학술논문

Effects of Cardiac Resynchronization Therapy on Muscle Sympathetic Nerve Activity.
Document Type
Article
Source
Pacing & Clinical Electrophysiology. Jan2014, Vol. 37 Issue 1, p11-18. 8p.
Subject
*SYMPATHETIC nervous system physiology
*HEART failure
*ANALYSIS of variance
*CARDIAC pacing
*CARDIOPULMONARY system
*EXERCISE tests
*GRIP strength
*MUSCLE contraction
*STATISTICS
*DATA analysis
*PRE-tests & post-tests
*OXYGEN consumption
*DATA analysis software
*DESCRIPTIVE statistics
*EXERCISE tolerance
*PROGNOSIS
Language
ISSN
0147-8389
Abstract
Introduction Muscle sympathetic nerve activity (MSNA) is an independent prognostic marker in patients with heart failure (HF). Therefore, its relevance to the treatment of HF patients is unquestionable. Objectives In this study, we investigated the effects of cardiac resynchronization therapy (CRT) on MSNA response at rest and during exercise in patients with advanced HF. Methods We assessed 11 HF patients (51 ± 3.4 years; New York Heart Association class III-IV; left ventricular ejection fraction 27.8 ± 2.2%; optimal medical therapy) submitted to CRT. Evaluations were made prior to and 3 months after CRT. MSNA was performed at rest and during moderate static exercise (handgrip). Peak oxygen consumption (VO2) was evaluated by means of cardiopulmonary exercise test. HF patients with advanced NYHA class without CRT and healthy individuals were also studied. Results CRT reduced MSNA at rest (48.9 ± 11.1 bursts/min vs 33.7 ± 15.3 bursts/min, P < 0.05) and during handgrip exercise (MSNA 62.3 ± 13.1 bursts/min vs 46.9 ± 14.3 bursts/min, P < 0.05). Among HF patients submitted to CRT, the peak VO2 increased (12.9 ± 2.8 mL/kg/min vs 16.5 ± 3.9 mL/kg/min, P < 0.05) and an inverse correlation between peak VO2 and resting MSNA (r = -0.74, P = 0.01) was observed. Conclusions In patients with advanced HF and severe systolic dysfunction: (1) a significant reduction of MSNA (at rest and during handgrip) occurred after CRT, and this behavior was significantly superior to HF patients receiving only medical therapy; (2) MSNA reduction after CRT had an inverse correlation with O2 consumption outcomes. [ABSTRACT FROM AUTHOR]