Toshiro Kuribayashi

Sustained cavity obliteration and apical aneurysm formation in apical hypertrophic cardiomyopathy

OBJECTIVES In patients with apical hypertrophic cardiomyopathy (ApHCM), we estimated the severity of cavity obliteration (CO) in the apical potion of the left ventricle and correlated it with various clinical findings including apical aneurysm. BACKGROUND Apical hypertrophic cardiomyopathy sometimes develops apical aneurysm. The apical CO is often exhibited in ApHCM along with apical hypertrophy and ischemia. It remains unclear, however, how the CO and others are related to aneurysm. METHODS In 46 patients with ApHCM, we measured CO time on M-mode echocardiography and corrected it by the R-R interval (cCOT). We divided the 46 patients into the following groups: 17 with cCOT <or=200 ms (no/mild CO group); 18 with cCOT >200 to <or=350 ms (moderate CO group); and 11 with cCOT >350 ms (severe CO group). We then compared apical aneurysm, hypertrophy, ischemia, QT interval, and the like between the three groups. RESULTS The severe CO group exclusively comprised 11 patients having apical aneurysm and paradoxic jet flow. Of the 11 patients, 10 exhibited irreversible defects on exercise single photon emission computed tomography with thallium-201. All with moderate CO showed reversible defects, and none with no/mild CO showed any defects. Left ventricular hypertrophy and the corrected QT interval (QTc) were largest in the severe CO group. There were high correlations between the cCOT, hypertrophy, ischemia, and QTc. Of the 11 patients with severe CO, 6 had nonsustained ventricular tachycardia and 1 had mural thrombus. CONCLUSIONS In ApHCM, sustained CO is an important pathophysiologic condition as well as hypertrophy, ischemia, and prolonged QTc, which are considered jointly related to the development of aneurysm through interactions.

Serum fatty acid levels, dietary style and coronary heart disease in three neighbouring areas in Japan: the Kumihama study

CHD mortality is extremely low in Japan, particularly in rural districts, when compared with that in Western countries. This has been partly attributed to the difference in dietary lifestyle. We investigated the factors influencing CHD mortality in a rural coastal district of Japan, comprising mercantile, farming, and fishing areas with distinct dietary habits. We prospectively examined the incidence of CHD from 1994 to 1998, as well as coronary risk factors and serum fatty acid concentrations. The incidence of angina pectoris was significantly (P=0.01) lower in the fishing area than in the mercantile and farming areas. Blood pressure, physical activity, prevalence of diabetes, serum levels of uric acid and HDL-cholesterol were similar between the three areas. Total- and LDL-cholesterol levels were significantly lower but the smoking rate was markedly higher in the fishing area than in the other two areas. Serum levels of saturated fatty acids and n-6 polyunsaturated fatty acids (PUFA) were lowest in the fishing area, but n-3 PUFA did not differ significantly. The n-6:n-3 PUFA ratio was lowest and eicosapentaenoic:arachidonic acid was highest in the fishing area. Although many previous studies have emphasized the beneficial effect of n-3 PUFA in preventing CHD, the present study indicated that a lower intake of n-6 PUFA and saturated fatty acids has an additional preventive effect on CHD even when the serum level of n-3 PUFA is high because of high dietary fish consumption.

Chronotropic incompetence and autonomic dysfunction in patients without structural heart disease.

AIMS An attenuated heart rate response to exercise, termed chronotropic incompetence (CI), has been reported to be an independent predictor of cardiovascular mortality. We examined the change in autonomic function during exercise testing and correlated the results with CI. METHODS AND RESULTS Exercise testing using a bicycle ergometer was performed in 172 patients who had no evidence of cardiac disease. Chronotropic incompetence was defined as the failure to achieve 85% of the age-predicted maximum heart rate, heart rate reserve <80%, or chronotropic response index <0.80. We analysed the relationship between CI and the change in two components of heart rate variability during exercise testing: high-frequency (HF) component (0.15-0.40 Hz) as an index of vagal modulation and the ratio of low-frequency (LF) component (0.04-0.15 Hz) to HF component as an index of sympathovagal balance. Heart rate variability indexes before exercise were similar in patients with and without CI. Percentage changes after exercise in the ratio of LF to HF component were higher in patients with CI than in those without CI (84 +/- 15 vs. 41 +/- 16%, P < 0.05), whereas percentage changes in an HF component were similar in the two groups. CONCLUSION Our data suggested that CI in patients without structural heart disease was mainly caused by a pathophysiological condition in which sympathetic activation was not well translated into heart rate increase. Further study is needed to determine the post-synaptic sensitivity of the beta-adrenergic receptor pathway in relation to CI.

