Magnetocardiographic indices of left ventricular hypertrophy.

Objective We tested the hypothesis that multichannel magnetocardiographic (MCG) mapping can detect and quantify the degree of left ventricular hypertrophy (LVH). Design A cross-sectional study. Setting Helsinki University Central Hospital, a tertiary referral center. Participants Forty-two patients with pressure overload induced LVH by gender-specific echocardiographic criteria (LVH group), and 12 healthy middle-aged controls. Main outcome measures MCG QRS-T area integrals and QRS-T angle in magnetic field maps in relation to echocardiographic LVH as well as left ventricular (LV) mass and structure. Conventional 12-lead electrocardiographic (ECG) LVH indices (Sokolow–Lyon voltage, Cornell voltage, Cornell voltage duration product) were assessed for comparison. Results MCG QRS- and T-wave integrals provided complementary information of echocardiographic LV mass. Their combination, the QRS-T integral, and the QRS-T angle were increased in patients with LVH and, in those patients, correlated significantly with LV mass indexed to body surface area (r = 0.455; P = 0.002 and r = 0.379; P = 0.013, respectively). A QRS-T integral > 16 000 fT⋅s had identical sensitivity of 62% at 92% specificity as the gender-adjusted Cornell voltage duration product of 240 μV⋅s for the detection of LVH. Conclusions The MCG method can detect patients with LVH and also quantify the degree of LVH in patients with increased LV mass.