Improved lifestyle may cut sudden cardiac death risk

Medical Tribune August 2008 SFIX
David Brill

Primary care doctors can do more to lower the risk of sudden cardiac death (SCD) among their patients, according to a Singapore cardiologist.

Eighty percent of cases of SCD are thought to be caused by underlying coronary artery disease (CAD).

Many of these deaths could therefore be avoided by better tackling CAD, said Dr. Seow Swee Chong during the recent 39th National Medical Convention of the Singapore Medical Association.

“I think that awareness [of SCD] is not that high yet – particularly in the primary care setting,” he said.

“We are hoping that at the primary healthcare level we can have very good control of risk factors and lifestyle modification to prevent heart disease, and for these doctors to identify those who are at higher risk and refer for further assessment by a specialist so that appropriate therapy can be given.”

Tackling CAD begins with prevention, said Seow, a consultant at the Heart Institute, National University Hospital.

“The risk factors are smoking, high blood pressure, diabetes, high cholesterol, sedentary lifestyle and obesity. If you have these risk factors they should be treated and controlled adequately.”

He added that patients should be screened at a certain age to identify silent risk factors. For men this should be done at around 40 and for women around 50, he said.

Early detection of CAD is also important in reducing the risk of SCD. Treadmill exercise testing and cardiac nuclear perfusion scans can be used to demonstrate ischemia, while CT, MRI and coronary angiography can be employed to visualize the coronary arteries.

Once CAD is identified “we have to be aggressive and consistent in our treatment,” said Seow.

“We need then to bring the cholesterol and blood pressure down to adequate levels to prevent progression of disease, and give other medications to reduce the chance of heart attack, like beta blockers and aspirin.”

He referred to studies showing that statins can reduce overall mortality in patients who have heart failure, while the aldosterone antagonist eplerenone reduces morbidity and mortality in post-myocardial infarction patients with left ventricular dysfunction. [Am Heart J 2007 Apr;153(4):573-8; N Engl J Med 2003 Apr 3;348(14):1309-21]

Implantable cardioverter defibrillators (ICDs) have also been shown to reduce the risk of SCD in selected patients. For primary prevention, the decision to use an ICD should be made on the basis of certain criteria such as the patient’s left ventricular ejection fraction and the presence of tachycardias on electrophysiological testing, Seow said.

Patients who have already survived a cardiac arrest are at very high risk of recurrence, however, and ICD use among this population should be considered as standard for secondary prevention of SCD, he said.