BackgroundThe effects of right ventricular apical pacing (RVAP) and right ventricular outflow tract (RVOT) septal pacing on atrial and ventricular electrophysiology have not been thoroughly compared.Methods and ResultsTo identify a more favorable pacing strategy with fewer adverse effects, 80 patients who had complete atrioventricular block with normal cardiac function and who were treated with either RVAP (n=42) or RVOT septal pacing (n=38) were recruited after an average of 2 years of follow‐up. The data from electrocardiography and echocardiography performed before pacemaker implantation and at the end of follow‐up were collected. The patients in the RVOT septal pacing and RVAP groups showed similar demographic and clinical characteristics before pacing treatments. After a mean follow‐up of 2 years, the final maximum P‐wave duration; P‐wave dispersion; Q‐, R‐, and S‐wave complex duration; left atrial volume index; left ventricular end‐systolic diameter; ratio of transmitral early diastolic filling velocity to mitral annular early diastolic velocity; and interventricular mechanical delay in the RVOT septal pacing group were significantly less than those in the RVAP group (P<0.05). The final left ventricular ejection fraction of the RVOT septal pacing group was significantly higher than that of the RVAP group (P<0.05).ConclusionsCompared with RVAP, RVOT septal pacing has fewer adverse effects regarding atrial electrical activity and structure in patients with normal cardiac function.
Heart rate acceleration capacity and deceleration capacity are independent risk factors for DCM, and acceleration capacity is a predictive factor for heart failure exacerbation in patients with DCM.
How deceleration capacity (DC) and acceleration capacity (AC) of heart rate associated with atrial fibrillation (AF) and ablation is still not clear. The dynamic changes of AC, DC and conventional heart rate variability (HRV) parameters were characterized in 154 subjects before circumferential pulmonary veins isolation (CPVI) and three days, 3 months and 6 months after CPVI. The DCs of the recurrent group decreased significantly at each time point after CPVI; the DCs of the recurrence-free group before CPVI and three days, 3 months and 6 months after CPVI were 7.06 ± 1.77, 3.79 ± 1.18, 4.22 ± 1.96 and 3.97 ± 0.98 ms respectively, which also decreased significantly at each time point and were significantly lower than these of recurrent group. Conversely, the AC of recurrent and recurrence-free groups increased significantly at each time point after CPVI; the ACs of recurrence-fee group were significantly higher than these of recurrent group at each time point. No stable difference trend of HRV parameters was found between two groups. Further Kaplan–Meier analysis showed that DC < 4.8 ms or AC ≥ −5.1 ms displayed significant higher recurrence-free rates. In conclusion, high AC and low DC imply higher AF-free rate after ablation.
ImportanceThe overall success rate of circumferential pulmonary vein isolation (CPVI) treatment in patients with paroxysmal atrial fibrillation (AF) remains suboptimal, especially in older patients.ObjectiveTo explore the incremental benefit of low-voltage-area ablation after CPVI in older patients with paroxysmal AF.Design, Setting, and ParticipantsThis randomized clinical trial was an investigator-initiated trial to compare the efficacy of additional low-voltage-area ablation beyond CPVI vs CPVI alone in older patients with paroxysmal AF. Participants were patients aged 65 to 80 years with paroxysmal AF who were referred for catheter ablation. They were enrolled in 14 tertiary hospitals in China from April 1, 2018, to August 3, 2020, and follow-up occurred through August 15, 2021.InterventionsPatients were randomized (1:1) to undergo CPVI plus low-voltage-area ablation or CPVI alone. Low-voltage areas were defined as areas with amplitude less than 0.5 mV in more than 3 adjacent points. If low-voltage areas existed, additional substrate ablation was performed in the CPVI plus group but not the CPVI alone group.Main Outcomes and MeasuresThe primary end point of the study was freedom from atrial tachyarrhythmia as documented by electrocardiogram during a clinical visit or lasting longer than 30 seconds during Holter recordings occurring after a single ablation procedure.ResultsAmong 438 patients who were randomized (mean [SD] age, 70.5 [4.4] years; 219 men [50%]), 24 (5.5%) did not complete the blanking period and were not included for efficacy analysis. After a median follow-up of 23 months, the recurrence rate of atrial tachyarrhythmia was significantly lower in the CPVI plus group (31/209 patients, 15%) compared with the CPVI alone group (49/205, 24%; hazard ratio [HR], 0.61; 95% CI, 0.38-0.95; P = .03). In subgroup analyses, among all patients with low-voltage area, CPVI plus substrate modification was associated with a 51% decreased risk of ATA recurrence compared with CPVI alone (HR, 0.49; 95% CI, 0.25-0.94; P = .03).Conclusions and RelevanceThis study found that additional low-voltage-area ablation beyond CPVI decreased the ATA recurrence in older patients with paroxysmal AF compared with CPVI alone. Our findings merit further replication by larger trials with longer follow-up.Trial RegistrationClinicalTrials.gov Identifier: NCT03462628
The effects of dilated cardiomyopathy (DCM) on cardiac autonomic regulation and electrophysiology, and the consequences of such changes, remain unclear. We evaluated the associations between heart rate acceleration capacity (AC) and deceleration capacity (DC), heart structural and functional changes, and cardiac death in 202 healthy controls and 100 DCM patients. The DC was lower and the AC was higher in DCM patients (both males and females). Multivariable, linear, logistic regression analyses revealed that in males, age was positively associated with AC in healthy controls (N = 85); the left atrial diameter (LAD) was positively and the left ventricular ejection fraction (LVEF) was negatively associated with AC in DCM patients (N = 65); age was negatively associated with DC in healthy controls (N = 85); and the LAD was negatively and the LVEF was positively associated with DC in DCM patients (N = 65). In females, only age was associated with either AC or DC in healthy controls (N = 117). Kaplan–Meier analysis revealed that male DCM patients with greater LADs (≥46.5 mm) (long-rank chi-squared value = 11.1, P = 0.001), an elevated AC (≥-4.75 ms) (log-rank chi-squared value = 6.8, P = 0.009), and a lower DC (≤4.72 ms) (log-rank chi-squared value = 9.1, P = 0.003) were at higher risk of cardiac death within 60 months of follow-up. In conclusion, in males, DCM significantly affected both the AC and DC; a higher AC or a lower DC increased the risk of cardiac death.
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