Related Experiment Videos
Cardiac changes implicated in chronic heart block
1Department of Cardiology, Institute of Post-Graduate Medical Education and Research, Calcutta.
Insights
Chronic heart block can stem from primary heart disease or conditions like diabetes and hypertension. Histopathology revealed fibrosis in the conduction system, potentially explaining heart failure in diabetic patients.
Area of Science:
- Cardiology
- Pathology
- Medical Research
Background:
- Chronic heart block is a significant cardiac condition.
- Its underlying causes can be idiopathic or secondary to other diseases.
- Understanding the histopathological basis is crucial for patient outcomes.
Purpose of the Study:
- To investigate the histopathological findings in patients with chronic heart block.
- To explore the association between conduction system abnormalities and conditions like diabetes, hypertension, and ischemic heart disease.
- To determine the role of myocardial and vascular changes in heart block.
Main Methods:
- Studied fifteen cases of chronic heart block.
- Conducted histopathological examination of the conduction system in six whole heart autopsy samples.
- Examined partial autopsy samples from nine cases.
- Correlated findings with clinical history of hypertension, diabetes, and ischemic heart disease.
Main Results:
- All six whole heart samples showed atrioventricular (AV) nodal fibrosis extending to the proximal bundle of His.
- Myocardial fibrosis was observed in five cases.
- Diabetic microangiopathy was present in four cases, with associated conduction system fibrosis in three.
- Atherosclerotic changes were noted in intramural vessels in three cases.
Conclusions:
- Fibrosis of the conduction system is a key finding in chronic heart block, irrespective of underlying causes.
- Diabetic microangiopathy and other vascular changes may contribute to conduction defects and associated cardiac issues like cardiomegaly and heart failure.
- Idiopathic heart block may represent a primary myocardial degenerative process.
Abstract:
Fifteen cases of chronic heart block were studied. Eight of them could be designated as idiopathic or primary heart block; the others were associated with hypertension, diabetes and ischaemic heart disease, either singly or in various combinations. In six cases, the whole heart was available for histopathological study of the conduction system. In the other 9 cases, only a portion of the heart muscle was available for examination. A V nodal fibrosis extending upto the proximal bundle of His was seen in all the six whole heart autopsy materials. Fibrosis of the adjacent myocardium was seen in five cases. In three cases, conducting system fibrosis was associated with atherosclerotic (1 case) or diabetic changes (3 cases) of the intramural vessels. In the 9 partial autopsy studies, myocardial fibrosis was seen in two cases, diabetic microangiopathy in one and atherosclerotic changes in two including an old thrombus in one. Thus, diabetic microangiopathy was seen in total four cases. These changes may be responsible for the cardiomegaly and cardiac failure associated with conduction defects observed in diabetes. In the idiopathic group also, heart block could be considered as a significant facet of a primary myocardial degenerative process.