Sudden Death in HCM Less Common than Thought

A recent study by Canadian researchers published in the American Heart Association journal Circulation found a much lower incidence of  HCM related sudden death than expected.  The study included deaths in individuals that occurred between the ages of 10 and 45 in the Canadian province of Ontario between 2005 and 2016.  According to lead author Dr. Paul Dorian of the University of Toronto, the expectation was that 1 incident of sudden cardiac death would be identified in every 100 to 200 people who had HCM.  Instead, researchers found that the likelihood of sudden death of HCM patients was instead only about 1 in 3,000 people/year.

The study also found that found 7 in 10 HCM-related sudden deaths occurred in people not previously diagnosed with the condition.  Men had more than 5 times the risk of sudden cardiac death than women, and most deaths occurred during rest or light activity: only about 17% happened during or immediately after exercise. 

As a result of the study, according to Dr. Dorian, “our findings allow us to lower the temperature on our degree of worry about the condition.”

Another clinical take away from the study, according to the researchers, is that current exercise guidelines for HCM patients may be too restrictive.

Docs Reliably Identify HCM Patients in Need of ICDs

According to a paper published last week in JAMA Cardiology, doctors at Tufts University’s HCM Center have been able to identify 95% of their patients at high risk of sudden cardiac death (SCD) from HCM.  Tufts applied an updated and modified version of the risk factors enumerated in the American College of Cardiology/American Heart Association Guidelines promulgated  in 2011.

Continue reading “Docs Reliably Identify HCM Patients in Need of ICDs”

Cardiac MRI Helps Assess Sudden Death Risk

A recent study by doctors at the Cleveland Clinic suggests that the presence of late gadolinium enhancement  (LGE) should be added to the various risk factors currently used to assess patients who are at low or intermediate risk of sudden death.  The presence and balancing of these risk factors are used by patients and doctors to determine the need for implantable cardiac defibrillators (ICDs).   LGE is an indication of cardiac scar tissue and can be seen on cardiac MRI scans.  This study recommended that LGE comprising a total of 15% or more of left ventricular mass be used as an additional risk factor. The study found that this indicator worked equally well when applied to both obstructed and non-obstructive HCM patients.

Interestingly, an earlier but recent study published by Cleveland Clinic doctors found that the risk factors currently in use to determine the need for an ICD fall short as applied to patients with the obstructive form of HCM.

Risk factors in common use today have been propounded by the American College of CardiologyAmerican Heart Association (ACC/AHA) in the U.S., while a different set of guideline and a mathematical risk calculator was promulgated more recently in Europe by the European Society of Cardiology (ESC).  You can find more about the ACC/AHA and ESC guidelines here.

A second and related finding of this study by the Cleveland Clinic, known for its large HCM program and high volume of myectomies, was that patients who undego  myectomy appear to experience a protective effect from their surgeries.  Even when found to have 25% or more LGE, patients in this study who previously underwent myectomy experienced a lower than expected rate of adverse events.

Sudden Cardiac Death in Young Athletes

Editor’s Note:  This post originally appeared on the blog of Dr. Howard J. Luks. Dr. Luks  wrote this blog entry in collaboration with HCM expert Dr. Srihari S. Naidu of New York’s Westchester Medical Center. You can find the original post here.  You can find both Dr. Luks and Dr. Naidu on Twitter @hjluks and @SrihariNaiduMD.

Sudden cardiac death in young athletes continues with alarming frequency.  The most common cause of sudden death in the young athlete is hypertrophic cardiomyopathy or HCM.  Simply put, HCM means the heart muscle is bigger.  Many of us believe that bigger muscle means stronger muscle.  That is not always the case with the heart.  The heart is a mechanical pump with a complex arrangement of chambers which store the blood. How that pump works is controlled by a very complex electrical system.  Hypertrophic cardiomyopathy can interfere with one or both of these critical functions of the heart and lead to sudden cardiac death.

Continue reading “Sudden Cardiac Death in Young Athletes”

HCM Top Cause of Death in Male Athletes

 

HCM is the most frequent cause of death in male athletes according to a soon to be published study analyzing competitive athlete causes of death between 1980 and 2011.  

More than 1/3 of deaths were due to HCM, which was almost four times more common in males than females. Deaths in minorities were almost 5 times greater than in whites.

The complete study will be published in October in The American Journal of Medicine.

 

 

 

 

Causes of SCD Identified Using Genetic Testing

 

According to a recent study by doctors in Australia and New Zealand, unexplained sudden cardiac deaths in children and adolescents can often be explained through the use of genetic testing.

 

 

 

LV Wall Thickness Shouldn’t Alone Justify ICD 

HCM experts in the U.K. have found that extreme left ventricular wall thickness does not automatically correlate with an increased risk of sudden death.  Thus, results from a recent study published in the American Heart Association’s Circulation:  Arrhythmia and Electrophysiology,  suggest that extreme hypertrophy NOT be the sole factor justifying the implantation of an implantable defibrillator.