New Onset of Pacemaker Dependency After Permanent Pacemaker Implantation

Prognosis of pacing-dependent patients with cardiovascular implantable electronic devices

BACKGROUND

Data on the prognostic significance of pacing dependency in patients with cardiovascular implantable electronic devices (CIEDs) are sparse.

METHODS

The prognostic significance of pacing dependency defined as absence of an intrinsic rhythm ≥ 30 bpm was determined in 786 patients with CIEDs at the authors' institution using univariate and multivariate regression analysis to identify predictors of all-cause mortality.

RESULTS

During 49 months median follow-up, death occurred in 63 of 130 patients with pacing dependency compared to 241 of 656 patients without pacing dependency (48% versus 37%, hazard ratio [HR] 1.34; 95% confidence interval [CI]: 1.02-1.78, P = 0.04). Using multivariate regression analysis, predictors of all-cause mortality included age (HR 1.07; 95% CI: 1.05-1.08, P < 0.01), history of atrial fibrillation (HR 1.32, 95% CI: 1.03-1.69, P < 0.01), chronic kidney disease (HR 1.28; 95% CI: 1.00-1.63, P = 0.048) and New York Heart Association (NYHA) class ≥ III (HR 2.00; 95% CI: 1.52-2.62, P < 0.01), but not pacing dependency (HR 1.15; 95% CI: 0.86-1.54, P = 0.35).

CONCLUSIONS

In contrast to age, atrial fibrillation, chronic kidney disease and heart failure severity as indexed by NYHA functional class III or IV, pacing dependency does not appear to be an independent predictor of all-cause mortality in patients with CIEDs.

Increased Risk of Heart Failure in Elderly Patients Treated with Beta-Blockers After AV Node Ablation

INTRODUCTION

Controversy exists regarding the indication of beta-blockers (BB) in different scenarios in patients with cardiovascular disease. We sought to evaluate the effect of BB on survival and heart failure (HF) hospitalizations in a sample of pacemaker-dependent patients after AV node ablation to control ventricular rate for atrial tachyarrhythmias.

METHODS

A retrospective study including consecutive patients that underwent AV node ablation was conducted in a single center between 2011 and 2019. The study's primary endpoints were the incidence of all-cause mortality, first HF hospitalization and the cumulative incidence of subsequent hospitalizations for HF. Competing risk analyses were employed.

RESULTS

A total of 111 patients with a mean age of 73.9 years were included in the study. After a median follow-up of 45.5 months, 43 patients had died (38.7%) and 31 had been hospitalized for HF (27.9%). The recurrent HF hospitalization rate was 74/1000 patients/year. Patients treated with BB had a non-significant trend to higher mortality rates and a higher risk of recurrent HF hospitalizations (incidence rate ratio 2.23, 95% confidence interval 1.12-4.44; p = 0.023).

CONCLUSION

After an AV node ablation, the use of BB is associated with an increased risk of HF hospitalizations in a cohort of elderly patients.

Aortic Valve Calcification as a Predictor of Post-Transcatheter Aortic Valve Replacement Pacemaker Dependence

Background

Atrioventricular block requiring permanent pacemaker (PPM) implantation is a common complication of transcatheter aortic valve replacement (TAVR). The mechanism of atrioventricular (AV) block during TAVR is not fully understood, but it may be due to the mechanical stress of TAVR deployment, resulting in possible injury to the nearby compact AV node. Aortic valve calcification (AVC) may worsen this condition and has been associated with an increased risk for post-TAVR PPM implantation. We performed a retrospective analysis to determine if AVC is predictive for long-term right ventricular (RV) pacing in post-TAVR pacemaker patients at 30 days.

Methods

A total of 262 consecutive patients who underwent TAVR with a balloon-expandable valve were analyzed. AVC data were derived from contrast-enhanced computed tomography and characterized by leaflet sector and region.

Results

A total of 25 patients (11.1%) required post-TAVR PPM implantation. Seventeen patients did not require RV pacing at 30 days. Nine of these 17 patients had no RV pacing requirement within 10 days. The presence of intra-procedural heart block (P = 0.004) was the only significant difference between patients who did not require PPM and those who required PPM but they were not RV pacing-dependent at 30 days. Non-coronary cusp (NCC) calcium volume was significantly higher in patients who were pacemaker-dependent at 30 days (P = 0.01) and a calcium volume of > 239.2 mm³ in the NCC was strongly predictive of pacemaker dependence at 30 days (area under the curve (AUC) = 0.813). Pre-existing right bundle branch block (RBBB) (odds ratio (OR) 105.4, P = 0.004), bifascicular block (OR 12.5, P = 0.02), QRS duration (OR 70.43, P = 0.007) and intra-procedural complete heart block (OR 12.83, P = 0.03) were also predictive of pacemaker dependence at 30 days.

