ABSTRACT
Objective: To observe the influence of circumferential pulmonary vein isolation (CPVI) on P-wave polarity and amplitude and to investigate whether the changes of P-wave are associated with patient outcomes after initial CPVI. Methods Fifty patients with paroxysmal atrial fibrillation (AF) underwent CPVI. For each patient, electrocardiograph (ECG) recordings were taken before and 7 days after ablation. The P-wave polarities and amplitudes were analyzed. Successful CPVI was defined as freedom of symptomatic and asymptomatic AF at the end of two consecutive follow-ups. Results: The amplitude of positive P-wave was significantly decreased in the leads of I, II, III, aVF, V5, and V6 after ablation (P<0.05). The amplitude of negative P-wave was significantly decreased in the leads of aVR and aVF after ablation (P<0.05). The total amplitude of P-wave was significantly decreased in the leads of I, II, aVR, V5 and V6 after ablation (P<0.05). The negative P-wave in the lead of III and the positive P-wave in the lead of aVL were increased after ablation. The amplitudes of negative, positive and total P-waves before and after ablation were not significantly different between successful CPVI (n=39) and failure CPVI (n=11) groups. Conclusion: CPVI can result in noticeable reduction of P-wave amplitude in several leads of ECG, indicating the reduction of left atrial electric capacity. The changes of P-wave polarity indicate a P-wave vector shift. The reduction degree of P-wave amplitude has no predictive value for the success or failure of CPVI.
ABSTRACT
Objective To establish a multivariate reference range for ECG while considering the relation between multiple variables. Methods A total of 777 female undergraduates in a university were taken as the subjects and the P-wave amplitude was taken as an example to establish a multivariate reference range for P-wave amplitude by using Mahalanobis Depth Function. Results P-wave amplitude of the female undergraduates was established as follows, for a 95% CI of multivariate reference range,Depth≥0.035 521 6. Conclusion Multivariate reference range for ECG obtained in this study allows for a comprehensive utilization of the ECG data and can help the clinical diagnosis using ECG.
ABSTRACT
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.
Subject(s)
Humans , Atrioventricular Block , Electrocardiography , Electrodes , Electrophysiologic Techniques, Cardiac , Exercise Test , Follow-Up Studies , Motor Activity , Posture , Prospective Studies , Respiration , Sinoatrial NodeABSTRACT
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.