Clinical outcomes in patients with atrioventricular block undergoing pacemaker: 3-year follow-up

PURPOSE

Left ventricular function can be affected by chronic ventricular pacing. Different right ventricular (RV) pacing sites have shown heterogeneous clinical outcomes. We investigated these factors in patients receiving permanent pacemaker (PPM) implants.

METHODS

This multicenter, retrospective analysis of PPM use in South Korea, included all patients undergoing de novo transvenous PPM implantation for atrioventricular block from 2017 to 2019. Clinical characteristics, 12-lead electrocardiograms, echocardiography, and laboratory parameters were evaluated. Composite outcomes are defined by two coprimary endpoints: (1) hospitalizations and (2) cardiac death by heart failure during follow-up period.

RESULTS

There were 167 patients (66 males; overall mean age 75.3 ± 11.9 years), divided into two groups according to the pacing site: 83 apical RV (RVA) vs. 84 septal RV (RVS). There were no significant baseline differences. Paced QRS duration (pQRSd) increased with RVA (168.5 ± 20.1 vs. 159.1 ± 16.3 ms; p < 0.001). Over a median 31-month follow-up, there were 15 hospitalizations and 2 deaths. More patients with RVA were hospitalized or died (16% vs. 5%, respectively; p = 0.049). In Cox proportional regression analysis, pQRSd (hazard ratio [HR] 1.046; 95% confidence interval [CI] 1.004-1.091; p = 0.033), and diastolic dysfunction (HR 7.343; 95% CI 2.035-26.494; p = 0.002) were independent predictors of composite clinical outcomes.

CONCLUSIONS

RVS placement shortened the pQRSd and improved clinical outcomes. However, the determinants of these were pQRSd and diastolic dysfunction. Therefore, clinicians should try to shorten the pQRSd when implanting a PPM, and patients with diastolic dysfunction should be monitored intensively.

Leadless pacing with Micra TPS: A comparison between right ventricular outflow tract, mid-septal, and apical implant sites

BACKGROUND

With its steerable transcatheter delivery system, the Micra can be deployed in nonapical positions within the right ventricle, potentially allowing reduction of the paced QRS width. We sought to evaluate the safety and long-term performance of the right ventricular outflow tract (RVOT) pacing using the Micra transcatheter pacing system (TPS). We also compared the paced QRS between RVOT, mid-septal, and apical implant positions.

METHODS

All patients who underwent a Micra TPS implantation at the University Hospitals of Leuven were enrolled in this observational study. Right ventricular (RV) position of the device was assessed on per-procedural ventriculography. Paced QRS was analyzed and follow-up completed at 1 month and then every 6 months.

RESULTS

Among the 133 patients included (mean follow-up: 13 ± 11 months), 45 were implanted in the RVOT, 58 midseptally, and 30 at the apex. All implant procedures were successful and no pericardial effusion was encountered within the 30 days post-implant. Two major complications were reported with devices implanted at the apex. Pacing impedance was significantly higher in the RVOT compared to the mid-septal and apical position (P < .001). Pacing threshold and R-wave amplitude did not differ over time in either position. The median narrowest paced QRS duration was observed in the RVOT (142 ms) compared to mid-septal (159 ms; P < .001), and apical position (181 ms; P < .001).

CONCLUSION

Implantation of the Micra TPS in the RVOT is safe and feasible. Electrical performance over time was comparable to mid-septal and apical positions. The narrowest paced QRS complexes is achieved with RVOT pacing.

Post-pacemaker implant QRS duration and heart failure admission in patients with sick sinus syndrome and complete atrioventricular block

AIMS

High demand right ventricular pacing may elicit left ventricular systolic dysfunction known as pacing-induced cardiomyopathy, increasing the risks of heart failure (HF) hospitalization. Percentage of demand ventricular pacing is different between patients with sick sinus syndrome (SSS) and those with complete atrioventricular block (CAVB). This study aims to compare the incidence of HF admission and pacing-induced cardiomyopathy between patients with SSS and CAVB.

METHODS AND RESULTS

A total of 824 patients who received single ventricular or dual-chamber pacemaker implantation at our hospital between January 2003 and December 2012 were recruited for the study. Patients with HF, those without complete cardiac echocardiography, and those with significant coronary artery disease were excluded. Finally, 315 patients with SSS and 289 patients with CAVB were enrolled in this study. The CAVB group had a higher pacing percentage (39.37 ± 9.17% vs. 83.82 ± 33.06%; P < 0.001), longer pacing QRS duration (142.56 ± 33.02 ms vs. 156.63 ± 25.18 ms; P < 0.001), and higher prevalence of follow-up left ventricular ejection fraction ≤40% (1.3% vs. 4.2%; P = 0.040). However, the incidence of HF admission was similar between the two groups (log-rank P = 0.647). Age [hazard ratio (HR), 95% confidence interval (CI): 1.121, 1.054-1.193], diabetes mellitus (HR, 95% CI: 2.667, 1.159-6.136), pacing QRS duration ≥163 ms (HR, 95% CI: 3.506, 1.491-8.247), and left atrial size (HR, 95% CI: 1.070, 1.012-1.131) were independent predictors of HF admission. The Kaplan-Meier curve showed a significant difference in HF admission over a 3.5 year follow-up period (3.5 years: P value = 0.004; 5 years: P value = 0.002) between patients with pacing QRS duration ≥163 and <163 ms.

