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Published on: May 26, 2010
Electrocardiographic findings in experimental murine myocarditis--arrhythmias in the chronic stage
Abstract:
We studied serial electrocardiographic changes in murine myocarditis due to encephalomyocarditis (EMC) virus. After taking control electrocardiograms using standard extremity and 2 precordial leads, 86 mice were intraperitoneally inoculated with a 0.1 ml of the M variant of EMC virus suspension containing 100 TCID50. Electrocardiograms were recorded everyday from the 2nd to the 14th day, and thereafter once every 3-5 days until the 35th day. The cumulative incidence of myocarditis was 90% (77 out of 86). The control electrocardiogram showed a heart rate of 528 +/- 87 beats/min (mean +/- SD) and PR intervals of 0.03-0.05 sec, and significant rhythm or conduction disturbances were not found. Various electrocardiographic abnormalities, such as atrial (10%) and ventricular (21%) premature contractions, were noticed on the 4th to the 14th day. After 15-35 days arrhythmias still remained in 3 mice. The presence of arrhythmias in the chronic stage of myocarditis suggests that arrhythmias in some patients with no other clinical manifestations may be a sequela of the previous viral myocarditis. Thus, this study may contribute clinically to the clarification of the electrocardiographic characteristics in viral myocarditis.
Insights
Viral myocarditis in mice caused significant electrocardiographic changes, including arrhythmias. These findings suggest viral-induced heart inflammation may lead to long-term heart rhythm disturbances in humans.
Area of Science:
- Cardiology
- Virology
- Immunology
Background:
- Viral myocarditis is a significant cause of heart disease.
- Encephalomyocarditis virus (EMC) is a known cause of myocarditis in animal models.
- Electrocardiographic (ECG) changes are crucial for diagnosing and monitoring heart conditions.
Purpose of the Study:
- To investigate serial electrocardiographic changes in mice with encephalomyocarditis virus (EMC)-induced myocarditis.
- To determine the incidence and types of arrhythmias associated with viral myocarditis.
- To explore the potential long-term cardiac sequelae of viral myocarditis.
Main Methods:
- 86 mice were inoculated with EMC virus.
- Serial electrocardiograms (ECGs) were recorded daily for 14 days, then every 3-5 days until day 35.
- ECGs were analyzed for heart rate, PR intervals, and rhythm or conduction disturbances.
Main Results:
- A 90% cumulative incidence of myocarditis was observed.
- Electrocardiographic abnormalities, including atrial and ventricular premature contractions, were frequent between days 4-14.
- Arrhythmias persisted in 3 mice during the chronic stage (15-35 days post-inoculation).
Conclusions:
- Viral myocarditis can induce significant and persistent electrocardiographic abnormalities.
- The study suggests that arrhythmias in the chronic stage may be a sequela of previous viral myocarditis.
- Findings may aid in clarifying electrocardiographic characteristics of viral myocarditis in clinical settings.
