Idiopathic isolated global T wave inversion: a report of 10 patients.

Ten patients (9 females and 1 male) between the age of 40-60 years with atypical chest pain and isolated global T wave inversion (in the absence of QRS complex or ST segment abnormality) and normal coronary arteries are described. The cause of these changes remains unknown.

Effect of pulmonary circulation on vector impedance cardiogram.

Vector impedance cardiograms in horizontal lead configuration [VICG(H)] were recorded in 34 normal subjects, 18 patients with mitral stenosis, 9 patients with mitral regurgitation, 14 patients with aortic regurgitation and 13 patients with non- cyanotic septal disorders. Data in normal subjects revealed that most of the phase reversal points in VICG(H) waveform did not coincide with those of conventional impedance cardiogram. The shape of VICG(H) waveform and values of VICG indices were observed to be markedly affected in patients having significant alteration in the pulmonary circulation and the changes observed were specific of the type of the disorder. The results of the study suggested that right side of the heart had dominant contribution in generation of VICG(H) waveform.

Physiological correlates of impedance plethysmographic waveform.

A review of investigations into the origin of impedance plethysmographic waveform is presented in this article. Attempts made by several investigators in the comparison of impedance plethysmographic estimations of peripheral blood flow with that obtained by standard methods are briefly described. Investigations indicating the negligible contribution from contact impedance at body electrode interface are highlighted. Temporal correlation of impedance plethysmographic waveform recorded from thorax with various important events of the cardiac cycle is summarised and various hypotheses on the genesis of this waveform are presented.