JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
in a combined approach leading to the development of hybrid procedures incorporating epicardial lesion sets along with catheter-based endocardial approaches. Utilizing a hybrid approach to atrial fibrillation allows transmural, complete lesions and lesion sets can be completed in areas difficult to approach from an endocardial aspect alone when combining a minimally invasive epicardial approach with additional safety when applying lesions near the right phrenic nerve or esophagus. In this report, we describe a novel approach to the hybrid AF ablation, utilizing a comprehensive endovascular approach preceding and guiding the epicardial ablation that was created in response to the challenge of non-PAF and as a collaborative approach to optimize each approach’s strengths and overcoming the logistic difficulties of real-time intraoperative mapping. The endovascular approach was often met with anatomic complexities or large areas of arrhythmic substrate that could not be addressed with an endovascular approach alone, therefore resulting in recurrent atrial arrhythmias after multiple such procedures. By using the electrophysiology study and ablation to guide, direct and tailor the epicardial approach, 87.5% of patients with either persistent or long-standing persistent AF were free of atrial arrhythmias at one year, as documented with continuous monitoring, and all documented events were noted to be paroxysmal in nature requiring no re- intervention. This success rate validates the utility of a “reverse” hybrid approach (an endovascular guided epicardial approach) for the management of persistent and long-standing persistent atrial fibrillation. Literature has shown that there can be multiple extra-pulmonic vein sources of initiation and maintenance of AF with the most common sites including the superior vena cava, ligament of Marshall, coronary sinus, crista terminalis, and left atrial posterior wall. 19,20 The lesion set performed in this approach is systematic and certainly comprehensive which attributes to the high success rates. The posterior left atrial wall is highly arrhythmogenic with a high concentration of fibrosis with heterogeneity of conduction propertieswith sites of fast-organizedactivity andhigh incidence of dominant frequencies. 18,21 However, attempts at isolation of the posterior wall have proven difficult with either endocardial or
epicardial alone since the gaps in the lines are arrhythmogenic. In an answer to this challenge, a multidisciplinary approach utilizing a pericardioscopic convergent procedure to epicardially segment the posterior left atrium has garnered improved success rates. 12,22,23 We utilized the improved pericardial access via a thoracoscopic approach to perform a comprehensive segmentation of the left atrial posterior wall along with other substratemodification. This allowed us to successfully isolate the pulmonary veins and silence the posterior left atrium, resulting in superior clinical results. The autonomic ganglionated plexi (GP) have also been shown to likely contribute to the perpetuation of the AF substrate. GPs are anatomically located along the ligament of Marshall, the great vessels, at the right superior pulmonary vein (PV)-atrial junction, at the left superior PV-atrial junction, at the left inferior PV-atrial junction, and at the junction of the inferior vena cava. Direct stimulation of GPs trigger pulmonary vein ectopy and perpetuate atrial fibrillation by reduction of PV sleeve action potential duration, and shortening of the fibrillation cycle length. 24 Thus, we systematically performed GP mapping with ablation as this significantly increases success rates in patients with non-PAF. 25 Another strength of the described procedure is that it addresses the often ignored arrhythmogenic regions in the non-PAF heart such as the ligament of Marshall (LOM), left atrial appendage (LAA) and coronary sinus with its inter-atrial musculature sleeves. The LOM contains parasympathetic and sympathetic nerve fibers along with Marshall bundles that insert into the LA free wall and CS forming connections and substrate for reentrant excitation. 26 In addition, the anatomical proximity of the LOM to the sympathetic nervesmay provide amechanism for adrenergic atrial tachyarrhythmia in humans. Thus, we directed our lesion set to the LOM by having the surgeon perform a LOM dissection; furthermore, LAA clipping likely modified the remaining LOM as well by mechanical disruption. The LAA is under-recognized and under-addressed as potential substrate for initiating and maintain atrial fibrillation, particularly with redo ablations as depicted by DiBiase et al. 27 This was suggested in our small database when we saw five patients terminate their AF with LAA clipping. We believe that the LAA clipping provides both a thromboembolic and an electrophysiologic benefit.
Recurrence Details
Arrhythmia during blanking period
Time to Recurrence (days) 319
Recurrence Rhythm
Repeat ablation required
DCCV Yes
Patient AF Type 2 LSPeAF
Prior EP
Yes
Yes
AT
No
6
LSPeAF
Yes
No
341
AT
Yes
No
8
PeAF
Yes
Yes
303 234
AT
No No
No No
35
LSPeAF
No
No
AF
38
PeAF
No
Yes
108
AT
No
No
Table 4. Recurrence Details AF: Atrial fibrillation AT: Organized atrial rhythm DCCV: Cardioversion required
LSPeAF: Long-standing persistent atrial fibrillation PeAF: Persistent atrial fibrillation
J La State Med Soc VOL 169 MAY/JUNE 2017 75
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