ONLINE APPENDIX
Cardiac Magnetic Resonance Imaging
Cardiac Magnetic Resonance Imaging (CMR) was performed at baseline and at nine months
only using a 3T Magnetom Trio scanner (Siemens, Erlangen, Germany). Each patient was
positioned on the scanner in the supine position with body array and spine matrix RF coils for
signal reception. Images of the left ventricle (LV) were acquired using a 2D ECG-gated breath
hold segmented CINE TrueFISP sequence prescribed in the short-axis plane over an anatomical
region extending from the atrio-ventricular ring to the apex of the LV. The sequence repetition
time (TR) was 3.4ms, echo time (TE) 1.5ms, and (variable) flip angle of typically 50 o. Images
were acquired in step-wise fashion, each with 6mm thick with 4mm inter-slice gap.
Image analysis was performed by an independent MRI Physicist with cardiac MRI experience,
using commercially available software (‘Argus’, Siemens VB15, Erlangen, Germany). Regions of
interest were placed around the left ventricular borders at end diastole (as shown in Figure 1)
in order to derive LV mass. Papillary muscles were assigned to the LV blood pool if they could
be clearly distinguished from the myocardial wall, but otherwise they were assigned to the LV
mass. Protuberant trabeculae were assigned to the LV blood pool as far as possible. Contouring
was performed twice for every dataset to ensure that repeatability was consistently <5%.”