SUMMARY To determine the relationship of phase changes and abnormalities of ventricular contraction and conduction, we performed phase image analysis of blood pool scintigrams in 29 patients. Eleven patients had no evidence of blood pool contraction or ECG conduction abnormalities, four had contraction abnormalities, seven had abnormal conduction and seven had abnormalities of both variables.The phase delay generally related to the degree of contraction abnormality. The mean phase delay in hypokinetic segments differed from that in normokinetic segments in the same patient (p < 0.025), the phase delay of akinetic and dyskinetic segments differed from that in normokinetic segments (p < 0.001) and the phase delay in dyskinetic segments differed from that in akinetic segments (p < 0.005), but there was a significant overlap in the phase delay in normal and hypokinetic segments. Also, in patients with conduction abnormalities, the minimal associated regional phase delay presented a phase dispersion and a pattern of contraction consistent with the pattern of conduction and different from normal.A single study performed both at rest and with stress demonstrated the effect of heart rate on phase assessment and confirmed the independent effects of contraction and conduction on phase delay. Acquisition and analytic methods should add significantly to the resolution of the phase method.EQUILIBRIUM multiple-gated blood pool scintigraphy is an accurate noninvasive method for determining ventricular size and function.1' 2 Analytic methods that use digital computer manipulation have been applied to the blood pool study to extract additional data.8' 4 Such manipulation produces functional images as the ejection fraction image, which color-codes the end-diastolic frame of the blood pool scintigram in terms of regional ejection fraction, while the stroke volume image color-codes the end-diastolic frame in terms of regional stroke volume. Recently, the phase image has been developed. MethodsPhase image analysis was performed on two series of consecutive patients, in whom blood pool scintigraphy was required clinically for the noninvasive assessment of ventricular size and function. One group included patients with a normal ejection fraction and segmental wall motion and without electrocardiographic conduction delay. A second consecutive series of patients had reduced left ventricular ejection fraction and obvious contraction abnormalities on qualitative visual blood pool assessment or significant electrocardiographic intraventricular conduction delay with QRS > 0.12 second. All patients were in normal sinus rhythm.The history of each patient was reviewed for infarction, and a 12-lead ECG was obtained on the day of scintigraphy. Electrocardiographic abnormalities were noted. Evidence of infarction was confirmed historically and supported by the presence of ECG Q waves . 0.04 second in duration. Conduction abnormalities, including evidence of left bundle branch block and right bundle branch block,7 were documented and pacemaker ar...

SUMMARY To determine whether cardiomyopathy could be distinguished from coronary artery disease, we used thallium scanning to study 25 patients with severe left ventricular dysfunction and chronic heart failure. Ten patients had normal coronary arteries and idiopathic cardiomyopathy (ejection fraction 20 + 5 %), and 15 patients had multivessel coronary disease and left ventricular dysfunction (ejection fraction 25 + 6%). The exercise time and maximal heart rate were similar in the two groups. Two patients with cardiomyopathy and 11 with coronary artery disease had a positive exercise ECG (p < 0.05). Thallium scans showed perfusion defects in all 25 patients. The perfusion defects were complete in nine coronary artery disease patients (60%) and in one patient (10%) with cardiomyopathy (p < 0.05). Extensive defects involving more than 40% of the left ventricular circumference, the number of segments involved, redistribution on the 4-hour scan, lung uptake and ventricular size were similar in the two groups. Perfusion defects on thallium scanning can occur in patients with idiopathic dilated cardiomyopathy and chronic heart failure. Thallium scanning cannot be reliably used in patients with chronic heart failure to distinguish coronary artery disease from cardiomyopathy unless complete defects are present.

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