T-peak to T-end on ECG predicts VT/VF episodes in Brugada syndrome patients with implanted ICD
Episodes of ventricular tachycardia/ventricular fibrillation (VT/VF) in patients with Brugada syndrome can be predicted by electrocardiogram (ECG) findings at the time of implantable cardioverter-defibrillator (ICD) placement including T-peak to T-end interval, according to a study presented at the 23rd ASEAN Federation of Cardiology Congress (AFCC) held in Bangkok, Thailand.
T-peak to T-end interval of >110 mg also has high specificity for appropriate ICD shocks in this cohort, researchers said.
“Risk stratification in Brugada syndrome for prediction of either newly developed or recurrent VT/VF is very important, but still lacking,” researchers noted. “Previous studies reported that prolongation of the T-peak to T-end interval in an ECG may be associated with VT/VF.”
In total, the study analysed 32 Brugada syndrome patients (mean age 37±12.7 years; 96.9 percent male) with implanted ICDs due to primary prevention (n=3; 9.4 percent), history of syncope (n=12; 37.5 percent) and history of sudden cardiac death (n=17; 53.1 percent). [AFCC 2018, abstract P013]
Overall, 13 patients (40.6 percent) had 313 appropriate ICD shocks (sustained VT/VF) during a mean follow-up period of 7.3±4.9 years. These appropriate ICD shocks significantly correlated with history of sudden cardiac death and longer T-peak and T-end interval from an ECG.
T-peak to T-end ≥110 ms provided the optimal sensitivity and specificity values, with a sensitivity of 53.8 percent, specificity of 89.5 percent, positive predictive value of 77.8 percent, negative predictive value of 73.9 percent and positively likelihood ratio of 5.1.
A previous study revealed that no single clinical risk factor, nor electrophysiologic study (EPS) alone, could identify patients with the Brugada type 1 ECG who were at highest risk. Delise and colleagues suggested a multiparametric approach (including syncope, family history of sudden death and positive EPS) to identify populations at highest risk. [Eur Heart J 2011;32:169-176]
Additionally, patients with a spontaneous type 1 ECG and at least two risk factors were considered at highest risk, while the rest are at low risk, according to Delise and his team.
The present retrospective study sought to assess the T-peak to T-end interval, other clinical and electrocardiographic parameters as predictors of appropriate implantable ICD shocks in Brugada syndrome patients. Consecutive patients who underwent ICD placement due to Brugada syndrome at a tertiary care, academic hospital in Thailand between 1997 and 2017 were included.
Appropriate ICD shocks were predicted by analysing clinical and ECG parameters at first diagnosis. T-peak to T-end was defined as the duration from the peak to termination of T wave on lead V2.
An inherited disease, Brugada syndrome is characterized by a coved-type ST-segment elevation in the right precordial leads and elevated risk of sudden cardiac death, in the absence of structural abnormalities. Its diagnosis and definition are based on characteristic ECG pattern that can be present spontaneously or unmasked by drugs. [Eur Heart J 2017;40:3029-3034]