Imaging Technique Highlights Cardiac Arrest Candidates

John Canty (University at Buffalo)

Medical researchers from University at Buffalo have adapted Positron Emission Tomography (PET) imaging to identify patients at the highest risk for sudden cardiac arrest. Results of the clinical trial testing the technique are scheduled for presentation today at a meeting of the Heart Rhythm Society.

The university says the Prediction of Arrhythmic Events with Positron Emission Tomography (PAREPET) clinical trial, is the largest PET imaging study ever done on sudden cardiac arrest. The study that began in 2004 involves more than 200 patients in Western New York with advanced heart disease.

In the study, the Buffalo researchers, led by medical professor John Canty (pictured right), use PET imaging to quantify the amount of heart muscle in the patients, where nerves in the heart have died or become damaged due to inadequate blood flow, called denervated myocardium. To trace and measure this condition, the technique adds a radioactive tracer to the norepinephrines — neurotransmitters — released from the heart’s neurons.

“The principal question we posed with this study was whether the amount of denervated myocardium could predict sudden cardiac arrest,” says James Fallavollita, also a Buffalo medical researcher and lead author of the study paper. “We found that when at least 38 percent of the heart was denervated, there was a significant increase in the risk of sudden cardiac arrest.”

The findings can improve the ability to diagnose those at risk for sudden cardiac arrest, as well as identify potential treatment options, including an implantable cardiac defibrillator (ICD). ICDs are used to prevent sudden cardiac arrest in patients with advanced heart disease, but many patients’ devices are never triggered. Current criteria for identifying ICD candidates are based on the percentage of blood pumped by the heart with each beat.

“Since many patients who suffer a cardiac arrest do not have severely depressed heart function,” says Canty, “PET imaging may be able to identify high risk individuals who, in the future, could be considered candidates for an ICD.”

Read more:

• Blood Biomarker Can Help Predict Imminent Heart Attack Risks
• NIH Trials to Assess Emergency Cardiac Arrest Treatments

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