Early Invasive vs. Delayed Intervention for Atrial Fibrillation

Atrial fibrillation (AF) is a common heart rhythm disorder that affects quality of life and increases the risk of stroke and death. Its name comes from the fibrillation (i.e. quivering) of the two upper chambers (atrium) of the heart instead of a coordinated contraction, causing a rapid, irregular heart rate. In most cases, abnormal electrical impulses that set off AF come from the veins that carry blood from the lungs to the left upper chamber (atrium) of the heart (the pulmonary veins).

The standard treatment for patients afflicted with AF is to use medicines to control the AF episodes. When medications are ineffective, or result in significant side-effects, then patients typically move to an invasive catheter ablation procedure. These catheter ablation procedures have been developed to remove the faulty electrical pathways responsible for AF, and thus can potentially cure the arrhythmia.

Given that AF is a chronic progressive disease it is thought that curing atrial fibrillation early in its course will result in long-term benefit. The medications used to treat AF (“anti-arrhythmic drugs”) work to improve the symptoms of AF, but don’t treat the underlying disease. On the other hand catheter ablation has the ability to cure AF.

Our industry partner, Medtronic CryoCath (Pointe Claire, Quebec), has developed a purpose-built tool-set for AF catheter ablation. This system utilises a balloon catheter, which is placed in the upper left chamber of the heart via the veins in the groin. This catheter is able to freeze the heart tissue responsible for AF. By freezing the heart to very low temperatures the heart tissue responsible for AF can be killed, potentially curing the arrhythmia.

The basis of the current program is the thought that skipping the drug treatment phase will result in better outcomes for patients and the health care system. Specifically we think that the results of the surgical cryoablation procedure will be improved by early treatment, as the arrhythmia has had less time to alter the structural and electrical function of the heart. This should translate into better procedure results, better symptom and quality of life improvement, improved physical health, mental health and work performance, and a lower chance of developing more advanced arrhythmias. From a societal standpoint this may translate into reduced health care utilization (direct costs related to reduced emergency room visits and hospitalizations) as well as a reduction in days of work missed due to illness resulting in increased productivity (indirect costs).
The program consists of four projects, each examining a different aspect of early ablation:

Project 1 – the degree of arrhythmia elimination with early intervention vs. drug therapy
Project 2 – quality of life impact of early intervention vs. drug therapy
Project 3 – economic benefit of early intervention vs. drug therapy
Project 4 – the development of a patients’ decision-making tool regarding the optimal management of AF