Recovery Trajectory in Tachycardia Induced Heart Failure Model

O, Jung Hwan; Park, Seung Il; Won, Jun Ho; Kim, Eun Ki; Lee, Chong Kook

Abstract

BACKGROUND: Tachycardia induced heart failure model would be the model of choice for the dilated cardiomyopathy. This more closely resembles the clinical syndrome and does not require major surgical trauma, myocardial ischemia and pharmacological or toxic depression of cardiac function. When heart failure is progressive, application of new surgical procedures to the faling heart is highly risky. It has been shown that recovery trajectory from heart failure is a new method in decreasing animal mortality. The purpose is to establish the control datas for recovery trajectory in the canine heart failure model. MATERIAL AND METHOD: 21 mongrel dogs were studied at 4 stages(baseline, at the heart failure, 4 and 8 weeks after recovery). Heart failure was induced during 4 weeks of continuous rapid pacing using a pacemaker. Eight weeks of trajectory of recovery period was allowed. Indices of left ventricular function and dimension were measured every 2 weeks and the hemodynamics were measured by use of Swan-Ganz catheterization and thermodilution method every 4 weeks. Values were expressed as mean+/-standard deviation. RESULT: 4(20%) dogs died due to heart failure. Left ventricular end-diastolic volume at the 4 stages were 40.8+/-7.4, 82.1+/-21.1, 59.9+/-7.7 and 46.5+/-6.5ml. Left ventricular end-systolic volume showed the same trend. Ejection fractions were 50.6+/-4.1, 17.5+/-5.8, 36.3+/-7.3, and 41.5+/-2.4%. Blood pressure and heart rate showed no significant changes. Pressures of central vein, right ventricle, pulmonary artery, and pulmonary capillary wedge showed significant increase during the heart failure period, normalizing at the end of recovery period. Stroke volumes were 21.5+/-8.2, 12.3+/-3.5, 17.9+/-4.6, and 15.5+/-3.4ml. Blood norepinephrine level was 133.3+/-60.0pg/dL at the baseline and 479.4+/-327.3pg/dL at the heart failure stage(p=0.008).
CONCLUSION
Development of tachycardia induced heart failure model is of high priority due to ready availability and reasonable amenability to measurements. Recovery trajectory after cessation of tachycardia showed reduction of cardiac dilatation and heart function. Application of new surgical procedures during the recovery period could decrease animal mortality.