Heart Rate Variability in a Progressive Heart Failure Model with Rapid Ventricular Pacing

2008 ◽  
Vol 11 (5) ◽  
pp. E295-E299 ◽  
Author(s):  
Chiyo Ootaki ◽  
Amy Manzo ◽  
Keiji Kamohara ◽  
Zoran B. Popović ◽  
Kiyotaka Fukamachi ◽  
...  
Author(s):  
Peter W. Walsh ◽  
Craig S. McLachlan ◽  
Leigh Ladd ◽  
Arie Blitz ◽  
R. Mark Gillies ◽  
...  

Numerous large animal models of chronic cardiac ischemia have been developed to explore either pathological mechanisms and or device interventions in developed heart failure models. Traditionally chronic heart failure in large animal models such as sheep or pigs has been induced by either coronary ligation with or without reperfusion. Coronary ligation is often attempted in the open chest surgical model or more recently in the closed chest animal via angiography [1]. Both techniques can be challenging and also induce high mortality with the risk of myocardial stunning and resultant shock and or lethal arrhythmias. There is also difficulty in developing stable heart failure across cases where infarct sizes can be variable. One strategy to over come this variability has been via rapid ventricular pacing, however inducing heart failure does not induce sustained heart failure in many cases if the pacing is switched off, and additionally pacing does not induce some of the underlying pathology seen in the development of heart failure [1].


2005 ◽  
Vol 289 (4) ◽  
pp. H1729-H1735 ◽  
Author(s):  
Sophie Motte ◽  
Myrielle Mathieu ◽  
Serge Brimioulle ◽  
Anne Pensis ◽  
Lynn Ray ◽  
...  

Heart failure is associated with autonomic imbalance, and this can be evaluated by a spectral analysis of heart rate variability. However, the time course of low-frequency (LF) and high-frequency (HF) heart rate variability changes, and their functional correlates during progression of the disease are not exactly known. Progressive heart failure was induced in 16 beagle dogs over a 7-wk period by rapid ventricular pacing. Spectral analysis of heart rate variability and respiration, echocardiography, hemodynamic measurements, plasma atrial natriuretic factor, and norepinephrine was obtained at baseline and every week, 30 min after pacing interruption. Progressive heart failure increased heart rate (from 91 ± 4 to 136 ± 5 beats/min; P < 0.001) and decreased absolute and normalized (percentage of total power) HF variability from week 1 and 2, respectively ( P < 0.01). Absolute LF variability did not change during the study until it disappeared in two dogs at week 7 ( P < 0.05). Normalized LF variability increased in moderate heart failure ( P < 0.01), leading to an increased LF-to-HF ratio ( P < 0.05), but decreased in severe heart failure ( P < 0.044; week 7 vs. week 5). Stepwise regression analysis revealed that among heart rate variables, absolute HF variability was closely associated with wedge pressure, right atrial and pulmonary arterial pressure, left ventricular ejection fraction and volume, ratio of maximal velocity of early (E) and atrial (A) mitral flow waves, left atrial diameter, plasma norepinephrine, and atrial natriuretic peptide (0.45 < r < 0.65, all P < 0.001). In tachycardia-induced heart failure, absolute HF heart rate variability is a more reliable indicator of cardiac dysfunction and neurohumoral activation than LF heart rate variability.


1993 ◽  
Vol 265 (5) ◽  
pp. R1132-R1140 ◽  
Author(s):  
N. B. Olivier ◽  
R. B. Stephenson

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.


EP Europace ◽  
2003 ◽  
Vol 4 (Supplement_2) ◽  
pp. B15-B15
Author(s):  
F. Giraldi ◽  
M. Kloss ◽  
C. Fantoni ◽  
F. Regolip ◽  
H. Klein ◽  
...  

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