Ventricular tachycardia and fibrillation (VT/VF) complicating Brugada syndrome, 
a genetic disorder linked to SCN5A mutations, and VF complicating acute 
myocardial infarction (AMI) have both been linked to phase 2 reentry. Because of 
these mechanistic similarities in arrhythmogenesis, we examined the contribution 
of SCN5A mutations to VT/VF complicating AMI. Nineteen consecutive patients 
developing VF during AMI were enrolled. Wild-type (WT) and mutant SCN5A genes 
were co-expressed with SCN1B in TSA201 cells and studied using whole-cell 
patch-clamp techniques. One missense mutation (G400A) in SCN5A was detected in a 
conserved region among the cohort of 19 patients. A H558R polymorphism was 
detected on the same allele. Unlike the other 18 patients who each developed 1-2 
VF episodes during acute MI, the mutation carrier developed six episodes of 
VT/VF within the first 12 hours. All VT/VF episodes were associated with ST 
segment changes and were initiated by short-coupled extrasystoles. We describe 
the first sodium channel mutation to be associated with the development of an 
arrhythmic storm during acute ischemia. These findings suggest that a loss of 
function in SCN5A may predispose to ischemia induced arrhythmic storm. These 
results could be very useful for forensic implications regarding genetic 
screening in relatives.