Back to Search
Start Over
Early Changes in Rat Heart After High‐Dose Irradiation: Implications for Antiarrhythmic Effects of Cardiac Radioablation
- Source :
- Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease
- Publication Year :
- 2021
- Publisher :
- Ovid Technologies (Wolters Kluwer Health), 2021.
-
Abstract
- Background Noninvasive cardiac radioablation is employed to treat ventricular arrhythmia. However, myocardial changes leading to early‐period antiarrhythmic effects induced by high‐dose irradiation are unknown. This study investigated dose‐responsive histologic, ultrastructural, and functional changes within 1 month after irradiation in rat heart. Methods and Results Whole hearts of wild‐type Lewis rats (N=95) were irradiated with single fraction 20, 25, 30, 40, or 50 Gy and explanted at 1 day or 1, 2, 3, or 4 weeks’ postirradiation. Microscopic pathologic changes of cardiac structures by light microscope with immunohistopathologic staining, ultrastructure by electron microscopy, and functional evaluation by ECG and echocardiography were studied. Despite high‐dose irradiation, no myocardial necrosis and apoptosis were observed. Intercalated discs were widened and disrupted, forming uneven and twisted junctions between adjacent myocytes. Diffuse vacuolization peaked at 3 weeks, suggesting irradiation dose‐responsiveness, which was correlated with interstitial and intracellular edema. CD68 immunostaining accompanying vacuolization suggested mononuclear cell infiltration. These changes were prominent in working myocardium but not cardiac conduction tissue. Intracardiac conduction represented by PR and QTc intervals on ECG was delayed compared with baseline measurements. ST segment was initially depressed and gradually elevated. Ventricular chamber dimensions and function remained intact without pericardial effusion. Conclusions Mononuclear cell–related intracellular and extracellular edema with diffuse vacuolization and intercalated disc widening were observed within 1 month after high‐dose irradiation. ECG indicated intracardiac conduction delay with prominent ST‐segment changes. These observations suggest that early antiarrhythmic effects after cardiac radioablation result from conduction disturbances and membrane potential alterations without necrosis.
- Subjects :
- Male
cardiac radioablation
medicine.medical_specialty
Time Factors
Heart Ventricles
030204 cardiovascular system & hematology
Radiosurgery
Pathophysiology
Electrocardiography
03 medical and health sciences
0302 clinical medicine
Heart Rate
Internal medicine
Mechanisms
medicine
Animals
Arrhythmia and Electrophysiology
Irradiation
antiarrhythmic effect
Original Research
ventricular arrhythmia
business.industry
Myocardium
Arrhythmias, Cardiac
Dose-Response Relationship, Radiation
Rat heart
Rats
radiation
Microscopy, Electron
Animal Models of Human Disease
Echocardiography
Rats, Inbred Lew
030220 oncology & carcinogenesis
Cardiology
Antiarrhythmic effect
Cardiology and Cardiovascular Medicine
business
Follow-Up Studies
Subjects
Details
- ISSN :
- 20479980
- Volume :
- 10
- Database :
- OpenAIRE
- Journal :
- Journal of the American Heart Association
- Accession number :
- edsair.doi.dedup.....7a040502ea036c807baea35ad830ec76