Tomoyoshi Kashima

Diastolic bulging of the interventricular septum toward the left ventricle. An echocardiographic manifestation of negative interventricular pressure gradient between left and right ventricles during diastole.

Diastolic bulging of the interventricular septum (IVS) toward the left ventricle was observed by real-time cross-sectional echocardiography in three patients with primary pulmonary hypertension and one patient with secondary pulmonary hypertension after closure of an atrial septal defect. M-mode echocardiography showed a characteristic abnormal pattern of septal motion in diastole and in systole. In two patients, we attempted to correlate M-mode motion to the interventricular pressure gradient. During diastole, the interventricular pressure gradient between the left and right ventricles was negative and the pressure gradient curve was very similar to the M-mode echogram of the IVS. Banding studies in which acute right ventricular hypertension was produced in dogs showed similar shape changes, suggesting that the diastolic shape and motion of the septum are determined by the interventricular pressure gradient between the ventricles. Diastolic bulging of the IVS toward the left ventricle in our patients results from negative interventricular pressure gradient between the left and right ventricles during diastole.

Relation between QT interval and heart rate. applications and limitations of Bazett's formula.

We studied the relationship between QT interval and RR interval when the heart rate was changed by atrial pacing, atropine, isoproterenol, and exercise in nine healthy adult males. The following results were obtained: (1) QT shortening with an increase in heart rate was minimal in atrial pacing and an equation QT = k4 square root RR was obtained from the QT-RR relationship during atrial pacing (r = 0.64, p less than 0.001); (2) shortening of QT with shortening of RR was least in atrial pacing; (3) during recovery from exercise it was largest and almost coincident with Bazetts formula; (4) Bazetts formula, therefore, is clearly applicable in the evaluation of ECGs recorded at rest or after exercise; (5) Bazetts formula can not be applied in the evaluation of an effect of some drug or maneuver on the QT when such a drug or maneuver can affect both the QT and the RR directly. The RR-dependent QT change can be estimated from the equation QT = k4 square root RR and the difference between a measured QT and the estimated RR-corrected QT would be a genuine effect of the drug or maneuver on the QT at that heart rate. We conclude that atropine, isoproterenol and exercise actually shorten the QT interval.

Hemodynamic determinants of pulmonary valve motion during systole in experimental pulmonary hypertension.

To clarify the determinants of pulmonary valve (PV) motion in pulmonary hypertension, we examined the correlations among PV echo patterns, the pulmonary artery (PA) flow curve just above the PA orifice and the pulmonary artery-right ventricle (PA-RV) pressure gradient. By constricting the PA, we could produce a variety of PV echo patterns, including midsystolic semiclosure in open-chest dogs. Throughout the experiments, the PV echo pattern and PA flow curve were similar in pattern and timing. When the PV echo showed midsystolic semiclosure with reopening, the PA flow curve showed a transient decrease followed by a transient increase during midsystole. The PA-RV pressure gradient became transiently positive (PA pressure > RV pressure) and then negative in midsystole only when the PV echo showed midsystolic semiclosure with reopening. In conclusion, PV motion during systole may be instantaneously determined by PA flow change and the PA-RV pressure gradient during the cardiac cycle in experimental pulmonary hypertension.

Real-time cross-sectional echocardiographic evaluation of the interatrial septum by right atrium-interatrial septum-left atrium direction of ultrasound beam.

Real-time cross-sectional echocardiography was performed to record the interatrial septal echogram by right atrium-interatrial septum-left atrium (ASA) direction of the ultrasound beam by positioning the transducer to the right of the sternum. The configuration of the interatrial septum (IAS) and the change of the configuration through each cardiac cycle were studied in 10 normal subjects and 29 patients with left or right atrial overloading.In normal subjects the IAS was slightly convex toward the right atrium (RA) in end-systole and slightly convex toward the left atrium (LA) in end-diastole, respectively. In patients with mitral stenosis, the IAS protruded archwise toward the RA both in end-systole and in end-diastole, and showed only minimum difference through each cardiac cycle. In patients with acute mitral regurgitation, the IAS was markedly convex toward the RA in end-systole and slightly convex toward the LA in end-diastole; thus, the difference of the configuration of the IAS was increased. In patients with chronic mitral regurgitation, the IAS was moderately convex toward the RA in end systole and flat or slightly convex toward the RA in end-diastole. In patients with tricuspid regurgitation, the interatrial septal echogram showed several patterns. However, the change in the configuration of the IAS throughout the cardiac cycle showed a characteristic pattern, i.e., it was more convex toward the LA or less convex toward the RA in end-systole than in end-diastole.The observation of the change in the interatrial septal configuration may be useful in the diagnosis of right or left atrial overloading. The mechanism by which the configuration is altered seems to be the interatrial pressure gradient through each cardiac cycle.

