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Sabzwari SRA, Tzou WS. Systemic Diseases and Heart Block. Rheum Dis Clin North Am 2024; 50:381-408. [PMID: 38942576 DOI: 10.1016/j.rdc.2024.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2024]
Abstract
Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.
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Affiliation(s)
- Syed Rafay A Sabzwari
- University of Colorado Anschutz Medical Campus, 12631 East 17th Avenue, Mail Stop B130, Aurora, CO 80045, USA
| | - Wendy S Tzou
- Cardiac Electrophysiology, University of Colorado Anschutz Medical Campus, 12401 E 17th Avenue, MS B-136, Aurora, CO 80045, USA.
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Sabzwari SRA, Tzou WS. Systemic Diseases and Heart Block. Cardiol Clin 2023; 41:429-448. [PMID: 37321693 DOI: 10.1016/j.ccl.2023.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.
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Affiliation(s)
- Syed Rafay A Sabzwari
- University of Colorado Anschutz Medical Campus, 12631 East 17th Avenue, Mail Stop B130, Aurora, CO 80045, USA
| | - Wendy S Tzou
- Cardiac Electrophysiology, University of Colorado Anschutz Medical Campus, 12401 E 17th Avenue, MS B-136, Aurora, CO 80045, USA.
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Abstract
Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.
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Ono Y, Fujita M, Ono S, Ogata S, Tachibana S, Tanaka Y. A rabbit model of fatal hypothyroidism mimicking "myxedema coma" established by microscopic total thyroidectomy. Endocr J 2016; 63:523-32. [PMID: 26924647 DOI: 10.1507/endocrj.ej16-0005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Myxedema coma (MC) is a life-threatening endocrine crisis caused by severe hypothyroidism. However, validated diagnostic criteria and treatment guidelines for MC have not been established owing to its rarity. Therefore, a valid animal model is required to investigate the pathologic and therapeutic aspects of MC. The aim of the present study was to establish an animal model of MC induced by total thyroidectomy. We utilized 14 male New Zealand White rabbits anesthetized via intramuscular ketamine and xylazine administration. A total of 7 rabbits were completely thyroidectomized under a surgical microscope (thyroidectomized group) and the remainder underwent sham operations (control group). The animals in both groups were monitored without thyroid hormone replacement for 15 weeks. Pulse rate, blood pressure, body temperature, and electrocardiograms (ECG) were recorded and blood samples were taken from the jugular vein immediately prior to the thyroidectomy and 2 and 4 weeks after surgery. The thyroidectomized rabbits showed a marked reduction of serum thyroxine levels at 4 weeks after the surgical procedure vs. controls (0.50±0.10 vs. 3.32±0.68 μg/dL, p<0.001). Additionally, thyroidectomized rabbits exhibited several signs of hypothyroidism such as hypothermia, systolic hypotension, bradycardia, and low voltage on ECGs, compared with controls. Of the 7 rabbits with severe hypothyroidism, 6 died from 4 to 14 weeks after the thyroidectomy possibly owing to heart failure, because histopathologic examinations revealed a myxedema heart. In summary, we have established a rabbit model of fatal hypothyroidism mimicking MC, which may facilitate pathophysiological and molecular investigations of MC and evaluations of new therapeutic interventions.
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Affiliation(s)
- Yosuke Ono
- Department of General Medicine, National Defense Medical College, Tokorozawa, Japan
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Seol SH, Kim DI, Park BM, Kim DK, Song PS, Kim KH, Jin HY, Seo JS, Jang JS, Yang TH, Kim DK, Kim DS. Complete Atrioventricular Block Presenting With Syncope Caused by Severe Hypothyroidism. Cardiol Res 2012; 3:239-241. [PMID: 28348695 PMCID: PMC5358139 DOI: 10.4021/cr221w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2012] [Indexed: 11/28/2022] Open
Abstract
A 75-year-old man was admitted to our hospital with syncope. Electrocardiogram showed complete atrioventricular block and bradycardia with the minimum heart rate of 22 beats/ min. There was a possible indication for temporary cardiac pacemaker implantation. Laboratory data on admission revealed high TSH level with low free T4 level. To rule out functional atrioventricular block, we treated several days with thyroxine. A follow-up electrocardiogram showed improved heart rate without any atrioventricular block. We found that severe hypothyroidism caused a complete atrioventricular block with syncope, and thyroxine replacement completely improved these conditions.
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Affiliation(s)
- Sang-Hoon Seol
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Haeundae Paik Hospital, Busan, Korea
| | - Doo-Il Kim
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Haeundae Paik Hospital, Busan, Korea
| | - Bo-Min Park
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Haeundae Paik Hospital, Busan, Korea
| | - Dong-Kie Kim
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Haeundae Paik Hospital, Busan, Korea
| | - Pil-Sang Song
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Haeundae Paik Hospital, Busan, Korea
| | - Ki-Hun Kim
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Haeundae Paik Hospital, Busan, Korea
| | - Han-Young Jin
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Busan Paik Hospital, Busan, Korea
| | - Jeong-Sook Seo
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Busan Paik Hospital, Busan, Korea
| | - Jae-Sik Jang
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Busan Paik Hospital, Busan, Korea
| | - Tae-Hyun Yang
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Busan Paik Hospital, Busan, Korea
| | - Dae-Kyeong Kim
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Busan Paik Hospital, Busan, Korea
| | - Dong-Soo Kim
- Division of Cardiology, Department of Internal Medicine, Inje University College of Medicine, Busan Paik Hospital, Busan, Korea
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Khaleeli AA, Memon N. Factors affecting resolution of pericardial effusions in primary hypothyroidism: a clinical, biochemical and echocardiographic study. Postgrad Med J 1982; 58:473-6. [PMID: 7134084 PMCID: PMC2426548 DOI: 10.1136/pgmj.58.682.473] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Echocardiography detected pericardial effusions in five out of six consecutive untreated patients with severe primary hypothyroidism and suspected myopathy, whereas the chest X-ray suggested only one. During L-thyroxine replacement, serial echocardiograms detected decrease in the size of the effusions in all the patients. This occurred before the serum thyroid stimulating hormone (TSH) levels had significantly changed, although there was a small but significant rise in serum thyroxine. In one patient complete resolution of the effusion occurred before the patient became euthyroid, a previously unreported finding. Small voltage complexes, T-wave inversion and non-specific T-wave flattening were the commonest electrocardiographic abnormalities noted. The former invariably and the latter two abnormalities frequently, reverted to normal before the patient became biochemically and clinically euthyroid. T-wave inversion in a particular lead, however, did not invariably do so, suggesting that permanent structural change might possibly have occurred. The plasma creatine kinase (CK) was raised in four patients, and markedly raised at levels usually associated with muscular dystrophy, in two. At the onset of resolution of the pericardial effusions, the total plasma CK had fallen significantly in all patients in whom it was raised.
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