However, for pulmonary vein anatomy and measurements, it requires a complementary procedure (ie, a simultaneous 3-D acquisition [MRA]). In a study that matched 400 patients to either preprocedural cardiac CT or cardiac MR (CMR), procedural characteristics (fluoroscopy time, procedure duration, pulmonary veins identified, targeted, and isolated) and arrhythmia recurrence rates were not significantly different [31]. In 2 studies, MRI heart was shown to have more accurate and reproducible measurements of LA volume, which, when increased, is an independent predictor or postablation recurrence [31,32]. Among various MR sequences, long inversion time-delayed enhanced CMR has the highest reported diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.2%) for thrombus assessment compared with TEE [28]. Multiple studies have shown that the identification of presence of LA fibrosis on late gadolinium enhancement imaging is an independent predictor of postablation arrhythmia recurrence [33- 36]. This has led to the investigation of LA substrate-based ablation, in which these atrial fibrotic lesions are targeted in addition to the pulmonary veins to curb recurrence rates [37]. The prospective, multicenter Efficacy of Delayed Enhancement MRI-Guided Ablation vs Conventional Catheter Ablation of Atrial Fibrillation (DECAAF II) trial showed that among patients with persistent AF, MRI-guided fibrosis ablation plus pulmonary vein isolation, compared with pulmonary vein isolation catheter ablation only, resulted in no significant difference in atrial arrhythmia recurrence [6]. Other LA parameters such as LA volume, sphericity, LA volume index, LA emptying function, peak strain, and LA T1 relaxation time have also been assessed with MRI heart [32].
Preprocedural Planning for Left Atrial Procedures in Atrial Fibrillation. However, for pulmonary vein anatomy and measurements, it requires a complementary procedure (ie, a simultaneous 3-D acquisition [MRA]). In a study that matched 400 patients to either preprocedural cardiac CT or cardiac MR (CMR), procedural characteristics (fluoroscopy time, procedure duration, pulmonary veins identified, targeted, and isolated) and arrhythmia recurrence rates were not significantly different [31]. In 2 studies, MRI heart was shown to have more accurate and reproducible measurements of LA volume, which, when increased, is an independent predictor or postablation recurrence [31,32]. Among various MR sequences, long inversion time-delayed enhanced CMR has the highest reported diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.2%) for thrombus assessment compared with TEE [28]. Multiple studies have shown that the identification of presence of LA fibrosis on late gadolinium enhancement imaging is an independent predictor of postablation arrhythmia recurrence [33- 36]. This has led to the investigation of LA substrate-based ablation, in which these atrial fibrotic lesions are targeted in addition to the pulmonary veins to curb recurrence rates [37]. The prospective, multicenter Efficacy of Delayed Enhancement MRI-Guided Ablation vs Conventional Catheter Ablation of Atrial Fibrillation (DECAAF II) trial showed that among patients with persistent AF, MRI-guided fibrosis ablation plus pulmonary vein isolation, compared with pulmonary vein isolation catheter ablation only, resulted in no significant difference in atrial arrhythmia recurrence [6]. Other LA parameters such as LA volume, sphericity, LA volume index, LA emptying function, peak strain, and LA T1 relaxation time have also been assessed with MRI heart [32].