Electrophysiologic Therapeutics in Heart Failure in Adult Congenital Heart Disease

Heart failure (HF) affects millions of Americans and remains a serious problem in children, not only in terms of lives lost but also in terms of morbidities and its effect on society (Rossano et al., 2012). Arrhythmias are intricately intertwined in the pathophysiology of HF, and its implications in pediatrics are far reaching. Currently, it is estimated that as much as 50% of deaths in HF may be due to malignant arrhythmias (Tomaselli and Zipes, 2004). The mechanisms of these arrhythmias can be diverse and are dependent on the underlying electrophysiological changes caused not only by HF itself but also by the processes that led to the final pathway. In a population where etiologies of HF are varied, including primary or acquired cardiomyopathy and structural heart disease, this interplay can be quite complex. Indeed, both the acute and chronic treatments of HF itself are known to have proarrhythmic proclivity (Stump et al., 2000). Additionally, chronic sustained tachyarrhythmias can lead to myocardial ischemia secondary to prolonged periods of decreased diastolic filling, resulting in the progression of ventricular dysfunction (tachycardia-induced cardiomyopathy) (Fenelo et al., 1996). As such, understanding of the implications of arrhythmias and their management strategies in the different paradigms of HF in children remains essential. In this chapter, we aim to review the interplay of dysrhythmias and ventricular dysfunction and HF from several perspectives. Firstly, we hope to gain a better understanding of the molecular mechanisms for arrhythmogenesis in HF. We will then focus from a clinical perspective on both rhythm abnormalities implicated in causing HF as well as cardiomyopathy and their consequent arrhythmias. Lastly, we will discuss current concepts in the treatment of these arrhythmias.

Heart failure (HF) affects millions of Americans and remains a serious problem in children, not only in terms of lives lost but also in terms of morbidities and its effect on society (Rossano et al., 2012). Arrhythmias are intricately intertwined in the pathophysiology of HF, and its implications in pediatrics are far reaching. Currently, it is estimated that as much as 50% of deaths in HF may be due to malignant arrhythmias (Tomaselli and Zipes, 2004). The mechanisms of these arrhythmias can be diverse and are dependent on the underlying electrophysiological changes caused not only by HF itself but also by the processes that led to the final pathway. In a population where etiologies of HF are varied, including primary or acquired cardiomyopathy and structural heart disease, this interplay can be quite complex. Indeed, both the acute and chronic treatments of HF itself are known to have proarrhythmic proclivity (Stump et al., 2000). Additionally, chronic sustained tachyarrhythmias can lead to myocardial ischemia secondary to prolonged periods of decreased diastolic filling, resulting in the progression of ventricular dysfunction (tachycardia-induced cardiomyopathy) (Fenelo et al., 1996). As such, understanding of the implications of arrhythmias and their management strategies in the different paradigms of HF in children remains essential. In this chapter, we aim to review the interplay of dysrhythmias and ventricular dysfunction and HF from several perspectives. Firstly, we hope to gain a better understanding of the molecular mechanisms for arrhythmogenesis in HF. We will then focus from a clinical perspective on both rhythm abnormalities implicated in causing HF as well as cardiomyopathy and their consequent arrhythmias. Lastly, we will discuss current concepts in the treatment of these arrhythmias.