Induction and maintenance of an experimental model of severe cardiomyopathy with a novel protocol of rapid ventricular pacing.

Abstract

OBJECTIVE:

An animal model of chronic severe heart failure is needed to evaluate new mechanical devices, surgical procedures, and medical therapies. The purpose of this study was to evaluate a unique new model of severe heart failure developed by means of a novel protocol of rapid ventricular pacing.

METHODS:

Heart failure was induced in 8 mongrel dogs by means of rapid ventricular pacing (230 beats/min) for 4 weeks. After a sham operation, maintenance pacing at a reduced rate (190 beats/min) was continued for another 4 weeks.

RESULTS:

Left ventricular systolic function was significantly reduced at week 4 and remained low at week 8, including the slope of the end-systolic pressure-volume relationship (2.4 +/- 1.0 vs 0.7 +/- 0.2 vs 0.8 +/- 0.3 mm Hg/mL [baseline vs week 4 vs week 8, respectively]), ejection fraction (63% +/- 5% vs 28% +/- 7% vs 33% +/- 5%), and cardiac output (3.1 +/- 0.7 vs 2.0 +/- 0.3 vs 2.2 +/- 0.7 L/min). Significant ventricular remodeling changes took place with increased ventricular volumes and circumferential wall stress, which were stable between weeks 4 and 8. Serum catecholamine and atrial natriuretic polypeptide levels also increased from baseline but stabilized between weeks 4 and 8. The end-diastolic pressure-volume relationship also showed stable diastolic function between weeks 4 and 8.

CONCLUSIONS:

Induction pacing at 230 beats/min readily created severe heart failure in all animals, and a new technique of maintenance pacing provided a consistent model of severe heart failure. This model can be used to study a variety of new interventions for heart failure.

• Authors: Masami Takagaki, Patrick M McCarthy, Tomotsugu Tabata, Ray Dessoffy, Lisa A Cardon, Jason Connor, Yoshie Ochiai, James D Thomas, Gary S Francis, James B Young, Kiyotaka Fukamachi
• Journal: The Journal of thoracic and cardiovascular surgery (J Thorac Cardiovasc Surg) Vol. 123 Issue 3 Pg. 544-9 (Mar 2002) ISSN: 0022-5223 [Print] United States
• PMID: 11882829 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Animals
• Cardiac Pacing, Artificial
• Cardiomyopathy, Dilated (diagnostic imaging, physiopathology)
• Disease Models, Animal
• Dogs
• Echocardiography, Three-Dimensional
• Hemodynamics
• Ventricular Function, Left