Ann Thorac Surg 2008;86:988. doi:10.1016/j.athoracsur.2008.04.054
© 2008 The Society of Thoracic Surgeons
New Technology
Invited Commentary
Adam E. Saltman, MD, PhD
Department of CT Surgery, Maimonides Medical Center, 4802 10th Ave, Brooklyn, NY 11219
(Email: adamsaltman{at}mac.com).
Atrial fibrillation, especially without adequate ventricular rate control, adversely affects cardiac output and leads to symptoms of fatigue, shortness of breath, and exercise intolerance. Prolonged tachycardia may even result in frank cardiomyopathy. Therefore, it is often desirable to restore sinus rhythm; however, when normal rhythm can not be restored, an attempt should be made to maximize cardiac output and ameliorate the detrimental effects of the rapid, irregular rhythm. This is especially true in persistent and permanent atrial fibrillation, in which pharmacologic and ablative rhythm-control therapies have been less than satisfying so far.
In this group of patients, rate control is often the best goal. Probably the most well-known and best documented therapy of this nature is atrioventricular nodal (AVN) ablation with permanent ventricular pacemaker implantation. Although AVN ablation does not remove the risk of thromboembolism, it has been shown to improve quality of life and prevent or even reverse tachycardia-induced cardiomyopathy. So for now, AVN ablation is an important standard against which other rate control strategies must be compared.
In this report, Yanulis and colleagues [1] describe their experience using coupled ventricular pacing in a canine model of persistent atrial fibrillation. Although coupled pacing did not correct the fibrillation, they found that by exploiting the phenomenon of post-extrasystolic potentiation ejection fraction (and presumably cardiac output) increased, and ventricular dimensions decreased. As this did not require ablation of the AVN or special lead implantation techniques, coupled pacing may become a very attractive therapy.
The next step is obvious, that is, coupled pacing should be compared with AVN ablation both in pre-clinical, controlled experiments, and in clinical trials. But good research raises more questions than it answers. Is measuring cardiac output enough? What about symptom relief? Should pacing be applied only from the right ventricle? We eagerly await this group's next investigations into this interesting and provocative therapy.
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References
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- Yanulis GE, Lim P, Ahmad A, Popovi
ZB, Wallick DW. Coupled pacing reverses the effects of persistent atrial fibrillation on the left ventricle Ann Thorac Surg 2008;86:984-988.[Abstract/Free Full Text]
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