The effects of QRS duration and pacing sites on the acute hemodynamic change during right ventricular pacing / 대한내과학회지

ABSTRACT

BACKGROUND: Intraventricular conduction disturbances, as manifested by increased QRS duration, are common in patients with advanced left ventricular (LV) dysfunction and adversely affect LV systolic and diastolic function. It has been reported that the patients with prolonged paced QRS duration have more serious heart disease, and the paced QRS duration can be a useful indicator of impaired LV function. Hemodynamic effects of paced QRS duration and pacing site during right ventricular (RV) pacing are unknown. METHODS: A total of 14 patients who underwent electrophysiologic study for paroxysmal supraventricular tachycardia at Chonnam National University Hospital were examined. All the patients had no structural heart disease. RV pacing was performed at 10 different sites with cycle length of 600 ms and 500 ms using a 6-7F deflectable quadripolar electrode catheter (Livewire, St. Jude Medical, Minneapolis, MN, USA). Systolic, diastolic, and mean blood pressures were measured after stabilization of blood pressure during pacing. RESULTS: Blood pressures (systolic/diastolic/mean) decreased from 146 +/- 31/95 +/- 28/125 +/- 23 mmHg to 128 +/- 33/80 +/- 25/107 +/- 20 mmHg, respectively. The change of QRS duration during pacing and the systolic blood pressure (SBP) before pacing were higher in the group with paced QRS duration greater than 140 msec (59.1 +/- 13.6 msec vs 84.9 +/- 18.7 msec, 141 +/- 30 mmHg vs 152 +/- 38 mmHg, p<0.001, p=0.011, respectively). The decrease of SBP during pacing was higher in the group with paced QRS duration greater than 140 msec (13 +/- 11 mmHg vs 24 +/- 14 mmHg, p=0.009). The decrease of SBP during pacing was related with QRS duration during pacing (r=0.500, p=0.001), the change of QRS duration during pacing (r=0.426, p=0.001), and SBP during sinus rhythm (r=0.342, p=0.001) on linear correlation analysis. Pacing site, however, did not affect acute hemodynamic change during pacing. The independent factors associated with the decrease of SBP during pacing were SBP before pacing and QRS duration during pacing. CONCLUSION: We concluded that acute deleterious hemodynamic effects of RV pacing are related with paced QRS duration but not with pacing site. Ventricuar pacing at the area of paced QRS duration less than 140 msec is recommended particularly in high risk patients.