The survival benefit of bystander cardiopulmonary resuscitation in a paramedic served metropolitan area.

We investigated the survival benefit bystander cardiopulmonary resuscitation (CPR) for out-of-hospital emergencies in a paramedic served area of metropolitan Los Angeles. Clinical information for all events occurring between January 1 and December 31, 1978 was obtained from paramedic report forms and hospital medical records. Bystander CPR was performed for 93 cases and, of these, 20 (22 per cent) survived to hospital discharge, as compared to 7 (5 per cent) of the 150 patients not receiving bystander CPR (p less than 0.001). Twelve (27 per cent) of the 45 patients in ventricular fibrillation (VF) who had bystander CPR survived, as compared to 4 (6 per cent) of 70 VF patients without bystander CPR (p less than 0.01). We conclude that bystander CPR, initiated prior to arrival of paramedics, produced a fourfold improvement in survival. Overall there was a 10 per cent survival rate at hospital discharge. Survival rates reported from Seattle may not necessarily be generalized to larger cities.

Cardiac effects of acute ethanol ingestion unmasked by autonomic blockade.

We assessed the effects of ethanol and autonomic blockade on left ventricular function in nine normal subjects, age 20--35 years, using M-mode echocardiography and systolic time intervals. On day 1, measurements were made of heart rate, mean velocity of circumferential fiber shortening, and left ventricular pre-ejection period and left ventricular ejection time ratio (PEP/LVET), during a control period and after autonomic blockade. Autonomic blockade was produced with intravenous propranolol (0.2 mg/kg body weight) and atropine (0.04 mg/kg body weight). On day two, measurements were again made during a control period, then with ethanol alone, followed by addition of autonomic blockade to ethanol. One hundred eighty milliliters of ethanol were ingested over 60 minutes, resulting in a mean blood ethanol level of 110 mg/dl (range 77--135 mg/dl) at 60 minutes post-ingestion. There were no significant differences between the control data on days 1 and 2. Blood pressure was unchanged throughout the study. study. On day 1, autonomic blockade alone resulted in the expected increase in heart rate (p less than 0.001), with a proportional increase in mean velocity of circumferential fibr shortening (p less than 0.01), and an increase in PEP/LVET (p less than 0.01). On day 2, ethanol alone resulted in no significant changes except for a slight increase in PEP/LVET (p less than 0.02). Ethanol plus autonomic blockade, (day 2), compared with autonomic blockade alone (day 1), revealed a decrease in mean velocity of circumferential fiber shortening (p less than 0.05), and an increase in PEP/LVET (p less than 0.01), with a decrease in intrinsic heart rate (p less than 0.001). We conclude that in normal subjects: 1) autonomic blockade does not directly affect contractility; 2) acute ethanol ingestion alone does not produce important changes in cardiac function; and, 3) ethanol in the autonomic blockaded heart causes a significant decrease in contractility. Thus, we infer that ethanol has a negative inotropic effect which is masked by catecholamines and/or autonomic nervous system discharge.

Echocardiographic evaluation of posterior left ventricular wall motion in muscular dystrophy.

Maximal systolic endocardial velocity (SEVM) and maximal diastolic endocardial velocity (DEVM) were determined echocardiographically in patients with muscular dystrophy (MD). The SEVM of the muscular dystrophy patients was 5.5 +/- 0.9 cm/sec and the DEVM was 13 +/- 3 cm/sec. The SEVM in MD was significantly less than that seen in age-matched normals (P less than 0.05), persons with myotonia congenita (P less than 0.02), deconditioned patients (P less than 0.001), or older normal persons (P less than 0.05). The Sevm of the MD patients was not significantly different from persons with spinal muscular atrophy. The DEVM of the muscular dystrophy patients was significantly less (P less than 0.001-0.05) than any other group. No correlation could be found between age, heart rate, type or severity of dystrophy and SEVM or DEVM values. The echocardiogram was more selective in correctly identigying muscular dystrophy patients than the electrocardiogram. The abnormality in DEVM was present despite lack of symptoms, normal cardiovascular examination, normal chest X-ray and normal electrocardiograms in 18 of 22 patients. We believe that the DEVM correlates with myocardial relaxation.

Posterior mitral leaflet motion in mitral stenosis.

A reduced rate of diastolic closure of the anterior mitral leaflet has been shown to occur in mitral stenosis, primary pulmonary hypertension, and in cases with reduced left ventricular compliance. Posterior notion of the posterior mitral leaflet in diastole has been the distinguishing feature to rule out the diagnosis of mitral stenosis. We have analyzed echocardiograms of 167 patients with mitral stenosis and have found 16 cases where the posterior mitral leaflet moved posteriorly, that is, in an opposite direction from the anterior mitral leaflet. Two other features were found that were helpful in establishing the diagnosis of mitral stenosis in these atypical cases, namely, thickening of the mitral leaflets and reduction or absence of the artrial wave.

Echocardiographic differentiation of mediastinal tumors from primary cardiac disease.

Three cases of mediastinal tumors (thymic cyst, fibrosarcoma, fibrolipoma) mimicking primary cardiac disease were studied by echocardiography. The echocardiographic findings of the thymic cyst are presented and the echocardiograms in the other two patients discussed. Intrinsic cardiac pathology was excluded and discovery of abnormal extracardiac echoes prompted further investigation. In each instance, the echocardiographic interpretation of the nature and position of each extracardiac mass was confirmed by surgery or autopsy. We conclude that echocardiography is a useful noninvasive technique in differentiating between cardiac and extracardiac disease, and should be performed whenever an unusual or enlarged cardiac silhouette is encountered.