Hypertrophic cardiomyopathy without obstruction is benign for many people

1st April 2016

Some people with hypertrophic cardiomyopathy (HCM) have obstruction to blood flow out of their hearts – while others don’t.

Now a new study has shown that most people without the obstruction do not develop severe heart failure and are likely to live as long as the general population.

Contributing to the low mortality was the effectiveness of internal defibrillators (ICDs) and the up-to-date fairly accurate ways doctors were able to work out which patients would benefit from the devices. This meant that patients were dying suddenly infrequently.

The research, led by Dr Martin Maron from the Hypertrophic Cardiomyopathy Centre at Tufts Medical Centre in Boston, has just been published in the Journal of the American College of Cardiology.

In a related editorial, Professor Perry M. Elliott, from the Barts Heart Centre in London, said: “The low mortality in this study can be seen as a testament to the beneficial effect of targeted therapy, specifically, ICDs, heart transplantation and stroke prevention.

“However, the low annual death rate should not mask the fact that sudden cardiac death and progressive heart failure do remain a significant problem for some patients.”

The researchers looked at data from 573 patients (mean age, 44 years; 66% men) with hypertrophic cardiomyopathy at three medical centres, and analysed 249 (mean age, 41 years; 67% men) with non-obstructive HCM, looking for heart failure progression, heart transplant and mortality over 6.5 years.

During the study, 90% of those with nonobstructive HCM remained at in the lowest class of heart failure and only one in ten progressed to class III or IV.
Seven patients with nonobstructive HCM (2.8%) who progressed to class III or IV HF required heart transplants.

During the study period, eight patients with nonobstructive hypertrophic cardiomyopathy died (rate, 0.5% per year), and patients had a 5-year survival rate of 99% and a 10-year survival rate of 97%, the researchers wrote. These rates did not significantly differ from the expected mortality rate in the age- and sex-matched general US population.

For more about hypertrophic cardiomyopathy see here