Cardiac involvement is common in patients with Duchenne type muscular dystrophy (DMD). However, published reports of long-term follow-up studies in the same patients are very rare. The purpose of this study was to clarify the natural course of cardiac dysfunction in DMD, and to analyze the relationship between the deterioration of cardiac function and skeletal muscular function.
The cardiac function was serially evaluated for 2-12 years in 34 patients with DMD. The systolic time intervals and echocardiography were used for evaluating the cardiac function. The PEP/ET (pre-ejection period/ejection time) of systolic time intervals significantly deteriorated in 9-12 years (p<0.001). The maximal systolic and diastolic endocardial velocity (MSEV and MDEV) and the D/S ratio of echocardiography significantly deteriorated in 5 years (p<0.001). The D/S ratio is the ratio of the mean systolic velocity and the mean diastolic velocity of the left ventricular posterior wall.
In almost half the patients, the deterioration of these parameters was correlated with that of Swinyard's stage. The Swinyard's functional ability stage demonstrates the grade of the skeletal muscular dysfunction. However, there was no correlation between the deterioration of cardiac function and Swinyard's stage in the other half of the patients. Correlation coefficient in the whole group was 0.32 (p=n.s.) between the PEP/ET and Swinyard's stage, and was -0.15 (p=n.s.) between the D/S ratio and Swinyard's stage. Although the mean left ventricular ejection fraction calculated using echocardiography was slightly decreased for 5 years, no significant change was detected in the whole group.
One patient had progressive deterioration of left ventricular function despite mild skeletal muscular dysfunction, and died from congestive heart failure. The cardiac dysfunction was predominant. We named it'cardiac type' DMD.
Since deterioration of cardiac function was not always correlated with deterioration of skeletal muscular function (Swinyard's stage), cardiac function must be carefully monitored in patients with DMD.

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To evaluate the relationship of 24 hour total heart beats (THB) or ventricular arrhythmias and cardiopulmonary function, 29 patients with Duchenne's muscular dystrophy (DMD) were studied using Holter electrocardiographic and echocardiographic recordings.
The THB were 144, 428±12, 237 beats per 24 hours in the child group (8 to 15 years, n=12) and 136, 355±19, 991 beats per 24 hours in the adult group (16 to 25 years, n=17). The THB in the adult group significantly correlated well with %VC (r=-0.74), PaCO₂ (r=0.67), PaO₂ (r=-0.59) and the respiration rate (r=0.71), but not in the child group. In both groups, the echocardiographic parameters of the left ventricular size and function (left ventricular dimension, ejection fraction and D/S ratio) did not significantly correlate with the THB. Premature ventricular contractions (PVCs) were observed in 14 of the 29 patients (48.3%), and high risk PVCs (Lown's grade 3-4b) were observed in 11 of these 14 patients (78.6%). Echocardiographic parameters of the left ventricular function in the high risk PVC group were significantly deteriorated as compared with the low risk PVC group (Lown's grade 0-2) (p<0.02-P<0.001).
We conclude that the THB in the adult group was mainly related to depressed pulmonary function, and the severity of the PVCs in both the adult and child groups was mainly related to the degree of left ventricular dysfunction.

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In order to evaluate the short- and mid-term results of percutaneous aortic balloon valvuloplasty, 40 consecutive elderly patients, who had undergone balloon valvuloplasty for calcific aortic stenosis, were prospectively followed up by means of clinical and echo-Doppler examinations. Although valvuloplasty often dramatically improves hemodynamics and relieves symptoms, these benefits seem to be short-lived in most cases. Restenosis, defined as a loss of 50% or more of the increase in aortic valve area obtained by the dilatation, has a very high rate of occurrence. Aortic balloon valvuloplasty should therefore be reserved for truly inoperable cases and can be performed in hemodynamically unstable patients, who may later undergo surgery.

