Heart transplantation associated arrhythmias
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
- Patients with end-stage cardiac disease who are managed with heterotopic heart transplantation, very commonly have arrhythmias post-transplantation, especially in the early postoperative period.
- Most arrhythmias are benign like premature atrial complexes and premature ventricular complexes that do not result in symptoms.
- More dangerous and life-threatening arrhythmias may also occur, which result in significant morbidity and mortality.
Mechanisms and Risk Factors
Various mechanisms are involved in both Bradyarrhythmias and Tachyarrythmias. Some of them are-
Graft ischemia time
Patients with graft ischemia time >4 hours are classified as high risk. Subsequent endocardial fibrosis also contributes to arrhythmias.
Bicaval and Biatrial Anastomosis
- Biatrial method:
Part of the recipient right and left atria are retained which is sutured to respective atrial of the donor. This allows surgeons to preserve the recipient's sinus node, however, due to disruption of blood supply and denervation, this is rendered non-functional. There is a complete conduction block across the suture line in the right atrium.
- Bicaval method:
An anastomosis is made at the level of two vena cavae, the great vessels, and the left atrial cuff around the pulmonary vein. There is less sinus nodal injury, tricuspid regurgitation, and atrial dilatation making it the preferred technique of the current times. Potential advantages: associated with a reduced hospital stay, decreased incidence of atrial dysrhythmias and conduction disturbances, less mitral and tricuspid incompetence secondary to atrioventricular (AV) geometry distortion and right ventricular failure. Potential disadvantages: increased ischemic time and the possibility of narrowing of the caval anastomosis.
Denervation and Reinnervation
Complete denervation of the donor heart is done and during the process of renevervation may be nonuniform.
Cardiac Allograft Vasculopathy/ Cardiac transplant Atherosclerosis
Rejection
Maybe the cause in both early and late postoperative periods. Persistent AF warrants an evaluation for ongoing rejection.
Classification
| Types of Arrhythmias | Occurrence | Common mechanism | Treatment | ||
| Tachyarrhythmias | Supra-ventricular tachy- arrthymia
(SVT) |
Atrial fibrillation | Common in early postoperative period Over all frequency 47.3% (Elkaryoni et al.) |
1. Graft manipulation (primary graft failure) | 1. Evaluate and manage the trigger
2. Persistent cases: Catheter ablation |
| 2. Inflammatory changes (pericardial inflammation) | |||||
| 3. Autonomic hypersensitivity | |||||
| 4. Ischemia | |||||
| 5. Denervation | |||||
| 6. Early rejection | |||||
| 7. Ionotrpes | |||||
| Atrial flutter | Common in the immediate postoperative period (>1 month) Over all frequency 7.6% (Elkaryoni et al.) |
1. AR - 28% cases
2. Remodeling of atria (late-onset) 3. Atrial suture lines - conduction barriers 4. Recipient to donor atrial conduction 5. Increased risk with bi-atrial method 6. Increased risk with older donor age |
1. Evaluate and manage the trigger
2. Persistent cases: Radiofrequency ablation | ||
| Other SVTs | Focal atrial tachycardia | Formation of depolarization foci near the atrial scar that takes control of the heart rhythm. Foci can be found in donor atrium or in the atrial remnant of the recipient which passes into the donor. | Focal catheter ablation | ||
| Atrial reentrant tachycardia & Nodal reentrant tachycardia | Requires a preexisting route in the donor that allows a macroreentrant. | Radiofrequency ablation (RFA) | |||
| Atrial macro-reentrant tachycardia | site of origin is mostly in the upper right atrium, around the native and donor suture line | Radiofrequency ablation (RFA) | |||
| Recipient-to-donor atrial conduction tachycardia | Site of origin usually right atrial anastomosis. | Radiofrequency ablation (RFA) | |||
| Ventricular tachycardias Over all frequency 7.6% (Elkaryoni et al.) |
Non-sustained | Early post-transplant period | 1.Acute rejection
2. Graft vasculopathy
3. Severe cardiac allograft vasculopathy (in symptomatic cases) |
ICD placement (in symptomatic cases) | |
| Sustained | Early post-transplant period | 1. Acute rejection (if presenting during immediate postoperative period)
2. Allopathic vasculopathy 3. LV dysfunction |
Prompt for coronary angiography and cardiac biopsy | ||
| Ventricular fibrillation | 1.1% | Transplant coronary artery disease | |||
| Bradyarrhytmia | Sick sinus syndrome (SSS) | 0.5 %
(Elkaryoni et al.) |
1. Sympathetic denervation
2. Ischemic injury to the sinus node 3. Graft ischemia or rejection 4. Drug effects |
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| Sudden cardiac arrest | 3.7%
(Elkaryoni et al.) |
1. SSS
2. Cardiac allograft vasculopathy 3. Transplant coronary artery disease |
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| Heart Block | 0.3%
(Elkaryoni et al.) |
1. Postoperative injury
2. Progressive conduction system disease associated with coronary artery disease
3. LV dysfunction
4. Chronic rejection
5. Injury from endomyocardial biopsies. |
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Post heart transplant Arrhythmias can be divided into tachyarrhythmias (heart rate > 100/min) and bradyarrhythmia (heart rate < 60 /min). Tachycardias are further classified based on place of origin, such as supraventricular arrhythmias originate between the sinus node and the AV node, whereas ventricular arrhythmias originate below the AV node at the ventricular level.
