Background: There is overlap in myocardial viability information by rest thallium-201 (Tl) uptake and contractile reserve under low dose dobutamine (LDD). In this study, we investigate a new protocol that involves acquisition of the delayed rest redistribution (RR) Tl images under LDD to help provide combined Tl uptake & contractile reserve viability information in a single study.

Several studies have correlated conduction abnormalities on the 12-lead electrocardiogram (ECG) with echocardiographic findings.(1-3) Echocardiographic studies on left bundle branch block (LBBB) produce variable findings that are related to the underlying cardiac pathophysiology. However, paradoxical septal motion on echocardiography is seen in most and is presumed secondary to abnormal septal activation related to a proximal conduction abnormality. We have previously reported that nonspecific widening of the QRS complex in the absence of typical electrocardiographic criteria for right bundle branch block (RBBB) or LBBB is associated with evidence of left ventricular (LV) dysfunction.(4) Although the mechanism of QRS widening was unknown, it was hypothesized that increased LV fibrosis in the presence of LV dysfunction led to an intraventricular conduction delay (IVCD), suggesting the presence of peripheral conduction disease. The present report has 3 purposes: (1) to support the existence of peripheral conduction disease by evaluating upper septal motion on echocardiography in patients with typical electrocardiographic criteria for either an IVCD or LBBB-peripheral conduction block was presumed in the presence of normal upper septal motion (no paradoxical septal motion) using echocardiography; (2) to compare LBBB versus IVCD in relation to echocardiographic findings of LV dysfunction; and (3) to compare the LV echocardiographic systolic function in patients with LBBB and paradoxical septal motion in comparison with normal septal motion.

Right ventricular (RV) systolic function analysis by echocardiography has traditionally required RV endocardial border definition with subsequent tracing and is often inaccurate or impossible in technically poor studies. The atrioventricular plane displacement (AVPD) method attempts to use the descent of the tricuspid annular ring, a reflection of the longitudinal shortening of the right ventricle, as a surrogate marker for RV systolic function. We hypothesized that RV ischemia induced during right coronary artery occlusion proximal to the major right ventricular branches would result in severe right ventricular systolic dysfunction detectable by the AVPD method. During this pilot study, seven patients undergoing elective proximal RCA angioplasty had echocardiographic measurement of RV AVPD performed at baseline (i.e., immediately prior to RCA balloon inflation), during the last 30 seconds of first RCA balloon inflation, and at 1 minute after balloon deflation (recovery). Lateral and medial RV AVPD were significantly reduced from baseline values during intracoronary balloon inflation. ( Lateral: 2.45 cm ± 0.22 vs 1.77 cm ± 0.13, P < 0.001; medial: 1.46 cm ± 0.37 vs 1.28 cm ± 0.32, P < 0.05 ). Additionally, lateral and medial RV AVPD significantly returned towards baseline values during recovery. ( Lateral: 2.39 cm ± 0.20, P < 0.001; medial: 1.58 cm ± 0.27, P = 0.01 ). At baseline, all lateral RV AVPD values were > 2.0 cm, whereas during balloon inflation all were < 2.0 cm. No such clear distinction was found in medial RV AVPD values. Proximal RCA angioplasty is associated with a significant reduction in lateral and medial RV AVPD. Thus RV AVPD may serve as a marker for RV systolic dysfunction.

Abu-Judeh, H. H.; Qureshi, A.; Atay, S.; Kumar, M.; Infantino, M.; Elmquist, T. H.; Naddaf, S.; Braff, R.; Abdel-Dayem, H. M. Author Information