A 67-year-old man presents to the cardiology clinic for routine follow-up. One year ago, he sustained a large anterior ST-elevation myocardial infarction and underwent successful percutaneous coronary intervention. Since that time, he has developed ischemic cardiomyopathy. His current medications include aspirin, atorvastatin, sacubitril-valsartan, metoprolol succinate, spironolactone, empagliflozin, and furosemide. He reports strict adherence to therapy. Despite treatment, he continues to experience dyspnea when climbing one flight of stairs and becomes fatigued after walking several blocks. He denies syncope, palpitations, or recurrent chest pain. Temperature is 36.7°C (98.1°F), blood pressure is 112/68 mm Hg, pulse is 64/min, and respiratory rate is 16/min. Oxygen saturation is 98% on room air. Physical examination demonstrates trace bilateral ankle edema but is otherwise unremarkable. Laboratory studies reveal stable renal function and normal electrolytes.
Transthoracic echocardiography demonstrates the following:
ECG demonstrates normal sinus rhythm with a QRS duration of 104 milliseconds.
Which of the following is the most appropriate next step to reduce this patient’s risk of sudden cardiac death?
The correct answer is:
A) Implantable cardioverter-defibrillator placement
This patient has ischemic cardiomyopathy with persistent symptomatic HFrEF (LVEF ≤35%) despite more than 3 months of optimal guideline-directed medical therapy. He meets criteria for primary prevention impantable cardioverter-defibrillator (ICD) placement to reduce the risk of sudden cardiac death from ventricular tachyarrhythmias.
Patients with severe left ventricular systolic dysfunction are at substantial risk for ventricular tachycardia and ventricular fibrillation due to scar-mediated reentry circuits within infarcted myocardium. Although modern medical therapy reduces this risk, sudden arrhythmic death remains a major cause of mortality in HFrEF. Multiple clinical trials have demonstrated that ICD implantation improves survival in appropriately selected patients by terminating life-threatening ventricular arrhythmias.
Answer choice B: Increase furosemide dosage, is incorrect.
Loop diuretics improve symptoms by reducing congestion but do not reduce the risk of sudden cardiac death. This patient has minimal volume overload and is already receiving appropriate diuretic therapy. Increasing the dose would not address his greatest mortality risk.
Answer choice C: Long-term amiodarone therapy, is incorrect.
Amiodarone can suppress ventricular arrhythmias but has not demonstrated the same mortality benefit as ICD therapy for primary prevention in patients with severe HFrEF. Furthermore, chronic therapy is associated with significant pulmonary, hepatic, thyroid, and dermatologic toxicities.
Answer choice D: Permanent pacemaker placement, is incorrect.
Pacemakers are indicated for symptomatic bradycardia or high-grade atrioventricular block. This patient has normal sinus rhythm and no evidence of conduction system disease.
Answer choice E: Radiofrequency catheter ablation, is incorrect.
Catheter ablation is used for selected supraventricular and ventricular arrhythmias. This patient has no documented arrhythmia requiring ablation. The goal here is prevention of sudden arrhythmic death before a malignant arrhythmia occurs.
Key Learning Point
Patients with symptomatic HFrEF and an ejection fraction ≤35% despite optimal guideline-directed medical therapy should receive an ICD for primary prevention of sudden cardiac death. ICDs improve survival by terminating life-threatening ventricular arrhythmias.