Conclusions

In patients who required PPM after TAVR, quantification of AVC by non-coronary leaflet calcium volume was found to be a novel predictor for RV pacing dependence at 30 days. The association of NCC calcification and PPM dependence may be related to the proximity of the conduction bundle to the non-coronary leaflet. Further studies are necessary to improve risk prediction for long-term RV pacing requirements following TAVR.

Permanent pacemaker implantation after cardiac surgery: Optimization of the decision making process

BACKGROUND

Conduction disturbances necessitating permanent pacemaker (PPM) implantation after cardiac surgery occur in 1% to 5% of patients. Previous studies have reported a low rate of late PPM dependency, but there is lack of evidence that it might be related to implantation timing. In this study, we sought to determine whether PPM implantation timing and specific conduction disturbances as indications for PPM implantation are associated with late pacemaker dependency and recovery of atrioventricular (AV) conduction.

METHODS

Patients with a PPM implanted after cardiac surgery were followed in an outpatient clinic. Two outcomes were assessed: AV conduction recovery and PPM dependency, defined as the absence of intrinsic rhythm on sensing test in VVI mode at 40 bpm.

RESULTS

Of 15,092 patients operated between September 2008 and March 2019, 185 (1.2%) underwent PPM implantation. One hundred seventy-seven of these patients met the criteria for inclusion into this study. Follow-up data were available in 145 patients (82%). Implantation was performed at ≤6 days after surgery in 58 patients (40%) and at >6 days after surgery in 87 patients (60%). The median time from implantation to last follow-up was 890 days (range, 416-1998 days). At follow-up, 81 (56%) patients were not PPM dependent. Multivariable analysis showed that PPM implantation at ≤6 days after surgery is a predictor of being not PPM dependent (odds ratio [OR], 5.40; 95% confidence interval [CI], 2.43-12.04; P < .001) and of AV conduction recovery (OR, 4.96; 95% CI, 2.26-10.91; P < .001). Sinus node dysfunction as indication for PPM implantation was predictive of being not PPM dependent (OR, 6.59; 95% CI, 1.67-26.06; P = .007).

CONCLUSIONS

We recommend implanting a PPM on postoperative day 7 to prevent unnecessary implantations and avoid prolonged hospitalization.

Predictors of pacing-dependency in patients with cardiovascular implantable electronic devices

BACKGROUND

Data on the prevalence and predictors for the development of pacing-dependency in patients with cardiovascular implantable electronic devices (CIEDs) are sparse.

METHODS

Pacing-dependency defined as an absence of intrinsic rhythm of ≥ 30 bpm was determined in 802 consecutive patients with CIEDs who visited the documented pacemaker or implantable cardioverter- defibrillator outpatient clinic for routine follow-up.

RESULTS

A total of 131 (16%) patients were found to be pacing-dependent 67 ± 70 months after CIED implant. Multivariate analysis revealed a significant association between pacing-dependency and the following clinical variables: second or third-degree atrioventricular (AV) block at implant (OR = 19.9; 95% CI: 10.9-38.5, p < 0.01), atrial fibrillation at implant (OR = 2.15; 95% CI: 1.16-4.05, p = 0.02), left ventricular ejection fraction (LVEF) ≤ 30% (OR = 2.06; 95% CI: 1.03-4.15, p = 0.04), B-type natriuretic peptide (BNP) > 150 pg/mL (OR = 2.12; 95% CI: 1.16-3.97, p = 0.02), chronic kidney disease (OR = 1.86; 95% CI: 1.08-3.26, p = 0.03), and follow-up duration after implantation > 5 years (OR = 3.29; 95% CI: 1.96-5.64, p < 0.01). None of the remaining clinical variables including age, gender, diabetes mellitus, underlying heart disease, prior cardiac surgery or medication during follow-up including betablockers and amiodarone predicted pacing-dependency.

CONCLUSIONS

Pacing-dependency is associated with second or third-degree AV-block at implant, atrial fibrillation before implant, low LVEF, elevated BNP, chronic kidney disease and follow-up duration after implant.

Stability of intrinsic rhythm in pacemaker-dependent patients during pacemaker replacement: Can we predict the need for temporary pacing?

BACKGROUND

In pacemaker-dependent patients, the risk of asystole must be managed during device replacement. This study aimed to examine whether we could predict the indication for temporary pacing (TP) during the generator replacement.

METHODS

We studied 105 consecutive patients who underwent pacemaker replacement due to battery depletion at Juntendo Nerima Hospital between September 2005 and December 2016. We examined the relationship between the stability of the intrinsic rhythm (IR) during pacemaker replacement and several clinical factors including age, gender, sick sinus syndrome or atrioventricular (AV) block, duration of pacing, structural heart disease, use of anti-arrhythmic drugs, and the presence/absence of a stable IR (>40 bpm) at the outpatient clinic (OPC) just before pacemaker replacement.

