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Implantable cardioverter-defibrillators in a heart transplant population: A single-center experience
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RESEARCH CORRESPONDENCE Implantable cardioverter-defibrillators in a heart transplant population: A single-center experience
Table 1 ICD
Antoinette Neylon, MB, BCh, Carla Canniffe, MB, BCh, Barbara Parlon, RGN, Niall Mahon, MD, and James O. O’Neill, MD
Sex Male Female Reason for transplant DCM Ischemic CM Myocarditis Mean age OHT Time OHT to ICD LVEF at implant
From the Mater Misericordiae Hospital, Dublin, Ireland
The use of implantable cardiac defibrillators (ICDs) for the prevention of sudden cardiac death (SCD) in patients with ischemic and non-ischemic cardiomyopathies is well described. However, little is known about the role these devices might play in the prevention of SCD in orthotopic heart transplant (OHT) recipients. Nevertheless, in some transplant centers, 1.5% to 2% of recipients receive ICD implants for the prevention of SCD.1,2 Sudden death after transplant is common, with estimates suggesting SCD is the mode of death in up to 35% of recipients.3 In a population of patients with heart failure, almost all arrhythmic deaths are a result of ventricular tachyarrhythmia, whereas in the transplant population the most commonly described terminal arrhythmias are asystole and electromechanical dissociation (EMD).3 As outcomes continue to improve after OHT, the natural history of arrhythmia occurrence in these patients is changing. Therefore, we describe our experience of ICD implants in a heart transplant population. Our report summarizes all adult OHT recipients who had ICDs implanted for the prevention of SCD. ICD implantation was deemed appropriate if the patient was considered at high risk for SCD by at least 2 experienced clinicians. High-risk features included angiographic severity of cardiac allograft vasculopathy (CAV), ejection fraction, previously documented ventricular arrhythmias, and prior unexplained syncope. Outcome data on death and retransplantation were also collected. Between 1983 and 2012, 296 transplants were performed, and of these patients, 10 (3.4%) had an ICD inserted after transplantation. All patients had devices for primary prevention of SCD. Table 1 summarizes the baseline characteristics of the patients, and electrocardiogram findings are presented in Table 2. All patients who underwent ICD insertion had survived 410 years after transplant. The mean age at OHT was 39 ⫾ 14.2 years. Mean time from OHT to ICD was 16 ⫾ 6 years.
Baseline Characteristics of OHT Patients Receiving
Variable
No. patients (%) 8 (80%) 2 (20%) 5 4 1 39 years (⫾ 14.2 years) 16 ⫾ 6 years 49% (⫾ 12%)
CM, cardiomyopathy; DCM, dilated cardiomyopathy; ICD, implantable cardiac defibrillator; LVEF, left ventricular ejection fraction; OHT, orthotopic heart transplant.
The indications for ICD insertion were severe CAV in 8 patients and sustained ventricular tachycardia in 2 patients. Before device insertion, 2 patients had experienced unexplained syncope. Table 3 summarizes the individual indications for ICD and subsequent events. The mean follow-up after device implantation was 29 ⫾ 12 months. One patient had successful anti-tachycardia pacing (ATP) for ventricular tachycardia 13 months after ICD implantation. One patient died of SCD. Post-mortem device interrogation showed ventricular fibrillation, appropriately shocked by the device with the restoration of sinus rhythm; however, subsequent EMD resulted in death. This patient (patient 5) had been listed for retransplantation on the basis of severe symptomatic diastolic dysfunction and CAV. Also, this patient had defibrillation threshold testing at the time of ICD implantation with no adverse clinical sequelae. At routine follow-up, 1 patient had a 6-beat run of ventricular tachycardia monitored. To date, there have been no complications or infections associated with ICD insertion, and there have been no inappropriate device therapies delivered. Heart transplantation has become the most effective treatment for end-stage heart disease. Improvements in surgical technique, immunosuppression, and patient monitoring have yielded 1-year survival rates of almost 90% and 10-year survival of 450%. The mortality in the later years after transplant is about 4% per year, and this is significantly higher than the age-matched general population. SCD after transplant is a major contributor to this higher mortality.
