Hirokazu Yamaguchi

Vasodilatory capacity of coronary resistance vessels in dilated cardiomyopathy

Both the endothelium-dependent and endothelium-independent vasodilatory responses of coronary resistance vessels were studied in patients with dilated cardiomyopathy (DCM). A 3F coronary Doppler catheter was placed in the proximal left anterior descending artery in 14 patients with DCM and in 10 patients with chest pain syndrome and a normal heart (control subjects). The ratio of maximum mean coronary blood flow velocity after intracoronary administration of the endothelium-independent vasodilator papaverine (10 mg) to resting mean coronary blood flow velocity (Vp/Vo) in patients with DCM was diminished compared with that in control subjects (2.2 +/- 0.6 vs 4.1 +/- 0.9, p < 0.001). The ratio after administration of the endothelium-dependent vasodilator acetylcholine (40 micrograms) (Va/Vo) in 10 DCM patients was also diminished compared with that in seven control subjects (1.3 +/- 0.5 vs 2.4 +/- 0.8, p < 0.01). In DCM patients, Vp/Vo was correlated with left ventricular end-diastolic pressure (r = -0.48, p < 0.05), left ventricular end-diastolic volume index (r = -0.68, p < 0.01), ejection fraction (r = 0.75, p < 0.01), and left ventricular end-diastolic wall stress (r = -0.73, p < 0.01). However, Va/Vo was not correlated with any of these parameters. These results indicate that impairment of the vasodilatory capacity of coronary resistance vessels in DCM may be related to endothelial dysfunction and to an extravascular factor resulting from left ventricular dysfunction.

A Mechanism of Ischemic Preconditioning during Percutaneous Transluminal Coronary Angioplasty

Manifestation of ischemic preconditioning and its mechanisms during percutaneous transluminal coronary angioplasty (PTCA) was evaluated. Twenty-two patients with angina pectoris, who had one-vessel coronary artery disease of the proximal left anterior descending artery but without visual collateral circulation, underwent elective PTCA performed by balloon inflations of 90 s, repeated three times or more. Changes in standard 12-lead electrocardiogram, hemodynamics and oxygen saturation of the great cardiac vein by a fiber-optic catheter were analyzed. Anginal chest pain occurred in 21 patients (95%) during the first balloon inflation, and in only 9 patients (41%) during the third inflation. In comparison with the first inflation, the third produced less shifts in ST junction (p < 0.01) and peak T (p < 0.01), which were measured and averaged by 4 chest leads from V2 to V5. The heart rate-blood pressure product during the third inflation was equivalent to that during the first. The great cardiac vein oxygen saturation decreased equally during the first and third inflations. However, the ratio of the saturation at reactive hyperemia after balloon deflation to baseline was higher (p < 0.01) in the third than in the first inflation. The adenosine content of the great cardiac vein measured in 11 patients just prior to balloon deflation was also higher (p < 0.05) in the third inflation than the value in the first. Repeated coronary artery occlusion during PTCA could cause ischemic preconditioning, which may be derived from mechanisms common to accelerated reactive hyperemia, for example an increase in intrinsic adenosine levels.

RIGHT-TO-LEFT SHUNTING THROUGH A PATENT FORAMEN OVALE CAUSED BY PULMONARY HYPERTENSION ASSOCIATED WITH RHEUMATOID ARTHRITIS AND SJOGREN'S SYNDROME : A CASE REPORT

This case report presents a fifty-four-year-old woman with right-to-left shunt in the atrium. It seemed clinically at first that the shunt was due to atrial septal defect. However, she also had pulmonary disease associated with rheumatoid arthritis and Sjögrens syndrome. At autopsy atrial septal defect was not evident, but a patent foramen ovale and pulmonary artery disease were observed. This case suggests that pulmonary hypertension secondary to rheumatoid arthritis and Sjögrens syndrome could lead to right-to-left shunting through a patent foramen ovale.

