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Heart Rhythm. 2014 Nov;11(11):1957-65. doi: 10.1016/j.hrthm.2014.06.025. Epub 2014 Jun 20.

Impact of left ventricular hypertrophy on QT prolongation and associated mortality.

Author information

1
Department of Internal Medicine, Division of Cardiovascular Diseases.
2
Department of Molecular Pharmacology and Experimental Therapeutics.
3
Department of Internal Medicine, Division of General Internal Medicine.
4
Department of Statistics.
5
Department of Health Care Policy and Research.
6
Department of Internal Medicine, Division of Cardiovascular Diseases; Department of Molecular Pharmacology and Experimental Therapeutics; Department of Pediatrics, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota. Electronic address: ackerman.michael@mayo.edu.

Abstract

BACKGROUND:

QT prolongation on electrocardiogram (ECG) is a risk marker of ventricular arrhythmias and all-cause mortality. Left ventricular hypertrophy (LVH) on ECG is also associated with poor outcome. Patients satisfying ECG voltage criteria for LVH frequently show concomitant QT prolongation.

OBJECTIVE:

This study aimed to explore the impact of marked QT prolongation on all-cause mortality in patients copresenting with LVH voltage criteria and prolonged QT on ECG.

METHODS:

We evaluated 3364 ECGs with corrected QT (QTc) interval ≥460 ms detected by Mayo Clinic's QT alert system from November 2010 through June 2011. Every ECG with QTc interval ≥460 ms was evaluated for the presence of LVH voltage criteria by using Sokolow-Lyon voltage, Cornell voltage, and Cornell product.

RESULTS:

Concomitant LVH voltage criteria were present in 181 of 3364 ECGs (5.3%) with QTc interval ≥460 ms. Mortality during a follow-up period of 217 ± 184 days was 13% (23 of 181). Independent of age and hypertension, the QTc interval predicted mortality in patients with LVH voltage criteria (hazard ratio 1.31 per 10-ms increase; 95% confidence interval 1.09-1.58; P < .01). Patients with LVH voltage criteria and QTc interval ≥500 ms had highest mortality (log rank, P < .001).

CONCLUSION:

The QTc interval was an independent predictor of mortality in patients with concomitant LVH voltage and prolonged QTc interval on ECG. Mortality was highest in those with QTc interval ≥500 ms. QT prolongation on ECGs with concomitant LVH voltage criteria should not be regarded as a harmless byproduct of LVH, but should be used as a significant marker of increased mortality risk similar to that in patients without LVH voltage criteria.

KEYWORDS:

Electrocardiogram; Left ventricular hypertrophy; Mortality; QTc

PMID:
24956189
DOI:
10.1016/j.hrthm.2014.06.025
[Indexed for MEDLINE]

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