Cardiac Implantable Electronic Devices Following Heart Transplantation

Cardiac resynchronization therapy with conduction system pacing in a long-term heart transplant recipient: A case report

We performed cardiac resynchronization therapy by means of conduction system pacing in a heart transplant patient suffering from heart failure with reduced ejection fraction and atrial fibrillation with conduction disturbance (bifascicular block and QRS >160 ms). ECG monitoring showed paroxysmal atrioventricular block. Biventricular pacing was not feasible due to the absence of a suitable coronary sinus branch for pacing. His bundle pacing was performed, and an implantable cardioverter-defibrillator was implanted due to severe left ventricular dysfunction. Cardiac allograft vasculopathy was excluded. During follow-up, the patient's left ventricular function improved, and symptoms alleviated with a high percentage of ventricular stimulation.

Outcomes in orthotopic heart transplantation following pacemaker implantation

BACKGROUND

Bradyarrhythmias including sinus node dysfunction (SND) and atrioventricular block (AVB) can necessitate pacemaker (PPM) implantation in orthotopic heart transplant (OHT) recipients. Prior studies have shown conflicting findings regarding the effect of PPM implantation on survival. We evaluated the effect of PPM indication on long-term re-transplant-free survival in OHT patients.

METHODS

We conducted a retrospective cohort study of OHT patients at UCLA Medical Center from 1985 to 2018. Indication for PPM (SND, AVB) was identified. Cox proportional hazards model with pacemaker implantation as a time-varying covariate was used to evaluate its effect on the primary endpoint of retransplant or death. We included 1609 OHTs in 1511 adult patients with median follow-up of 12 years.

RESULTS

At transplant, patients were aged 53 ± 13 years and 1125 (74.5%) were male. Pacemakers were implanted in 109 (7.2%) patients; 65 for SND (4.3%) and 43 for AVB (2.8%). Repeat OHT was performed in 103 (6.4%) cases and 798 (52.8%) patients died during the follow-up period. The risk of the primary endpoint was significantly higher in patients requiring PPM for AVB (HR 3.0, 95% CI 2.1-4.2, p < .01) after controlling for age at OHT, gender, hypertension, diabetes, renal disease, history of repeat OHT, acute rejection, transplant coronary vasculopathy, and atrial fibrillation, but not PPM for SND (HR 1.0, 95% CI 0.70-1.4, p = 1.0).

CONCLUSIONS

Patients who required PPM for AVB, but not SND, were at significantly higher risk of death or retransplant compared to patients who did not require PPM.

Cardiac resynchronization therapy in an orthotopic heart transplant recipient

Although cardiac resynchronization therapy (CRT) is an established therapy in selected patients with heart failure with reduced ejection fraction (HFrEF), its role in orthotopic heart transplant (OHT) recipients remains understudied. We describe a case of successful CRT implantation in an OHT recipient for HFrEF and high-grade atrioventricular block. This case highlights the deliberations made given the lack of clinical trial and observational evidence for this therapy in OHT recipients.

Learning Objective

This case demonstrates the feasibility of cardiac resynchronization therapy (CRT) in an orthotopic heart transplant (OHT) recipient and adds to the scarcely reported data on the utility of CRT in this population. Given the exclusion of OHT recipients from the major CRT trials, further research is required to refine the indications for CRT implantation in this population.

Risk factors and outcomes of sudden cardiac arrest in pediatric heart transplant recipients

BACKGROUND

Sudden cardiac arrest (SCA) is a prevailing cause of mortality after pediatric heart transplant (HT) but remains understudied. We analyzed the incidence, outcomes, and risk factors for SCA at our center.

METHODS

Retrospective review of all pediatric HT patients at our center from January 1, 2009 to January 1, 2021. SCA was defined as an abrupt loss of cardiac function requiring cardiopulmonary resuscitation and/or mechanical circulatory support (MCS). Events that occurred in the setting of limited resuscitative wishes, or while on MCS were excluded. Patient characteristics and risk factors were analyzed.

