Protective effect of coronary sinus obstruction from primary ischemia-induced ventricular fibrillation in the dog

We examined whether partial coronary sinus obstruction affects the latency of the early ventricular fibrillation (VF) of acute ischemia. During baseline trials 15 of 19 open-chest dogs fibrillated repeatedly and predictably within 2 to 5 minutes (251.6 +/- 64 seconds) after reversible, double coronary artery occlusion without developing profound hemodynamic deterioration. The effect of partial coronary sinus obstruction sufficient to increase coronary sinus pressure to 40 mm Hg could be adequately tested in 11 dogs. Coronary sinus obstruction consistently prevented VF in five dogs, significantly prolonged the VF latency in three (p < 0.01 to p < 0.001), and had no clear effect in another three. The overall effect was significant at the p < 0.01 level. VF latency prolongation/prevention was also positively correlated to the residual coronary sinus pressure at the time of VF (r = 0.76; p < 0.008), as well as the baseline VF latency (r = 0.75; (p < 0.008). The protective effect of coronary venous hypertension most likely reflects preservation of adequate extracellular fluid in the ischemic region after the perfusion arrest. This extracellular fluid may constitute a key component in the prevention of early ischemic arrhythmias by preserving interstitial hydraulic continuity and tissue homogeneity through enhanced dilution and diffusion of solutes.