August 1, 1986AJP Heart and Circulatory Physiology
Influence of pacing site on canine left ventricular contraction
Why the study?
Does pacing site influence left ventricular contraction and effective ventricular muscle mass in isolated canine hearts?
Population
8 isolated supported canine hearts constrained to contract isovolumically
Comparison
Pacing from different sites at 130 beats/min vs Atrial pacing (used as reference)
Design
Preclinical
Authors
Discussion
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Member takes
Implication
RV pacing lowers peak LVP versus atrial pacing in isolated canine hearts; hypothesis-generating for dyssynchrony effects, requires in vivo confirmation.
Key Points
- This research aims to assess how different pacing sites influence left ventricular contraction and pressure generation in canine hearts.
- Experiments conducted on isolated canine hearts constrained to contract isovolumically.
- Pacing sites included atrium, left ventricular apex, left ventricular free wall, right ventricular free wall, and right ventricular endocardium at a rate of 130 beats/min.
- Measurements of peak left ventricular pressure recorded and compared among different pacing sites.
- Peak left ventricular pressure was highest with atrial pacing, averaging 26 +/- 10% greater than that from right ventricular free wall pacing.
- There was a linear negative correlation (r = 0.971) between peak pressure changes and QRS complex duration changes with an average slope of -0.51 mmHg/ms.
- End-systolic pressure-volume relation slope decreased with ventricular pacing compared to atrial pacing, while volume axis intercept remained constant.
Structured PICO
Does pacing site influence left ventricular contraction and effective ventricular muscle mass in isolated canine hearts?
P
Population
8 isolated supported canine hearts constrained to contract isovolumically
I
Intervention
Pacing from different sites (atrium, LV apex, LV free wall, right ventricular free wall, right ventricular endocardium) at 130 beats/min
C
Comparator
Atrial pacing (used as reference)
O
Outcome
Magnitude and time course of isovolumic LV pressure (P) generationsurrogate
Direct ventricular pacing, particularly from the right ventricular free wall, reduces peak left ventricular pressure and effective ventricular muscle mass compared to atrial pacing in isolated canine hearts.
Cite This Study
Burkhoff et al. (1986) studied this question.