1053-2498/$ - see front matter r 2016 International Society for Heart and Lung Transplantation. All rights reserved. http://dx.doi.org/10.1016/j.healun.2015.12.011
The Journal of Heart and Lung Transplantation, Vol ], No ], Month ]]]]
2 Table 2
ECG Findings of Individual Patients
Patient
Rate
Rhythm
P–R interval (msec)
QRS interval (msec)
ECG findings
1 2 3 4 5 6 7 8 9 10
107 67 86 80 90 78 104 93 65 75
Sinus Sinus Sinus Sinus Sinus Sinus Sinus Sinus Sinus AF
202 194 146 232 350 160 158 176 182 NA
96 152 100 104 100 120 90 94 100 160
RBBB, non-specific ST segment changes RBBB, LAD RBBB, anterior TWI LAE, PRWP Non-specific ST segment changes RBBB RAD, PRWP, anterior TWI RBBB, LAD, PRWP No specific abnormality RBBB, non-specific ST segment changes
AF, atrial fibrillation; ECG, electrocardiogram; LAD, left axis deviation; LAE, left atrial enlargement; NA, not available; PRWP, poor R-wave progression; RAD, right axis deviation; RBBB, right bundle branch block; TWI, T-wave inversion.
made us wary of routine defibrillation threshold testing after implantation, as the induction of ventricular fibrillation and subsequent defibrillation could deteriorate to EMD and lead to the death of a patient presenting for an elective medical procedure. In patients without transplants, the value of routine defibrillation threshold testing has been called into question because of the small but measurable risk of complications. In 2009, a US national survey of ICDs in transplant recipients identified 44 patients who had received defibrillators.6 The appropriate shock rate was 13.6% with an inappropriate shock rate of 6.8%. At follow-up, 32% of patients had died from other causes, including heart failure, arrhythmia, rejection, and renal failure. The survey also examined physician’s opinions regarding future trends for ICD therapies. Device therapy as a bridge to retransplantation was cited by 46.4% of respondents as a reason that device use will increase over the next 5 years. Although the benefit of ICD therapy in patients waiting for a first transplant is proven, there are no data to suggest a similar benefit in the case of retransplantation. In our experience and in the cases reported by Marzoa-Rivas et al,5 EMD was the terminal event in the patients awaiting re-transplantation, suggesting that ICD therapy in this select cohort may not be advantageous. In conclusion, the use of ICDs in patients with remote OHT remains subject to analysis and is as yet unproven.
In a retrospective analysis of modes of death in 194 HT recipients, Vaseghi et al3 identified 41 sudden deaths; terminal rhythms were available in 26 of these. Asystole was the most common rhythm (34%), followed by pulseless electrical activity (20%) and ventricular fibrillation (10%). This study may suggest that denervation of the donor heart can alter susceptibility to ventricular tachyarrhythmias and reduce the potential mortality benefit of ICDs in this unique cohort of patients. CAV has emerged as the primary cause of late graft failure and death. Heart transplant recipients with significant ventricular dysfunction and CAV have the highest risk of SCD.2,3 CAV may lead to ischemia, infarction, and left ventricular dysfunction, acting as a substrate for ventricular arrhythmias. Higher grades of CAV have also been associated with longer Q–Tc intervals, which have independently been shown to be a predictor of sudden cardiac death. Cogert et al4 reported sudden death of 2 OHT patients with severe CAV within 4 months of ICD placement. In 2 further descriptions of sudden deaths in OHT patients with severe CAV and functioning ICDs by Marzoa-Rivas et al,5 EMD was revealed as the terminal rhythm. In our cohort, there was 1 SCD. Although the initial event was ventricular fibrillation, which was appropriately detected and defibrillated by the device, subsequent EMD resulted in death. This event has
Table 3
Patient Patient Patient Patient Patient Patient Patient Patient Patient Patient
Individual Indications for ICD and Subsequent Events
1 2 3 4 5 6 7 8 9 10
Grade CAVa
LVEF (%)
PCI
OHT to PCI (years)
Syncope
NSVT
ICD Events
3 2 3 1 3 3 3 3 3 3
45 35 55 40 40 65 60 55 60 35
No No Yes No No No No No Yes No
0 0 7 0 0 0 0 0 14 0
No No No No Yes No No Yes No No
No No No Yes No No No Yes No No
None ATP for VT None VT monitored Shock VF—EMD None None None None None
ATP, anti-tachycardia pacing; CAV, cardiac allograft vasculopathy; EMD, electromechanical dissociation; ICD, implantable cardiac defibrillator; LVEF, left ventricular ejection fraction; NSVT, non-sustained ventricular tachycardia; OHT, orthotopic heart transplant; PCI, percutaneous coronary intervention; VF, ventricular fibrillation; VT, ventricular tachycardia. a 0 ¼ not significant; 1 ¼ mild; 2 ¼ moderate; 3 ¼ severe.
