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Alternative methods of microvolt T wave alternans measurements in patients with left ventricular cardiac dysfunction


Authors: Lubomír Křivan;  Petr Lokaj;  Milan Kozák;  Milan Sepši;  Pavel Trčka;  Jitka Vlašínová;  Lucie Burešová;  Jindřich Špinar
Authors‘ workplace: Fakultní nemocnice Brno, Interní kardiologická klinika
Published in: Čas. Lék. čes. 2010; 149: 423-428
Category: Original Article

Overview

Background.
The presence of a microvolt T wave alternans (MTWA) is linked with increased risk of malignant arrhythmias and overall mortality. The most common method used for MTWA detection is a bicycle exercise test (BET). Method has still several limitations.

Aim.
To confirm that comparable MTWA results may be obtained by atrial and ventricular pacing during electrophysiology. To identify an anticipated relation between MTWA and malignant arrhythmia occurrence, or a death.

Methods.
We obtained MTWA during BET and consequently during atrial and ventricular pacing. All patients underwent a routine electrophysiology testing prior to prophylactic ICD implantation. The results were compared. The occurrence of malignant arrhythmias and death were registered during follow-up.

Results.
The group consisted of 39 patients. The results of MTWA obtained by BET, atrial and ventricular pacing did not show a significant difference. No difference was found among the three methods in the number of positive leads, and onset heart rate. Ventricular pacing increases the magnitude of MTWA comparing to the remaining two methods. No relation between MTWA results and occurrence of malignant arrhythmias or death was found.

Conclusions.
Atrial and ventricular pacing lead to comparable MTWA results as BET and may be used as alternative methods in patients where BET is not feasible.

Key words:
microvolt T wave alternans, bicycle exercise test, atrial pacing, ventricular pacing, malignant arrhythmias.


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