Key result
End-stage liver disease severity was associated with significantly increased myocardial repolarization lability, as evidenced by a higher QT variability index in Child class C patients compared to healthy controls.
Why the study?
Does end-stage liver disease severity and orthostatic stress (head-up tilt test) alter the QT variability index?
Cross-Sectional (n=48)
No
Does end-stage liver disease severity and orthostatic stress (head-up tilt test) alter the QT variability index?
Answers are grounded in this paper and cite their sources.
Myocardial repolarization lability, as measured by the QT variability index, is significantly increased in severe end-stage liver disease, which may contribute to the risk of malignant ventricular arrhythmias.
BACKGROUND: A prolonged QT interval can lead to malignant ventricular arrhythmias and sudden cardiac death, and has frequently been found in end-stage liver disease (ESLD). However, myocardial repolarization lability has not yet been fully investigated. We evaluated the QT variability index (QTVI), a marker of temporal inhomogeneity in ventricular repolarization and an abnormality associated with re-entrant malignant ventricular arrhythmias. We determined whether QTVI is affected by the head-up tilt test in ESLD. METHODS: We assessed 36 ESLD patients and 12 control subjects without overt heart disease before and after the 70-degree head-up tilt test. The electrocardiography signal (lead II) was recorded on a computer with an analog-to-digital converter. The RR interval (RRI) and QT interval were measured after recording 5 min of the digitized electrocardiography. Then, the QT intervals were corrected with Bazett's formula (QTc). QTVI was calculated through the following formula: QTVI = log10 [(QTv/QTm2)/(RRIv/RRIm2)], QTv/RRIv: variance of QTI/RRI, QTm/RRIm: mean of QT interval/RRI. RESULTS: Cirrhotic patients exhibited an elevated QTVI. In particular, Child class C patients had a significantly increased QTVI compared to Child class A patients and the control subjects in the supine position. However, the head-up tilt test did not cause a significant difference in QTVI in relation to the severity of ESLD. CONCLUSIONS: Myocardial repolarization lability was significantly altered in end-stage liver disease. Our data suggest that the severity of ESLD is associated with the degree of the alteration in the QT variability index.
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Huh et al. (2014) conducted a cross-sectional in End-stage liver disease (n=48). End-stage liver disease vs. Healthy controls was evaluated on QT variability index (QTVI) in the supine position (p=<0.05). End-stage liver disease severity was associated with significantly increased myocardial repolarization lability, as evidenced by a higher QT variability index in Child class C patients compared to healthy controls.
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