Abstract 17470: Scar Burden is Related to Left Ventricular Diastolic Function in Patients with Hypertrophic Cardiomyopathy and Preserved EF
Objectives: Evaluate the relation between scar extent and left ventricular (LV) diastolic function in hypertrophic cardiomyopathy (HCM) patients with normal EF and without previous septal reduction procedures. Methods: HCM patients (n = 29, age 61±11 yrs, 11 females) underwent imaging by cardiac magnetic resonance (CMR) and 2-D, Doppler, and speckle tracking echocardiography. CMR images were acquired after an intravenous bolus of gadolinium. LV volumes, EF, mass, and scar tissue distribution and extent were obtained by CMR. Diastolic function was assessed by mitral inflow, pulmonary venous flow, early (e') and late diastolic (a') velocities at septal and lateral mitral annulus, and longitudinal/radial early diastolic strain rate.
Results: Pts had normal LV volumes (end diastolic or EDV: 127±31, end systolic: 29±14 ml), EF (77±8%), increased LV mass (223±66 gm) and increased LA volume (44±19 ml/m2). Peak oxygen consumption was 18±5.5 ml/kg/min. Scar was noted in 82 septal, 21 lateral, 11 anterior and 16 inferior segments. Mean scar burden was 6±5% (range 0–20%). Scar extent was not related to presence or severity of dynamic obstruction whether at rest or upon provocation (p>0.3), but increased LV mass/EDV ratio was associated with higher scar burden (r= 0.57, p =0.002). No relation was observed between scar burden and indices of LV relaxation and early diastolic strain rate. On the other hand, significant correlations were noted between scar burden and indices of LV stiffness and filling pressures. This included deceleration time of mitral E velocity (r = −0.44, p =0.02), duration of atrial reversal velocity in pulmonary veins (0.43, p = 0.037), septal a' (r=−0.54, p<0.01), E/e' ratio (0.55, p<0.01), and ratio of septal E/e' to EDV (r= 0.42, p= 0.027).
Conclusion: In HCM patients with normal EF, scar burden is associated with increased LV stiffness and filling pressures. It is not related to dynamic obstruction nor to indices of myocardial relaxation. Given the irreversible nature of replacement fibrosis, the lack of a relation between it and dynamic obstruction, and its consistent association with increased chamber stiffness, these findings may account for limited symptomatic improvement after septal reduction procedures in patients with a large scar burden.
- Cardiovascular imaging
- Diastolic function
- Hypertrophic cardiomyopathy
- Magnetic resonance
- © 2010 by American Heart Association, Inc.