Cardiovascular magnetic resonance imaging for accurate sizing of the left atrium: predictability of pulmonary vein isolation success in patients with atrial fibrillation.

PURPOSE: To prospectively determine the most reproducible approach for left-atrial size assessment using cardiovascular magnetic resonance (CMR) imaging in patients with atrial fibrillation and its value for prediction of pulmonary vein isolation (PVI) treatment success.
MATERIALS AND METHODS: Eighty patients underwent CMR imaging prior to PVI; the CMR examination included standard cine sequences, a multislice cine sequence in 4-chamber orientation with full left-atrial coverage, and a contrast-enhanced MR angiography of the left atrium. Left-atrial size was determined as: diameter, area, volume segmented from angiography, and diastolic/systolic volumes from cine imaging (Simpson's rule). All measurements were carried out by two independent observers and repeated by one observer to assess inter- and intrareader variability. Treatment success was defined as persisting sinus rhythm after PVI (follow-up period 12.6 ± 6.6 months).
RESULTS: All left-atrial measurements showed substantial intrareader agreement. Interreader agreement was substantial for diastolic/systolic left-atrial volumes only. Calculated bias was found to be minimal (0.1%-4.9%). Predictability of PVI treatment success was best using cine volumetric measurements (cutoff value for diastolic volume, 112 mL) yielding a sensitivity and specificity of 80% and 70%, respectively.
CONCLUSION: Left-atrial volumetry based on cine imaging represented the most reproducible approach to determine left-atrial size. PVI success was predicted best using cine volumetry.