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The hydraulic load of the right and left ventricles and the clinical effects of nifedipine were evaluated in 8 normal subjects (mean age: 55 years) and 8 patients with cor pulmonale secondary to chronic obstructive lung disease (mean age: 57 years). It was found that there were differences in the right ventricular resistance (174.62±25.96 vs 468.57±178.81 dyne/sec/cm^-5), first zero crossing frequency (3.62±0.34 vs 6.07±3.56Hz), steady power (218.95±32.25 vs 359.44±37.46mW) and total power of right ventricle (275.81±36.18 vs 440.46±85.16mW) between the normal and cor pulmonale patients, respectively. However, no significant changes in characteristic impedance, pulsatile power or aortic impedance were observed in the right pulmonary artery. After administration of nifedipine to patients with cor pulmonale, there were significant changes in resistance (468.57±178.81 vs 256.36±178.56 dyne, /sec/cm^-5), steady power (359.44±37.46 vs 225.51±114.64) and total power (440.46 ±85.16 vs 289.27±50.85) of the pulmonary artery, respectively. Otherwise there were no significant changes in aortic input impedance or characteristic impedance of right pulmonary artery and pulsatile power.
In conclusion, we found that: 1) the hydraulic vascular load in the right ventricle was higher in patients with cor pulmonale, 2) characteristic impedance that was not increased in cor pulmonale patients may be due to a dilated pulmonary artery, 3) there was no impedance mismatch between left ventricle and systemic arterial system in patients with cor pulmonale, and 4) by reducing the pulmonary vascular resistance through nifedipine administration, the total external right ventricular power might be reduced, without affecting the proximal pulmonary arterial compliance.

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A prospective study was undertaken of the high-frequency components of the terminal portion of the QRS complex in 38 Chinese patients with acute myocardial infarction (AMI) (mean age 62±5.6 years) within the first week after the acute event (5.5±1.2 days). Another 44 normals served as controls (mean age 57±9.6 years). The electrocardiogram was averaged at a filter band pass of 80-300Hz. The low voltage span (LVS) of the signals less than 40μV in the terminal portion of QRS, the root-mean-square (RMS) voltage (V) of terminal 40 msec of the QRS complex, and the total duration of signal-averaged QRS vector complex were measured in both the normal subjects and patients. The LVS was abnormally prolonged in 16 of 38 patients (42%), and in only 16% of normals (p<0.05). The RMS-V was abnormal (<25μV) in 29 of 38 patients (76%), and in only 20% of normals (p<0.0005), and the signalaveraged QRS vector complex was abnormal (>120msec) in 26 of 38 patients (68%), and only 9% of normals (p>0.005). There was no significant correlation between any of the signal-averaged parameters, the site of AMI and total creative kinase (CK) or CK-MB values. The signal-averaged parameters also showed no relationship to either the cardiothoracic (C/T) ratio or the left ventricular ejection fraction, determined by the Tc-99m pertechnete first pass blood pool technique. Holter ECG monitoring was performed twice in all AMI patients, at 7 to 18 days after the acute event (12 days average) and 3 weeks after the first recording. There were only four episodes of non-sustained ventricular tachycardia (VT), all during the second monitoring period. Three episodes (10%) occurred in patients with positive late potentials (LPs), defined by an RMS-V<25μV in the terminal portion of QRS vector; one episode (11%) occurred in patients with negative LPs (9 patients). Although the incidence of LPs is significantly higher in patients with an AMI than in normal controls, the LPs detected by body surface signal-averaged ECG did not predict the occurrence of in- and out-of-hospital VTs. Thus, after AMI, Chinese patients may not be as prone to develop VTs as are Caucasians. Furthermore, the appearance of LPs is independent of cardiac size and left ventricular ejection fraction.

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To assess the relative contribution of sympathetic and vagal influences on diurnal variation of sinus node recovery time (SNRT) in sick sinus syndrome (SSS), the diurnal changes of SNRT and the effects of propranolol and subsequent atropine on SNRT were examined in 39 patients with SSS.
SNRT was measured before and after intravenous propranolol (0.1mg/kg), and after subsequent intravenous atropine (0.02mg/kg) in the cardiac catheterization laboratory. After completion of the electrophysiologic studies in the laboratory, SNRT was measured at 0 a.m. (midnight), 6 a.m. and 12 noon on the following day in the ward. After propranolol, SNRT was prolonged in 22 of 26 patients and shortened in 4 patients. After subsequent atropine, SNRT was prolonged in 5 of 26 patients and shortened in 21 patients. The patients with SNRT longer than 3sec had a tendency to have greater diurnal variation of SNRT than those with SNRT less than 3sec. A strong correlation (r=0.98) was found between SNRT after propranolol and the longest SNRT in a 24-hour period. A difference of SNRT between after propranolol and after subsequent atropine was significantly correlated (r=0.88) with a difference between the longest and the shortest SNRT in a 24-hour period.
These results suggest that the diurnal changes in SNRT are regulated by the autonomic nervous system in SSS. SNRT after propranolol may be useful in estimating the longest SNRT in a day.

