A 74-year-old man with past medical history significant for hyperlipidemia, obstructive sleep apnea, hypertension, tobacco use, type 2 diabetes mellitus, and chronic obstructive pulmonary disease presents to the emergency department with two days of chest tightness and worsening shortness of breath at rest. He is found to have ST elevations in the anterolateral leads. Emergent coronary angiography demonstrates 90% stenosis of proximal to mid LAD and he is treated with two drug-eluting stents. Transthoracic echocardiograms during hospitalization showed an LVEF of 25% with anterior and apical wall motion abnormalities. He is discharged on dual antiplatelet therapy along with metoprolol, valsartan, spironolactone, SGLT2 inhibitor, and rosuvastatin. At follow-up 3 months later, he reports home BP readings in 90s/50s mm Hg with intermittent shortness of breath and lightheadedness. Blood pressure in the office is 92/54 mmHg. ECG shows normal sinus rhythm with anterior Q waves, a narrow QRS, and no acute ST-segment or T-wave changes.  Repeat transthoracic echocardiogram shows an LVEF of 30%. What is the most appropriate next step?

A

Switch valsartan to sacubitril-valsartan

B

Consider implantable cardioverter defibrillator (ICD) placement

C

Consider cardiac resynchronization therapy 

D

Consider additional cardiac rehabilitation sessions

Explanation 

The correct answer is B – consider implantable cardioverter defibrillator (ICD) placement.

Generally, arrhythmic complications increase both morbidity and mortality rates in patients after ACS. Patients who present with AMI with reduced LVEF (≤40%) have increased risk of new-onset atrial fibrillation, bradyarrhythmias, and ventricular arrhythmias. Ventricular arrhythmias are common after ACS and more common in patients with reduced LVEF. The MADIT II trial (Multicenter Automatic Defibrillator Implantation Trial) demonstrated a 31% reduction in all-cause mortality (HR, 0.69 [95% CI, 0.51-0.93]) for prophylactic implantation of a cardiac defibrillator in patients with an LVEF ≤30% who were at least 30 days after MI or 3 months after revascularization for MI and had an anticipated life expectancy longer than 1 year. A mortality benefit for prophylactic ICD implantation has also been shown in patients with an LVEF ≤35% and New York Heart Association class II or III HF symptoms, as well as in patients with inducible ventricular tachycardia or ventricular fibrillation and an LVEF ≤40%.

This patient has an LVEF of <30% with at least NYHA class II symptoms, now 90 days post-revascularization for MI, which means he is a candidate for ICD placement for primary prevention of sudden cardiac death.

Answer choice A is incorrect because hypotension in this patient is a limitation to adding any more guideline-directed medical treatment, such as sacubitril/valsartan. This patient does not meet criteria for CRT implantation given his narrow QRS complex, so answer choice C is incorrect. Additional cardiac rehabilitation sessions (answer choice D) would not treat patients’ ongoing cardiomyopathy and SCD risk.

The 2025 ACS guidelines give a Class 1, LOE A recommendation for ICD implantation in patients post-MI with LVEF ≤40% at least 40 days post-MI and at least 90 days post-revascularization to reduce mortality.

In addition, in patients post-ACS, ICD implantation is reasonable in patients with clinically relevant ventricular arrhythmias >48 hours and within 40 days post-MI to improve survival (LOE 2a, LOE C-EO).

Some may wonder about the use of a temporary wearable cardioverter-defibrillator after the initial presentation. In the VEST trial, this strategy did not significantly reduce the primary endpoint, a composite of sudden death or death from ventricular tachyarrhythmias at 90 days) in patients with AMI and LVEF ≤ 35%. Notably, there was a lower incidence of death from any cause in the wearable vest group compared to the no-device group and overall, greater benefit was seen in those who were compliant with the device. As such, use of a wearable cardioverter-defibrillator could be considered in high-risk patients with reduced LVEF as a bridge to consideration for the need for an ICD. Per the guidelines, in patients early after MI, usefulness of a temporary wearable cardioverter-defibrillator is uncertain in patients with an LVEF ≤35% to improve survival (COR 2b, LOE B-R).

Main Takeaway

In patients post MI, implantable cardioverter defibrillator (ICD) implantation is recommended in selected patients with an LVEF of less than or equal to 40% at least 40 days post MI and at least 90 days post revascularization to reduced death.

Guideline Loc.

Section 9.2