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  • br Conclusions br Disclosures br Introduction Since their in

    2019-05-15


    Conclusions
    Disclosures
    Introduction Since their introduction, at the end of fifties, cardiovascular implantable devices (CIEDs) have widely expanded in number and in their functions [1,2]. The dramatic increase in the number of CIEDs implanted in the last decade is mainly due to the aging of population and to the expanding indications for both primary prevention of sudden cardiac death (SCD) and non-pharmacological treatment of T-5224 failure, following a huge prevalence, indeed, of implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy devices (CRT-D/P) implants. On the basis of Eucomed data, 395,000 pacemakers (PM) and 62,000 ICDs were implanted in European countries, included in the Eucomed survey, during 2009. But as several countries are missing in the survey, real data of total implantation rate in European Community in 2009 reached the number of almost 500,000 PM and more than 71,000 ICDs [3,4]. If we look at data coming from a worldwide survey, more than 1 million PM and 300,000 ICDs were implanted only in the 2009 all over the globe [5], with an annual increase of CIEDs implants which is still today around 5% [6]. Besides such a huge increase of the number of patients wearing CIEDs, we are witness of a wide and unstoppable proliferation of technology generating electromagnetic signals. Thus, more and more tools and instruments for everyday use can create electromagnetic interference (EMI) potentially able to interact with CIEDs\' normal functioning.
    Non-medical environment
    Medical environment
    Conclusions
    Conflicts of interest
    Introduction Sudden cardiac death (SCD) has remained unsolved global problem. The actual rate of sudden death is still incompletely defined, and varies among the studies; however, the most widely cited estimation is in the range of 300,000–350,000 cases annually [1]. In recent prospective studies using multiple sources in the United States, Netherlands, Ireland, and China [2–4], SCD rates range from 50 to 100 per 100,000 in the general population [3]. Regional incidence of SCD has periodically been reported. The incidence of SCD in Europe is around one per 1000 population per year [2], similar to those in US. In Asia, data from Japan showed a similar incidence to that seen in the US and Europe, with the annual rate estimated to be 1–2 per 1000 population per year [5]. In China, from a project involving four major cities the annual incidence of SCD was estimated to be 0.42 per 1000 population [4]. In Hong Kong, the SCD incidence rate was found to be only 0.018 per 1000 population [3]. Malignant ventricular arrhythmia is the most commonly rhythm abnormality (80%) in patients with cardiac arrest [6,7]. Other bradyarrhythmias were also found associated with sudden death [6–10]. Prompt recognition and cardiopulmonary resuscitation save life in cardiac arrest patients, and external defibrillation is the most critical step to treat ventricular arrhythmia. This scheme has been adopted to the national guideline for patients who suffer from cardiac arrest. Due to success in treating ventricular arrhythmia, the implantable automatic defibrillators (ICD) were introduced for treating ventricular arrhythmia by Mirowki et al. [11]. Winkle et al. and Fogoros et al. have first shown the efficacy of ICDs in treating ventricular arrhythmia [12,13]. However, both studies were not randomized or controlled. Apart from SCD protection, there have been subsequent studies regarding the utilities of ICDs. In law of the minimum review, we discuss the prototype randomized controlled trials (MADIT trials) that studied the efficacy of ICDs and its applications.
    MADIT trial In early 1980, the Multicenter Post-infarction Research Group reported the declination of left ventricular function associated with the increase in the one-year cardiac mortality, with exponential relationship when ejection fraction less than 0.35 [14]. Non-sustained ventricular tachycardia, ventricular dysfunction and coronary artery disease were found to increased risk of sudden death. Buxton et al. have shown left ventricular ejection fraction is the strongest predictor for sudden cardiac death [15]. They have also shown that inducible VT significantly predicts the risk of death in patients with coronary artery disease [15]. Bigger et al. confirmed that unsustained ventricular tachycardia was associated with 30% two-year mortality rate in patient with coronary artery disease [16]. Antiarrhythmic drugs have been widely used to treat for non-sustained ventricular tachycardia; however, the survival benefit from antiarrhythmic therapy has not been proven [17]. Previous findings from major trial suggested that antiarrhythmic drugs class IC increased cardiac mortality in patients with coronary artery disease [18]. From these outcomes, the need for ICD trials was heightened to address the efficacy of sudden death prevention in these high-risk patients. The Multicenter Automatic Defibrillator Implantation Trial (MADIT or MADIT-I trial) was initiated in 1991 [19,20]. This was the first trial that demonstrated the role of ICD for primary prevention of SCD in asymptomatic patients with ischemic cardiomyopathy.