Detection of Segmental Wall Motion Abnormalities With Nuclear Stethoscope

A segmental wall motion abnormality (SWMAb) will affect ventricular compliance in such a way as to disturb the temporal relationships of the ventricular emptying and filling curve. Therefore, we hypothesize that a change in an externally recorded left ventricular (LV) time/activity (T/Act) curve could be used to predict the presence of an existing SWMAb. Two parameters of the LV T/Act curve were evaluated: transformation of the normal two component (rapid and slow) filling phase to (1) a single rapid filling phase, and (2) to a three or more component filling phase curve, excluding the atrial kick. We examined 115 patients at rest (heart rate < 90/min) in whom the Nuclear Stethoscope (NS) T/Act curve was obtained 30 min before a standard multiple gated (MuG) study that was viewed in cine mode for SWMAb. Normal SWM was seen in 64 by MuG, while 51 had SWMAb of marked or moderate degree. An abnormal filling phase (either of the above two criteria) was seen in 45 of the 51 with MuG SWMAb (.88 sensitivity), while a normal filling phase was present in 62 of the 64 with normal MuG (.97 specificity). We also tested the approach proposed by Strashun et al (1980) for detection of regional cardiac dysfunction with Nuclear Stethoscope which is based on abnormally high (> 1.0) ratio of ejection fraction/relative cardiac output (EF/RCO). Using this criterion, sensitivity in our patients was 44% and specificity 56%. For EF/RCO > 1.0, sensitivity and specificity were respectively equal to 62% and 40%. We believe an abnormal filling phase is a far more reliable criterion for detection of SWMAb using a non-imaging ECG gated scintillation detector than the EF/RCO ratio, and that the NS LV T/Act curve analysis will be useful to identify accurately SWMAb's.