Magnetocardiographic Study of Ventricular repolarization in hypertensive Patients with and without Left Ventricular Hypertrophy

The aim of this study was to evaluate magnetocardiographic (MCG) ventricular repolarization (VR) parameters in patients (pts) with essential hypertension (EH), associated or not with left ventricular hypertrophy (LVH). Methods: 20 pts with pharmacologically treated EH (average BP systolic: 148.5±11, diastolic: 91.5±4.9) since at 8.5±6.3 years, 7 without and 13 with evidence of LVH (4 at ECG, 8 at ECHO, and 1 at both), were studied with a 36-channel MCG system (sensitivity of 20 fT/Hz½) and with 12 lead-ECG, in an unshielded hospital room. To assess VR, HR-corrected, QTend, JTpeak, JTend, Tpeak-end intervals and QT dispersion (QTd) were measured from both MCG and ECG waveforms. The magnetic field gradient orientation (MFO) during the ST interval and Tpeak were also computed. 20 normal age-matched volunteers (NV) were used for comparison. Results: (see Table) As compared to NV, only MCG QTend and QTd were significantly longer in H pts without differences of QRS duration (p = .08). The difference was significant for QTd only (p < .05), if EH pts without LVH were excluded. ST MFO was greater in EH (p < .01). Conclusions: In pts with EH, MCG detects VR alterations and enhanced QTd, not evidence by 12-lead ECG.