF ≤40%, mildly reduced 41–49%, preserved ≥50%. Congestion shows as JVD, crackles, S3, edema, orthopnea, and PND. Guideline-directed therapy for HFrEF: ARNI/ACEi/ARB, evidence-based beta-blocker, MRA, and SGLT2 inhibitor, with loop diuretics for congestion.
Arrhythmias. AF is irregularly irregular without P waves; manage rate/rhythm and anticoagulate by CHA₂DS₂-VASc. SVT usually responds to vagal maneuvers then adenosine. Unstable tachyarrhythmia → synchronized cardioversion; pulseless VT/VF → defibrillation. Mobitz II and third-degree block require pacing.
Valves. Aortic stenosis: crescendo–decrescendo systolic murmur radiating to the carotids, with syncope, angina, dyspnea. Mitral regurgitation: holosystolic murmur to the axilla. Aortic regurgitation: early diastolic decrescendo murmur.
Traps
- Give oxygen only for hypoxemia; routine oxygen does not help.
- Nitroglycerin in an inferior/RV infarct can cause profound hypotension.
- New LBBB alone is no longer an automatic STEMI equivalent.
- Beta-blockers harm patients in decompensated HF or cardiogenic shock.
Rule of thumb
Time is muscle: door-to-balloon ≤90 minutes; door-to-needle ≤30 minutes.