Left Atrial Dysfunction in Apical Hypertrophic Cardiomyopathy Assessed by Cardiovascular Magnetic Resonance Feature-tracking

Purpose: To evaluate the left atrial (LA) function in participants with apical hypertrophic cardiomyopathy (AHCM) by cardiovascular magnetic resonance feature tracking (CMR-FT). Materials and Methods: Thirty typical AHCM (TAHCM) patients, 23 subclinical AHCM (SAHCM) patients and 32 normal healthy volunteers who underwent CMR exam were retrospectively analyzed. LA reservoir, conduit, and contractile function were quantified by volumetric and CMR-FT derived strain and strain rate (SR) parameters from 2-chamber and 4-chamber cine imaging. Results: Compared with healthy participants, both TAHCM and SAHCM patients had impaired LA reservoir function (total strain [%]: TAHCM 31.3 +/- 12.2, SAHCM 31.8 +/- 12.3, controls 40.4 +/- 10.7, P<0.01; total SR [/s]: TAHCM 1.1 +/- 0.4, SAHCM 1.1 +/- 0.5, controls 1.4 +/- 0.4, P<0.01) and conduit function (passive strain [%]: TAHCM 14.4 +/- 7.6, SAHCM 16.4 +/- 8.8, controls 23.3 +/- 8.1, P<0.01; passive SR [/s]: TAHCM -0.5 +/- 0.3, SAHCM -0.6 +/- 0.3, controls -1.0 +/- 0.4, P<0.01). Regarding contraction function, although TAHCM and SAHCM patients had preserved active emptying fraction and strain (all P>0.05), patients with TAHCM had the lowest active SR value among the 3 groups (P=0.03). LA reservoir and conduit strain were both significantly associated with left ventricular mass index and maximal wall thickness (all P<0.05). A moderate correlation between LA passive SR and left ventricular cardiac index (P<0.01). Conclusions: The LA reservoir and conduit function are predominately impaired and appeared in both SAHCM and TAHCM patients.