Practice viewpoints: AICD, who and when?

Automatic implantable cardioverter-defibrillator (AICD) is a costly but effective treatment modality for the prevention of sudden cardiac death (SCD). Causes of SCD are age-dependent, disease-specific and affected by racial/ethnic differences. Atherosclerotic heart disease (ASHD) is the most frequent underlying disease in individuals ≥35 years old. Available information suggests that Asians have a lower rate of SCD compared with African black individuals and Caucasians. Whether it is for secondary or for primary prevention, physicians should be educated to perform a thorough diagnostic work-up and be able to identify transient and/or reversible causes of lethal ventricular tachyarrhythmias such as acute myocardial infarction, residual ischaemia, electrolyte imbalance, adverse effect of drugs, valvular heart diseases, etc before contemplating AICD implantation. Correction of these reversible causes may avoid the necessity of AICD implantation. The status of left ventricular function is not sufficiently specific for guiding AICD implantation in ASHD patients after acute myocardial infarction. The urgent need is to develop better biological or physiological markers for risk stratification so that patients who would actually benefit from AICD implantation can be readily identified. Such an approach will make the use of AICD more cost-effective. Based on molecular genetic data obtained from patients with inherited structural cardiovascular diseases and malignant arrhythmogenic disorders in which the risk of SCD appears to be gene- and/or mutant-specific, a continuous search for genetic markers for better risk stratification is warranted in patients suffering from ASHD.