Effective renal plasma flow was determined by using I-131 labeled iodo-ortho-hippurate in 17 Chinese patients admitted to the coronary care unit with uncomplicated acute myocardial infarction. The first determination, immediately after admission, was significantly higher than the second determination done a week later, 444.5±153.9 vs. 371.1±124.9 ml/min (p<0.02). The initial rise of effective renal plasma flow (ERPF) after acute myocardial infarction seemed to be correlated to the initial elevation of atrial natriuretic peptide (ANP), which was determined sequentially 6 times in each patient (91.3±39.4, 25.6±9.7, 37.4±12.3, 51.8±18.2, 65.6±20.8, 57.4±19.2pg/ml, respectively). It was concluded that, in the presence of uncomplicated acute myocardial infarction, patients may show renal vasodilatation, and that the elevation of ANP may play some role in this.

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Among 12, 720 patients subjected to coronary angiography because of clinical suspicion of coronary heart disease, 2, 234 (78% men and 22% women) were free from major modifiable coronary risk factors. They did not report alcohol consumption, use of antiplatelet or lipid lowering agents, oral contraceptives or sex hormones; there was no history of bilateral oophorectomy, smoking, diabetes mellitus, hypertension, or obesity; the ratio of total to high-density lipoprotein cholesterol was ≤4.5. We examined lesions causing ≥50% stenosis to total obliteration of the 3 great coronary arteries or of their major branches, and classified these patients as having single-, double-, or triple-vessel disease, or normal angiograms (no luminal irregularities). We related the extent of the coronary angiographic involvement to age and sex.
From the fourth to the eighth decade of life: a) prevalence of normal angiography was significantly higher in women; b) percentage of cases with single-vessel disease was similar in both sexes and gradually reduced with aging; c) prevalence of double-vessel disease in women did not vary significantly, although a slight decline was seen at older ages; in men figures at the fifth and sixth decades were significantly greater than in women; d) percentages by decade of triple-vessel disease in males were 24, 34, 41, 49 and 57%, respectively; corresponding values in women were 11, 13, 15, 27 and 44% (p<0.01 at each decade of age); with advances of age the sex gap in triple-vessel disease narrowed, but did not disappear.
Thus, atherosclerosis tended with age to involve more vessels rather than more subjects in both genders, indicating that in the absence of modifiable coronary risk factors coronary vessels remained clearly susceptible to the influence of age, both in men and women. In these patients the feminine gender exerted a substantial protection that persisted for the entire span of life.

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This study was designed to assess if low dose lidocaine (L) (0.8mg/min at a constant rate infusion following a 100 mg bolus) combined with magnesium sulfate (M) (2.5mg/min) controlled warning ventricular arrhythmias (a total of 119, 806 ectopic beats and 146 runs of sustained ventricular tachycardia) in 7 (17%) out of 41 patients undergoing ambulatory monitoring. L alone was administered during the first 48 hours, then L+M for 48 hours, followed by L alone for a further 48 hours. Every 12 hours L serum levels were measured. Serum levels of L alone ranged from 0.33 to 2.06mg/l (mean: 1.28±0.7mg/l) during the first 48 hours and from 0.30 to 2.96mg/l (mean: 1.24±1.02 during the last 48 hours). When the subjects received L+M, L serum levels were 0.69 to 3.28mg/l (mean: 1.60±0.9 with p less than 0.05, statistically significant). Ambulatory monitoring also displayed a 70% reduction in warning ventricular arrhythmias during L+M treatment. L+M are more effective in the control of warning ventricular arrhythmias and we can also administer a lower dose of lidocaine when given in combination.

