Rate versus Rhythm Control – An Open and Shut Case?

Accessible online at: www.karger.com/hed Atrial fibrillation (AF) and heart failure (HF) are the cardiovascular epidemics of the 21st century. AF is the most common sustained arrhythmia in man and is a significant cause of health care expenditure in the industrialized world. Although predominantly an arrhythmia of the aged (110% of individuals over the age of 65 years will experience AF), both the AF itself and the clinical context in which it occurs are very heterogeneous. The prevalence and persistence of AF and the relative inefficacy of pharmacotherapy have complicated the management of this rhythm disturbance and have motivated the search for alternative methods to manage patients. Catheter-based techniques are increasingly utilized rhythm and rate control therapeutic modalities in patients with AF [e.g. 1, 2]. Finally, the risk of thromboembolism adds to the complexity and patient dissatisfaction associated with treatment of AF. In the past several years four randomized clinical trials (AFFIRM, Dutch RACE, PIAF and STAF) have been published that demonstrate the equivalence (or noninferiority) of rate versus rhythm control strategies on mortality and other major trial endpoints [3–6]. In general the rate control therapeutic approaches were associated with a trend toward lower mortality, a reduced frequency of hospitalization and a lower incidence of drug-associated side effects. Case closed, right? Not so fast. The populations in these trials share a number of demographic features that may limit the generalizability of these data to all patients with AF. First, the mean age of patients in all of these trials exceeded 65 years. Second, patients in AF with their ventricular rate controlled were minimally symptomatic. Third, in most cases, patients had a prior clinically recognized episode of AF. Fourth, the efficacy of pharmacological rhythm control was at best marginal, thus patients were subjected to the risk of antiarrhythmic drugs with only marginal therapeutic benefit. As a corollary it is not surprising that patients in the rhythm control arms of these trials suffered thromboembolic complications at rates comparable to patients managed with rate control strategies. The limited efficacy of rhythm control strategies is in part responsible for the increased hospitalization rate in this group; patients were admitted to hospital for antiarrhythmic drug therapy, cardioversion and decompensation of underlying structural heart disease. Contemporary methods such as radiofrequency catheter ablation may afford improved rhythm control [1, 2] allowing for the constitution of a true rhythm control group. Landolina et al. [7] nicely summarize the limitations of a broad general application of rate control as a first-line management approach to AF. In addition they report a small prospective nonrandomized study of younger patients with advanced HF that suggests that a rhythm control strategy has a reasonable chance of success and may have a salutary effect on left ventricular function. It is important to note that in addition to the atrial remodeling