QT spatial dispersion and sudden cardiac death in hypertrophic cardiomyopathy: Time for reappraisal.
BACKGROUND
The 12-lead surface electrocardiographic (ECG) analysis is able to provide independent predictors of prognosis in several cardiovascular settings, including hypertrophic cardiomyopathy (HCM). The present single-center study investigated the possible ability of several ECG-derived variables in stratifying sudden cardiac death (SCD) risk and, possibly, in improving the accuracy of the 2014 European Society of Cardiology guidelines.


METHODS
A total of 221 consecutive HCM outpatients were recruited and prospectively followed. All of them underwent a full clinical and instrumental examination, including a 12-lead surface ECG to calculate the dispersion for the following intervals: QRS, Q-Tend (QT), Q-Tpeak (QTp), Tpeak-Tend (TpTe), J-Tpeak (JTp), and J-Tend (JT). The study composite end-point was SCD, aborted SCD, and appropriate implantable cardioverter defibrillator (ICD) interventions.


RESULTS
During a median follow-up of 4.4 years (25th-75th interquartile range: 2.4-9.4 years), 23 patients reached the end-point at 5-years (3 SCD, 3 aborted SCD, 17 appropriate ICD interventions). At multivariate analysis, the spatial QT dispersion corrected according to Bazett's formula (QTcd) remains independently associated to the study endpoint over the HCM Risk-SCD score (C-index 0.737). A QTcd cut-off value of 93ms showed the best accuracy in predicting the SCD endpoint within the entire HCM study cohort (sensitivity 56%, specificity 75%, positive predictive value 22%, negative predictive value 97%).


CONCLUSIONS
Our data suggest that the QTcd might be helpful in SCD risk stratification, particularly in those HCM categories classified at low-intermediate SCD risk according to the contemporary guidelines.
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy. Electronic address: damiano.magri@uniroma1.it.
Damiano
D
Magrì
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Caterina
C
Santolamazza
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Luca
L
Limite
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Vittoria
V
Mastromarino
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Matteo
M
Casenghi
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Paola
P
Orlando
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Erika
E
Pagannone
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Maria Beatrice
MB
Musumeci
Department of Scienze Economiche, Politiche e delle Lingue Moderne, Libera Università SS Maria Assunta, Rome, Italy; Centre for Innovation and Leadership in Health Sciences, University of Southampton, Southampton, UK.
Antonello
A
Maruotti
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Agnese
A
Ricotta
Department of Cardiovascular Sciences, University of Insubria, Varese, Italy.
Giada
G
Oliviero
Department of Cardiovascular, Respiratory, Anesthesiological, Nephrologic and Geriatrics Sciences, "Sapienza" University, Rome, Italy.
Gianfranco
G
Piccirillo
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy; IRCCS, Neuromed, Pozzilli (IS), Italy.
Massimo
M
Volpe
Department of Clinical and Molecular Medicine, "Sapienza" University, Rome, Italy.
Camillo
C
Autore
D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016757:Death, Sudden, Cardiac; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D012680:Sensitivity and Specificity
Guidelines; HCM Risk-SCD score; Hypertrophic cardiomyopathy; QT dispersion; Sudden cardiac death