VDD Pacemaker in an Unipolar Lead for Clinical Practice / 中国实用内科杂志

Objective To inquire into the forward clinical results of ventricular pacing, dual-chamber sensing, atrial-triggered, and ventricular-inhibited (VDD) Pacemaker in an unipolar lead.Methods 16 patients with the pacemaker were studied from 1993 to 2002, including 12 male patients and 4 female patients at 49 to 75 years old (average age 64 4 7 8 years old). They were in normal sinus rhythmia with complete or high degree atrial-ventricular block. Lead electrode was inserted through subclavian venous access, and the pacemaker was implanted in the same side as the electrode.Results All patients were followed up from 1 to 112 months (average 68 8 6 3 months) after pacemaker implantation. Their heart functions were improved, symptoms disappeared, life quality remarkably improved. Atrial sensing of VDD was good. One patient was died from coronary heart disease with heart failure by following up for 42 months, but the rest were healthy. Conclusions VDD pacemaker implantation was simple, easy to perform if its indication was appropriate. It could alleviate patients symptom and its therapy was effective. We should think highly of using VDD pacemaker, especially at poor region.

Clinical Investigation of P Wave Amplitude and Atrial Synchronous Ventricular Pacing in Different Body Position and Physical Activity with a Single-Pass Lead VDD Pacing

BACKGROUND: Single pass lead VDD pacing preserves atrioventricular synchrony with a single lead system which incorporates floating atrial electrodes. The objectives of this study were to measure whether different body postures and physical activities cause significant changes of the atrial electrogram amplitudes and to evaluate the effectiveness of its atrial sensing, ventricular sensing and pacing. METHOD: Prospective study was done in 7 patients with high degree AV block and normal sinus node function in whom a single lead VDD pacing system was implanted. The P wave amplitude was been measured in different condition during follow-up period. RESULTS: 1) During follow-up period, the P wave amplitude showed variation with changes in posture and respiration, but there was no consistent increase or decrease in amplitude. The lowest P wave amplitude was above the minimal atrial sensing value of 0.2 mV. 2) The percentage of atrial synchronous ventricular pacing recorded in Holter ECG and during Treadmill exercise test was more than 99%. 3) Atrial oversensing or VA cross sensing were not observed in any of the patients. CONCLUSIONS: Despite floating atrial electrode, the single pass lead VDD pacing maintains reliable atrial sensing and ventricular pacing in different body position and physical activity, so it may offer an excellent alternative in patients with high grade AV block and intact sinus node function.

Clinical Investigation of P Wave Amplitude and Atrial Synchronous Ventricular Pacing in Different Body Position and Physical Activity with a Single-Pass Lead VDD Pacing

BACKGROUND: Single pass lead VDD pacing preserves atrioventricular synchrony with a single lead system which incorporates floating atrial electrodes. The objectives of this study were to measure whether different body postures and physical activities cause significant changes of the atrial electrogram amplitudes and to evaluate the effectiveness of its atrial sensing, ventricular sensing and pacing. METHOD: Prospective study was done in 7 patients with high degree AV block and normal sinus node function in whom a single lead VDD pacing system was implanted. The P wave amplitude was been measured in different condition during follow-up period. RESULTS: 1) During follow-up period, the P wave amplitude showed variation with changes in posture and respiration, but there was no consistent increase or decrease in amplitude. The lowest P wave amplitude was above the minimal atrial sensing value of 0.2 mV. 2) The percentage of atrial synchronous ventricular pacing recorded in Holter ECG and during Treadmill exercise test was more than 99%. 3) Atrial oversensing or VA cross sensing were not observed in any of the patients. CONCLUSIONS: Despite floating atrial electrode, the single pass lead VDD pacing maintains reliable atrial sensing and ventricular pacing in different body position and physical activity, so it may offer an excellent alternative in patients with high grade AV block and intact sinus node function.