Electrocardiographic changes induced by the stellate ganglion block in normal subjects

In order to examine the laterality of the sympathetic control of the human heart, electrocardiographic changes induced by a unilateral stellate ganglion block (SGB) were observed. 10ml of 1% lidocaine was used for the block and post-block ECG was recorded just after the appearance of Horners sign. Patients who developed vocal hoarseness were excluded. 15 recordings of 14 subjects with right SGB and 16 recordings of 12 subjects with left SGB were used for analysis. A significant increase in the P-P interval from 0.90 +/- 0.17 sec to 0.96 +/- 0.16 sec. was observed only with right SGB and the predominance of the right side in the sympathetic nervous control of the human heart was thus demonstrated. The atrioventricular conduction time was not affected by either the right or left SGB. The QTc was slightly but significantly prolonged only by the right SGB, from 0.40 +/- 0.04 sec. to 0.43 +/- 0.04 sec. This prolongation was not large enough to support a definite conclusion and further investigations should be made.

Noninvasive pulsed Doppler echocardiographic detection of the direction of shunt flow in patients with atrial septal defect: usefulness of the right parasternal approach.

Noninvasive pulsed Doppler echocardiography combined with two-dimensional echocardiography by the right parasternal approach was performed to detect the shunt flow through the defect in 31 patients with suspected secundum atrial septal defect (ASD). A defect of the interatrial septum was seen on the two-dimensional echocardiograms of 30 of 31 patients. In all the 30 patients, Doppler signals of shunt flow could be recorded by placing the sample volume in the center of the defect on the two-dimensional echocardiogram. Neither a defect nor Doppler signal indicating shunt flow were demonstrated in any of 15 normal control subjects. Cardiac catheterization indicated significant shunt flow in all the 31 patients with suspected ASD. Doppler signals obtained from the center of the defect showed left-to-right and/or right-to-left shunt flow patterns. The direction of the shunt flow was mainly left to right, with its peak in late systole and atrial systole in 28 of 30 patients; mainly right-to-left flow was present in the remaining two patients, who had Eisenmengers syndrome. The direction of flow as predicted by the Doppler signal was confirmed by the coincidence of direction of flow as seen on the contrast two-dimensional echocardiogram. In 22 patients for whom the measurement of the pulmonary-to-systemic flow ratio by oximetry was believed to be reasonably accurate, the ratio was fairly well correlated with Doppler-determined left-to-right shunt flow velocity (r = .71, SEE = 6.7 cm/sec).(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic analysis of interatrial septal motion.

Abstract Interatrial septal motion was analyzed in 12 normal subjects and 19 patients with right or left atrial overloading using a new method for recording echograms of the mid portion of the interatrial septum through each cardiac cycle. In normal subjects, septal motion was characterized by eight distinct points that were identified and designated on the septal echogram. The septum showed gradual anterior motion (toward the right atrium) in mid and end systole and in early diastole. After reaching the most anterior point, it moved posteriorly (toward the left atrium). During mid diastole it showed very little motion. After the P wave of electrocardiogram it showed slight posterior and then anterior motion. In all eight patients with mitral stenosis, the motion of the interatrial septum was diminished. In all seven patients with mitral regurgitation due to chordal rupture, the septal motion was increased. Systolic fluttering of the septum was observed in four of seven patients. In two patients with Ebsteins anomaly, paradoxical motion of the interatrial septum (posterior motion in systole) was observed. In two patients with primary pulmonary hypertension, septal motion was very much decreased. Interatrial septal motion was thought to result from the interatrial pressure gradient through each cardiac cycle. This method of recording the motion of the interatrial septum seems to be useful for diagnosing right or left atrial overloading and for studying hemodynamic events in both atria.

