Background. QT dispersion (QTd) is increased in patients with dilated cardiomyopathy.
Increased QTd has been associated with the risk of sudden death. We studied: a) the relation
between QTd on 12-lead ECG and QTd-ECG Holter; b) the relation between QTd apex
(QTda) and QTd end (QTde) on ECG Holter and the risk of ventricular arrhythmias in patients with
dilated cardiomyopathy. Methods and Results. 65 patients with dilated cardiomyopathy (33 idiopathic and 32 post-ischemic
etiology; NYHA II-III) were studied. We divided the patients into: Group A -patients with
not-sustained ventricular arrhythmias-; and Group B -patients without arrhythmias-. A significant
direct correlation between QTd calculated from 12-lead ECG and from ECG Holter was
found in all patients. QTda/24h was not significantly different in the two groups (Gr.A 59.9±7.8
msec vs Gr.B 53.6±8.4 msec p=ns) while QTde/24h was significantly higher in Group A (Gr.A
81.9±5.9 msec vs Gr.B 44.5±6.8 msec; p<0.005). In post-ischemic etiology (32 pts; 17 with arrhythmias)
the correlation between QTde/24h and ventricular arrhythmias was confirmed (Gr.A
81.4±7.8 msec vs Gr.B 42.6±6.2 msec p<0.002). Conclusions. ECG Holter recordings can evaluate QTd as well as the QTd on 12-lead ECG.
An increased QTde/24h seems to be correlated with the occurence of ventricular arrhythmias in
patients with dilated cardiomyopathy and can then be a useful tool to select patients at high risk
for sudden death. (Heart International 2006; 2: 33-8)
Keywords
QTdispersion, ECG-Holter, Ventricular arrhythmias, Dilated cardiomyopathy, Sudden death
Article:
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Correspondence
Elia De Maria, MD, Via Tebaldini, 5, Sant’Eufemia, 25135 Brescia – Italy, e.demaria@inwind.it