RESULTS

Of the 105 patients, we excluded 1 patient who required TP because of bradycardia-dependent torsades de points. Therefore, we evaluated 104 patients for the indication for TP. TP was underwent in 19 patients (18%) because of an absence or instability of the IR during pacemaker replacement. The indication for TP was significantly correlated with AV block (84% vs 48%, P = .0044) and the absence of a stable IR at the last OPC visit (89% vs 24%, P < .0001). For predicting the indication for TP, the following values of no stable IR at the last OPC visit were obtained: 89% sensitivity, 77% specificity, 46% positive predictive value, and 97% negative predictive value.

CONCLUSIONS

The presence of a stable IR at the last OPC visit was a good predictor (97%) of no indication for TP during pacemaker replacement.

Management of patients with cardiac implantable electronic devices (CIED) undergoing radiotherapy: A consensus document from Associazione Italiana Aritmologia e Cardiostimolazione (AIAC), Associazione Italiana Radioterapia Oncologica (AIRO), Associazione Italiana Fisica Medica (AIFM)

The management of patients with a cardiac implanted electronic device (CIED) receiving radiotherapy (RT) is challenging and requires a structured multidisciplinary approach. A consensus document is presented as a result of a multidisciplinary working group involving cardiac electrophysiologists, radiation oncologists and physicists in order to stratify the risk of patients with CIED requiring RT and approaching RT sessions appropriately. When high radiation doses and beam energy higher than 6MV are used, CIED malfunctions can occur during treatment. In our document, we reviewed the different types of RT and CIED behavior in the presence of ionizing radiations and electromagnetic interferences, from the cardiologist's, radiation oncologist's and medical physicist's point of view. We also reviewed in vitro and in vivo literature data and other national published guidelines on this issue so far. On the basis of literature data and consensus of experts, a detailed approach based on risk stratification and appropriate management of RT patients with CIEDs is suggested, with important implications for clinical practice.

Long-term Intrinsic Rhythm Evaluation in Dogs with Atrioventricular Block

Background

Atrioventricular block (AVB) is a conduction abnormality along the atrioventricular node that, depending on etiology, may lead to different outcomes.

Objectives

To evaluate variations of intrinsic rhythm (IR) in dogs that underwent pacemaker implantation (PMI).

Animals

Medical records of 92 dogs affected by 3rd degree atrioventricular block (3AVB), advanced 2nd degree AVB (2AVB), paroxysmal 3AVB, 2:1 2AVB, or 3AVB with atrial fibrillation (AF) were retrospectively reviewed.

Method

The patient IR was documented with telemetry on the day of 1 – (95% CI, 1–2), 33 – (95% CI, 28–35), 105 – (95%CI, 98–156), and 275 days (95%CI, 221–380) after PMI. According to AVB grade at different examinations, AVB was defined as progressed, regressed, or unchanged.

Results

In 48 dogs, 3AVB remained unchanged, whereas in 7 it regressed. Eight cases of 2AVB progressed, 3 regressed and 2 remained unchanged. Eight cases of paroxysmal 3AVB progressed and 3 remained unchanged. Four dogs affected by 2:1 2AVB progressed, 2 regressed, and 1 remained unchanged. All cases with 3AVB with AF remained unchanged. Regression occurred within 30 days after PMI, whereas progression was documented at any time. Variations in IR were associated with type of AVB (P < .03) and time of follow‐up (P < .0001).

Conclusions and clinical importance

The degree of AVB assessed at the time of PMI should not be considered definitive because more than one‐third of the cases in this study either progressed or regressed. Additional studies would be necessary to elucidate possible causes for transient AVB in dogs.

Predictors of pacemaker dependence and pacemaker dependence as a predictor of mortality in patients with implantable cardioverter defibrillator

BACKGROUND

The prevalence, predictors, and survival for the development of pacemaker dependence (PD) in patients implanted with an implantable cardioverter defibrillator (ICD) are unknown.

METHODS

This was a retrospective analysis of 1,550 consecutive patients with ICD implantation at a single center from 1996 to 2008 with a mean of 4.2 ± 3.4 years. Patients with implant intrinsic heart rates less than 40 beats/min (n = 48) and cardiac resynchronization therapy (n = 444) were excluded leaving 1,058 patients in this study. PD was defined as an intrinsic rhythm <40 beats/min after inhibiting the pacemaker, <50 beats/min with transient symptoms of dizziness relieved by resumption of pacing and right ventricle pacing despite algorithms to promote intrinsic conduction at the 3 monthly follow-up ICD clinic visits. Multivariate regression and Cox proportional hazard models were used for analysis.