Research Correspondence Routine defibrillation threshold testing at implantation may be inappropriate. The use of ICDs as a bridge to retransplantation may not be beneficial.
Disclosure statement None of the authors has a financial relationship with a commercial entity that has an interest in the subject of the presented manuscript or other conflicts of interest to disclose.
References 1. Tsai VW, Cooper J, Garan H, et al. The efficacy of implantable cardioverter-defibrillators in heart transplant recipients: results from a multicenter registry. Circ Heart Fail 2009;2:197-201.
3 2. Ptaszek LM, Wang PJ, Hunt SA, Valantine H, Perlroth M, Al-Ahmad A. Use of the implantable cardioverter-defibrillator in long-term survivors of orthotopic heart transplantation. Heart Rhythm 2005;2: 931-3. 3. Vaseghi M, Lellouche N, Ritter H, et al. Mode and mechanisms of death after orthotopic heart transplantation. Heart Rhythm 2009; 6:503-9. 4. Cogert GA, Shivkumar K, Patel JK, et al. Implantable cardioverter defibrillators in heart transplant patients at risk for sudden death: shocking news? J Heart Lung Transplant 2003;22:S178-9. 5. Marzoa-Rivas R, Perez-Alvarez L, Paniagua-Martin MJ, et al. Sudden cardiac death of two heart transplant patients with correctly functioning implantable cardioverter defibrillators. J Heart Lung Transplant 2009;28:412-4. 6. McDowell DL, Hauptman PJ. Implantable defibrillators and cardiac resynchronization therapy in heart transplant recipients: results of a national survey. J Heart Lung Transplant 2009;28:847-50.
RESEARCH CORRESPONDENCE Implantable cardioverter-defibrillators in a heart transplant population: A single-center experience
Table 1 ICD
Antoinette Neylon, MB, BCh, Carla Canniffe, MB, BCh, Barbara Parlon, RGN, Niall Mahon, MD, and James O. O’Neill, MD
Sex Male Female Reason for transplant DCM Ischemic CM Myocarditis Mean age OHT Time OHT to ICD LVEF at implant
From the Mater Misericordiae Hospital, Dublin, Ireland
The use of implantable cardiac defibrillators (ICDs) for the prevention of sudden cardiac death (SCD) in patients with ischemic and non-ischemic cardiomyopathies is well described. However, little is known about the role these devices might play in the prevention of SCD in orthotopic heart transplant (OHT) recipients. Nevertheless, in some transplant centers, 1.5% to 2% of recipients receive ICD implants for the prevention of SCD.1,2 Sudden death after transplant is common, with estimates suggesting SCD is the mode of death in up to 35% of recipients.3 In a population of patients with heart failure, almost all arrhythmic deaths are a result of ventricular tachyarrhythmia, whereas in the transplant population the most commonly described terminal arrhythmias are asystole and electromechanical dissociation (EMD).3 As outcomes continue to improve after OHT, the natural history of arrhythmia occurrence in these patients is changing. Therefore, we describe our experience of ICD implants in a heart transplant population. Our report summarizes all adult OHT recipients who had ICDs implanted for the prevention of SCD. ICD implantation was deemed appropriate if the patient was considered at high risk for SCD by at least 2 experienced clinicians. High-risk features included angiographic severity of cardiac allograft vasculopathy (CAV), ejection fraction, previously documented ventricular arrhythmias, and prior unexplained syncope. Outcome data on death and retransplantation were also collected. Between 1983 and 2012, 296 transplants were performed, and of these patients, 10 (3.4%) had an ICD inserted after transplantation. All patients had devices for primary prevention of SCD. Table 1 summarizes the baseline characteristics of the patients, and electrocardiogram findings are presented in Table 2. All patients who underwent ICD insertion had survived 410 years after transplant. The mean age at OHT was 39 ⫾ 14.2 years. Mean time from OHT to ICD was 16 ⫾ 6 years.
