ICD in post myocardial infarction LV dysfunction
- Previous MI has been documented in as many as 75% of SCA. SCD rates in those with previous MI is 4-6 times that in general population. High risk indicators are late VT/VF, LV dysfunction, frequent VPC and NSVT and inducible VT at EPS. ICD is recommended in VT/VF survivors with no reversible etiology. If there is inducible VT/VF, those with LVEF less than or equal to 40% need an ICD. The cut off LVEF is less than or equal to 35% those in symptomatic patients. The cut off is lower at LVEF of 30% or less regardless of any arrhythmic events or symptoms. ICD does reduce mortality significantly in those with post MI LV dysfunction.
- Early ICD implantation was not shown to reduce mortality in previous studies, though recent studies, especially with risk stratification haves shown some promise. The earlier negative trial was DINAMIT.