Author + information
- Received May 14, 1985
- Revision received August 6, 1985
- Accepted September 18, 1985
- Published online February 1, 1986.
- John S. Pirolo, BS,
- Grover M. Hutchins, MDa and
- G. William Moore, MD, PHD
- ↵aAddress for reprints: Grover M. Hutchins, MD, Department of Pathology, The Johns Hopkins Hospital, Baltimore, Maryland 21205.
The reasons for the marked variability in expansion of myocardial infarcts are unknown. To examine this question, the hearts in 204 patients with a single myocardial infarct, autopsied at The Johns Hopkins Hospital and studied after coronary arteriography and fixation in distension, were reviewed. There were 58 (28%) hearts with marked infarct expansion, 34 (17%) with moderate expansion and 112 (55%) with no or minimal expansion. The degree of expansion was greater in larger, more transmural infarcts (p < 0.001). Infarcts with greater expansion had significantly more endocardial thrombus (p < 0.001) and endocardial fibroelastosis (p < 0.01). Larger heart weight and degree of left ventricular hypertrophy had a significant negative correlation with infarct expansion (p < 0.05). A markedly greater degree of expansion was noted in the 101 infarcts (50%) caused by lesions in the distribution of the left anterior descending coronary artery as compared with the 57 infarcts (28%) secondary to right coronary lesions and the 46 infarcts (23%) in the distribution of the left circumflex coronary artery (p < 0.001).
The results show that expansion is associated with large infarcts but is less marked in hearts with ventricular hypertrophy. Expansion occurs predominantly in infarcts in the left anterior descending coronary artery distribution, that is, regions of the left ventricular myocardium with the greatest curvature. These results suggest that the degree to which an infarct expands may be influenced by the preinfarction thickness of the ventricular wall.
This study was supported by National Institutes of Health Grant T35 AM-07384 from the National Institute for Arthritis, Diabetes, Digestive and Kidney Diseases, Grant HL-17655 from The National Heart, Lung, and Blood Institute and Grant LM-03651 from The National Library of Medicine, Bethesda, Maryland.
- Received May 14, 1985.
- Revision received August 6, 1985.
- Accepted September 18, 1985.
- American College of Cardiology Foundation