Fig. 5. QT dispersion in 10 patients with congestive heart failure who were treated with biventricular pacing (6 men and 4 women, aged 62 ± 8 years, and left ventricular ejection fraction 19 ± 7%). There was no significant difference in QT intervals between right ventricular (RV) pacing and sinus rhythm (SR; 437 ± 36 ms vs 426 ± 28 ms; p = 0.26). QT intervals were significantly shorter during biventricular (BV) pacing (407 ± 30 ms) than during right ventricular pacing (437 ± 36 ms; p < 0.01) and during sinus rhythm (426 ± 28 ms; p < 0.01). QT dispersion was significantly increased during RV pacing compared with sinus rhythm (81 ± 30 vs 59 ± 16 ms; p < 0.01). Biventricular pacing was associated with less QT dispersion (37 ± 17 ms) compared with sinus rhythm (59 ± 16 ms; p = 0.01) and right ventricular pacing (81 ± 30 ms, p < 0.01). This was also true after correction of QRS durations. It seems that biventricular pacing is associated with less QT dispersion, which may play a role in prevention of sudden cardiac death in patients with congestive heart failure patients with biventricular pacing.

with excess mortality. Two large-scale studies, CArdiac REsynchronisation in Heart Failure (CARE-HF) study in Europe and Comparison of Medical Therapy, Pacing, and Defibrillation in Chronic Heart Failure (Companion) in the United States, are ongoing to examine the long-term effects of biventricular pacing on survival.

Fig. 4. Kaplan-Meier Estimates of the time to death or hospitalization for worsening heart failure in the control and resynchronization groups. The risk of an event was 40% lower in the resynchronization group (95% confidence interval, 4 to 63%; p = 0.03). Reprinted from ref. 16. © 2002, Massachusetts Medical Society. All rights reserved.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook

Post a comment