Key result
Low-level carotid baroreceptor stimulation significantly reduced the incidence of ventricular fibrillation to 30% compared to 80% in the sham group during acute ischemia in dogs.
Why the study?
Does low-level carotid baroreceptor stimulation reduce ventricular arrhythmias during acute ischemia in a canine model?
RCT (n=20)
Randomized
No
Does low-level carotid baroreceptor stimulation reduce ventricular arrhythmias during acute ischemia in a canine model?
In a canine model of acute ischemia, low-level carotid baroreceptor stimulation significantly reduced ventricular arrhythmias and modulated autonomic tone without altering blood pressure.
Does not support clinical use; leaves open translation of baroreceptor stimulation for ischemic VF prevention to humans.
BACKGROUND: The autonomic imbalance during acute ischemia is involved in the occurrence of life-threatening arrhythmias. OBJECTIVE: To investigate the effect of autonomic nervous system (ANS) modulation by low-level carotid baroreceptor stimulation (LL-CBS) on ventricular ischemia arrhythmias. METHODS: Anesthetized dogs were received either sham treatment (SHAM group, n = 10) or LL-CBS treatment (LL-CBS group, n = 10). The voltage lowering the blood pressure was used as the threshold for setting LL-CBS at 80% below the threshold. Treatment started 1 hour before left anterior descending coronary (LAD) occlusion, and continued until the end of experience. Ventricular effective refractory periods (ERP), monophasic action potential duration at 90% (APD90), ventricular arrhythmias, indices of heart rate variability, left stellate ganglion nerve activity (LSGNA) and infarct sizes were measured and analyzed. RESULTS: Ventricular ischemia resulted in an acute reduction of blood pressure, which was not significantly affected by LL-CBS. After 1 hour of LL-CBS, there was a progressive and significant increase in ERP, increase in APD90, and decrease in LSGNA vs the SHAM group (all P<0.05). LL-CBS apparently reduced premature ventricular contractions (PVC, 264±165 in the SHAM group vs 60±37 in the LL-CBS group; P<0.01) during LAD occlusion. Number of episodes of ventricular fibrillation (VF) was 8 in the Control group versus 3 in the LL-CBS group (80% versus 30%, P<0.05). LL-CBS obviously increased high frequency (HF) component (P<0.05) and decreased low frequency/high frequency ratio (P<0.05) compared with the SHAM group. Ischemic size was not affected by LL-CBS between the two groups. CONCLUSIONS: LL-CBS reduced the occurrences of ventricular arrhythmias during acute ischemia without affecting blood pressure. The procedure was associated with changes of electrophysiological characteristics, nerve activity and heart rate variability. Therefore, LL-CBS may protect from ventricular arrhythmias during acute ischemic events by modulating ANS.
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Liao et al. (2014) conducted an RCT in Acute myocardial ischemia (n=20). Low-level carotid baroreceptor stimulation (LL-CBS) vs. Sham treatment (electrode implanted without stimulation) was evaluated on Incidence of ventricular fibrillation (VF) during 1 hour of LAD occlusion (p=<0.05). Low-level carotid baroreceptor stimulation significantly reduced the incidence of ventricular fibrillation to 30% compared to 80% in the sham group during acute ischemia in dogs.
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