RESULTS

The mean age was 64 ± 13 years; 79% were male with a primary indication for the ICD in 57%. PD occurred in 142 (13.4%) of patients, with a mean time to PD of 2.6 ± 1.9 years. PD was associated with a 48% increased odds for mortality versus non-PD ICD patients during the mean follow-up time of 4.2 ± 3.4 years (adjusted odds ratio = 1.48 [95% confidence interval 1.080-2.042]; P = 0.015). Older age, a history of atrial fibrillation, amiodarone use, and secondary prevention were the strongest predictors for the development of PD.

CONCLUSIONS

In this single-center ICD cohort, the development of PD was not uncommon and was associated with decreased survival.

Radiography of pacemakers and implantable cardioverter defibrillators

OBJECTIVE

The purpose of this article is to review the normal and abnormal radiographic appearances of cardiac pacemaker and implantable cardioverter defibrillator systems.

CONCLUSION

Chest radiographs showing pacemakers and implantable cardioverter defibrillators contain identifying and clinically relevant information, such as MRI compatibility and possible malfunction. Accurate and timely reporting of these features provides important information that can improve patient care.

Utility of isoproterenol in unmasking latent escape rhythm in pacemaker dependent patients undergoing pacemaker replacement

Pacemaker generator replacement in dependent patients may be managed with a bridging temporary pacing lead or by replacing the generator very expediently. The 2 options involve a small risk, and temporary pacing introduces additional cost. This study was conducted to explore the utility of a graduated rate-decrease protocol with isoproterenol support in unmasking an intrinsic rhythm that would obviate the 2 strategies. The protocol was used in 100 consecutive pacemaker-dependent patients (mean age 74.4 +/- 13.7 years, 56% men) who underwent permanent pacemaker replacement. Device lower rates were decremented in 1-minute intervals to 60, 50, 40, and 30 beats/min. If no intrinsic rhythm of > or =30 beats/min was observed after 1 minute, isoproterenol was infused at 1 microg/min for 2 minutes, followed by 2 microg/min for 2 minutes. Of the 100 patients, 59 demonstrated intrinsic rhythm during pacing step-down alone. Of the remaining 41 patients, 28 (68.3%) demonstrated intrinsic rhythm during isoproterenol infusion. The escape rhythm was junctional in 29%, idioventricular in 23%, conducted atrial fibrillation in 16%, and sinus in 15%. Only 13 of 100 patients (13%) failed to demonstrate adequate intrinsic rhythm after the protocol. In conclusion, this suggests that a standardized protocol to elicit an underlying rhythm in patients previously assessed as pacemaker dependent effectively minimizes the need for temporary pacing during device replacement.

Determinants of pacemaker dependency after coronary and/or mitral or aortic valve surgery with long-term follow-up

The aim of the present study was to investigate potential preoperative, operative, and postoperative predictors of pacemaker (PM) dependency after coronary, mitral valve, and aortic valve surgery. One hundred two patients (mean age 68 +/- 11 years; 62% men) who had received a permanent PM after cardiac surgery were included. The presence of any pacing activity in VVI mode with a lower rate of 30 beats/min was defined as PM dependency. Median time to PM implantation was 10 days after the index surgery. Pacemaker indications were atrioventricular block (AVB), sinus node dysfunction, and slow atrial fibrillation in 70%, 20%, and 11% of patients, respectively. At baseline, PM dependency rates were 0%, 9%, and 15% for patients with sinus node dysfunction, slow atrial fibrillation, and AVB, respectively (p = 0.158). Corresponding values at last follow-up were 15%, 9%, and 41% (p = 0.02). During long-term follow-up, new PM dependency developed in 21 patients (23%). Most patients had AVB as the PM indication (18 of 21 patients; 86%). Cumulative probabilities of freedom from PM dependency in patients with AVB were 63% and 30% at 5 and 10 years, respectively. Of several demographic, preoperative clinical, electrocardiographic, operative, and postoperative characteristics of patients, preoperative history of syncope (odds ratio [OR] 6.58, 95% confidence interval [CI] 1.11 to 38.87), body mass index >or=28.5 kg/m2 (OR 2.88, 95% CI 1.08 to 7.67), bypass time >or=105 minutes (OR 4.81, 95% CI 1.54 to 15.02), and AVB as PM indication (OR 5.14, 95% CI 1.51 to 17.44) were independent predictors of long-term PM dependency in multivariate logistic regression analysis. In conclusion, the long-term PM dependency rate was relatively high in patients with postoperative AVB requiring permanent PM implantation. A preoperative history of syncope, body mass index >or=28.5 kg/m2, bypass time of 105 minutes, and AVB as PM indication were independent predictors of long-term PM dependency after cardiac surgery.