Hitoshi Tanio

Assessment of clinical features in transient left ventricular apical ballooning

OBJECTIVES We sought to assess the clinical features of transient left ventricular (LV) apical ballooning. BACKGROUND Although several cases regarding transient LV apical ballooning have been reported, the etiology remains unknown. METHODS We investigated 17 patients (14 women, median age 74 years old with a range of 54 to 91 years old) who fulfilled the following criteria: 1) transient LV apical ballooning; 2) ST-T segment change in several leads in electrocardiogram; and 3) no history of old myocardial infarction, valvular heart disease, subarachnoid hemorrhage, or pheochromocytoma. RESULTS Emotional and physical stress were observed in 16 patients (94%). Technetium-99m tetrofosmin tomographic imaging revealed decreased uptake at the apex of the left ventricle in 11 patients (85%) that later returned to uniform. No significant stenosis or angiographical slow flow in epicardial coronary arteries was observed (n = 9). Provocative focal vasospasm was induced in only one patient (14%) (n = 7). Moreover, no significant abnormality in the coronary microcirculation was detected by Doppler guidewire (n = 3) or contrast echocardiography (n = 1). No patients showed a rise in viral antibody titers. Biopsy specimens revealed interstitial fibrosis in six patients (100%) and slight cell infiltration in three others (50%) (n = 6). CONCLUSIONS These findings suggested that neither abnormalities in the coronary circulation nor acute myocarditis was related to the etiology. Although neurogenic stunned myocardium induced by emotional or physical stress was suggested as the etiology, further investigations are necessary.

Left ventricular regional wall stress in dilated cardiomyopathy

Left ventriculography with simultaneous pressure micromanometry was performed in 11 normal control subjects and 17 patients with dilated cardiomyopathy (DCM). Left ventricular silhouettes in the right anterior oblique projection were divided into eight areas, and regional wall stress was computed by Janzs method in each area excluding the two most basal areas. Wall stress was higher in DCM patients than in control subjects (p less than 0.01). The percent area changes from end diastole to end systole in each area were lower in DCM patients than in control subjects (mean for six areas, 22 +/- 14% versus 54 +/- 9%, respectively, p less than 0.01), but the coefficient of variation for the percent area changes in the six areas of the left ventricle in DCM patients was greater than that in control subjects (32 +/- 17% versus 15 +/- 4%, respectively, p less than 0.01), indicating regional differences in hypokinesis. There was a significant negative correlation between end-systolic regional wall stress and percent area change (r = -0.60 to -0.86, p less than 0.05) in each area. Thus, excessive regional afterload may play an important role in causing regional hypokinesis in DCM.

Direct Measurement of Aortic and Vena Caval Flow to Evaluate the Effect of Vasodilators in Experimental Acute mitral regurgitation

To evaluate the effect of bunazosin hydrochloride (Bz), a newly developed α1-blocker, on arterial and venous blood flow and on left ventricular function in acute left heart failure, we produced acute mitral regurgitation in seven open chest anesthetized dogs by transmyocardial chordal sectioning. With the administration of Bz (1μg/kg/min for 5 minutes intravenously) or nitroprusside (Np: 1.7 μg/kg/min for 3 to 5 minutes intravenously), the mean aortic pressure and systemic vascular resistance (SVR) decreased to the same levels. With Np, cardiac output (CO) did not change (from 1.80±0.72 to 1.87±0.80 L/min; NS), and mean inferior vena caval blood flow (IVCF) decreased by 5.5% (from 1.25±0.40 to 1.19±0.40 L/min; p < 0.01.). With Bz, CO increased significantly from 1.83±0.46 to 1.98±0.72 L/min (p < 0.05), and IVCF also increased significantly from 1.09 + 0.34 L/min to 1.18 + 0.33 L/min (p < 0.01). This suggests that Bz decreases SVR to the same level as Np, but the vasodilatory effect of Bz on the venous system is smaller than that of Np. We conclude that Bz is useful in treating heart failure where cardiac output must be augmented, while maintaining venous return.