Sudden cardiac death prevention

As left ventricular dysfunction is a major predictor of sudden arrhythmic death, cardiac death and total mortality, it can be stated that in general sudden cardiac death prevention is achievable with the combination of an implantable cardioverter defibrillator (ICD) and medical therapy. 

Costantini O, Hohnloser SH, Kirk MM, et al. The ABCD (Alternans Before Cardioverter Defibrillator) Trial Strategies Using T Wave Alternans to Improve Efficiency of Sudden Cardiac Death Prevention. J Am Coll Cardiol 2009 53(6) 471-9. 

The desired outcomes for treatment are to terminate the arrhythmia and restore sinus rhythm, and to prevent sudden cardiac death. 

In patients who have experienced VT and are at risk for sudden cardiac death, implantation of an implantable cardioverter-defibrillator (ICD) is the treatment of choice.44 An ICD is a device that provides internal electrical cardioversion of VT or defibril -lation of VF the ICD does not prevent the patient from developing the arrhythmia, but it reduces the risk that the patient will die of sudden cardiac death as a result of the arrhythmia. Whereas in the past ICD implantation required a thoracotomy, these devices now may be implanted transvenously, similarly to pacemakers, markedly reducing the complication rate. 

The desired outcomes for treatment include the (1) prevention of torsades de pointes, (2) termination of torsades de pointes, (3) prevention of recurrence, and (4) prevention of sudden cardiac death. 

The long-term goals after MI are to (1) control modifiable coronary heart disease (CHD) risk factors (2) prevent development of systolic heart failure (3) prevent recurrent MI and stroke and (4) prevent death, including sudden cardiac death. 

While most -blocking agents on acute administration have little direct electrophysiological effects, studies in rabbits [94] and man [95] have shown that chronic administration of y -blockers increases APD. This increase in APD (and hence refractory period) has been postulated to contribute to the effectiveness of -receptor blocking agents in the prevention of sudden cardiac death [94]. Direct Class III action has been claimed for the y -blockers oxprenolol (30) [96,97], nadolol (31) [96] and atenolol (10) [98] in addition... 

Abstract Two thirds of the nearly half a million deaths per year in the United States due to sudden cardiac death (SCD) is attributed to coronary artery disease (CAD) and most commonly results from untreated ventricular tachyarrhythmias. Patients with ischemic cardiomyopathy and left ventricular dysfunction are at highest risk for SCD, but this still defines only a small subset of patients who will suffer SCD. Multiple lines of evidence now support the superiority of implantable cardioverter defibrillator (ICD) therapy over antiarrhythmic therapy for both primary and secondary prevention of SCD in advanced ischemic heart disease. Optimization of ICD therapy in advanced ischemic cardiomyopathy includes preventing right ventricular pacing as well as the use of highly effective anti-tachycardia pacing to reduce the number of shocks. While expensive, ICD therapy has been shown to compare favorably to the accepted standard of hemodialysis in cost effectiveness analyses. 

Strategies for Prevention of Sudden Cardiac Death in Ischemic Cardiomyopathy... 

Implantable Cardioverter Defibrillators for Secondary Prevention of Sudden Cardiac Death... 

The results of MADIT II were met with some skepticism, but later confirmed by the recent Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) [24]. This study evaluated the benefit of ICD therapy versus amiodarone or placebo as primary prevention in over 2,500 patients with stable NYHA class II or III heart failure and EF < 35%, without the requirement for NSVT or EPS. Patients with both ischemic and nonischemic etiologies for cardiomyopathy were included. Over a follow-up of 4 years, there was no benefit of amiodarone over placebo for overall mortality, but ICD therapy resulted in a significant 23% reduction in overall mortality [p = 0.007] (Fig. 3.5). The benefit of ICD therapy was comparable for ischemic and nonischemic cardiomyopathy. 

Prevention of myocardial infarction (MI) and sudden cardiac death (SCD). 

Once the patient experienced HF symptoms, the risks for this patient will substantially increase. The objectives of any treatment in this Stage C population are (1) relief of the HF symptoms, (2) disappearance of HF symptoms and (3) prevention of progression of HF and sudden cardiac death. Treatments described in Stage A and B are also of value for this Stage C population. 

ICD implantation is recommended for prevention of sudden cardiac death in patients with ARVC with documented sustained VT or ventricular fibrillation. Drug therapy with amiodarone or stalol can be effective in selected patients with ARVC. 

Moricizine is indicated for the treatment of documented ventricular arrhythmias, particularly sustained ventricular tachycardia. Moricizine was evaluated in the CAST II clinical trial for the prevention of postinfarction ventricular premature complexes. It was ineffective and found to be proarrhythmic. Patients in the moricizine arm of the trial exhibited a greater incidence of sudden cardiac death than did controls. 

Prevent death, including sudden cardiac death... 

The indications for implantation of an ICD have expanded considerably (Table 17-7). Initially, its efficacy was evaluated in patients who had already suffered a documented episode of ventricular tachycardia or ventricular fibrillation (secondary prevention), but now primary prevention trials have been published or are being planned. These results will help clinicians in choosing the proper therapy for patients with life-threatening arrhythmias. For instance, the Sudden Cardiac Death in Heart Failure Trial (SCD-Heft) is a primary prevention trial that evaluated survival in patients withLV dysfunction... 

In AFCAPS/TexCAPS, a primary prevention trial conducted in 6605 men and women aged 57 to 63 years with average total cholesterol and LDL concentrations (<221 mg/dL and <150 mg/dL, respectively) who were treated with lovastatin 20-40 mg/day for 5.2 years, a 37% reduction p <. 001) was shown in the risk for first acute major coronary event (fatal or nonfatal MI, unstable angina, or sudden cardiac death)." The need for revascularization procedures also was reduced by 33% p <. 001). The implications of this trial are enormous potentially millions of normal people could benefit... 

Sudden Cardiac Death Survivors 2 Primary Prevention of Sudden Cardiac Death 3... 

Walker ML, Rosenbaum DS. Repolarization alternans implications for the mechanism and prevention of sudden cardiac death. Cardiovasc Res 2003 57(3) 599-614. 

Leaf, A., Kang, J.X., Xiao, Y.-F., and Bilhnan, G.E. 2003. Qinical prevention of sudden cardiac death by n-3 polyunsaturated fatty acids and mechanism of prevention of arrhythmias by n-3 fish oils. Circulation 107, 2646-2652. 

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