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The conduction system in transplanted hearts
S Bharati1, M Billingham, M Lev
1Congenital Heart and Conduction System Center, Christ Hospital and Medical Center, Oak Lawn, Ill. 60463.
Insights
Cardiac transplant patients show persistent inflammation and fibrosis in the conduction system (CS) and coronary arteries. These pathological changes may contribute to arrhythmias and sudden cardiac death in recipients.
Area of Science:
- Cardiovascular Pathology
- Transplant Medicine
- Cardiac Electrophysiology
Background:
- Cardiac transplantation is a life-saving procedure for end-stage heart failure.
- Long-term complications, including arrhythmias and sudden death, remain a concern in heart transplant recipients.
- The conduction system (CS) and coronary vasculature are susceptible to damage post-transplant.
Purpose of the Study:
- To investigate the pathological changes in the conduction system (CS) of cardiac allografts.
- To correlate these findings with clinical outcomes such as arrhythmias and sudden death.
- To compare post-mortem findings with pre-transplant endomyocardial biopsy data.
Main Methods:
- Serial section examination of the conduction system (CS) in six explanted hearts from cardiac transplant recipients.
- Histopathological analysis for myocarditis, fibrosis, arteriosclerosis, and arteriolosclerosis.
- Comparison of autopsy findings with available endomyocardial biopsy results.
Main Results:
- All hearts exhibited hypertrophy and enlargement, with varying degrees of myocarditis and arteriosclerosis/arteriolosclerosis, predominantly in the atria.
- Myocarditis and fibrosis were consistently found throughout the conduction system (CS), including the sinoatrial (SA) node, atria, atrioventricular (AV) node, and bundle branches.
- Autopsy revealed more significant myocarditis and fibrosis in the CS than estimated by endomyocardial biopsies.
- Widespread coronary artery disease affected both large and small vessels.
Conclusions:
- Fibrotic changes and persistent inflammation are common in the conduction system (CS) of transplanted hearts.
- Coronary artery disease is a ubiquitous finding in these hearts.
- Pathological alterations in the CS and coronary arteries may underlie arrhythmias and sudden death post-cardiac transplantation.
Abstract:
This is a serial section examination of the conduction system (CS) in six patients who died seven months, 11 months, two years four months, four years two months, 11 years, and 16 years eight months following cardiac transplantation. The heart was hypertrophied and enlarged in all. There was myocarditis of varying degree in all cases with arteriosclerosis and arteriolosclerosis. These findings were more dominant in the atria than in the ventricles. In the CS, myocarditis with fibrosis was found in all in the approaches to the sinoatrial (SA) node, the SA node, the atria, the atrioventricular (AV) node, and the bundle and bundle branches, to a varying degree. When compared with the endomyocardial biopsy findings, the autopsied cases revealed more myocarditis and fibrosis than those estimated to be present in the biopsy specimen. In summary, this study demonstrates that there are fibrotic changes in the CS with the persistence of inflammatory phenomena of the myocardium and the CS to a varying degree in transplanted hearts. This is accompanied by the ubiquitous coronary artery disease affecting not only the large coronaries but also the small vessels. The pathologic changes in and around the CS may be responsible for arrhythmias and sudden death in some cases of cardiac transplantation.