Baseline Characteristics of OHT Patients Receiving
Variable
No. patients (%) 8 (80%) 2 (20%) 5 4 1 39 years (⫾ 14.2 years) 16 ⫾ 6 years 49% (⫾ 12%)
CM, cardiomyopathy; DCM, dilated cardiomyopathy; ICD, implantable cardiac defibrillator; LVEF, left ventricular ejection fraction; OHT, orthotopic heart transplant.
The indications for ICD insertion were severe CAV in 8 patients and sustained ventricular tachycardia in 2 patients. Before device insertion, 2 patients had experienced unexplained syncope. Table 3 summarizes the individual indications for ICD and subsequent events. The mean follow-up after device implantation was 29 ⫾ 12 months. One patient had successful anti-tachycardia pacing (ATP) for ventricular tachycardia 13 months after ICD implantation. One patient died of SCD. Post-mortem device interrogation showed ventricular fibrillation, appropriately shocked by the device with the restoration of sinus rhythm; however, subsequent EMD resulted in death. This patient (patient 5) had been listed for retransplantation on the basis of severe symptomatic diastolic dysfunction and CAV. Also, this patient had defibrillation threshold testing at the time of ICD implantation with no adverse clinical sequelae. At routine follow-up, 1 patient had a 6-beat run of ventricular tachycardia monitored. To date, there have been no complications or infections associated with ICD insertion, and there have been no inappropriate device therapies delivered. Heart transplantation has become the most effective treatment for end-stage heart disease. Improvements in surgical technique, immunosuppression, and patient monitoring have yielded 1-year survival rates of almost 90% and 10-year survival of 450%. The mortality in the later years after transplant is about 4% per year, and this is significantly higher than the age-matched general population. SCD after transplant is a major contributor to this higher mortality.
1053-2498/$ - see front matter r 2016 International Society for Heart and Lung Transplantation. All rights reserved. http://dx.doi.org/10.1016/j.healun.2015.12.011
The Journal of Heart and Lung Transplantation, Vol ], No ], Month ]]]]
2 Table 2
ECG Findings of Individual Patients
Patient
Rate
Rhythm
P–R interval (msec)
QRS interval (msec)
ECG findings
1 2 3 4 5 6 7 8 9 10
107 67 86 80 90 78 104 93 65 75
Sinus Sinus Sinus Sinus Sinus Sinus Sinus Sinus Sinus AF
202 194 146 232 350 160 158 176 182 NA
96 152 100 104 100 120 90 94 100 160
RBBB, non-specific ST segment changes RBBB, LAD RBBB, anterior TWI LAE, PRWP Non-specific ST segment changes RBBB RAD, PRWP, anterior TWI RBBB, LAD, PRWP No specific abnormality RBBB, non-specific ST segment changes
AF, atrial fibrillation; ECG, electrocardiogram; LAD, left axis deviation; LAE, left atrial enlargement; NA, not available; PRWP, poor R-wave progression; RAD, right axis deviation; RBBB, right bundle branch block; TWI, T-wave inversion.
made us wary of routine defibrillation threshold testing after implantation, as the induction of ventricular fibrillation and subsequent defibrillation could deteriorate to EMD and lead to the death of a patient presenting for an elective medical procedure. In patients without transplants, the value of routine defibrillation threshold testing has been called into question because of the small but measurable risk of complications. In 2009, a US national survey of ICDs in transplant recipients identified 44 patients who had received defibrillators.6 The appropriate shock rate was 13.6% with an inappropriate shock rate of 6.8%. At follow-up, 32% of patients had died from other causes, including heart failure, arrhythmia, rejection, and renal failure. The survey also examined physician’s opinions regarding future trends for ICD therapies. Device therapy as a bridge to retransplantation was cited by 46.4% of respondents as a reason that device use will increase over the next 5 years. Although the benefit of ICD therapy in patients waiting for a first transplant is proven, there are no data to suggest a similar benefit in the case of retransplantation. In our experience and in the cases reported by Marzoa-Rivas et al,5 EMD was the terminal event in the patients awaiting re-transplantation, suggesting that ICD therapy in this select cohort may not be advantageous. In conclusion, the use of ICDs in patients with remote OHT remains subject to analysis and is as yet unproven.
