ICDs are not insurance policies…

Although this study did not make headlines, its findings jumped off the page of the 566 page supplement listing all of HeartRhythm 2010’s abstracts. 
The presentation, from a Harvard group, revealed more sobering news on the risks of ICD implantation.  Enlightenment on ICD complications was hidden away in this study that primarily looked at something else. (It was hard to get a link to the exact page of the journal, so I added a ‘cut-paste’ version at the end of this post.)
Before going forward, as a prologue, it should be clear that I am strongly for ICD therapy. I also believe, however, for ICDs to improve outcomes they require wisdom in their application, skill in their implantation and vigilance in their follow-up.
The abstract was a small study of 30 ICD patients implanted for suspected Brugada Syndrome, a rare congenital heart rhythm disorder which many clinicians look for, but few find. The researchers present two clinically relevant observations. 
First, although all thirty patients had suspected Brugada Syndrome, only two (of 30) patients received appropriate shocks from their ICD; these two had previously known arrhythmias. The other 28 patients who were implanted for primary prevention (prophylactically) did not have an arrhythmia requiring ICD therapy. This is important news for practicing heart rhythm doctors, as all of us have faced the decision of whether to implant an ICD in a seemingly healthy patient with suspected Brugada syndrome. My count is five patients seen for this problem.
Even more clinically relevant, was the striking, but likely generalizable to the real world, rate of ICD complications. They report that five patients (15%) received thirteen inappropriate shocks. Additionally, of a young (average age 46), seemingly healthy cohort, the researchers report there were eight patients (24%) who developed 11 device related complications during follow-up.
At Harvard, nearly one in three ICD patients developed implant-related ICD complications, and one in five had painful inappropriate shocks.  
The point is not in criticizing a high complication rate; on the contrary, their intellectual honesty is laudable, and these complication rates probably mirror reality.
The larger point–which deserves more emphasis–in the reporting of real-life complications of ICD therapy is that ICDs are not akin to insurance policies against death. An insurance policy confers no inherent risk to the policy holder, whereas the ICD patient is exposed to well delineated finite risks. 
In providing extremely useful information on an uncommon disorder which electrophysiologists occasionally see, and realistic data on the important, but often down-played ICD risks, Dr William Stevenson’s group deserves significant praise for an outstanding abstract.
This is the kind of study that directly benefits practicing heart rhythm doctors.
Daniel Steven, MD, Kurt C. Roberts-Thomson, MBBS, PhD, Jens Seiler, MD, Keiichi Inada, MD, Usha Tedrow, MD, MS, Bruce Koplan, MD, MPH, Michael O. Sweeney, MD, Laurence M. Epstein, MD and William G. Stevenson, MD. Brigham and Women’s Hospital, Boston, MA
Introduction: Important progress has been made in understanding the pathophysiology and clinical characteristics of patients with Brugada syndrome (BS), but risk stratification remains difficult and controversial. Methods: Data of 58 patients referred for possible BS between 1995 and 2008 were retrospectively reviewed. A total of 33 (57%) patients underwent ICD implantation for BS, 30 (91%) with no documented sustained arrhythmia but had a positive drug challenge (n= 8 (27%)) or concerning findings at electrophysiology study (n= 22 (73%)). Results: The cohort consisted of 30 (91%) men and 3 (9%) women (age at ICD placement: 46.4 ± 11.7 years). The patients were followed for 7.9 ± 3.6 years. The ECG consisted of type I Brugada in 18 (54.5%) and type II in 12 (36.4%) patients. In three patients (9.1%) no ECG abnormality was observed in the absence of antiarrhythmic drugs. During the follow-up (FU), 2 patients (both received their ICD for secondary prevention) required 2 ICD shock for termination of one VT and one VF episode. In the primary prevention cohort no ventricular arrhythmias were noted. Five patients (15%) experienced 13 inappropriate shocks. In three patients, ICD discharge was related to rapid conducted atrial fibrillation and short coupled premature ventricular capture beats in one patients. In one patient, retrospective evaluation did not reveal the reason for ICD discharge. Eight patients (24%) developed 11 device related complications during the FU consisting of severe subclavian vein thrombosis (1), lead revision for high shock threshold (1), early battery depletion (4), pericardial effusion (1), revision for lead fracture (2) and infected devices (2). Conclusions: Risk stratification for patients with BS for primary prevention remains challenging. The present data indicate that patients without prior cardiac arrest seem to be at low risk for long-term occurrence of ventricular arrhythmias. ICD placement inherits the risk of device related complications and inappropriate shock delivery in this young cohort with a considerably longer life expectancy as compared to patients with structural heart disease requiring ICD implantation.