The J-point elevation is a common electrocardiographic variant considered for years as benign ECG manifestation. Recently a high prevalence of this pattern was found in patients (pts) with idiopathic VF but the screening of subjects at risk for sudden cardiac death is difficult. Aim of the study was to evaluate the long-term evolution of the incidentally found ECG pattern of prominent J-wave and the prevalence of late potentials (LPs) testing (depolarization marker) and time domain T-wave alternans (TD-TWA) (repolarization marker) in healthy young individuals over a period of 4 years.
We studied 70 healthy young subjects (subjs) (13w, 57m) out of 77 of a previous study population, mean age 30±13 years, with incidental discovery of J-point elevation on the 12 lead ECG, who underwent 4 years ago LP testing by SAECG and time domain T-wave alternans (TD-TWA) by 24 hours Holter monitoring. They underwent annual clinical assessment, new ECG, SAECG and TD-TWA over a period of 4 years. Seventy consecutive healthy young subjs with normal ECG served as control population. All pts consented to LPs were considered positive when at least 2 criteria were met. The greater TD-TWA was chosen for assessment and it was defined as positive when the max voltage was >75 uV.
In 4 years follow-up nobody developed any significant arrhythmias. The ECG localization of J-wave was initially in 15 subjs inferior, 40 anterior and 15 diffuse and remained identical without deterioration after 4 years. LPs were positive in 22 subjs (31%) and TD-TWA in 11 subjs (16%). Prevalence in healthy subjects with normal ECG is 4% and 3.2% respectively. Neither max TWA (p=0.751) nor LPs (p=0.493) were correlated to J- point ECG localization.
In our population of healthy young individuals with prominent J-point, the ECG pattern was not variable over time. The long-term prevalence of the depolarization marker LPs was significantly higher than in healthy subjects without prominent J-wave but it was not associated with any arrhythmic consequences in 4 years follow-up.