Overview of Cardiac Arrhythmias and Treatment Strategies

Abstract

Maintenance of normal cardiac rhythm requires coordinated activity of ion channels and transporters that allow well-ordered propagation of electrical impulses across the myocardium. Disruptions in this orderly process provoke cardiac arrhythmias that may be lethal in some patients. Risk of common acquired arrhythmias is increased markedly when structural heart disease caused by myocardial infarction (due to fibrotic scar formation) or left ventricular dysfunction is present. Genetic polymorphisms influence structure or excitability of the myocardial substrate, which increases vulnerability or risk of arrhythmias in patients. Similarly, genetic polymorphisms of drug-metabolizing enzymes give rise to distinct subgroups within the population that affect specific drug biotransformation reactions. Nonetheless, identification of triggers involved in initiation or maintenance of cardiac arrhythmias remains a major challenge. Herein, we provide an overview of knowledge regarding physiopathology of inherited and acquired cardiac arrhythmias along with a summary of treatments (pharmacologic or non-pharmacologic) used to limit their effect on morbidity and potential mortality. Improved understanding of molecular and cellular aspects of arrhythmogenesis and more epidemiologic studies (for a more accurate portrait of incidence and prevalence) are crucial for development of novel treatments and for management of cardiac arrhythmias and their consequences in patients, as their incidence is increasing worldwide.

Keywords: cardiac arrhythmias; electrical remodeling; non-pharmacologic interventions; pathophysiology; pharmacology; structural remodeling.

Figure 1

Non-pharmacologic interventions: implantable devices and catheter ablation.

Figure 2

Non-pharmacologic interventions: ischemic conditioning; post-conditioning by angioplasty (left panel) and remote (or distant) organ conditioning (right panel). The middle panel shows site of myocardial ischemia that could be affected by ischemic conditioning treatment.