RESULTS

Fourteen of 254 (6%) experienced SCA at a median of 3 (1, 4) years post-HT. Seven (50%) events occurred out-of-hospital. Eleven (79%) died from their initial event, 2 (18%) after failure to separate from extracorporeal membrane (ECMO). In univariate analysis, black race, younger donor age, prior acute cellular rejection (ACR) episode, pacemaker and/or ICD in place, and pre-mortem diagnosis of allograft vasculopathy were associated with SCA (P = .003-0.02). In multivariable analysis, history of ACR, younger donor age, and black race retained significance. [OR = 6.3, 95% CI: 1.6-25.4, P = .01], [OR = 0.9, 95% CI: 0.8-1, P = .04], and [OR = 7.3, 95% CI: 1.1-49.9, P = .04], respectively. SCA occurred in 3 patients with a functioning ICD or pacemaker, which failed to restore a perfusing rhythm.

CONCLUSIONS

SCA occurs relatively early after pediatric HT and is usually fatal. Half of events happen at home. Those who received younger donors, have a history of ACR, or are of black race are at increased risk. ICDs/pacemakers may offer limited protection.

Utilization of Implantable Cardioverter-Defibrillators in Patients With Heart Transplant (from National Inpatient Sample Database)

Heart transplant (HT) recipients represent a unique and vulnerable population in whom medium and long-term outcomes are significantly affected by the risk of arrhythmias and sudden cardiac death. The use of implantable cardioverter-defibrillators (ICDs) in this population remains debated. A retrospective analysis of the National Inpatient Sample data between 2009 and 2018 was conducted. Hospitalization data on patients who underwent HT, or who had a preexisting HT, and who received a new ICD were included (excluding the preexisting ICD). Outcomes assessed included inpatient mortality, length of stay, and inflation-adjusted costs. We explored temporal trends in ICD placement and mean length of stay, and predictors of ICD placement. Between 2009 and 2018, 22,673 hospitalizations were recorded for HT, during which patients either received a concurrent new ICD placement (n = 70 [0.31%]) or no new ICD placement (n = 22,603 [99.7%]). During the same period, 146,555 admissions were recorded in patients with a history of HT. ICD placement in patients with a preexisting HT was associated with significantly higher inflation-adjusted costs ($55,680.7 vs $17,219.2; p <0.001). Predictors of ICD placement in preexisting patients with HT included cardiac arrest during hospitalization (odds ratio [OR]:14.3 [3.5 to 58.6]), drug abuse (OR:6.0 [1.3 to 27.1]), and previous PCI (OR:6.0 [2.1 to 17.3]). In conclusion, ICD placement in patients with HT history was associated with significantly higher inflation-adjusted costs. In patients with HT history, factors predicting ICD placement included cardiac arrest at hospitalization, previous PCI, and drug abuse.

Implantable Cardioverter Defibrillators in Patients with Orthotopic Heart Transplant: A Multicenter Case Series

BACKGROUND

Sudden cardiac death (SCD) is common after orthotopic heart transplant (OHT). No clear guidelines for implantable cardioverter defibrillator (ICD) implantation in OHT patients at high risk for SCD currently exist.

OBJECTIVES

To assess the safety, efficacy, and benefit of ICDs and resynchronization therapy post-OHT. We also provide a systematic review of previous reports.

METHODS

A retrospective multicenter cohort study within the United States. Patients with ICD post-OHT between 2000 and 2020 were identified.

RESULTS

We analyzed 16 patients from 4 centers. The mean standard-deviation (SD) age was 43 (18) years at OHT and 51 (20) years at ICD implantation. The mean (SD) duration from OHT to ICD implantation was 9 (5) years. The mean (SD) left ventricular ejection fraction (LVEF) was 35% (17%). There were 2 (13%) post-procedural complications: 1 hematoma and 1 death. Mean (SD) follow-up was 24 (23) months. Survival rate was 63% (10/16) at 1 year and 56% (9/16) at 2 years, with 6/7 of those who died having LVEF < 35% at the time of the ICD implantation. Patients were more likely to receive appropriate therapy if their ICD was implanted for secondary (5/8) rather than primary (0/8) prevention (P = 0.007). Of those who did, 4 patients survived to 30 days post-ICD therapy. Severe CAV was not associated with the rate of appropriate therapy.

CONCLUSIONS

Beneficial outcomes were observed when ICDs were implanted for secondary prevention only, and in patients with higher baseline LVEF. We also observed benefits with resynchronization therapy. This article is protected by copyright. All rights reserved.