ABSTRACT
A consistent 12-lead electrocardiogram (ECG) morphology and characteristic frontal plane axis shift from sinus rhythm to ventricular tachycardia (VT) was demonstrated in 10 consecutive patients with idiopathic right ventricular outflow tract (RVOT) VT. All arrhythmias were successfully ablated on the septal side of the RVOT.
Subject(s)
Electrocardiography , Heart Septum/physiopathology , Pulmonary Valve/physiopathology , Tachycardia, Ventricular/physiopathology , Adult , Body Surface Potential Mapping , Bundle-Branch Block/physiopathology , Bundle-Branch Block/surgery , Cardiac Pacing, Artificial , Catheter Ablation , Coronary Angiography , Echocardiography , Female , Follow-Up Studies , Heart Rate , Heart Septum/surgery , Humans , Male , Middle Aged , Physical Exertion , Pulmonary Valve/surgery , Tachycardia, Ventricular/surgery , Ventricular Dysfunction, Right/physiopathology , Ventricular Dysfunction, Right/surgery , Ventricular Premature Complexes/physiopathology , Ventricular Premature Complexes/surgeryABSTRACT
The present commercial market supports many nonsteroidal endocardial pacing leads of differing construction. In order to compare the performance of these configurations, we studied the long-term pacing properties of three representative lead types by randomized clinical trial in 99 patients undergoing a first elective VVI implant. Thirty-one patients received sintered platinum leads, 36 activated pyrolytic carbon leads, and 32 vitreous carbon leads. All received generators capable of noninvasive threshold testing. Acute sensing parameters were R wave amplitude and ST segment elevation measured from the endocardial electrogram. Noninvasive voltage thresholds were measured at implantation, 2 days, 1, 3, and 6 months, and yearly thereafter for 5 years. There were no significant differences between leads in pacing or sensing capabilities at implantation. All three demonstrated similar increases in thresholds, peaking at 1 month, then falling to a plateau by 6 months and did not vary significantly thereafter. There were no significant differences in thresholds between leads during 5 years of follow-up. The lowest mean threshold at 5 years was 0.93 V at 0.5 ms. This study suggests that: (1) although these lead types all perform well, none offers any particular clinical advantage over another; (2) the degree of early threshold peaking precludes immediate postimplant output reduction, but later thresholds are sufficiently low to enable reductions in pacing output; (3) safe low energy pacing requires greater attention to the lead-generator combinations; (4) data obtained at subsequent annual follow-up provided no additional useful clinical information to that obtained at 1 year; and (5) in the absence of other differences, cost can be the deciding factor in lead selection.
