Background: Chronic stable large animal models of heart failure are difficult to establish. We report an ovine model of chronic stable heart failure achieved by a technique of repetitive myocardial infarctions (one of the most common causes of cardiac failure) with catheter-based techniques.
Methods and results: Ejection fraction (EF) was assessed by echocardiography. A perfusion catheter was positioned in either the left anterior descending or circumflex artery by using standard angioplasty techniques. Myocardial infarction was induced by a Gelfoam embolism via this catheter and was confirmed by electrocardiographic (ECG) changes and new segmental abnormalities. The procedure was repeated at 2 weekly intervals until the EF was less than 40%. Target EF was achieved in 15 animals, with a mean of 3.4 embolizations (range 2 to 8). Baseline EF was 68%, with a mean final EF of 33%. This resulted in a 54% reduction in EF (range 44% to 68%) from baseline values. Two animals developed late symptomatic heart failure and died, whereas EF was stable at 3-month follow-up echocardiography in the remaining animals with no significant spontaneous improvement.
Conclusion: Chronic stable heart failure can be established in sheep with catheter-based skills and a microembolization technique that causes repetitive myocardial infarctions.