September 1, 1991AJP Heart and Circulatory Physiology
Load-dependent left ventricular relaxation in conscious dogs
Key result
Late systolic intra-aortic balloon inflation (50 +/- 5 ms before aortic dicrotic notch) accelerated the initial rate of left ventricular pressure decline and abbreviated contraction duration.
Population
8 conscious dogs
Comparison
Intra-aortic balloon inflation during late systole vs Baseline state (no balloon inflation)
Design
Preclinical
Authors
Discussion
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Member takes
Implication
Load-dependent LV relaxation in conscious dogs warrants human validation; leaves open clinical translation.
Structured PICO
P
Population
Eight conscious dogs studied to assess load-dependent left ventricular relaxation.
I
Intervention
Intra-aortic balloon inflation during late systole (with and without propranolol, verapamil, or caffeine)
C
Comparator
Baseline state (no balloon inflation)
O
Outcome
Left ventricular relaxation parameters (peak -dP/dt, time constant of relaxation [tau], and time to 50% pressure fall [P50])surrogate
Left ventricular relaxation in conscious dogs is load-dependent, and this load dependence is attenuated by caffeine, suggesting involvement of the sarcoplasmic reticulum.
Cite This Study
Zile et al. (1991) studied this question. Intra-aortic balloon inflation during late systole vs. Baseline state was evaluated on Left ventricular relaxation (P50, peak -dP/dt, tau). Late systolic intra-aortic balloon inflation (50 +/- 5 ms before aortic dicrotic notch) accelerated the initial rate of left ventricular pressure decline and abbreviated contraction duration.