CONCLUSIONS

There was no difference in HF admission between patients with SSS and CAVB, although the CAVB group had a higher pacing percentage. Post-pacemaker implant pacing QRS duration ≥163 ms was the most important predictor of HF admission.

Correlation of pacing site in right ventricle with paced QRS complex duration

Background

Pacing from RV mid septum and outflow tract septum has been proposed as a more physiological site of pacing and narrower paced QRS complex duration. The paced QRS morphology and duration in different RV pacing sites is under continued discussion. Hence, this study was designed to address the correlation of pacing sites in right ventricle with paced QRS complex duration.

Methods

Two hundred fifty-two consecutive patients who underwent pacemaker implantation were enrolled. Baseline clinical characteristics were recorded for each patient. All patient underwent fluoroscopy, electrocardiogram and echocardiography post pacemaker implantation. Paced QRS duration was calculated from the leads with maximum QRS duration.

Results

Mean paced QRS (pQRS) duration was significantly higher in apical septum group with a mean of 148.9 ± 14.8 m s compared to mid septum (139.6 ± 19.9 m s; p-value 0.003) and RVOT septum (139.6 ± 14.8 m s; p-value 0.002) groups, respectively. There was no significant difference between mid-septal and RVOT septal pQRS duration. On multivariate analysis, female gender, baseline QRS duration and RVOT septal pacing were the only predictors for narrow pQRS duration (<150 msec).

Conclusion

RV mid-septal and RVOT septal pacing were associated with significantly lower pQRS duration as compared with apical pacing. Based on multivariate analysis RVOT septal pacing appears to be preferred and more physiological pacing site.

Paced QRS duration predicts left ventricular function in patients with permanent pacemakers - One-year follow-up study using equilibrium radionuclide angiography (ERNA)

Permanent pacing, being non physiological, often results in ventricular dysfunction over time. Narrower paced QRS duration from pacing the right ventricular outflow tract septum, might result in relatively preserved ventricular function over long term follow up.

Medium-term effects of septal and apical pacing in pacemaker-dependent patients: a double-blind prospective randomized study

BACKGROUND

Pacing the right ventricle is established practice, but there remains controversy as to the optimal site to preserve hemodynamic function.

AIMS

To evaluate clinical and hemodynamic differences between apical and septal pacing in pacemaker-dependent patients.

METHODS

Patients receiving their first pacemaker for advanced atrioventricular block, with the atria in sinus rhythm, were randomized to receive apical (Group A) or septal (Group S) ventricular leads. After implant, with the device programmed VVI 70 beats/min fixed rate, patients underwent a 6-minute walk test and a transthoracic echocardiogram. Then, DDDR was programmed at nominal settings. The same tests were performed at 6 months and 12 months follow-up. If ventricular pacing was less than 98%, the patient was excluded.

RESULTS

A total of 142 patients were included in the study. During the study year, 71 (50%) were excluded for not fulfilling the condition of 98% ventricular pacing. Groups A and S had 34 and 37 patients, respectively. Age and gender were similar in the groups. At implant, QRS duration was significantly greater in Group A (158 ms) than Group S (146 ms; P = 0.018), and the QRS axis was different: -74.5° in Group A and 1° in Group S (P < 0.001). At 1 year, the 6-minute walk improved significantly in both groups: Group A 15% (P = 0.048) and Group S 24% (P = 0.001). Left ventricular ejection fraction (LVEF) increased from 0.57 to 0.61 (P = 0.008) in Group S, without significant change in Group A.

CONCLUSIONS

After 1 year, pacemaker-dependent patients with septal ventricular leads have better clinical and functional (LVEF) outcome.

Paced QRS duration as a predictor for clinical heart failure events during right ventricular apical pacing in patients with idiopathic complete atrioventricular block: results from an observational cohort study (PREDICT-HF)

AIMS

The aim of this study was to investigate the predictive ability of paced QRS duration (pQRSd) for heart failure events among patients receiving right ventricular apical pacing (RVAP).

METHODS AND RESULTS

A total of 194 patients with complete atrioventricular block receiving pacemaker treatment were enrolled and stratified to group 1, pQRSd < 160 ms, n = 53; group 2, 160 ≤ pQRSd < 190 ms, n = 97; and group 3, pQRSd ≥ 190 ms, n = 44. Study outcomes were heart failure events, changes in pQRSd, and changes in left ventricular ejection fraction (LVEF). During the 3-year follow-up, the incidence of heart failure events was 9.4, 27.8, and 56.8% in groups 1, 2, and 3, respectively (P < 0.001). Among the patients without heart failure events, the pQRSd at 3 years remained longer than that at baseline (162.1 ± 22.6 vs. 160.9 ± 22.1 ms, P < 0.05), whereas among patients who experienced heart failure events, the prolonged pQRSd at 3 years seemed more pronounced as compared with baseline (184.1 ± 21.1 vs. 179.8 ± 21 ms, P < 0.001). Linear regression demonstrated that a decrease in LVEF was positively correlated with pQRSd over time (relative risk 0.423; P < 0.05). The receiver operating charactersitic curve showed that the cut-off value of pQRSd was 165 ms with a sensitivity of 0.789.

CONCLUSION

A prolonged pQRSd has a detrimental effect on long-term cardiac function during RVAP in patients with complete atrioventricular block. pQRSd could be a useful predictor to identify patients who are at risk for heart failure events during RVAP.