In a retrospective analysis of modes of death in 194 HT recipients, Vaseghi et al3 identified 41 sudden deaths; terminal rhythms were available in 26 of these. Asystole was the most common rhythm (34%), followed by pulseless electrical activity (20%) and ventricular fibrillation (10%). This study may suggest that denervation of the donor heart can alter susceptibility to ventricular tachyarrhythmias and reduce the potential mortality benefit of ICDs in this unique cohort of patients. CAV has emerged as the primary cause of late graft failure and death. Heart transplant recipients with significant ventricular dysfunction and CAV have the highest risk of SCD.2,3 CAV may lead to ischemia, infarction, and left ventricular dysfunction, acting as a substrate for ventricular arrhythmias. Higher grades of CAV have also been associated with longer Q–Tc intervals, which have independently been shown to be a predictor of sudden cardiac death. Cogert et al4 reported sudden death of 2 OHT patients with severe CAV within 4 months of ICD placement. In 2 further descriptions of sudden deaths in OHT patients with severe CAV and functioning ICDs by Marzoa-Rivas et al,5 EMD was revealed as the terminal rhythm. In our cohort, there was 1 SCD. Although the initial event was ventricular fibrillation, which was appropriately detected and defibrillated by the device, subsequent EMD resulted in death. This event has
Table 3
Patient Patient Patient Patient Patient Patient Patient Patient Patient Patient
Individual Indications for ICD and Subsequent Events
1 2 3 4 5 6 7 8 9 10
Grade CAVa
LVEF (%)
PCI
OHT to PCI (years)
Syncope
NSVT
ICD Events
3 2 3 1 3 3 3 3 3 3
45 35 55 40 40 65 60 55 60 35
No No Yes No No No No No Yes No
0 0 7 0 0 0 0 0 14 0
No No No No Yes No No Yes No No
No No No Yes No No No Yes No No
None ATP for VT None VT monitored Shock VF—EMD None None None None None
ATP, anti-tachycardia pacing; CAV, cardiac allograft vasculopathy; EMD, electromechanical dissociation; ICD, implantable cardiac defibrillator; LVEF, left ventricular ejection fraction; NSVT, non-sustained ventricular tachycardia; OHT, orthotopic heart transplant; PCI, percutaneous coronary intervention; VF, ventricular fibrillation; VT, ventricular tachycardia. a 0 ¼ not significant; 1 ¼ mild; 2 ¼ moderate; 3 ¼ severe.
Research Correspondence Routine defibrillation threshold testing at implantation may be inappropriate. The use of ICDs as a bridge to retransplantation may not be beneficial.
Disclosure statement None of the authors has a financial relationship with a commercial entity that has an interest in the subject of the presented manuscript or other conflicts of interest to disclose.
References 1. Tsai VW, Cooper J, Garan H, et al. The efficacy of implantable cardioverter-defibrillators in heart transplant recipients: results from a multicenter registry. Circ Heart Fail 2009;2:197-201.
3 2. Ptaszek LM, Wang PJ, Hunt SA, Valantine H, Perlroth M, Al-Ahmad A. Use of the implantable cardioverter-defibrillator in long-term survivors of orthotopic heart transplantation. Heart Rhythm 2005;2: 931-3. 3. Vaseghi M, Lellouche N, Ritter H, et al. Mode and mechanisms of death after orthotopic heart transplantation. Heart Rhythm 2009; 6:503-9. 4. Cogert GA, Shivkumar K, Patel JK, et al. Implantable cardioverter defibrillators in heart transplant patients at risk for sudden death: shocking news? J Heart Lung Transplant 2003;22:S178-9. 5. Marzoa-Rivas R, Perez-Alvarez L, Paniagua-Martin MJ, et al. Sudden cardiac death of two heart transplant patients with correctly functioning implantable cardioverter defibrillators. J Heart Lung Transplant 2009;28:412-4. 6. McDowell DL, Hauptman PJ. Implantable defibrillators and cardiac resynchronization therapy in heart transplant recipients: results of a national survey. J Heart Lung Transplant 2009;28:847-50.