Abnormal course, abnormal flow, and systolic compression of the septal perforator associated with impaired myocardial perfusion in hypertrophic cardiomyopathy

BACKGROUND The septal perforators in hypertrophic cardiomyopathy (HCM) show systolic compression. The compression is thought to be related to the malpositioned septal perforators, but its relation to the development of myocardial ischemia remains controversial. METHODS We examined echocardiographically the blood flow and course of the major septal perforator in 142 consecutive patients with HCM; of these, 94 underwent coronary angiography to assess systolic compression of the septal perforators and 110 had thallium-201 scintigraphy. We then analyzed the relation of the findings in comparison with the results in 15 patients with valvular aortic stenosis (AS). RESULTS The major septal perforator was visualized in 82 patients with HCM and in 8 patients with AS. The visualization did not depend on the pressure gradient between the left ventricle and aorta in the HCM patients, but did in the AS patients. In AS the perforator always showed a normal course near to, and convexly toward, the right ventricle. In 71 of the 82 HCM patients, the perforator was distant from the right-sided endocardium of the ventricular septum and often convex toward the left. The greater the leftward deviation, the higher was the grade of compression. In 48 of the 82 patients with HCM and in all of the 8 patients with AS who showed the flow signal, the septal perforator showed systolic retrograde flow; in the patients with HCM there was a significant correlation (r = 0.54, P <.05) between the peak velocity and the degree of leftward deviation. Furthermore, higher degrees of the leftward deviation and higher degrees of the systolic compression of the major perforator were each associated with a higher incidence of exercise-induced defect of thallium-201. CONCLUSION The echocardiographic, angiographic, and scintigraphic findings in HCM may be closely related to one another. We speculate that the series of abnormalities is initiated by a high intramural pressure and impedance on the septal perforators due to their deviation toward the left.

Tetralogy of Fallot, pulmonary valve stenosis, ventricular septal defect, and hypertrophic cardiomyopathy in WKY/NCrj rats.

ABSTRACT: We examined anatomically the hearts of 198 WKY/NCrj rats of 20 litters. There were 51 rats with moderate to severe thickening of the pulmonary valve and 19 rats with a ventricular septal defect; the two lesions occurred together in 16 rats, in 15 of which there were overriding of the aorta, stenosis of the pulmonary outflow tract, and hypertrophy of the right ventricle, fulfilling the criteria for tetralogy of Fallot in man. The papillary muscle of the conus was absent in 65 rats. The heart was abnormally heavy in 18. We analyzed the relationship between cardiac hypertrophy and valvular lesions and septal defects in these rats plus 27 selected WKY rats with abnormally heavy hearts. Of the 151 rats with neither severe valvular lesions nor septal defects, six rats had abnormally heavy hearts and 67 rats had disproportionate ventricular septal thickening. This situation in the rats is similar to hypertrophic cardiomyopathy. The occurrence of these abnormalities, isolated or in association, in rats of an established inbred strain strongly suggests that they are etiologically or genetically linked, and that the rats should be a useful animal model for these diseases in man.

Enhanced vagal modulation and exercise induced ischaemia of the inferoposterior myocardium

Objective: To determine whether the Bezold-Jarisch reflex or enhancement of vagal nerves, which are preferentially distributed in the inferoposterior myocardium, results from exercise induced ischaemia in this region. Methods: On the basis of exercise myocardial scintigraphy and coronary angiography, 145 patients were classified as follows: group I, 34 patients with inferoposterior ischaemia; group A, 32 with anterior ischaemia; and control, 79 without ischaemia. The relation between ischaemic areas and ECG leads with ST segment changes and vagal modulation assessed by heart rate variability (HRV) (high frequency (HF) component (0.15–0.40 Hz) and coefficient of HF component variance (CCVHF), which is the square root of HF divided by mean RR interval) were assessed. Results: The rate of ST segment depression in any lead did not differ between group I and group A. HF and CCVHF were similar before exercise but higher in group I than in group A and the control group after exercise (mean (SEM) HF: 94 (17) ms2, 41 (7) ms2, and 45 (6) ms2, respectively, p  =  0.021; CCVHF: 1.18 (0.09)%, 0.81 (0.07)%, and 0.89 (0.05)%, p  = 0.0053). Furthermore, the percentage change in CCVHF before and after exercise was higher in group I than in group A or controls (mean (SEM) 22 (10)%, −24 (4)%, and −21 (3)%, p < 0.0001). The optimal cut off for diagnosis of inferoposterior ischaemia was −5% with a sensitivity of 74%, specificity 75%, and accuracy 75%. Conclusions: Vagal modulation as assessed by HRV analysis was enhanced in association with exercise induced inferoposterior ischaemia. Exercise ECG testing combined with HRV analysis would increase accuracy in the diagnosis of ischaemic areas in selected patients with angina pectoris.