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To evaluate the significance of the signal-averaged P wave in various pathological conditions of the atrium, signal-averaged electrocardiograms and echocardiograms were studied in the following 4 groups: (1) 10 normal subjects (control group), (2) 24 patients with paroxysmal atrial fibrillation or flutter (AF) (AF group), (3) 12 patients with left atrial overload without AF (LA group), and (4) 10 patients with right atrial overload without AF (RA group). Original P wave durations showed no significant difference among the 4 groups. Filtered P wave durations (F-PDs) in the AF and LA groups were significantly longer than that in the control group. F-PD correlated significantly with left atrial dimension (LAD). F-PD in AF patients with LAD shorter than 40mm was significantly longer than that in the control group, but there was no significant difference in F-PD between AF patients with LAD longer than 40mm and the LA group. Root mean square voltages of original P waves were significantly higher in the LA and RA groups than that in the control group, but in AF patients it did not differ from that in the control group. In conclusion, the signal-averaged P wave is useful to predict atrial fibrillation, but prolongation of F-PD is seen not only in patients with AF but also in patients with LA overload.

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To evaluate the relationship between angina pectoris caused by dynamic exercise and the time course of heart rate (HR) and hemodynamics during dynamic exercise in 15 patients with hypertrophic cardiomyopathy (HCM) with normal epicardial coronary arteries, the supine ergometer exercise test was performed during cardiac catheterization.
The HCM patients were divided into a chest pain group (n=6) and a no chest pain group (n=9) based upon the results of the ergometer exercise test. There was no significant difference in the level of ST-segment depression after exercise in both the chest pain and no chest pain groups (-2.1±0.6mm vs -2.6±1.1mm, NS). Increase in heart rate (HR) and left ventricular end-diastolic pressure (LVEDP) in the early phase of the exercise test was significantly greater in the chest pain group compared with the no chest pain group.
These observations suggest that in HCM patients, the occurrence of exertional chest pain has a close relationship with the rapid increase in HR and LVEDP in the early phase of dynamic exercise, but does not have a relationship with the gradual increase in these parameters.

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Myocardial damage and cardiopulmonary functions in patients with Duchenne's muscular dystrophy (DMD) were assessed using thallium-201 myocardial single-photon emission computed tomography (SPECT) and technetium-99m multigated radionuclide angiography. Twenty-five patients with DMD were divided into 4 groups according to percent of perfusion defect (%PD) calculated by the bull's-eye method and age. PD was detected in 24 (96.0%) of 25 patients with DMD, and it spread from the left ventricular lateral wall to the anterior wall and/or interventricular septum. PD was detected even in a 6-year-old DMD boy. Patients in Group I (%PD_??_10% and age<15 years old) were shown to have a higher risk of left-sided heart failure without respiratory failure. Patients in Group II (%PD_??_10 and age_??_15) showed decreased pulmonary function and worsened arterial blood gas values as compared with Group IV (%PD<10 and age_??_15). There was no significant difference in cardiac function among the 4 groups. It is postulated that myocardial damage in Group II patients is dependent primarily on a deficiency of dystrophin and on chronic respiratory failure, and that some of them are at risk of cardiopulmonary failure. It is concluded that myocardial SPECT is useful for the early diagnosis of myocardial damage and evaluation of cardiopulmonary function in DMD patients.

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Two brothers, 25 and 19 years old, were affected by asymmetrical hypertrophic cardiomyopathy. The older brother had waddling gait and weakness of the proximal girdle muscles, while the younger had a broad-based gait and weakness of selected limb girdle muscles. EMG exam was myopathic. Serum enzyme, CPK and aldolase were elevated. Histochemical reactions in muscle revealed "core-like" areas, subsarcolemmal rims of mitochondria and lipid accumulation. Succinatedehydrogenase stain showed a lack of activity in both biopsies, with the exception of intrafusal fibers. Microphotometric quantitative measurements confirmed the defect in both biopsies. Biochemical measurements of several mitochondrial enzymes in muscle showed a reduced activity of succinate-dehydrogenase (33%) and succinate-cytochrome C reductase (36-47%) which are both components of complex II. On myocardial biopsy lipid and mitochondrial abnormalities were found. This mitochondriopathy represents a new phenotype of partial complex II defect.

