Body surface electrocardiographic mapping to assess left ventricular diastolic overload in valvular heart disease

In order to assess diastolic overload by electrocardiogram (ECG), we performed body surface ECG mapping (MAP), and then compared the results with echocardiographic, roentgenographic and cardiac catheterization findings. Eighty-seven unipolar electrocardiograms were simultaneously recorded for the following groups: 1) 40 normal subjects, 2) 46 patients with diastolic overload [32 patients with aortic regurgitation (AR) and 14 patients with mitral regurgitation (MR)]. QRS isopotential maps were constructed at 10, 20, 30, 40, 50 and 60 msec from the QRS onset. On the potential departure map, the area where the QRS voltage was greater than the normal limits (mean + 2SD of normal control) was designated as "+2SD area". In patients with diastolic overload, +2SD area was found on the left anterior chest and back at 40, 50 and 60 msec from QRS onset. Subjects were classified into the following 3 groups according to the location of their +2SD area: 1) group A (n = 23) in which the +2SD area was found on the left anterior chest and back, 2) group B (n = 17) in which the +2SD area was found only on the back, and 3) group N (n = 6) in which no +2SD area was found. Group A had a markedly greater left ventricular end-diastolic internal dimension than the other groups (A 63.6 +/- 6.8 mm, B 53.9 +/- 5.5 mm, N 50.7 +/- 6.0 mm, A vs. B, N p less than 0.01), and a greater cardiothoracic ratio than the other groups (A 58.5 +/- 5.6%, B 52.5 +/- 7.0%, N 52.3 +/- 4.7%, A vs. B, N p less than 0.01). There was no significant difference in wall thickness among the 3 groups. The regurgitation severity assessed by cardiac catheterization was greater in group A than in the other groups. Among AR patients, the +2SD area was located on the upper back and the upper anterior chest, whereas among MR patients, it tended to be located on the lower portions. The potential departure map is a useful noninvasive analytic method for determining the extent and grade of diastolic overload. Furthermore, the location of the +2SD area may be used to discriminate between AR and MR.