[Electrophysiological, hemodynamic and histological effects of fulguration on the ventricular myocardium in the dog]

The myocardial repercussions of endocavitary fulguration depend upon the interaction of different physical phenomena. We studied the influence of energy level on the one hand and of the physical properties of the catheter (Ct) on the other hand on the cardiac effects of right endoventricular fulguration in the dog. A monopolar anodal shock was delivered in 12 dogs. Two levels of energy were applied: 25 J (group A, n = 6) and 100 J (group B, n = 6), and three Ct were used which differed in resistance (R) and active surface (S): Ct 1 (R = 0.3 omega, S = 12 mm2), Ct 2 (R = 0.3 omega, S = 2 mm2) and Ct 3 R = 2 omega, S = 13 mm2). Immediately after fulguration a significant rise of the right ventricular effective refractory periods was observed in group B only (193 +/- 28 vs 174 +/- 19 ms; p less than 0.03). Compared to baseline values, the systolic and diastolic pressures fell by 12% (p less than 0.01) and 18% (p less than 0.01) respectively in group A and by 33% (p less than 0.05) and 34% (p less than 0.002) respectively in group B. In contrast, there was no significant difference between variations of these parameters with the three types of Ct. The incidence of complex ventricular arrhythmia was higher in group B (5/6) than in group A (1/6).(ABSTRACT TRUNCATED AT 250 WORDS)