Electrode Placement Affects Heart Failure Monitoring

Monitoring more effective if leads are placed on the left side

22 mar 2009-- Monitoring of heart failure patients is more effective if electrodes are placed on the left side rather than the more commonly used right side, according to a study published in the March 24 issue of the Journal of the American College of Cardiology.

Noting that most monitoring of congestive heart failure relies on right-side heart sensors, Dirar S. Khoury, Ph.D., from Methodist Hospital Research Institute in Houston and colleagues implanted cardiac resynchronization therapy systems using standard leads in various configurations in 15 normal dogs, where five were implanted with an additional left atrial pressure lead sensor. They then measured steady-state impedance signals along six different vectors during induction of congestive heart failure over several weeks.

The researchers found that during induction of heart failure, impedance fell gradually at different rates for different vectors. Left ventricle-dependent vectors were superior to vectors solely dependent on right-sided cardiac measurements, having a greater reduction in magnitude, a better correlation with left ventricle end-diastolic volume, and a stronger association with left atrial pressure.

"Impedance vectors employing a left ventricle lead are highly responsive to physiologic changes during congestive heart failure," Khoury and colleagues conclude. "Measuring multiple impedance signals could be useful for optimizing ambulatory monitoring in heart failure patients."

Abstract
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