Early repolarization in the right precordial leads(V1-3) occurs in up to 5% of the population (AMJ Med 2003) and is considered as benign. The same repolarization pattern in the inferior leads is not and has been associated with increased arrhythmogenicity ie., ventricular fibrillation. Studies now show that elevation of the J-point in the inferior + lateral leads of greater than 2mm, is associated with increased arrhythmogenicity. If you have a patient with a ventricular arrhythmia, or a history of syncope and you have ruled out all other causes, don’t disregard an early repolarization, in the infero-lateral leads. Refer these patients to cardiology. They may need monitoring. More studies need to be done in this area. The current work is very recent, so your cardiology registrar may not be aware of them.
Here are two studies to consider.
STUDY 1:
Haissaguerre M. etal NEJM May 8, 2008 358:19 “Sudden Cardiac Arrest Associated with Early Repolarization”
- 206 case subjects under 60 years of age enrolled.
- Patients all had history of idiopathic ventricular fibrillation (i.e. normal echo, normal angio and no known repolarization abnormalities). They were matched with a control group.
- Early repolarization, in this study was defined as a J-point (QRS-ST Junction) in at least 2 leads of >1mm (0.1mV)
RESULTS
- Early repolarization occurred more frequently in the case patients than controls (p<0.001)
- The early repolarization was present in inferior and lateral leads.
- Mapping was performed on only a limited (n=8) number of cases, but did show ectopic patterns in the ventricular myocardium or Purkinje tissue.
- Case patients all received an implantable defibrillator and were followed. Those with the early repolarization showed a trend towards more significant episodes of recurrence of VF (P=0.001). The median number of episodes of VF in the repolarization group was 8, compared to 2 in the control group.
CONCLUSIONS
This study suggests a relationship between early repolarization and sudden cardiac arrest. It demonstrated a greater prevalence of early repolarization in inferolateral leads, in patients who had idiopathic ventricular fibrillation causing syncope and cardiac arrest.
STUDY 2:
Tikkanen et al NEJM December 24 2009 361; 2529 Long-term outcome associated with early repolarization in electrocardiography.
This paper looked at prognostic significance of J-point elevation infero-laterally. (ECG diagrams are taken from that paper)
- 5,676 men and 5,188 women were studied. They were part of a previous heart disease study in Finland. 10,957 patients between ages of 30 and 59.
- ECG’s were recorded, questionnaires related to past history and medication use completed.
- J-point elevation was present in 5.8% of group
– 3.5% in inferior leads
– 2.4% in lateral leads
– 0.1% in both inferior and lateral
- Follow-up was over 30 + 11 years
- 56.5% of patients died (n=6133)
- 32.1% of all deaths (n=1969) were cardiac
– Of these deaths 40.4% (n=795) were due to sudden arrhythmias.
- J-point elevation of at least 0.1mv (1mm) in inferior leads showed a trend towards higher death rate from cardiac causes but not significant (p=0.03)
- BUT a J-point elevation of >0.2mV (2mm) in inferior leads, was associated with an increased risk of death from cardiac causes (p<0.001) and from arrhythmias (p<0.001)
- J-point elevation in the lateral leads did not predict death from arrhythmia.
CONCLUSION
J-point elevation of >2mm in the inferior leads is associated with an increased risk of death from arrhythmia.
Something else to think about. I hope it helps.
Peter Kas
