Sudden Death in Hypertrophic Cardiomyopathy Usually Not at Exertion: Registry

Marlene Busko

September 07, 2016

ROME, ITALY — Most cases of sudden cardiac death in a pathology-registry study of people with hypertrophic cardiomyopathy (HCM) occurred during rest or sleep, not during exercise[1].

Notably, individuals who died on the playing field—mostly on the football pitch or the basketball court—were young men, Dr Gerardo Finocchiaro (George's University of London, UK) reported, in a press briefing prior to a rapid-fire abstract session at the European Society of Cardiology (ESC) 2016 Congress.

Specifically, in 184 pathology cases of patients with HCM who had died from sudden cardiac arrest, 78% of deaths occurred during rest; only 19% happened during exertion, and the remaining 12% of individuals had died in their sleep.

Moreover, only one in five individuals had known HCM. "Maybe these patients [with known HCM] may have been saved, but [they] were considered to be at low risk by the current risk-stratification calculator," Finocchiaro said, in reply to a question by the comoderator of the press briefing, Dr Kurt Huber (University of Vienna, Austria), who asked whether more of these patients needed ICDs.

"We know that there are patients who unfortunately die suddenly, even if they have zero or just one risk factor," he said, adding that this study "is in some way a snapshot of the current failure of risk stratification."

"What are your recommendations to patients, since with the exception of [arrhythmogenic right ventricular dysplasia] ARVD, cardiomyopathy patients such as those with HCM like to be active?" an audience member at the rapid-fire abstract session wanted to know.

"We need a randomized trial" to be better able to identify patients with HCM, stratify their risk, and know what exercise is safe for them, according to Finocchiaro.

Guidelines Caution Against Competitive Sports

Exercise is considered to be a trigger for fatal arrhythmias in HCM, and both American and European guidelines[2] recommend advising individuals with known HCM to avoid competitive sports, Finocchiaro noted.

For example, a 2015 Scientific Statement from the AHA/ACC states: "Athletes with a probable or unequivocal clinical expression and diagnosis of HCM (ie, with the disease phenotype of LV hypertrophy) should not participate in most competitive sports, with the exception of those of low intensity (class IA sports)."

A risk calculator published by the ESC identifies risk factors for sudden cardiac death in cardiomyopathy, including age, maximal left ventricular wall thickness, and left atrial size[3].

However, the role of sports and exercise in developing fatal arrhythmia and the rate of exercise-induced sudden cardiac death in patients with HCM is still not well characterized.

Thus, Finocchiaro and colleagues examined demographic variables and circumstances surrounding sudden cardiac death in a cohort of HCM cases referred to their center to characterize risk factors for exercise-induced sudden cardiac death in these patients.

From 1994 to 2014, 3684 cases of sudden cardiac death were referred to their cardiac pathology center in London, of which 184 cases were HCM.

All subjects had a detailed postmortem evaluation, including histologic analysis, and an expert cardiac pathologist confirmed the diagnosis of HCM. The researchers also obtained clinical information about the patients from the referring coroners.

The patients ranged in age from younger than 10 to older than 60, with a mean age of 39, and 79% were male.

Only 37 patients (20%) had an established diagnosis of HCM prior to their death. Forty patients (22%) had exhibited cardiac symptoms, including palpitations (16 patients), dyspnea (11), syncope (seven), and chest pain (six).

Twenty patients (11%) were recreational or competitive athletes and exercised more than 3 hours a week.

Multivariate analysis showed that in this cohort of individuals with HCM, older individuals had a slightly lower risk of sudden cardiac death on exertion (HR 0.94, 95% CI 0.92–0.97; P<0.001) and males had a 3.5-fold higher risk of dying during exercise (HR 3.47, 95% CI 1.04–10.19; P=0.03).

The researchers are currently performing molecular autopsies in spleens to shed more light on this hereditary disease, Finocchiaro said.

Finocchiaro has no relevant financial relationships.

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