Abstract
PurposeThe use of cardiac magnetic resonance (CMR) analysis has increased in patients with hypertrophic cardiomyopathy (HCM). Quantification of left ventricular (LV) measures will be affected by the inclusion or exclusion of the papillary muscles as part of the LV mass, but the magnitude of effect and potential consequences are unknown.MethodsWe performed Cine-CMR in (1) clinical HCM patients (n = 55) and (2) subclinical HCM mutation carriers without hypertrophy (n = 14). Absolute and relative differences in LV ejection fraction (EF) and mass were assessed between algorithms with and without inclusion of the papillary muscles.ResultsPapillary muscle mass in group 1 was 6.6 ± 2.5 g/m2 and inclusion of the papillary muscles resulted in significant relative increases in LVEF of 4.5 ± 1.8 % and in LV mass of 8.7 ± 2.6 %. For group 2 these figures were 4.0 ± 0.9 g/m2, 3.8 ± 1.0 % and 9.5 ± 1.8 %, respectively. With a coefficient of variation of 4 %, this 9 % difference in LV mass during CMR follow-up will be considered a change, while in fact the exact same mass may have been assessed according to two different algorithms.ConclusionsIn clinical HCM patients, CMR quantification of important LV measures is significantly affected by inclusion or exclusion of the papillary muscles. In relative terms, the difference was similar in subjects without hypertrophy. This underscores a general need for a uniform approach in CMR image analysis.
Highlights
Over the past few years, the use of cardiac magnetic resonance (CMR) imaging has steadily increased in patients with hypertrophic cardiomyopathy (HCM)
We studied the impact of inclusion and exclusion of the papillary muscles on the quantification of LVEF and left ventricular (LV) mass in clinical HCM patients with overt hypertrophy
The observed absolute differences in LV mass differed significantly between groups 1 and 2 (p < .01), while the absolute differences in LVEF were not significant (p = 0.13). To our knowledge this is the first study that addresses the basic question of how much inclusion or exclusion of the PMs affects everyday CMR image analysis in patients with HCM in particular, and in relation to a group of controls without hypertrophy
Summary
Over the past few years, the use of cardiac magnetic resonance (CMR) imaging has steadily increased in patients with hypertrophic cardiomyopathy (HCM). CMR is not yet part of the current risk stratification [1], several studies have been undertaken to address the impact of CMR for future patient management [2, 3]. CMR is the current gold standard for quantification of these parameters, because of its superior accuracy and reproducibility [7]. Uniformity in CMR image analysis is lacking on how to deal with measurements of the papillary muscles, despite recommendations in the current CMR guidelines. Studies on normal values of LV parameters used to include the papillary muscles in the LV mass [10,11,12]. We studied the impact of inclusion and exclusion of the papillary muscles on the quantification of LVEF and LV mass in clinical HCM patients with overt hypertrophy. We studied the impact in a group of subclinical HCM mutation carriers without hypertrophy
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