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Direct argon or thermal laser angioplasty (LA) was evaluated for thrombogenicity using angioscopy, and compared with balloon angioplasty (BA). In each of 8 dogs, 4 segments (both proximal and distal iliac arteries) were treated by laser-thermal and/or balloon angioplasty. One segment was treated by balloon angioplasty and 3 other segments were treated with either thermal LA with 7W using a "Hot-Tip" laser probe (2.0mm), or BA and thermal LA, or a special optical probe which emits a 3W argon laser beam. Mean percent area stenosis by thrombus was 44±23 in balloon-dilated, 23±21 in thermally-treated and balloondilated, 3±3 in thermally-treated, and 1±4 in directly-lased segments at 30min. It was 62±28 in balloon dilated, 31±29 in thermally-treated and balloon-dilated, 5±6 in thermally-treated, and 1±2 in directly-lased segments at 60min. Balloon-inflated segments had the highest percent area stenosis which was significantly higher than that of either the direct laser or thermally-treated segments (p<0.0005). Histology showed thermal necrosis in laser-treated sites, and wall tears in BA sites. Thus, LA can provide a less thrombogenic arterial surface than BA.

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Recently, the slope (E_c) of the left ventricular (LV) end-systolic force-diameter (F_es-D_es) relationship has been proposed as a new index for assessing myocardial contractility. Using this relationship, the effects of ISDN on LV myocardial contractility were evaluated in 10 healthy adult mongrel dogs. After the intravenous infusion of propranolol and atropine to produce autonomic blockade, the inferior vena cava was gradually occluded for 20sec to decrease preload while the dogs were kept apneic. The LV diameter was measured by ultrasonic crystals and LV pressure was measured by a micromanometer. After the control measurements, the dogs received intravenous ISDN (1, 5, 10, or 50μg/kg/min), and inferior vena caval occlusion was repeated. E_c and the extrapolated diameter intercept (D₀) of the LV F_es-D_es relationship were determined for each dog from the end-systolic data. The differences in heart rate between the control state and ISDN infusion at any dose were not statistically significant. The E_c and D₀ values also showed no significant changes with ISDN infusion (E_c: 80±19, 83±20, 84±17, 82±24, and 87±24g/cm for 0, 1, 5, 10, and 50μg/kg/min, respectively. D₀: 1.38±0.42, 1.38±0.40, 1.38±0.38, 1.34±0.40, and 1.36±0.40cm for 0, 1, 5, 10, and 50μg/kg/min, respectively). These findings suggested that intravenous ISDN did not affect myocardial contractility in the normal in situ canine left ventricle.

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Left atrioventricular (A-V) valve anomalies are very frequent in corrected transposition, but left A-V valve replacement has seldom been reported. These anomalies are an important cause of morbidity and mortality in these patients, and due to anatomical presentation valve replacement may be difficult. We present 4 cases of left A-V value replacement with emphasis given to Ebstein's anomaly of the left A-V valve.

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A 52-year-old man had suffered from attacks of palpitation for 10 years. The frequency of the attacks had been increasing since June 1991. The electrocardiogram (ECG) at the time of attack showed a heart rate of 175bpm and RP'/P'R>1, indicating long RP' tachycardia. Electrophysiological examination of the heart revealed an accessory pathway in the left lateral position. During the tachycardia, PVCs from the right ventricular apex (RVA) captured the atria. On the basis of these findings the patient was diagnosed as having had atrioventricular (AV) reciprocating tachycardia (AVRT). Ventriculoatrial (VA) conduction indicated a decremental conduction curve by single premature stimulation from the RVA, and the atrial cycle length following PVC during tachycardia was prolonged (paradoxical delay). When verapamil was administered intravenously, tachycardia induced by the premature stimulation showed prolongation of the VA interval, associated with an increased tachycardia cycle length. Tachycardia in this patient was completely controlled by administration of verapamil.

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A patient was found to have a mobile catheter fragment in the right atrium incidentally during echocardiography. On further investigation, it was learned that the catheter had been inserted 9 years earlier during surgery and had probably been broken during removal. The patient did not experience any symptoms during this period. The catheter was removed percutaneously without any complications using a system similar to the loopsnare catheter.

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