Influences of localized aortic valve damage on coronary artery blood flow in acute aortic regurgitation: an experimental study.

We examined the influences of localized aortic valve damage on coronary artery blood flow and the prognosis in acute aortic regurgitation. Aortic regurgitation was produced in 18 open-chest dogs by extensively cutting one of the three aortic cusps with a nerve knife introduced via the cardiac apex. The dogs were separated into three groups of six dogs each. In each group the noncoronary cusp (NCC), the right coronary cusp (RCC), or the left coronary cusp (LCC) was cut. Aortic and left ventricular pressures; the phasic aortic, left anterior descending (LAD), and right coronary artery (RCA) blood flows; and electrocardiograms were simultaneously recorded before and after production of acute AR. All dogs in the NCC and RCC groups survived for at least 30 to 60 min, but all dogs in the LCC group died after 5 to 9 min of production of acute AR due to left ventricular failure. After 2 min of aortic regurgitation, the total, systolic, and diastolic LAD flows were 39 +/- 14, 19 +/- 9, and 20 +/- 8 ml/min (mean +/- SD) in the NCC group, 41 +/- 15, 31 +/- 9, and 10 +/- 6 ml/min in the RCC group, and 9 +/- 5, 19 +/- 5, and -10 +/- 2 ml/min in the LCC group, respectively. The corresponding RCA flows were 19 +/- 9, 15 +/- 6, and 4 +/- 3 ml/min in the NCC group, 13 +/- 8, 21 +/- 12, and -8 +/- 4 ml/min in the RCC group, and 14 +/- 4, 19 +/- 4, and -5 +/- 1 ml/min in the LCC group, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac involvement in congenital myopathy

We examined cardiac changes in 8 patients (4 men and 4 women, age 21-43 years) with congenital myopathy proven by skeletal muscle biopsy. Of 8 patients, 4 showed cardiac changes, including 1 with cytoplasmic body myopathy (patient 1), 2 with minimal change myopathy (patients 2 and 3) and 1 with nemaline myopathy (patient 4). Patients 1 and 2 showed left ventricular dilatation with severe global hypokinesis of left ventricular wall. These clinical features were quite similar to those of dilated cardiomyopathy and the patients were in NYHA class 3 or 4. Patient 3 had severe mitral regurgitation with mitral valve prolapse. This patient also had a persistent left superior vena cava and hypoplasia of the aorta, and her cardiac function was in NYHA class 3. Patient 4 showed moderate global left ventricular hypokinesis but the left ventricle was not dilated. This patient also had sino-atrial block and type A Wolff-Parkinson-White syndrome. His cardiac function was NYHA class 1. In conclusion, various types of congenital myopathy are associated with cardiac changes which can result in severe congestive heart failure.

Histologic and ultrastructural studies on the myocardium in spontaneously diabetic KK mice: a new animal model of cardiomyopathy.

The hearts from spontaneously diabetic KK mice and control mice were examined by light and electron microscopy. Myocardial degeneration, myocardial fibrosis and calcium deposits in the myocardium were extensive in KK mice aged 8 weeks. In myocytes of newborn KK mice, an irregular arrangement of myofibrils and poorly formed Z bands were found. Ultrastructural changes in myocytes of KK mice aged 4 weeks consisted of destruction of mitochondria, degenerated myofibrils and abnormalities of Z bands. However, increased mucopolysaccharides in interstitium and thickened basement membranes of capillaries were not found in KK mice, in contrast to the previous reports of myocardial changes in diabetic C57BL/KsJ mice, alloxan-diabetic dogs and hypertensive-diabetic rats. These observations suggest that the cardiomyopathy found in KK mice is not secondary to diabetes mellitus but is caused by other factors. In conclusion, myocardial ultrastructural abnormalities are present in newborn KK mice. Thus, this animal can be used as a model of cardiomyopathy.