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An electron microscopic immunocytochemical study of left ventricular myocardium was carried out in 16 patients with heart disease of various etiologies in order to characterize the secretory granules arising in the ventricular muscle cells. The electron-dense granules observed in the ventricular muscle cells were demonstrated only in 3 patients with dilated cardiomyopathy and chronic congestive heart failure. They were scattered throughout the cytoplasm of the ventricular muscle cells at paranuclear, interfibrillar and subsarcolemmal areas, and tended to be most numerous in the vicinity of the Golgi apparatus. These granules were often found to be bound by limiting membranes of homogeneous electron density. Protein A-gold electron microscopic immunocytochemistry with anti-α-human atrial natriuretic polypeptide resulted in specific staining of the granules. These findings, taken together indicate that the secretory granules containing atrial natriuretic polypeptide (ANP) exist in the ventricular muscle cells in a particular category of patients with dilated cardiomyopathy and chronic congestive heart failure. Thus, it is suggested that human ventricular muscle cells have retained the genetic ability to form specific ANP-containing granules in certain clinical disorders.

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The effects of insulin treatment on plasma renin activity (PRA), plasma atrial natriuretic peptide (ANP) and body fluid volume were studied in 16 hospitalized patients with insulin-independent diabetes mellitus. Parameters were recorded for 2 days during treatment by diet alone and for 3 weeks after starting insulin. Blood samples were obtained weekly from 9 patients for the measurement of fasting plasma glucose, hematocrit, PRA and plasma ANP. A 24-hr urine sample was collected to determine the urinary excretion of glucose and sodium. In a separate group of 7 patients, plasma volume and extracellular fluid volume were determined by the Evans blue and sodium thiocyanate dilution tests, respectively.
In the group of 9 diabetic patients, significant (p<0.05) reductions in fasting plasma glucose, hematocrit and the urinary excretion of sodium and glucose were seen with insulin treatment. PRA fell significantly (p<0.05) from 5.2±1.2ng/ml/hr (mean±SEM) on the control days to 2.3±0.5 on the 21st day after starting treatment. Plasma levels of ANP averaged 35±5pg/ml on the control days and these did not change significantly. In the other group of 7 patients, both plasma volume and extracellular fluid volume increased significantly (p<0.05) with insulin treatment. A sodium-retaining effect of insulin and a decrease in osmotic diuresis may have increased the body fluid volume and caused the fall in PRA. Thus, a vasodilatory action of insulin may assist in compensation for the increase in body fluid volume, preventing a rise in plasma ANP levels.

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Actomyosin was prepared from human myocardium and its protein composition was examined by SDS-polyacrylamide gel electrophoresis. For some preparations, particularly actomyosin isolated from elderly subjects, a high molecular weight (HMW) band (identified as a breakdown product of myosin heavy chain) appeared, while the troponin-T subunit decreased. Myofibril associated protease (MFP) activity showed no significant difference as a function of proteolysis. In agreement with the proteolysis of troponin-T and myosin, the Ca²⁺ sensitivity of Mg²⁺-ATPase activity decreased while the extent of the stimulation of Ca²⁺-ATPase by N-ethylmaleimide remained unchanged. This type of proteolysis would affect the Ca²⁺-dependent regulation of muscle contraction but not the contractility per se.

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We have studied the effects of propranolol on the number and function of beta-adrenoceptors of cultured heart cells from mice. After 24hrs in culture, heart cells were incubated for 48hrs with either standard medium or medium containing propranolol. After a washing period of 30min, beta-adrenoceptors were measured with a receptor binding assay. The dissociation constant (Kd) did not differ between control and cultured heart cells pretreated with propranolol. By contrast, the maximum number of binding sites (Bmax) was 2.5 times higher in propranolol-pretreated than control cultured heart cells. The increase in the rate of beating and the elevation of cyclic AMP content induced by 10^-5M isoproterenol were significantly higher for cultured cells pretreated with propranolol than for control cells. These results indicate a correlation between an increased number of beta-adrenoceptors and increased physiological responses of cultured heart cells after propranolol withdrawal.

