Differences of hemodynamic changes during supraventricular tachycardias: simulation of AVRT and AVNRT in dogs

Cho, Eun Ju; Kim, Jae Hyung; Rho, Tai Ho; Jin, Seung Won; Kim, Hee Yeol; Lee, Man Young; Kim, Chong Jin; Chae, Jang Seong; Hong, Soon Jo; Choi, Kyu Bo

Abstract

BACKGROUND
Tachyarrhythmias have various clinical features according to their tachycardia rates, systolic function of the left ventricle, the origin site and the mechanisms. Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) might cause different hemodynamic changes due to their different mechanisms.
METHODS
To evaluate the hemodynamic differences of supraventricular tachycardias, atrial tachycardia (atrial pacing with AOO mode, 180/min, group I), AVRT (VA pacing interval 80 msec with DOO mode, 180/min, group II) and AVNRT (VA pacing interval 0 msec, 25 msec with DOO mode, 180/min, group III) were simulated in eleven dogs. Hemodynamic parameters were systemic arterial pressure including systolic, mean and diastolic arterial pressure (SAP, MAP, DAP respectively), mean pulmonary arterial wedge pressure (MPAWP) and cardiac output (CO).
RESULTS
The MAP was highest in group I (87.0+/-20.4 mmHg) and decreased with decreasing VA interval of no significance. The SAP was higher in group II (109.8+/-22.6 mmHg) than in group III (95.3+/-27.1 mmHg) (p<0.05). The level of MPAWP had no significant differences among three groups and showed no peculiar pattern with changes of VA interval. The CO was higher in group I (1.18+/-0.32 L/min) than in other two groups with significant difference (p<0.01) and decreased with shortening of VA interval without significance.
CONCLUSION
Above results suggested that the AVRT and AVNRT have different effects on hemodynamic changes, those from different timing of atrial contraction, especially on SAP and CO. So hemodynamic compromise during tachycardia could be more severe in AVNRT than in AVRT inspite of their similar QRS morphology and tachycardia rate.