Tachyarrhythmias
Supraventricular tachyarrhythmias (SVT)
It includes-
- Atrial Premature Complexes (benign)
- Atrial Fibrillation
- Atrial Flutter- Most common > 3 weeks postoperatively
- Others like AV Reentrant Tachycardias, Atrial reentrant tachycardia
Ventricular Arrythmias
It includes-
- Ventricular premature beats- seen in upto 100% of the patients in the early postoperative period [4]
- Nonsustained Ventricular Tachycardia
- Sustained Ventricular Tachycardia
- Ventricular Fibrillation
Bradyarrhythmias
Sinus Bradycardia
Posttransplantation bradycardia is caused by- [5]
- Prolonged organ ischemic time
- Antiarrhythmic drug effects
- Surgical trauma and surgical suture lines
Sinus Node Dysfunction
Complete Heart Block
Treatment
The treatment of posttransplant arrhythmias depends on the type and etiology.
- Catheter ablation/ Radiofrequency ablation - Employed in various tachyarrythmias.
- Pacemaker insertion- Considered in persistent bradyarrythmias and heart block.
- ICD insertion - For prevention of Sudden Cardiac Death (SCD)
Medical Therapy
- Empiric treatment of rejection with steroid therapy is done when the suspected etiology is rejection.
- Limited evidence is present but the use of antiarrhythmic therapy can be employed with careful consideration of safety and tolerability.
Prevention
Preventive care can be taken by targeting the etiology of the arrhythmias. This involves-
- Detection and prompt treatment of rejection.
- Prevention of cardiac allograft vasculopathy.
- Limited data is available on ICD implantation for prevention of sudden cardiac death. [6]
References
- ↑ Ventura, Hector O.; Mehra, Mandeep R.; Smart, Frank W.; Stapleton, Dwight D. (1995). "Cardiac allograft vasculopathy: Current concepts". American Heart Journal. 129 (4): 791–799. doi:10.1016/0002-8703(95)90331-3. ISSN 0002-8703.
- ↑ Creswell, Lawrence L.; Schuessler, Richard B.; Rosenbloom, Michael; Cox, James L. (1993). "Hazards of postoperative atrial arrhythmias". The Annals of Thoracic Surgery. 56 (3): 539–549. doi:10.1016/0003-4975(93)90894-N. ISSN 0003-4975.
- ↑ 3.0 3.1 Thajudeen, Anees; Stecker, Eric C.; Shehata, Michael; Patel, Jignesh; Wang, Xunzhang; McAnulty, John H.; Kobashigawa, Jon; Chugh, Sumeet S. (2012). "Arrhythmias After Heart Transplantation: Mechanisms and Management". Journal of the American Heart Association. 1 (2). doi:10.1161/JAHA.112.001461. ISSN 2047-9980.
- ↑ Scott, Christopher D.; Dark, John H.; McComb, Janet M. (1992). "Arrhythmias after cardiac transplantation". The American Journal of Cardiology. 70 (11): 1061–1063. doi:10.1016/0002-9149(92)90361-2. ISSN 0002-9149.
- ↑ Jacquet, Luc; Ziady, Galal; Stein, Keith; Griffith, Bartley; Armitage, John; Hardesty, Robert; Kormos, Robert (1990). "Cardiac rhythm disturbances early after orthotopic heart transplantation: Prevalence and clinical importance of the observed abnormalities". Journal of the American College of Cardiology. 16 (4): 832–837. doi:10.1016/S0735-1097(10)80330-4. ISSN 0735-1097.
- ↑ McDowell, Deryk L.; Hauptman, Paul J. (2009). "Implantable Defibrillators and Cardiac Resynchronization Therapy in Heart Transplant Recipients: Results of a National Survey". The Journal of Heart and Lung Transplantation. 28 (8): 847–850. doi:10.1016/j.healun.2009.04.016. ISSN 1053-2498.