In a canine model of pacing-induced congestive heart failure, peak early filling rate initially decreased but progressively increased from 108 to 168 mL/s by 4 weeks (P < .05).
In a canine model of pacing-induced heart failure, early filling deceleration time reflects LV stiffness, with filling patterns changing dynamically as LA pressure overcomes impaired LV relaxation.
Absolute Event Rate: 168% vs 108%
p-value: p=< .05
BACKGROUND: The mechanism of the alterations in the pattern of left ventricular (LV) filling during the development of congestive heart failure (CHF) is not fully understood. METHODS AND RESULTS: We studied six conscious dogs instrumented to measure LV and left atrial (LA) pressures and LV volume as CHF was induced by rapid pacing. Diastolic filling dynamics were serially measured over 4 weeks during normal sinus rhythm. Four days after we initiated pacing, the peak early diastolic filing rate decreased from 108 +/- 24 to 88 +/- 27 mL/s (P < .05) as the maximal early diastolic LA-LV pressure gradient decreased associated with a slowing of the rate of LV relaxation. Subsequently, the peak early filling rate progressively increased, returning to control at 1 week, and by the fourth week, it had increased to 168 +/- 39 mL/s (P < .05). These changes in early filling rates occurred as the maximal early diastolic LA-LV pressure gradient increased in association with a progressive increase in LV pressure despite further progressive slowing of the rate of LV relaxation. Throughout the development of CHF, peak early filling rate and the maximal LA-LV pressure gradient correlated (r = .99, P < .001). The early filling deceleration rate increased and deceleration time progressively decreased over the 4 weeks as LV stiffness and net LA plus LV stiffness increased (P < .05). As predicted by a theoretical analysis, the deceleration time was linearly related to the reciprocal of the square root of LV stiffness (r = .94, P < .01). CONCLUSIONS: Early in CHF, slowing of LV relaxation reduces the maximal early diastolic LA-LV pressure gradient, decreasing the peak early filling rate. As CHF progresses, this is overcome by an increase in LA pressure that augments the early diastolic LA-LV pressure gradient, increasing peak early filling rate. Increasing LV stiffness during the development of CHF progressively shortens the early filling deceleration time and augments the early filling deceleration rate. These observations suggest that the early filling deceleration time reflects LV stiffness.
Ohno et al. (Sun,) conducted a other in Congestive heart failure (n=6). Rapid pacing-induced congestive heart failure vs. Baseline was evaluated on Peak early diastolic filling rate (p=< .05). In a canine model of pacing-induced congestive heart failure, peak early filling rate initially decreased but progressively increased from 108 to 168 mL/s by 4 weeks (P < .05).