Tetralogy of Fallot, Cardiac Hypertrophy, Pulmonary Hypertension, and Anomalies of Great Vessels in Fetuses and Neonates of WKY/NCrj Rats

ABSTRACT: We examined anatomically the hearts, lungs, and great vessels of 269 WKY/NCrj rats at three fetal and three neonatal stages. Severe pulmonary valve thickening was present in 16 and ventricular septal defects with overriding of the aorta in 15 of the 90 near-term fetuses and in 10 and nine, respectively, of the 79 neonates at 2-4 d of age. These abnormalities occurred together (tetralogy of Fallot) in seven of the near-term fetuses and in five of the neonates. A narrow pulmonary outflow tract was present in 55% of the fetuses and in 56% of the neonates. The wall of the pulmonary arterial branch was abnormally thick in 19% of the fetuses and in 26% of the neonates, most of which did not have septal defects. In about 80% of the fetuses, the middle latitudinal muscle bundle of the ventricular septum was not continuous with the left ventricular free wall, but rather with the right; after birth, it was discontinuous with both free walls. The heart was abnormally heavy in 49% of the 79 neonates. In about half of the heavy hearts, there were no septal defects or pulmonary valvular and arterial lesions. There were double aortic arches in four and right aortic arches in six of the total WKY fetuses and neonates; the ductus arteriosus was abnormally small in 47% and the aorta was large in 51% of the near-term fetuses. This constellation of congenital heart disease is genetic in origin, but altered by hemodynamics late in fetal life.

Three-layer ultrasonic tissue characterization of the ventricular septum is predictive of prognosis in patients with non-obstructive hypertrophic cardiomyopathy

AIMS A necropsy study of patients with hypertrophic cardiomyopathy (HCM) who died at a young age exhibited marked disarray and fibrosis in the mid-wall layer of the left ventricular (LV) myocardium. We assessed ultrasonic tissue characteristics in the three layers of the ventricular septum (VS), and correlated the result with long-term prognosis in HCM. METHODS AND RESULTS The magnitude of cyclic variation of integrated backscatter (CV-IB) was calculated in the three layers of the VS and the whole aspect of the LV posterior wall in 58 non-obstructive HCM patients and 20 healthy controls. All HCM patients were prospectively followed for an average period of 7.1 years for the occurrence of cardiac death or hospitalization due to heart failure. Each CV-IB of four regions was lower in HCM patients than in controls (all P < 0.01). CV-IB of the VS mid-wall layer was lower in 14 HCM patients with cardiac events than in patients without (5.4 ± 0.6 vs. 7.4 ± 0.5 dB, P = 0.033) although CV-IB of three other regions did not differ between the two groups. The optical cut-off point of %CV-IB <90%, i.e. the ratio of CV-IB in the VS mid-wall layer to the mean value in the layers on both sides, was an independent predictor of cardiac events (hazard ratio, 6.12; 95% confidence interval, 1.62-66.6; P = 0.013), with a positive predictive value of 44% and particularly with a high negative predictive value of 91%. CONCLUSION Patients with non-obstructive HCM are not likely to undergo cardiac events in the near future, when the CV-IB value is not significantly lower in the VS mid-wall layer than in the layers on both sides.

Vagal Enhancement as Evidence of Residual Ischemia After Inferior Myocardial Infarction

Background: Acute inferior myocardial infarction (MI) often induces transient sinus bradycardia through vagal enhancement, known as Bezold‐Jarisch reflex, which is explained by preferential distribution of vagal nerve in the inferior wall. We examined vagal activity in relation to the occurrence of residual ischemia in patients with old inferior MI and assessed its diagnostic usefulness.

Unilateral Absence of Pulmonary Artery

Yoshiki Akakabe, MD; Tatsuya Kawasaki, MD; Toshiro Kuribayashi, MD; Hiroki Sugihara, MD Department of Cardiology, Matsushita Memorial Hospital, Osaka, Japan (Akakabe, Kawasaki, Sugihara); Kuribayashi Clinic of Cardiology, Fukuoka, Japan (Kuribayashi) Address for correspondence: Yoshiki Akakabe, MD Department of Cardiology, Matsushita Memorial Hospital Sotojima 5–55, Moriguchi, Osaka 570–8540, Japan