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This Article Full Text Full Text (PDF) All Versions of this Article: 294/2/H867    most recent 00573.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Yeih, D.-F. Articles by Tseng, Y.-Z. Search for Related Content PubMed PubMed Citation Articles by Yeih, D.-F. Articles by Tseng, Y.-Z.

Temporal changes in cardiac force- and flow-generation capacity, loading conditions, and mechanical efficiency in streptozotocin-induced diabetic rats

¹Department of Cardiology, Far Eastern Memorial Hospital, Pan-Chiao, Taipei; ³Departments of Internal Medicine and Medical Research, Mackay Memorial Hospital; Mackay Medicine, Nursing and Management College, Taipei Medical University, Taipei; ²Department of Internal Medicine, National Taiwan University Hospital, Taipei; and ⁴Department of Cardiology, Show Chwan Memorial Hospital, Chang-Hua, Taiwan

Submitted 17 May 2007 ; accepted in final form 24 November 2007

Diabetes mellitus may result in impaired cardiac contractility, but the underlying mechanisms remain unclear. We aimed to investigate the temporal alterations in cardiac force- and flow-generation capacity and loading conditions as well as mechanical efficiency in the evolution of systolic dysfunction in streptozotocin (STZ)-induced diabetic rats. Adult male Wistar rats were randomized into control and STZ-induced diabetic groups. Invasive hemodynamic studies were done at 8, 16, and 22 wk post-STZ injection. Maximal systolic elastance (E_max) and maximum theoretical flow (Q_max) were assessed by curve-fitting techniques, and ventriculoarterial coupling and mechanical efficiency were assessed by a single-beat estimation technique. In contrast to early occurring and persistently depressed E_max, Q_max progressively increased with time but was decreased at 22 wk post-STZ injection, which temporally correlated with the changes in cardiac output. The favorable loading conditions enhanced stroke volume and Q_max, whereas ventriculoarterial uncoupling attenuated the cardiac mechanical efficiency in diabetic animals. The changes in E_max and Q_max are discordant during the progression of contractile dysfunction in the diabetic heart. In conclusion, our study showed that depressed Q_max and cardiac mechanical efficiency, occurring preceding overt systolic heart failure, are two major determinants of deteriorating cardiac performance in diabetic rats.

diabetes; contractile function; hemodynamics; mechanical efficiency; ventriculoarterial coupling

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