Magnetocardiographic indices of left ventricular hypertrophy

We tested the hypothesis that multichannel magnetocardiographic (MCG) mapping can detect and quantify the degree of left ventricular hypertrophy (LVH).

A cross-sectional study.

Helsinki University Central Hospital, a tertiary referral center.

Forty-two patients with pressure overload induced LVH by gender-specific echocardiographic criteria (LVH group), and 12 healthy middle-aged controls.

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.

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 16000 fT.s had identical sensitivity of 62% at 92% specificity as the gender-adjusted Cornell voltage duration product of 240 micro V.s for the detection of LVH.

The MCG method can detect patients with LVH and also quantify the degree of LVH in patients with increased LV mass.