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Cardiac aging, calcium overload, and arrhythmias
P U Carbonin1, M Di Gennaro, M Pahor
1Cattedra di Gerontologia, Universita' Cattolica del Sacro Cuore, Rome, Italy.
Experimental Gerontology
|January 1, 1990
Summary
Aging increases the risk of ventricular arrhythmias (VA). Physiological aging elevates calcium-related VA, while pathological aging from hypertension exacerbates programmed electrical stimulation-induced VA.
Area of Science:
- Cardiology
- Gerontology
- Physiology
Background:
- Aging impacts cardiac electrophysiology and arrhythmia susceptibility.
- Hypertension is a significant risk factor for cardiovascular disease and may interact with aging.
- Understanding age-related changes in arrhythmia mechanisms is crucial for cardiovascular health.
Purpose of the Study:
- To investigate the effects of aging on ventricular arrhythmias in different rat models.
- To differentiate the arrhythmogenic effects of physiological aging versus pathological aging (hypertension).
- To explore the underlying mechanisms of age-related ventricular arrhythmias.
Main Methods:
- Utilized isolated heart preparations from Wistar rats (NWR), Wistar Kyoto rats (WKY), and spontaneously hypertensive rats (SHR) of different ages.
- Assessed ventricular arrhythmias induced by high-calcium perfusion and programmed electrical stimulation (PES).
- Examined reperfusion- and reoxygenation-induced arrhythmias in Langendorff perfused hearts.
Main Results:
- Older NWR (24 months) exhibited more frequent calcium-induced delayed afterdepolarizations and triggered activity than younger NWR (6 months).
- Older spontaneously hypertensive rats (14 months) showed more severe reperfusion-induced ventricular arrhythmias compared to WKY rats.
- Programmed electrical stimulation-induced arrhythmias were significantly higher in older SHR compared to younger SHR and WKY rats, suggesting a role for fibrosis in hypertension-related aging.
Conclusions:
- Physiological aging is associated with an increased propensity for calcium-related ventricular arrhythmias.
- Pathological aging, characterized by sustained hypertension, increases the incidence of programmed electrical stimulation-induced ventricular arrhythmias, likely due to myocardial fibrosis facilitating reentry.
- Aging significantly alters cardiac susceptibility to different types of ventricular arrhythmias depending on the underlying physiological or pathological state.