To ICD or not ICD?
That is the question.
Background: Hypertrophic cardiomyopathy (HCM) is an important topic relevant to the Haitian community. It’s often part of small differential that is commonly seen in the Haitian population which include hypertensive cardiomyopathy and cardiac amyloidosis causing Heart failure with preserved ejection fraction (HFpEF). They all can have poorly treated hypertension, heart failure and increase in wall thickness on echocardiography. The distinction is relevant because treatment is different and importantly risk stratification for sudden cardiac death is an essential part of the evaluation. Furthermore, family counseling and screening is essential in HCM and in some types of Cardiac amyloidosis. In our review, we will be covering a case of HCM with a primary focus on sudden cardiac death (SCD) risk stratification. HCM puts patients at risk for SCD. HCM patients of advanced age are less likely than their younger counterparts to experience SCD. There are limited data and variable guidelines regarding primary prevention Implantable Cardioverter Defibrillators (ICD) in older HCM patients. This is relevant because most of our Haitian patients that we see with suspected HCM are indeed older in age.
Case: We present a 60-year-old female with shortness of breath found to be in new-onset atrial fibrillation. She underwent electrical cardioversion for symptomatic atrial fibrillation and was initiated on beta-blockade and anticoagulation. Transthoracic echocardiography revealed a normal ejection fraction, severely increased LV wall thickness and a dynamic mid-cavitary gradient, all concerning for HCM. Her LVOT gradient was 20 mmHg. Follow up cardiac MRI showed diffuse late gadolinium enhancement and a mid-ventricular septal wall thickness of 20mm, confirming the diagnosis of HCM. A thin-walled apical aneurysm was also noted. The patient was hospitalized for 7 days and was monitored continuously on telemetry; no episodes of ventricular ectopy were noted. Notably, she had no personal or family history of sudden death or syncope.
Decision-making: This patient had at least two independent markers of increased SCD risk: apical aneurysm and extensive LGE. However, her age, normal EF, absence of a family history of SCD and of a personal history of syncope & NSVT, all decreased the risk of ventricular arrhythmias. Based on the European Society of Cardiology’s (ESC) HCM Risk-SCD Calculator and the 2017 AHA/ACC/HRS guidelines for the prevention of SCD, an ICD was not deemed to be indicated. As such, in a shared decision with the patient, she was sent home with a 30-day event monitor. Three short runs (4-7 beats) of NSVT were eventually noted on the ambulatory monitor. Only then was an ICD inserted, under a II-B recommendation per the 2011 AHA/ACC/HRS guidelines. According to the new AHA/ACC 2020 guidelines, it would be a class II-A indication to offer ICD based on the presence of LV apical aneurysm.
Conclusion: This case highlights the evidence gaps in SCD risk stratification for patients with late onset HCM and underscores the importance of identifying the right patient population.
Garly St Croix MD
Michel Ibrahim MD