LVAD placement in failing hearts immediately decreased QRS duration (117 to 103 ms, P<0.01) and increased QTc (379 to 504 ms, P<0.01), followed by a delayed decrease in QTc (P<0.001).
Cohort (n=45)
Does LVAD implantation alter ventricular conduction and repolarization in patients with refractory heart failure?
LVAD implantation induces acute load-dependent changes in QRS and QT duration, followed by delayed reversal of electrophysiologic remodeling in the failing human heart.
p-value: p=<0.01
BACKGROUND: Recognizing that mechanical circulatory support with a left ventricular assist device (LVAD) induces changes in myocardial structure and contractile function, we examined whether there are changes in ventricular conduction and/or repolarization among failing human hearts after LVAD implantation. METHODS AND RESULTS: We examined 12-lead electrocardiograms before surgery, immediately after LVAD placement, and at a delayed (>1 week) postoperative time point in 23 patients who were receiving LVAD support for refractory heart failure. The immediate effects of hemodynamic unloading via LVAD placement included a decrease in QRS duration from 117+/-6 to 103+/-6 ms (P<0.01), an increase in absolute QT duration from 359+/-6 to 378+/-8 ms (P<0.05), and an increase in the heart rate-corrected QT interval (QTc) from 379+/-10 to 504+/-11 ms (P<0.01). None of these immediate changes were observed among 22 patients undergoing routine coronary artery bypass grafting. With sustained cardiac unloading via LVAD support, there was a marked decrease in the QTc from 504+/-11 to 445+/-9 ms (P<0.001). Studies in isolated cardiac myocytes, obtained at the time of transplantation, confirmed that delayed decreases in heart rate-adjusted QTc were the result of decreases in action potential duration after LVAD support. CONCLUSIONS: Acute electrocardiogram responses to LVAD placement demonstrate the dependence of QRS and QT duration on load in the failing human heart. Delayed decreases in QTc and action potential duration reflect reversal of electrophysiologic remodeling in the failing heart. Shortening of the action potential duration likely contributes to the improved cellular contractile performance observed after sustained LVAD support.
Harding et al. (Tue,) conducted a cohort in refractory heart failure (n=45). LVAD placement vs. routine coronary artery bypass grafting was evaluated on Electrocardiographic changes (QRS, QT, and QTc duration) (p=<0.01). LVAD placement in failing hearts immediately decreased QRS duration (117 to 103 ms, P<0.01) and increased QTc (379 to 504 ms, P<0.01), followed by a delayed decrease in QTc (P<0.001).