Ventricular repolarization dynamicity provides independent prognostic information toward major arrhythmic events in patients with idiopathic dilated cardiomyopathy.
OBJECTIVE
The purpose of this work was to evaluate whether ventricular repolarization dynamicity predicts major arrhythmic events in patients with idiopathic dilated cardiomyopathy (DCM).


BACKGROUND
Arrhythmic risk stratification in patients with DCM is still an open issue. Ventricular repolarization analysis should provide relevant information, but QT interval and QT dispersion failed in predicting arrhythmic risk.


METHODS
The following parameters were evaluated in 179 consecutive DCM patients without history of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) at enrollment: QRS duration, QT interval corrected for heart rate, and QT dispersion at electrocardiogram (ECG); left ventricular ejection fraction (LVEF) and left ventricular end-diastolic diameter at echocardiogram; and nonsustained ventricular tachycardia (NSVT), heart rate variability (standard deviation of RR intervals), and ventricular repolarization dynamicity as measured by means of 24-h ECG monitoring, by calculating the slope of linear regression analysis of QT end and RR intervals (QTe-slope) and the value of mean QT end corrected for heart rate.


RESULTS
During a mean follow-up of 39 months, 9 patients died suddenly and 15 experienced VT and/or VF. At multivariate analysis, LVEF (p = 0.047), NSVT (p = 0.022), and QTe-slope (p = 0.034) were significantly associated with arrhythmic events. Among the patients with a low LVEF, NSVT and/or steeper QTe-slope identified a subgroup at highest arrhythmic risk.


CONCLUSIONS
In patients with DCM, QT dynamicity is independently associated with the occurrence of major arrhythmic events and improves the predictive accuracy of stratifying arrhythmic risk of these patients.
Iacoviello
Massimo
M
Institute of Cardiology, University of Bari, Bari, Italy. massimo.iacoviello@cardio.uniba.it
Forleo
Cinzia
C
Guida
Pietro
P
Romito
Roberta
R
Sorgente
Antonio
A
Sorrentino
Sandro
S
Catucci
Silvana
S
Mastropasqua
Filippo
F
Pitzalis
Mariavittoria
M
D000328:Adult; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis* / Q000401:mortality; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D016014:Linear Models; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume; D016019:Survival Analysis; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000401:mortality; D020257:Ventricular Remodeling / Q000502:physiology