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PubMed1984

Phase image characterization of localized and generalized left ventricular contraction abnormalities.

To evaluate their phase image characteristics, 61 patients with varying left ventricular contraction abnormalities were studied. In 16 normal patients, the left ventricular phase image revealed a homogeneous pattern, a narrow bell-shaped histogram and an orderly spatial progression of phase angle (phi). In 16 patients with segmental abnormalities, the left ventricular phase image showed a region of uniformly delayed phase angle corresponding to the site of segmental abnormality, a discrete secondary histogram peak and a discontinuous, but orderly, spatial progression of phase angle. The mean phase angle (phi) (23.6 +/- 15.7 degrees) and its standard deviation (17.6 +/- 7.2 degrees) differed from the normal group (7.6 +/- 11.1 degrees, p less than 0.002 and 8.9 +/- 2.8 degrees, p less than 0.001). The percent of end-diastolic volume involved in the segmental abnormality, calculated using phase data in 13 of these and in 11 additional patients with a left ventricular aneurysm on ventriculography, correlated well with the percent akinetic segment on scintigraphic (r = 0.78) and angiographic (r = 0.84) study. In 18 patients with generalized abnormalities, the left ventricular phase image revealed multiple regions of inhomogeneous phase angle, a grossly irregular histogram and a disorderly spatial progression of phase angle. The mean phase angle (56.4 +/- 23.9 degrees) and standard deviation (27.3 +/- 7.1 degrees) differed from values in the normal group and from patients with segmental contraction abnormalities (both p less than 0.001). The mean phase angle and its standard deviation in scattered regions with abnormally prolonged phase angle differed significantly from abnormal regions in patients with segmental abnormalities (both p less than 0.001). These patterns of left ventricular phase angle demonstrate characteristics that may help differentiate between ventricles with segmental and generalized contraction abnormalities. Their relation to underlying pathophysiology and potential clinical implications should be considered.

Adult↗

PubMed1984

Phase image evaluation of patients with ventricular pre-excitation syndromes.

To localize bypass pathways, left and right ventricular regions were analyzed at rest by phase image analysis in 18 patients with ventricular pre-excitation syndromes. These were compared with image findings in 18 normal subjects. In each of 17 patients with pre-excitation, the site localized on electrophysiologic study correlated closely with the region of earliest ventricular phase angle. This site could be objectively separated from that in normal subjects in each of eight patients with an active left-sided pathway and in both patients with a right-sided pathway. Those with a septal pathway revealed earliest septal phase angle, but could not be separated from normal subjects. In the eight patients with an active left bypass tract, the onset, upstroke and peak of the left ventricular phase histogram preceded those of the right ventricular histogram. Those with a left-sided pathway demonstrated a mean left ventricular phase angle, a difference between mean left and mean right ventricular phase angle and a difference between earliest left and right ventricular phase angles which was significantly less than that in normal subjects (p less than 0.05). These variables presented characteristic converse changes in those with a right-sided pathway. Sequential phase changes in 10 studies suggested "fusion" of normal septal with lateral bypass fronts. Electrocardiographic and electrophysiologic localization of the bypass pathway agreed in only 8 of 14 patients with a recognized delta wave. The phase image represents a new, noninvasive method of evaluating ventricular pre-excitation. The method may provide useful information complementary to that of electrocardiographic and electrophysiologic analysis.

Adolescent↗