| Objectives: The aim of this study was to evaluate potential hemodynamic benefits of right ventricular outflow tract(RVOT) pacing by comparing with right ventricular apex(RVA) pacing, and to investigate safety and practicability of RVOT pacing with screw-in leads. Methods: Acute hemodynamic parameters were measured in 12 patients during pacing at RVA or RVOT sequently. Chronic hemodynamic findings were assessed by Doppler echocardiogram in 29 patients, 9 of whom received permanent pacing in right atrial appendage(RAA), 8 in RVOT, 12 in RVA. Data were collected 6.11 ?.01 538?.92 and 5.50 ?.88 months respectively after pacemakers implanted and pacing characteristics were also surveyed in this study. Results: Acute hemodynamic improvement was observed in RVOT pacing compared with RVA pacing: cardiac output(CO), cardiac index(CI) and systolic blood pressure(SBP) increased by 16.17%(6.37±1.13 vs 7.40±1.39L/min, p<0.05), 16.30%(3.68±0.61 vs 4.28±0.76 L/min in2, p<0.01) and 5.35%(124.58±20.94 vs 131.25±0.21mmHg. p<0.05), mean pulmonary aterial pressure(mPAP) and pulmonary capillary wedge pressure(PCWP) decreased by 15.31%(16.92±4.17 vs 14.33 ±3.28mmHg, p<0.01) and 27.80%(11.08±4.27 vs 8.00±3.36mmHg, p<0.01). To those who having mild left ventricle dysfunction, chronic findings indicated that hemodynamic parameters deteriorated in all pacing site. especially in RVA, but RVOT pacing, compared with RVA pacing, resulted in significant hemodynamic and clinical improvement. On the other hand, capture thresholds bad no significant difference between RVOT pacing and RVA pacing. No dislocation and damage of leads occurred in either RVOT or RVA, and all permanent pacemakers worked well both in the two ventricular pacing sites. Conclusions: To those who having mild left ventricular dysfunction, RVOT pacing may significantly improve both acute and chronic hemQdynamic parameters and clinical condition; RVOT pacing with screw-in lead is safe and practicable. |
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