Assessment and significance of left ventricular mass by cardiovascular magnetic resonance in hypertrophic cardiomyopathy.
OBJECTIVE
Our aim was to assess the distribution and clinical significance of left ventricular (LV) mass in patients with hypertrophic cardiomyopathy (HCM).


BACKGROUND
Hypertrophic cardiomyopathy is defined echocardiographically by unexplained left ventricular wall thickening. Left ventricular mass, quantifiable by modern cardiovascular magnetic resonance techniques, has not been systematically assessed in this disease.


METHODS
In 264 HCM patients (age 43 +/- 18 years; 75% men), LV mass by cardiovascular magnetic resonance was measured, indexed by body surface area, and compared with that in 606 healthy control subjects.


RESULTS
The LV mass index in HCM patients significantly exceeded that of control subjects (104 +/- 40 g/m(2) vs. 61 +/- 10 g/m(2) in men and 89 +/- 33 g/m(2) vs. 47 +/- 7 g/m(2) in women; both p < 0.0001). However, values were within the normal range (< or = mean +2 SDs for control subjects) in 56 patients (21%), and only mildly increased (mean +2 to 3 SDs) in 18 (16%). The LV mass index showed a modest relationship to maximal LV thickness (r(2) = 0.38; p < 0.001), and was greater in men (104 +/- 40 g/m(2) vs. 89 +/- 33 g/m(2) in women; p < 0.001) and in patients with resting outflow obstruction (121 +/- 43 g/m(2) vs. 96 +/- 37 g/m(2) in nonobstructives; p < 0.001). During a 2.6 +/- 0.7-year follow-up, markedly increased LV mass index proved more sensitive in predicting outcome (100%, with 39% specificity), whereas maximal wall thickness >30 mm was more specific (90%, with 41% sensitivity).


CONCLUSIONS
In distinction to prior perceptions, LV mass index was normal in about 20% of patients with definite HCM phenotype. Therefore, increased LV mass is not a requirement for establishing the clinical diagnosis of HCM. The LV mass correlated weakly with maximal wall thickness, and proved more sensitive in predicting outcome.
Olivotto
Iacopo
I
Regional Referral Center for Myocardial Diseases and Radiology Unit, Azienda Ospedaliera Universitaria Careggi, Florence, Italy. olivottoi@ao-careggi.toscana.it
Maron
Martin S
MS
Autore
Camillo
C
Lesser
John R
JR
Rega
Luigi
L
Casolo
Giancarlo
G
De Santis
Marcello
M
Quarta
Giovanni
G
Nistri
Stefano
S
Cecchi
Franco
F
Salton
Carol J
CJ
Udelson
James E
JE
Manning
Warren J
WJ
Maron
Barry J
BJ
D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D010641:Phenotype; D018570:Risk Assessment; D013318:Stroke Volume; D014463:Ultrasonography