CT evaluation of pulmonary venous anatomy variation in patients undergoing catheter ablation for atrial fibrillation
Introduction
Atrial fibrillation (AF) is a supraventricular tachyarrhythmia characterized by uncoordinated atrial activation with associated deterioration of atrial mechanical function. It is the most common cardiac arrhythmia; becomes more prevalent with age [1]; and is associated with an increased long-term risk of stroke, heart failure and all cause mortality [2]. The pulmonary veins (PVs) are the dominant source of ectopic depolarizations initiating AF in the majority of patients with paroxysmal AF, and catheter ablation has emerged as a realistic treatment strategy targeting these pulmonary venous triggers [3].
Catheter ablation is indicated in patients with AF who remain symptomatic despite the use of at least one antiarrhythmic medication. Confirmed electrical disconnection of the left atrium from the PVs is the cornerstone of catheter-based therapies for paroxysmal AF, and is an important component of more extensive ablation procedures for persistent AF. Contiguous radiofrequency ablation lesions are created proximal to the PV ostium within the PV antrum until entrance conduction block is demonstrated by circumferential mapping within the vein. It is imperative to avoid ablation within or close to the PV ostium as this may be complicated by PV stenosis leading to pulmonary hypertension and symptoms of dyspnea and hemoptysis.
The PV ostia are typically identified by selective contrast venography performed via a transseptal puncture [4]. Although technological advances do permit the creation of virtual anatomies, allowing tagging of the PV ostial positions and detection of intracardiac catheters within a magnetic or electrical field, the majority of laboratories continue to rely to a greater or lesser degree on the real-time information offered by fluoroscopy. Readily visible and stationary fluoroscopic landmarks against which to reference the positions of the PV ostia include the bronchi and lateral borders of the vertebral bodies.
Cardiac computed tomography (CT) and magnetic resonance imaging are being used increasingly in both the planning and execution of catheter ablation procedures for AF [5], [6], [7], [8]. There are limited data to support a benefit in terms of clinical outcome and also reduced procedural radiation exposure to the patient and operator alike. As it is our practice to perform cardiac CT in advance of left atrial ablation procedures, the purpose of the study was twofold: (1) to characterize the drainage pattern of the PVs and the size and shape of the ostia in an unselected population undergoing catheter ablation for AF and (2) to establish whether there was a genuine anatomical relationship between the PV ostia and the lateral margin of the adjacent thoracic vertebral body that could be useful to facilitate safe catheter ablation to achieve PV isolation.
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Patient population
Between September 2002 and March 2008, 207 CT scans of the PVs (CTPV) were performed at our institution. There were 31 scans performed post ablation and these were excluded. A retrospective review of 176 CTPV studies was therefore carried out. The study population consisted of 176 patients (122 male, age range 29–78 years, mean 56; 54 female, 26–75 years, mean 58), all of whom were referred for CTPV prior to catheter ablation for paroxysmal and persistent AF.
Image acquisition
There were 114 non ECG-gated and 62
PV ostial dimensions/indices
The mean AP, SI, and ostium index values are shown in Table 1. The mean SI dimension for each type of vein was larger than the mean AP dimension, except in the case of a single right common ostium. The mean AP and SI dimensions for the right PVs were 17.37±3.57 and 18.57±3.25 mm, respectively. The mean AP and SI dimension for the left PVs were 15.50±3.38 and 18.27±3.31 mm, respectively. The AP and SI diameters of the accessory veins were significantly smaller than the dimensions of the other
Discussion
This paper reports a number of findings: (1) cardiac CT can be used to assess PV dimensions and degree of vein ovality; (2) there is considerable anatomic variability in pulmonary venous to left atrial drainage, as well as vein size and ovality; (3) the vertebral margins are not reliable markers of the position of the PV ostia; and (4) ECG-gated CTPVs have the effect of shifting all 4 PV ostia to the right (septally) compared to non ECG-gated CTPVs. All of these findings have potential
Acknowledgments
The authors are grateful for support from the NIHR Biomedical Research Centre funding scheme.
Dr. Phang Boon Lim is supported by the British Heart Foundation.
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Association of the left common ostium with clinical outcome after pulmonary vein isolation in atrial fibrillation
2021, Indian Pacing and Electrophysiology JournalCitation Excerpt :The identification of factors associated with post PVI prognosis is of fundamental importance, and pulmonary venous anatomical abnormality is one of the topics studied. With the exception of accessory pulmonary veins, the left common pulmonary venous ostium (LCO) (Fig. 1) is the most common anatomic abnormality, and may affect 37% of the population [4–7]. Anatomically the LCO lacks the pulmonary carina that separates the ostia of the upper and lower PV, that is, fusion of the 2 left PVs in the LCO [8].
Cryoballoon Versus Radiofrequency Ablation for Atrial Fibrillation − Is There a Role for Individualised Patient Selection?
2019, Heart Lung and CirculationSingle-shot antral isolation of a common pulmonary vein by the hot balloon
2019, HeartRhythm Case ReportsCitation Excerpt :Balloon-based ablation modalities such as the cryoballoon (CB) and hot balloon (HB) have been developed to simplify pulmonary vein (PV) isolation, with favorable outcomes.1–3 Nonetheless, a left common PV trunk (LCPV) of the superior and inferior PVs is not rare and the incidence has been reported to be 9%–83%.4,5 The balloon adaptability to this anatomic variation is challenging, especially in CB-based ablation because of its fixed balloon size.
Second-generation cryoballoon for pulmonary vein isolation in patients with pulmonary vein abnormality: Safety, efficacy and lessons from re-ablation procedures
2018, International Journal of CardiologyCitation Excerpt :Anatomic variants of LA shape and the PVs may pose technical challenges during AF ablation procedures or result in a more distal isolation, thus potentially compromising effective lesion formation and acute efficacy, increasing periprocedural complications, and affecting clinical outcomes. LCPV is the most common abnormality and present in 9–83% of the patients, followed by a right middle pulmonary vein (RMPV) [7, 8]. In previous studies, the LCPV was defined as the presence of bifurcated PVs entering the LA contour together and at a distance between the virtual border of the LA and the bifurcation of both PVs >5 mm.
The impact of left common pulmonary vein on cryoballoon ablation of atrial fibrillation. A meta-analysis
2020, Indian Pacing and Electrophysiology JournalCitation Excerpt :Therefore, the use of the CB in the setting of anatomic PVs variations is not widely accepted, conversely in the point by point radio-frequency ablation the operator is more flexible in handling the ablation catheter and he can adjust the lesion line on the basis of PV anatomy. The most common variant anatomy is a LCPV, followed by a right middle pulmonary vein [4]. Chierchia et al. showed the efficacy of a segmental superior and inferior approach with CB technology in the setting of LCPV [20].