Novel approaches for the surgical treatment of atrial fibrillation: time for a guideline revision?

Abstract

Atrial fibrillation is a major health problem in Western countries, and is associated with considerable morbidity and resource consumption. Safe and reliable surgical techniques for the termination of this arrhythmia have been developed since the time of the original Cox "maze I" procedure. Novel equipment based on radiofrequency and microwave technologies can be employed to create transmural atrial lesions, even in the context of minimally invasive surgery to the atrioventricular valves via right minithoracotomy. The aim of this paper is to review the recent literature on this approach, and the clinical results in terms of arrhythmia termination and postoperative morbidity. With the aim to substantiate the practice of a simple, yet reliable, surgical ablation during minimally invasive heart valve surgery, we discuss the results of different patterns of atrial lesions having different degrees of surgical complexity. Finally, minimally invasive epicardial ablation for lone atrial fibrillation represents an emerging surgical indication. The results of state-of-the-art transcatheter ablation represent now its benchmark of comparison.

Keywords: atrial fibrillation; minimally invasive; outcomes; surgery.

Figure 1

Schematic drawing of surgical incisions. A) Full median sternotomy entails complete division of the sternal bone in the midline in order to expose the heart and the great vessels. B) The minimally invasive approaches for surgery to the atrioventricular valve(s) and AF ablation entail a right minithoracotomy, most frequently in the fourth intercostal space, the length of which ranges from 3 cm to 8–9 cm, depending on the technique. Abbreviation: AF, atrial fibrillation.

Figure 2

Setup of the port access system. Cardiopulmonary bypass is established by cannulation of the common femoral vessels (both for venous drainage from the inferior vena cava and arterial inflow in the common femoral artery). A second venous drainage cannula is placed in the superior vena cava through the right internal jugular vein. A right minithoracotomy in the inframammary groove is used to lead prosthetic material into the chest. A camera port is used to provide full videoscopic assistance during the procedure, and three additional instrument ports are used. An expandable balloon inserted through the femoral artery is used to clamp the ascending aorta from the inside (aortic endoclamp), and to deliver cardioplegia to protect the myocardium during the arrest period.

Figure 3

A) Left atrial lesions. Red interrupted line: Circular “box lesion” around the pulmonary vein orifices (or isolation of the left and right pulmonary cuffs independently) plus a lesion towards the mitral annulus (“mitral line”). Yellow interrupted line: Supplementary left atrial lesions, isolation of the left atrial appendage plus connecting line. B) Right atrial lesions. Cavocaval line, cavotricuspid line, isolation of the right atrial appendage plus connecting line towards the tricuspid annulus (the latter line is on the lateral right atrial wall). Abbreviations: RSPV, right superior pulmonary vein; RIPV, right inferior pulmonary vein; LSPV, left superior pulmonary vein; LIPV, left inferior pulmonary vein; RAA, right atrial appendage; LAA, left atrial appendage; SVC, superior vena cava; IVC, inferior vena cava.