Myocardial bioenergetic abnormalities in the rapid ventricular pacing model of congestive heart failure

To develop an improved animal model of congestive heart failure, 11 female farm pigs (wt, 42-46 kg) underwent rapid ventricular pacing at 230 beats/min for 7 days with a modified Medtronic unipolar pacemaker connected to an apical pacing lead. After 7 days the pacemaker was turned off, anesthesia induced, the chest opened, and cardiac hemodynamic and dimensional studies were performed. Results were subsequently compared with data from 12 control pigs that received no pacing. Two pigs died before measurements could be determined. Cardiac output in the paced animals (0.061 +/- 0.018 l.min-1.kg-1) was significantly less (P less than 0.05) than in control pigs (0.085 +/- 0.016 l.min-1.kg-1), when compared at the same resting heart rate. Left ventricular (LV) end-diastolic pressure (23.2 +/- 7.7 vs. 8.6 +/- 3.6 mmHg, P less than 0.01) and right ventricular (RV) end-diastolic pressure (9.0 +/- 3.1 vs. 4.4 +/- 1.7 mmHg, P less than 0.01) were significantly greater in the paced pigs. Significant increases in both septal-lateral LV end-diastolic dimension (60.3 +/- 3.9 vs. 52.1 +/- 7.2 mm, P less than 0.01) and RV end-diastolic dimension (47.2 +/- 5.7 vs. 40.8 +/- 4.7 mm, P less than 0.05) indicated biventricular dilation in the paced pigs. They also exhibited a significantly greater heart weight-to-total body weight ratio and clinical evidence of congestive heart failure, with hepatomegaly and ascites. These results demonstrate that 1 wk of rapid ventricular pacing at 230 beats/min produces a realistic model of congestive heart failure in the pig.

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644 Efficacy of novel tri-ventricular pacing in patients with congestive heart failure

EP Europace ◽

10.1016/s1099-5129(05)80440-4 ◽

2005 ◽

Vol 7 ◽

pp. 148-149

Keyword(s):

Heart Failure ◽

Congestive Heart Failure ◽

Ventricular Pacing

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Characterization of baroreflex impairment in conscious dogs with pacing-induced heart failure

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1993.265.5.r1132 ◽

1993 ◽

Vol 265 (5) ◽

pp. R1132-R1140 ◽

Cited By ~ 14

Author(s):

N. B. Olivier ◽

R. B. Stephenson

Keyword(s):

Heart Failure ◽

Blood Pressure ◽

Heart Rate ◽

Cardiac Output ◽

Peripheral Resistance ◽

Open Loop ◽

Ventricular Pacing ◽

Baroreflex Control ◽

Rapid Ventricular Pacing ◽

Reflex Control

Open-loop baroreflex responses were evaluated in eight conscious dogs before and during congestive heart failure to determine the effects of failure on baroreflex control of blood pressure, heart rate, cardiac output, and total peripheral resistance. Heart failure was induced by rapid ventricular pacing. Baroreflex function was determined by calculation of the range and gain of the open-loop stimulus-response relationships for the effect of carotid sinus pressure on blood pressure, heart rate, cardiac output, and total peripheral resistance. The range and gain of blood pressure responses were substantially reduced as early as 3 days after induction of heart failure (161 +/- 6 to 99 +/- 8 mmHg and -2.7 +/- 0.3 to -1.5 +/- 0.1, respectively) and remained depressed for the 21 days of heart failure. This depression in baroreflex control of blood pressure was associated with similar depressions in reflex range and gain for heart rate (125 +/- 9 to 78 +/- 11 beats/min and -2.05 +/- 0.2 to -1.16 +/- 0.2 beats/min, respectively) and cardiac output (1.74 +/- 0.2 to 0.46 +/- 0.2 l/min and -0.81 +/- 0.02 to -0.027 +/- 0.008 l/min, respectively). The group-averaged range and gain for reflex control of vascular resistance were not altered by heart failure. In three dogs, discontinuation of rapid ventricular pacing led to resolution of heart failure within 7 days and partial restoration of the range and gain of reflex control of blood pressure. We conclude that heart failure reversibly depresses baroreflex control of blood pressure principally through a concurrent reduction in reflex control of cardiac output, whereas reflex control of vascular resistance is not consistently affected.

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