Details

Autor(en) / Beteiligte

• Laveneziana, Pierantonio
• O'Donnell, Denis E
• Ofir, Dror
• Agostoni, PierGiuseppe
• Padeletti, Luigi
• Ricciardi, Giuseppe
• Palange, Paolo
• Duranti, Roberto
• Scano, Giorgio

Titel

Effect of biventricular pacing on ventilatory and perceptual responses to exercise in patients with stable chronic heart failure

Ist Teil von

• Journal of applied physiology (1985), 2009-05, Vol.106 (5), p.1574-1583

Ort / Verlag

Bethesda, MD: Am Physiological Soc

Erscheinungsjahr

2009

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• 1 Department of Internal Medicine, Section of Immunology and Respiratory Medicine, University of Florence, Florence, Italy; 2 Respiratory Investigation Unit, Department of Medicine, Queen's University, Kingston, Ontario, Canada; 3 Centro Cardiologico Monzino, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto di Cardiologia, University of Milan, Milan, Italy; 4 Division of Cardiology, Clinica Medica Careggi, University of Florence, Florence, Italy; 5 Department of Clinical Medicine, University "La Sapienza", Rome, Italy; and 6 Department of Pulmonary Rehabilitation, Fondazione Don C. Gnocchi, Florence, Italy Submitted 10 June 2008 ; accepted in final form 24 February 2009 Despite the growing evidence supporting the use of biventricular cardiac resynchronization therapy (CRT) in patients with chronic heart failure (CHF), the mechanisms whereby acute hemodynamic improvements lead to improved exertional dyspnea are not precisely known. We hypothesized that improved cardiac function and ventilation-perfusion relations following CRT would reduce ventilatory demand, thereby improving dynamic operating lung volumes and enhancing tidal volume expansion during exercise. This, in turn, would be expected to reduce perceived exertional dyspnea and contribute to improved exercise performance. In a randomized, double-blind, crossover study, we compared cardiovascular, metabolic, ventilatory responses (breathing pattern, operating lung volumes, pulmonary gas exchange) and exertional symptoms in seven stable CHF patients who undertook incremental cardiopulmonary cycle exercise test with CRT switched to the "on" (CRT on ) or "off" (CRT off ) modality. Following CRT on , peak oxygen uptake was significantly increased by 15%, and dyspnea ratings were lower for a given work rate (at work rate of 40 W, dyspnea = 1 ± 0.4 vs. 2.5 ± 0.9 Borg units, P < 0.05) and ventilation (at ventilation of 31 l/min, dyspnea = 2 ± 0.7 vs. 3.3 ± 1.1 Borg units, P < 0.05). CRT on was associated with improvements in ventilatory threshold, oxygen pulse, and oxygen uptake/work rate relationships (10.2 ± 1 vs. 7.9 ± 1.3 ml·min –1 ·W –1 , P < 0.05). CRT on reduced the ventilatory requirement during exercise as well as the steepness of ventilation-CO 2 production slope (35 ± 4 vs. 45 ± 7, P < 0.05). Changes in end-expiratory lung volume during exercise were less with CRT on than with CRT off (0.12 vs. 0.37 liter, P < 0.05), and breathing pattern was correspondingly slower and deeper. Biventricular pacing improved all noninvasive indexes of cardiac function and oxygen delivery during exercise. The decreased ventilatory demand, improved dynamic operating lung volumes, and the increased ability to expand tidal volume during exercise are potential factors in the reduction of exertional dyspnea. heart failure; dyspnea; dynamic lung hyperinflation; ventilation; resynchronization Address for reprint requests and other correspondence: P. Laveneziana, Pulmonologist, Respiratory Investigation Unit, Queen's Univ., 76 Stuart St., K7L 2V7 Kingston, ON, Canada (E-mail: pier_lav{at}yahoo.it )