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The kangaroo as a model for the study of hypertrophic cardiomyopathy in man
Insights
Sudden death in kangaroos was linked to hypertrophic cardiomyopathy (HC). Kangaroos exhibit left ventricular hypertrophy and abnormal heart dynamics, similar to human HC patients, suggesting a potential animal model for studying this condition.
Area of Science:
- Cardiology
- Comparative Pathology
- Animal Models
Background:
- Kangaroos exhibit unexplained left ventricular hypertrophy.
- They are susceptible to sudden death during excitement and exertion.
- Similarities were noted with human hypertrophic cardiomyopathy (HC).
Purpose of the Study:
- To investigate the cause of unexpected deaths in anesthetized kangaroos.
- To explore the potential of kangaroos as an experimental model for human hypertrophic cardiomyopathy.
Main Methods:
- Experiments were conducted on 14 anesthetized kangaroos.
- Retrospective analysis of cardiac data was performed.
- Comparison of ventricular dynamics between kangaroos and human HC patients.
Main Results:
- Ten out of 14 kangaroos developed ventricular fibrillation and died.
- Kangaroos showed rapid left ventricular pressure development and slow relaxation.
- A disparity between mechanical systole and electrical activation was observed, leading to ventricular extrasystoles.
Conclusions:
- Kangaroos display cardiac abnormalities consistent with hypertrophic cardiomyopathy.
- The findings suggest kangaroos may serve as a valuable model for studying HC-related fatal rhythm disturbances and ventricular dynamics.
Abstract:
In experiments in 14 anaesthetised kangaroos, 10 developed unexpected ventricular fibrillation and died. In seeking a cause for this, similarities were noted with hypertrophic cardiomyopathy (HC) in man. Like patients with this condition, kangaroos have unexplained left ventricular hypertrophy and are known to be susceptible to sudden death with excitement and exertion. Retrospective analysis of all data showed other features of hypertrophic cardiomyopathy: unusually rapid left ventricular pressure development in systole (peak dP/dt: kangaroo 3602 (SEM472); HC 1947(SEM172) mmHg X s-1), unusually slow left ventricular relaxation (exponential time constant: kangaroo 54(SEM7); HC 63 (SEM5) ms; relaxation time: kangaroo 128(SEM7); HC 112(SEM7) ms), and inappropriately long duration of mechanical systole in relation to ventricular depolarisation (393(SEM21) ms and 214(SEM15) ms respectively). A disparity between the duration of mechanical systole and electrical activation caused a type of incomplete tetanus to develop with ventricular extrasystoles, a phenomenon previously seen in patients with hypertrophic cardiomyopathy. These findings suggest that the kangaroo may be a useful experimental model for studying the fatal rhythm disturbances and abnormal ventricular dynamics in human hypertrophic cardiomyopathy.