Venoarterial Carbon Dioxide Tension Gradient in Acute Heart Failure

The venoarterial carbon dioxide tension gradient (P[v-a]CO2) was studied in patients with acute myocardial infarction. Seven patients with congestive heart failure (CHF group) and 10 patients without heart failure (control) were enrolled in this study. In all patients, hemodynamics were continuously monitored. Simultaneously, arterial and mixed venous blood were sampled, and blood gases and lactate concentration were analyzed. At the initial measurement before therapy, arterial and mixed venous pH and bicarbonate values were within the normal range, and there was no significant difference between the CHF group and controls. There was also no difference in arterial oxygen tension under the differential conditions of oxygen inhalation. However, cardiac index and mixed venous oxygen saturation (SvO2) were significantly lower, while the oxygen extraction ratio (OER) and arterial lactate were significantly higher in the CHF group than in the controls. On the other hand, P[v-a]CO2 was significantly higher in the CHF group (7.8 +/- 2.6 vs. 3.5 +/- 2.2 mm Hg, p < 0.01). This finding was due to the elevated mixed venous carbon dioxide tension in the CHF group, since arterial carbon dioxide tension was the same in both groups. Analysis of a total of 42 measurements obtained during the therapeutic course in the CHF group revealed a correlation of P[v-a]CO2 with cardiac index (r = -0.3, p < 0.05), OER (r = 0.57, p < 0.001), SvO2 (r = -0.56, p < 0.001) and lactate (r = 0.62, p < 0.001). The increase in P[v-a]CO2 observed in acute heart failure suggests the evidence of intracellular acidosis despite the absence of acidemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbamazepine-induced bradycardia-tachycardia syndrome with pharmacological analysis and concurrent ECG monitoring

The authors present a patient with carbamazepine-induced bradycardia-tachycardia syndrome, a rare type of drug-induced sinus node dysfunction. In this case, they established a clear-cut relationship between plasma carbamazepine concentration and the frequency of sinus arrests, following episodes of supraventricular tachycardia. As the pharmacological analysis of drug-induced sinus node dysfunction by concurrent ECG monitoring is very limited, the findings give an insight into the mechanism of this disorder.

Coronary Artery Aneurysms and Congestive Heart Failure — Possible Long-Term Course of Kawasaki Disease in an Adult — A Case Report

Multiple coronary artery aneurysms, rarely seen in patients with atherosclerotic heart disease, can be frequently observed in children with Kawasaki disease. However, their long-term clinical courses still remain obscure. A thirty-nine-year-old male came to our clinic because of congestive heart failure. A left ventriculogram revealed highly reduced wall motion. A coronary angiogram showed left main trunk aneurysm with complete occlusion of the left anterior descending artery and ramification of the right coronary artery close to the ostium. Six months after discharge, he died suddenly. On autopsy, aneurysms were observed in the left main trunk and right coronary artery, together with an old anteroseptal myocardial infarction. Although he did not have a clear history of febrile disease in childhood, he was highly suspected to be a long-term survivor of Kawasaki disease because of the unique form and distribution of the coronary artery aneurysms.

Acute myocardial infarction during pregnancy.

We report a 30-year-old woman who developed an acute myocardial infarction at 24 weeks of gestation. She did not undergo any kind of acute intervention. On the 8th hospital day, premature delivery was performed safely following premature rupture of membrane. Coronary angiogram was normal and no spasm was induced by provocative test with ergometrine maleate. The patient had abnormal values of fibrinogen, thrombin-antithrombin III complex and plasmin-alpha 2-plasmin inhibitor complex. Thus, thrombus formation might have been associated with the onset of acute myocardial infarction. This is the first case of acute myocardial infarction during pregnancy, showing normal coronary angiogram and negative pharmacological provocation of coronary spasm.

Left-ventricular filling disturbances in cardiac amyloidosis: study of atrial sound and diastolic inflow velocities

Cardiac amyloidosis is characterized by left ventricular filling disturbances in a relatively early stage. To investigate such disturbances more precisely, we studied atrial sound and left ventricular inflow velocity patterns. Twelve cases diagnosed as cardiac amyloidosis according to the clinical criteria including rectal biopsies and serum amyloid proteins or at autopsy were reviewed and analyzed. Their mean age was 60.9 +/- 12.5 years. Twelve age-matched cases with hypertrophic cardiomyopathy (HCM) served as the controls. We measured the amplitude of atrial sound by low-frequency phonocardiograms and the ratio of the heights of the A wave of apexcardiograms (ACG) to the total amplitude of the ACG. The mitral inflow velocity patterns were recorded using pulsed Doppler echocardiography. The rapid filling wave (R), atrial filling wave (A) and the ratio of A to R (A/R) were measured. In the amyloidosis group, atrial sound moderately increased in 2 cases, it was faint in 9 and not manifest in the remaining one. The A wave in the amyloidosis group was significantly smaller than that in the HCM group (p < 0.001) (12.4 +/- 3.9 vs 22.4 +/- 5.6%). In the left ventricular inflow velocity patterns, the R in amyloidosis was smaller than that in HCM (41.7 +/- 16.0 vs 56.4 +/- 12.1 cm/sec) (p < 0.02). The A in amyloidosis was also smaller than that in HCM (40.5 +/- 13.4 vs 58.1 +/- 13.0 cm/sec) (p < 0.006). The A/R was 1.0 +/- 0.34 in amyloidosis and 1.1 +/- 0.32 in HCM (N.S.). Both A and R were significantly less in amyloidosis than those in HCM.(ABSTRACT TRUNCATED AT 250 WORDS)