Spatial QT Dispersion Predicts Nonsustained Ventricular Tachycardia and Correlates with Confined Systodiastolic Dysfunction in Hypertrophic Cardiomyopathy.
OBJECTIVE
An increased dispersion of myocardial repolarization represents one of the mechanisms underlying the arrhythmic risk in hypertrophic cardiomyopathy (HCM). We investigated spatial myocardial repolarization dispersion indices in HCM patients with nonsustained ventricular tachycardia (NSVT) and, contextually, their main clinical determinants.


METHODS
Fifty-two well-matched HCM outpatients were categorized into two groups according to the presence or the absence of NSVT at 24-hour Holter electrocardiogram (ECG) monitoring. Each patient underwent a clinical examination, including Doppler echocardiogram integrated with tissue Doppler imaging, cardiac magnetic resonance, and 12-lead surface ECG to calculate the dispersion for the following intervals: QRS, Q-Tend (QTe), Q-Tpeak, Tpeak-Tend (TpTe), J-Tpeak, and J-Tend.


RESULTS
The NSVT group showed only QTe dispersion and TpTe dispersion values to be significantly higher than their counterparts. NSVT occurrence was independently predicted by late gadolinium enhancement presence (p=0.021) and QTe Bazett dispersion (p=0.030), the latter strongly associated with the myocardial performance index (MPI) obtained at the basal segment of the interventricular septum (p=0.0004).


CONCLUSIONS
Our data support QTe dispersion as an easy and noninvasive tool for identifying HCM patients with NSVT propensity. The strong relationship between QTe dispersion and MPI allows us to hypothesize an intriguing link between electrical instability and confined myocardial areas of systodiastolic dysfunction.
Department of Clinical and Molecular Medicine, 'Sapienza' University, Rome, Italy.
Damiano
D
Magrì
Gianfranco
G
Piccirillo
Agnese
A
Ricotta
Carlo Nicola
CN
De Cecco
Vittoria
V
Mastromarino
Andrea
A
Serdoz
Giuseppe
G
Muscogiuri
Mario
M
Gregori
Matteo
M
Casenghi
Filippo Maria
FM
Cauti
Giada
G
Oliviero
Maria Beatrice
MB
Musumeci
Antonello
A
Maruotti
Camillo
C
Autore
D002312:Cardiomyopathy, Hypertrophic / Q000150:complications* / Q000503:physiopathology; D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013599:Systole / Q000502:physiology; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology