A study of ECG pattern, cardiac structural abnormalities and familial tendency in patients with early repolarisation syndrome in South India.
BACKGROUND
Early repolarisation (ER) on ECG, which was initially believed to be benign, has of late been considered otherwise. Brugada syndrome has recently been thought to be an extension of the ER spectrum, and the familial tendency of the ER pattern is being highlighted. With attention being drawn to ER's association with idiopathic ventricular fibrillation (VF), the prognosis and lineage of patients with an ER pattern are under scrutiny.


OBJECTIVE
To analyse ER patterns on ECG, their presence in first-degree relatives and their association with structural heart disease. To classify different types of ER and estimate the prevalence of the high-risk notch/slur pattern in the population studied.


METHODS
We screened all patients presenting to our department from December 2011 to July 2014 for ER patterns. We excluded patients with other causes of ST elevation that mimicked the ER pattern, those aged <18 years, and those not willing to participate in the study. A complete physical examination, 12-lead ECG and echocardiography were performed on all study patients. Willing first-degree relatives were screened with a 12-lead ECG. Of the 963 patients with ER that we initially screened, 843 completed the study. A total of 4116 relatives were screened.


RESULTS
Of the 843 patients who completed the study, 687 (81.5%) were male and 156 (18.5%) were female. The majority were asymptomatic (70.11%), but had been referred for ECG abnormalities. Fifteen patients with chest pain were inadvertently thrombolysed and were later diagnosed to have ER. Their ER pattern was exaggerated during chest pain, which made this error highly likely. Among the 48 patients who had acute coronary syndrome (ACS), ER pattern was noticed in a different lead than those affected by ACS. Of these, 27 (56.25%) had ventricular tachycardia/VF during the acute phase. Six patients had electrical storm without evidence of ACS, and all had a global ER pattern with prominent notching/slurring on baseline ECG. The most common type of ER pattern was type I (lateral leads; 55.87%). Twenty-one patients had a Brugada pattern. Of all the patients with ER, only a third (34.16%) had the possibly high-risk notched/slurred ECG pattern. The majority (82.92%) had a structurally normal heart. We found that mitral valve prolapse (MVP), as assessed by >2 mm leaflet prolapse from the annulus, was more common in patients with ER (11.39%). Of the 4116 relatives screened, 2625 (63.78%) had an ER pattern; a quarter of family members had the inferolateral variety and over 60% of relatives had the lateral variety. We also noticed different ER patterns in the same family.


CONCLUSIONS
We found that exaggeration of the ER pattern during chest pain may lead to inadvertent thrombolysis. A notched/slurred ER pattern is found in only a third of patients, who need to be grouped separately, as they may constitute a high-risk category. Patients with ER had MVP at a higher prevalence (almost double) than the general population, probably explaining the high incidence of sudden cardiac death associated with MVP. A familial tendency to an ER pattern was found in more than half of first-degree relatives, with different ER patterns, even the Brugada pattern, found in the same family. This may be because Brugada and other ER patterns belong to the same spectrum and may share the same prognosis. Thus we conclude that further studies regarding ER, its association with MVP, risk stratification by notched ECG pattern, and familial distribution along with gene analysis are warranted.
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
K G
KG
Madhu
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
Vijo
V
George
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
T G
TG
Binu
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
R
R
Ranjith
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
Subair
S
Kunju
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
R
R
Baiju
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
K S
KS
Mohanan
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
R
R
Jayaram
Department of Cardiology , Government T D Medical College , Alappuzha, Kerala , India.
V V
VV
Radhakrishnan