Inserting an ICD for DCM may a be great therapeutic success for the physician as well as the patient . But there is one big truth hidden behind the statistical screen.
Following study provides dramatic data from Maanhiem in Germany in about 561 patients who had ICD .The long term patient outcome after appropriate shocks were much worse than those without shocks .This was more pronounced in Ischemic DCM .
Source : Streitner et al ,University Medical Centre Mannheim, Mannheim, Germany PLoS One. 2013 May 10;8(5):e6391
The fact that these patients continue to throw VT , some thing is wrong in the cellular milieu or a fresh scar / fibrosis / ischemia is progressing .Further , the VTs and the subsequent shocks set in temporary hemodynamic instability .We have evidence , EF can be depressed for days worsening the long-term out come.
While it is easy to blame it on natural course of DCM , there are solid reasons to believe , shock induced myocardial damage is definitely contributing to this excess mortality.
One important clinical tip is to screen all these so called Idiopathic DCM patients who had appropriate shocks. They should be monitored for fresh signs of any systemic illness , like a connective tissue disorder , chronic granulomatous lesions like sarcoid etc .To our surprise some specific myocardial disease may unmask themselves in the natural history. Identifying them may offer a dramatic cure .
Final message
Some where along our EP mind-set we are conditioned to think , as along as there is an ICD in situ and it appropriately shocks, every thing is bliss ! Blame it on semantics . The word “appropriate” inappropriately soothes our nerves.
The fact of the mater is , every appropriate shock is a grim reminder that the heart in question is restless electrically and VT continue to emanate from diseased myocardium . It could mean either the LV is destabilising , or the original disease is progressing or a new disease is evolving .
Mean while, paradoxically , inappropriate shocks give us a quixotic comfort , since the heart is not really throwing any dangerous arrhythmia, after all it is the device related false alarm that could be easily reprogrammed!
Reference
Dr.S.Venkatesan MD 