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We determined plasma and cardiac immunoreactive atrial natriuretic polypeptide (ir-ANP) levels in rats treated with deoxycorticosterone acetate (DOCA) and sodium chloride for 1, 7, and 28 days. Systolic blood pressure of DOCA-salt rats began to increase from the 7th day and reached 191±7mmHg at the 28th day. One day after treatment with DOCA-salt, plasma levels of ir-ANP were increased compared to that of control rats. This was accompanied by decreased cardiac ir-ANP content. However, at the 7th day of DOCA-salt treatment, both plasma and cardiac ir-ANP levels of DOCA-salt rats were not different from those of control animals. At the 28th day, DOCA-salt rats had high plasma irANP levels and no significantly different cardiac ir-ANP content compared to the controls. These data suggest that there are time-related changes in plasma ANP concentration during the development of DOCA-salt hypertension and higher plasma ANP levels might not necessarily be associated with a decreased cardiac ANP content.

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The left ventricle is represented as an elastic thick-walled cylinder contracting symmetrically. The force generated by the active state of the myocardium in the radial direction is represented by body force (force/unit volume) and is included in the mathematical formalism that describes the contraction of the left ventricle. An equation for the P-V relation in the left ventricle is derived and various applications to study cardiac mechanics are discussed. The results obtained tend to demonstrate that the active force generated by the myocardium during an ejecting contraction reaches its maximum value near the end of the systolic phase, when the slope E of the P-V line reaches its maximum value E_m, and that it is related to the peak isovolumic pressure.

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The cardiovascular effects of 2-amino-N-(2, 6-dimethylphenyl)-N-[3-(3-pyridyl)propyl]propionamide dihydrochloride (Ro 22-9194) were investigated in the canine isolated atrial preparation perfused with arterial blood from another donor dog. Intravenous administration of Ro 22-9194 (0.3-3mg/kg) reduced heart rate and systemic arterial blood pressure of the donor dog. Simultaneously, in the isolated atrium perfused with donor's blood, negative chronotropic and inotropic responses were induced in a dose-dependent manner. Direct administration of Ro 22-9194 (1-300μg) into the sinus node artery of the isolated atrium induced negative chrono- and inotropic responses and a transient increase in coronary blood flow in a dose-related manner. Mexiletine (1-300μg) also induced negative chrono- and inotropic responses. The potency of Ro 22-9194 for negative cardiac effects was similar to that of mexiletine. The negative cardiac effects of Ro 22-9194 were not modified by atropine in doses which significantly inhibited the cardiac effects of acetylcholine. Ro 22-9194 did not affect the cardiac responses to norepinephrine and to acetylcholine significantly. These results suggest that Ro 22-9194 has non-cholinergic cardiac depressant properties with its vasodilating action, and it has neither anti-adrenergic nor anti-cholinergic actions on the dog heart.

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A 65-year-old man with idiopathic myocarditis is described. He was admitted with symptoms of acute heart failure. Examination revealed left ventricular hypokinesis. Results of an endomyocardial biopsy showed "resolving myocarditis". Immunological studies of the peripheral blood showed a low helper-suppressor (CD4/CD8) ratio on admission and depressed natural killer (NK) cell activity coincident with the onset of myocarditis. We considered that this immunological imbalance may have occurred during the progression of myocarditis to dilated cardiomyopathy.

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Free left ventricular wall rupture following acute myocardial infarction usually results in cardiac tamponade and sudden death. Occasionally, the bleeding into the pericardial sac is arrested by the surrounding pericardial tissue causing formation of a pseudoaneurysm. The case herein reported presented with a refractory pericardial effusion 1 month after an anterior myocardial infarction. While echocardiography failed to reveal a pseudoaneurysm or to localize a rupture, cineventriculography disclosed the diagnosis of a minimal rupture of the left ventricular free wall. The patient was successfully treated by surgery.

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