open access

Vol 21, No 2 (2014)
Original articles
Published online: 2014-04-15
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Microvolt T-wave alternans in adults with complex congenital heart diseases

Olga Trojnarska, Aleksandra Ciepłucha, Agnieszka Bartczak, Lucyna Kramer, Stefan Grajek
DOI: 10.5603/CJ.a2013.0124
·
Cardiol J 2014;21(2):144-151.

open access

Vol 21, No 2 (2014)
Original articles
Published online: 2014-04-15

Abstract

Background: Sudden cardiac death (SCD) mostly resulting from ventricular arrhythmia remains a cause of mortality in 19–30% of adults with congenital heart defects. Indications for implantable cardioverter-defibrillators in primary prophylaxis are still under research. MicrovoltT wave alternans (MTWA) is one of the SCD risk stratification methods. We determined the incidence of MTWA in these patients and its coincidence with ventricular arrhythmia, as well as risk factors of ventricular arrhythmia/SCD.

Methods: 204 patients with complex congenital heart anomalies and 45 healthy volunteers underwent ambulatory ECG monitoring, a cardiopulmonary test, B-type natriuretic peptide assessment, echocardiography and an MTWA test. After excluding technically inadequate traces, the remaining 179 patients and 43 controls were classified into MTWA positive (+), negative (–) and indeterminate (ind) subgroups. Additionally, MTWA (+) and MTWA (ind) formed an ‘abnormal’ group, labeled MTWA (non–).

Results: Abnormal MTWA was observed more frequently in the study group compared to controls (59 [33.0%] vs. 1 [2.3%], p = 0.000001). The MTWA (non–) group compared to MTWA (–) presented a higher number of males (61.0% vs. 37.5%, p = 0.005), predominance of patients with NYHA > I (44.1% vs. 25.0%, p = 0.007), pulmonary hypertension (16.9% vs. 0.8%, p = 0.00007), lower blood saturation (97% [73–100] vs. 99% [69–100], p = 0.0003), higher incidence of malignant arrhythmia (9 [15.2%] vs. 3 [2.5%], p = 0.003), lower peak oxygen consumption VO2 [mL/kg/min] (23.1 ± 5.9 vs. 26.3 ± 6.7, p = 0.002), higher VE//VCO2 slope (36.0 [25–74] vs. 31.0 [21–58], p = 0.01). Multivariate logistic regression analysis proved that pulmonary hypertension (OR = 13.7, p = 0.03), male gender (OR = 10.4,p = 0.00002), VE/VCO2 slope (OR = 1.07, p = 0.045) and VO2 (OR = 0.89, p = 0.04) increasethe probability of MTWA (non–).

Conclusions: Abnormal MTWA is more frequent in adults with congenital heart diseases than in the healthy population. Its probability increases in patients demonstrating clinical findings conducive to lethal arrhythmia like heart failure and pulmonary hypertension.

Abstract

Background: Sudden cardiac death (SCD) mostly resulting from ventricular arrhythmia remains a cause of mortality in 19–30% of adults with congenital heart defects. Indications for implantable cardioverter-defibrillators in primary prophylaxis are still under research. MicrovoltT wave alternans (MTWA) is one of the SCD risk stratification methods. We determined the incidence of MTWA in these patients and its coincidence with ventricular arrhythmia, as well as risk factors of ventricular arrhythmia/SCD.

Methods: 204 patients with complex congenital heart anomalies and 45 healthy volunteers underwent ambulatory ECG monitoring, a cardiopulmonary test, B-type natriuretic peptide assessment, echocardiography and an MTWA test. After excluding technically inadequate traces, the remaining 179 patients and 43 controls were classified into MTWA positive (+), negative (–) and indeterminate (ind) subgroups. Additionally, MTWA (+) and MTWA (ind) formed an ‘abnormal’ group, labeled MTWA (non–).

Results: Abnormal MTWA was observed more frequently in the study group compared to controls (59 [33.0%] vs. 1 [2.3%], p = 0.000001). The MTWA (non–) group compared to MTWA (–) presented a higher number of males (61.0% vs. 37.5%, p = 0.005), predominance of patients with NYHA > I (44.1% vs. 25.0%, p = 0.007), pulmonary hypertension (16.9% vs. 0.8%, p = 0.00007), lower blood saturation (97% [73–100] vs. 99% [69–100], p = 0.0003), higher incidence of malignant arrhythmia (9 [15.2%] vs. 3 [2.5%], p = 0.003), lower peak oxygen consumption VO2 [mL/kg/min] (23.1 ± 5.9 vs. 26.3 ± 6.7, p = 0.002), higher VE//VCO2 slope (36.0 [25–74] vs. 31.0 [21–58], p = 0.01). Multivariate logistic regression analysis proved that pulmonary hypertension (OR = 13.7, p = 0.03), male gender (OR = 10.4,p = 0.00002), VE/VCO2 slope (OR = 1.07, p = 0.045) and VO2 (OR = 0.89, p = 0.04) increasethe probability of MTWA (non–).

Conclusions: Abnormal MTWA is more frequent in adults with congenital heart diseases than in the healthy population. Its probability increases in patients demonstrating clinical findings conducive to lethal arrhythmia like heart failure and pulmonary hypertension.

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Keywords

congenital heart disease, T-wave alternans, sudden cardiac death, ventricular arrhythmia, systemic right ventricle, univentricular heart, tetralogy of Fallot

About this article
Title

Microvolt T-wave alternans in adults with complex congenital heart diseases

Journal

Cardiology Journal

Issue

Vol 21, No 2 (2014)

Pages

144-151

Published online

2014-04-15

DOI

10.5603/CJ.a2013.0124

Bibliographic record

Cardiol J 2014;21(2):144-151.

Keywords

congenital heart disease
T-wave alternans
sudden cardiac death
ventricular arrhythmia
systemic right ventricle
univentricular heart
tetralogy of Fallot

Authors

Olga Trojnarska
Aleksandra Ciepłucha
Agnieszka Bartczak
Lucyna Kramer
Stefan Grajek

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