Systolic and Diastolic Dysfunction in Heart Failure

Summary

In this review, we summarize the effects of heart failure, induced by chronic rapid ventricular pacing, on the sequence of development of left ventricular (LV) systolic and diastolic dysfunction in conscious dogs. LV systolic and diastolic dysfunction were evident within 24 h after initiation of pacing, and progressed over a 3-week period. These alterations were associated with significant increases in LV end-diastolic and LV end-systolic volumes and wall stresses. When stresses and heart rate were matched at the same levels in the control and failure stages, the abnormalities in diastolic function were no longer observed, whereas LV systolic function remained depressed. There were no increases in connective tissue content in this model of heart failure at this advanced stage. Thus, pacing-induced heart failure in conscious dogs is characterized by major alterations in LV diastolic function under conditions of increased loading, which were correctable when loading conditions were normalized.