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This Article Full Text Full Text (PDF) All Versions of this Article: 288/5/H2171    most recent 00427.2004v1 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 Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by de Carvalho, F. C. Articles by Wajngarten, M. Search for Related Content PubMed PubMed Citation Articles by de Carvalho, F. C. Articles by Wajngarten, M.

Acute reduction of ventricular volume decreases QT interval dispersion in elderly subjects with and without heart failure

Heart Institute (InCor), Medical School, University of São Paulo, São Paulo, Brazil

Submitted 10 May 2004 ; accepted in final form 22 December 2004

To evaluate the effects of acute reduction in ventricular volume (VV) on QT interval dispersion (QTd), 14 men with heart failure (HF; 74.5 ± 2 yr of age) and 11 healthy male control subjects (68 ± 2 yr of age) were studied. For 15 min, lower body negative pressure (LBNP) was applied at –15 and –40 mmHg to reduce venous return. At baseline and during LBNP application, QTd was measured with an 87-lead, body-surface-mapping device; chamber volumes were assessed by radioisotope ventriculography; blood pressure (BP) and heart rate (HR) were continuously monitored; and blood samples were obtained for assessment of norepinephrine (Nor) levels. At –15 mmHg, LNBP application induced a significant decrease in VV but did not change BP and HR in both groups. In addition, Nor levels increased significantly (P 0.05) in the control group (from 286.7 ± 31.5 to 388.8 ± 41.2 pg/ml) and in HF patients (from 405.8 ± 56 to 477.6 ± 47 pg/ml), and QTd was significantly (P 0.05) decreased in the control group (57.2 ± 3.8 vs. 49.1 ± 3.4 ms) and in HF patients (67.8 ± 6 vs. 63.7 ± 5.9 ms). No additional decreases in VV or QTd were produced by –40 mmHg LNBP, but Nor levels did increase in both groups and reach 475.5 ± 34 and 586.5 ± 60 pg/ml (P < 0.05) in the control and HF groups, respectively; BP did not change, but HR also increased in both groups. In conclusion, an acute LBNP-induced reduction in VV caused a decrease in the QTd of elderly men regardless of the existence of HF. Because increased sympathetic activity with more intense LBNP was not accompanied by additional changes in QTd, altered QTd may be better related to changes in VV than to autonomic nervous system activity.

lower body negative pressure; cardiomyopathy; cardiac; norepinephrine; ischemic disease