Irfan Maqbool Khurram MD, Presenter: Nothing to Disclose

Farhan Maqbool MBBS, Abstract Co-Author: Nothing to Disclose

Roy Beinart MD, Abstract Co-Author: Nothing to Disclose

Hugh Calkins, Abstract Co-Author: Nothing to Disclose

Saman Nazarian MD, Abstract Co-Author: Scientific Advisor, Johnson & Johnson Advisory Board, Medtronic, Inc Research funded, Johnson & Johnson

Stefan L. Zimmerman MD, Abstract Co-Author: Nothing to Disclose

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is a major source of morbidity due to diminished cardiac function. This study describes a novel methodology for non-invasive measurement of left atrial (LA) function in patients with AF.

A total of 55 patients (81% male, 55% paroxysmal, age 60.4±10.2 years) underwent cardiac MRI prior to AF ablation. LA pressure was measured during sinus rhythm following trans-septal puncture for AF ablation. LA pressure (invasive) and volume (MRI derived) loops were prepared for all patients. LA diastolic function was assessed using a diastolic dysfunction score, defined as the ratio of the change in LA pressure to the change in LA volume during passive LA filling. Additionally, the ratio of pulmonary vein flow velocities during ventricular systole and diastole were obtained using phase contrast MRI (Figure, top panel, S/D ratio). LA volumes from 30 phases of the cardiac cycle were obtained from cine-MRI. LA systolic functions were calculated from the active emptying fraction during atrial contraction. Diastolic dysfunction scores greater than the 90th percentile (>1.6mmHg/ml) were considered to signify severe diastolic dysfunction.

The mean diastolic dysfunction score was 0.76±0.7 mmHg/ml. The score was higher (worst) in patients with persistent versus paroxysmal AF (1.0±0.9 versus 0.60±0.5,p=0.02). The mean S/D ratio was 1.04±0.6; and was lower in patients with persistent versus paroxysmal AF (0.9±0.5 versus 1.2±0.5, p=0.04). There was a negative linear association between diastolic dysfunction scores and S/D ratio measures (Figure, bottom panel, R2 0.262, p <0.001). In a multivariable analysis adjusting for age, LA systolic function and CHADS score, the S/D ratio was independently associated with the lack of severe diastolic dysfunction (OR 0.07 - 95% CI 0.007-0.85; p-0.03). 

The non-invasive MRI derived ratio of pulmonary vein flow velocities during systole and diastole are associated with the MRI/invasive derived diastolic dysfunction score, and appear to be a reasonable surrogate of LA diastolic function. 

Non-invasive PV flow characteristics by MRI yield comparable results to pressure/volume loops and may ease the assessment of LA diastolic function. More studies are needed to validate this association

Khurram, I, Maqbool, F, Beinart, R, Calkins, H, Nazarian, S, Zimmerman, S, MRI Based Non-invasive Measures Correlates with Invasive Measurements of Left Atrial Diastolic Function in Atrial Fibrillation Patients.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13025699.html