Cardiovascular magnetic resonance showed that left ventricular papillary muscle contribution to left ventricular mass was highest in LVH-positive Fabry disease (13%) compared to controls (7%; P<0.001).
Observational (n=478)
Does cardiovascular magnetic resonance reveal disproportionate left ventricular papillary muscle hypertrophy and altered T1 mapping in Fabry disease compared to other causes of left ventricular hypertrophy?
CMR demonstrates that disproportionate hypertrophy of left ventricular papillary muscles is most pronounced in Fabry disease and HCM, and in Fabry disease, it can occur without detectable storage by T1 mapping.
Absolute Event Rate: 13% vs 7%
p-value: p=<0.001
AIMS: Left ventricular papillary muscles (LVPM) can appear disproportionately hypertrophied, particularly in Fabry disease (FD) where storage appears detectable by cardiovascular magnetic resonance (CMR) T1 mapping. The aim of the study was to measure LVPM mass in heart diseases with left ventricular hypertrophy (LVH) and to gain insight into the mechanisms of LVPM hypertrophy in FD. METHODS AND RESULTS: Four hundred and seventy-eight cases were retrospectively recruited: 125 FD, 85 hypertrophic cardiomyopathy (HCM), 67 amyloid, 82 aortic stenosis (AS), 40 hypertension, 79 controls. LVPM contribution to LVM was manually contoured on CMR short axis cines. T1 values (septal, LVPM) were measured using ShMOLLI sequences in FD and controls. LVPM contribution to LVM was highest in LVH+ve FD and significantly increased compared to all other LVH+ve groups (FD 13 ± 3%, HCM 10 ± 3%, amyloid 8 ± 2%, AS 7 ± 3%, hypertension 7 ± 2%, controls 7 ± 1%; P < 0.001). LVH+ve HCM also had significantly increased LVPM. In LVH-ve cohorts, only FD had significantly increased LVPM (11 ± 3%; P < 0.001). In FD there was concordant septal and LVPM T1. LVH+ve FD: when septal T1 was low, LVPM T1 was low in 90%. LVH-ve FD: when septal T1 was normal, LVPM T1 was normal in 70% (indicating no detectable storage); when septal T1 was low, 75% had low LVPM T1 (indicating storage). LVPM hypertrophy was similar between the low and normal septal T1 groups (11 ± 3% vs. 10 ± 3%, P = 0.08). CONCLUSION: Disproportionate hypertrophy of LVPMs in LVH+ve hearts occurred in FD and HCM. This phenomenon also occurred in LVH-ve FD. Low T1 was not always present in FD LVPM hypertrophy, implying additional mechanisms activating hypertrophy signalling pathways.
Kozor et al. (Fri,) conducted a observational in Left ventricular hypertrophy (Fabry disease, HCM, amyloid, AS, hypertension) (n=478). Cardiovascular magnetic resonance (CMR) vs. Controls and other LVH etiologies was evaluated on Left ventricular papillary muscle (LVPM) contribution to left ventricular mass (LVM) (p=<0.001). Cardiovascular magnetic resonance showed that left ventricular papillary muscle contribution to left ventricular mass was highest in LVH-positive Fabry disease (13%) compared to controls (7%; P<0.001).