Impact of hypertrophic pattern and obstruction on cardiovascular magnetic resonance myocardial strain and left atrioventricular coupling in hypertrophic cardiomyopathy: a retrospective study.
LVH patterns on cardiac MR effectively differentiate myocardial strain in HCM, with P2 (septal+other non-apical segments) identifying a subtype with severe LVGLS impairment, P4 (isolated apical) showing preserved radial and circumferential strain, and obstruction independently correlating with compensatory enhancement of LVGCS.
Key Findings
Results
Left ventricular myocardial strain differed significantly among the four LVH distribution patterns in HCM patients.
199 HCM patients were divided into four patterns: P1 (isolated septal hypertrophy), P2 (septal+other segments, non-apical), P3 (apical+other segments), and P4 (isolated apical hypertrophy).
LVGLS, LVGRS, and LVGCS all differed significantly across the four groups (all p<0.05).
Cardiac magnetic resonance feature tracking was used to measure all strain parameters.
This was a retrospective study design.
Results
LVGLS impairment was most severe in the P2 pattern (septal plus other non-apical segments hypertrophy).
On multivariable analysis, P2 was independently associated with LVGLS impairment (β=2.14, adjusted p=0.007).
P2 represents a diffuse but non-apical hypertrophy pattern involving the septum and additional segments.
This association remained significant after adjustment for other covariates.
Results
Isolated apical hypertrophy (P4) was associated with better preserved radial and circumferential strain compared to other HCM patterns.
P4 showed better LVGRS and LVGCS than the other groups.
P4 was independently associated with better LVGRS and LVGCS on multivariable analysis (adjusted p<0.05 for both).
LVGLS did not show the same pattern of preservation in P4 as radial and circumferential strain.
Results
Obstructive HCM (HOCM) had higher absolute LVGRS and LVGCS than non-obstructive HCM (HNCM), but LVGLS did not differ between groups.
Absolute LVGRS and LVGCS were higher in HOCM than HNCM (both p<0.05).
LVGLS did not differ significantly between HOCM and HNCM.
After indexing LVGRS to left ventricular maximal wall thickness (LVGRS/LVMWT), the difference between HOCM and HNCM was no longer significant (p=0.999), suggesting the LVGRS augmentation may be attributable to wall thickness differences.
Obstruction was independently associated with LVGCS on multivariable analysis (adjusted p<0.05), interpreted as compensatory enhancement.
Results
HOCM was associated with higher left atrioventricular coupling index (LACI) and larger left atrial volumes compared to HNCM.
HOCM had higher LACI than HNCM (p<0.05).
Left atrial volumes were larger in HOCM than HNCM (all p<0.05).
LACI showed no independent association with hypertrophy pattern or obstruction on multivariable analysis (all adjusted p>0.05).
The authors concluded that LACI is not independently associated with LVH pattern or obstruction after accounting for other covariates.
Results
LACI was not independently associated with LVH distribution pattern or the presence of obstruction in HCM.
Multivariable analysis showed no independent association between LACI and hypertrophy pattern (all adjusted p>0.05).
Multivariable analysis showed no independent association between LACI and obstruction status (all adjusted p>0.05).
Despite HOCM showing higher LACI in unadjusted comparisons, this association did not persist after multivariable adjustment.
What This Means
This research suggests that the location and distribution of abnormal heart muscle thickening in hypertrophic cardiomyopathy (HCM) — a genetic heart condition where the heart muscle becomes abnormally thick — meaningfully affects how well the heart muscle squeezes and twists. Using a specialized cardiac MRI technique to measure heart muscle deformation (strain), the researchers found that patients whose thickening involved the septum and other non-apical regions (Pattern 2) had the most impaired ability to shorten along the length of the heart, while patients with thickening only at the tip of the heart (Pattern 4) retained relatively better pumping mechanics in other directions. This suggests that different patterns of HCM may represent meaningfully distinct subtypes with different functional consequences.
The study also found that patients with the obstructive form of HCM — where the thickened muscle blocks blood flow out of the heart — showed enhanced squeezing motion around the heart's circumference, which the researchers interpret as a compensatory mechanism. However, when accounting for the fact that obstructive HCM patients also tend to have thicker walls, the difference in another measure of squeezing (radial strain) disappeared, suggesting wall thickness rather than obstruction itself explains part of this difference. Obstructive HCM patients also had larger left atrial chambers, reflecting increased strain on the upper heart chambers.
Interestingly, a measure of how well the left atrium and left ventricle work together (left atrioventricular coupling index) was elevated in obstructive HCM patients in simple comparisons, but this association did not hold up after accounting for other factors, suggesting it is not independently driven by either the pattern of thickening or obstruction. These findings may help clinicians better characterize HCM subtypes using cardiac MRI, potentially informing risk assessment and individualized management strategies.
Li Y, Li Z, Chen S, Long L. (2026). Impact of hypertrophic pattern and obstruction on cardiovascular magnetic resonance myocardial strain and left atrioventricular coupling in hypertrophic cardiomyopathy: a retrospective study.. Open heart. https://doi.org/10.1136/openhrt-2026-004215