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.
A recent study by doctors at the Cleveland Clinic found that current guidelines used to assess risk of sudden cardiac death (SCD) in HCM fall short when applied to the population of patients with the obstructive form of HCM (HOCM).
The study looked at both the European Society of Cardiology (ESC) and American College of Cardiology (ACC)/American Heart Association (AHA) guidelines, and found that both sets of guidelines came up short in predicting SCD. In particular, the study found that patients who had previously undergone myectomy had a reduced risk of SCD that is not accounted for in existing risk models.
Conversely, the study found that patients with atrial fibrillation had a higher risk of SCD, which is also not reflected in the existing risk models.
A companion editorial by Dr. Harzell Schaff of the Mayo Clinic explains the likely reasons for the myectomy findings, while a second accompanying editorial by Dr. John Jefferies of Cincinnatti Children’s Hospital (who has recently accepted an appointment at the U. of Tennessee Health Science Center in Memphis) maintains that the ESC and ACC/AHA guidelines should be changed to reflect the lower SCD risk following myectomy.
Click here for previous coverage of the ESC and ACC/AHA guidelines. If you would like to try out the ESC Risk Calculator for yourself, click here.
A recent study published in the American Journal of Cardiology found that the standards propounded by the American College of Cardiology Foundation with the American Heart Association (ACC/AHA) were superior in predicting which patients would benefit from an implantable cardiac defibrillator (ICD) compared to the calculator set forth by the European Society of Cardiology (ESC). According to the study, the use of the ESC tool will result in more high-risk patients going unprotected against sudden death.
Specifically, the study found that out of a group of 288 HCM patients, 14 who experienced aborted sudden cardiac arrest (or 43%) would not have qualified for an ICD under the ESC risk model compared to 7% of patients under the ACC/AHA guidelines.
The ACC/AHA guidelines are:
A companion editorial by Dr. Andreas S. Barth pointed out the shortcomings of both models, and reaffirmed the necessity for shared decision making between physicians and patients. Dr. Barth also expressed hope that a more accurate predictive model will evolve, though he acknowledged the impossibility of designing a model which could predict future events with certainty.
The HCM Risk–SCD Score
In 2014, the European Society of Cardiology (ESC) introduced a numerical predictor (the “HCM Risk–SCD score”) to assist physicians in identifying those patients at highest risk for sudden cardiac death who would benefit from the implantation of a prophylactic implantable cardioverter-defibrillator.
Using an algorithm generated by the answers to a series of questions, the tool estimates the 5-year risk of sudden cardiac arrest for any particular patient. You can find the tool online here.
Continue reading “A Risk Calculator for Sudden Death -Results of HCM-EVIDENCE Study”
According to research presented at the 2016 European Society of Cardiology Congress today, sudden cardiac arrest from HCM, which has long been thought to result from exercise, is actually more likely to occur at rest, or even during sleep, according to Dr. Gherardo Finocchiaro, a cardiologist at St George’s University in London. Dr. Finocchiaro also pointed out that of the 184 HCM patients in his study, almost 80% had no previous symptoms of HCM, and only 1 in 5 had been diagnosed with HCM before their deaths. Interestingly, most of the sudden deaths from HCM analyzed in the study occurred in patients in their 30s and 40s.
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.