Showing papers in "Heart in 1975"

Effect of chronic beta-adrenergic receptor blockade in congestive cardiomyopathy.

Abstract: Adrenergic beta-blocking agents were given to 7 patients with advanced congestive cardiomyopathy who had tachycardia at rest (98 plus or minus 13 beats/min). The patients were on beta-adrenergic receptor blockade for 2 to 12 months (average 5-4 months). One patient was given alprenolol 50 mg twice daily and the other patients were given practolol 50 to 400 mg twice daily. Virus infection had occurred in 6 of the patients before the onset of symptoms of cardiac disease. All patients were in a steady state or were progressively deteriorating at the start of beta-adrenergic receptor blockade. Conventional treatment with digitalis and diuretics was unaltered or reduced during treatment with beta-blocking agents. An improvement was seen in their clinical condition shortly after administration of the drugs. Continued treatment resulted in an increase in physical working capacity and a reduction of heart size. Noninvasive investigations including phonocardiogram, carotid pulse curve, apex cardiogram, and echocardiogram showed improved ventricular function in all cases. The present study indicates that adrenergic beta-blocking agents can improve heart function in at lease some patients with congestive cardiomyopathy. Furthermore, it is suggested that increased catecholamine activity may be an important factor for the development of this disease, as has been shown in animal experiments.

Syndromes of asplenia and polysplenia. A review of cardiac and non-cardiac malformations in 60 cases withspecial reference to diagnosis and prognosis.

Abstract: This review presents the cardiac and non-cardiac malformations in 60 cases with asplenia and polysplenia with special reference to distinguishing factors which may be helpful in the clinical recognition of these syndromes. The asplenia cases were predominantly male and presented with cyanosis. They frequently had transposition of the great arteries (72%) with pulmonary stenosis or atresia (88%) and total anomalous pulmonary venous drainage (72%). Deaths were caused by cardiac failure and anoxia in 57 per cent of cases. Most of the patients died in the first year of life (79%), but longer survival is possible in the asplenia syndrome. The polysplenia cases were predominantly female and survived longer. The characteristic clinical findings were the relatively more benign presenting signs and the leftward or superiorly orientated P wave axis on the electrocardiogram. Conotruncal abnormalities were less common and total anomalous pulmonary venous drainage did not occur. On angiography the inferior vena caval drainage via the azygos system was clearly identified and this was present in all cases at surgery. Our study indicated that the cardiac anomalies in polysplenia were less severe than they were in asplenia and therefore the prognosis in the former syndrome is likely to be more favourable. Three families had two affects sibs but no single genetic factor could be identified. The aetiology of these syndromes remains undetermined.

Circumstances attending 100 sudden deaths from coronary artery disease with coroner's necropsies.

Abstract: The deaths of 100 men due to coronary artery disease which occurred so suddenly and unexpectedly as to merit a coroner's necropsy have been studied, with special reference to the exact circumstances of their occurrence. The most significant relationship of sudden death was with acute psychological stress. Moderate physical activity, the time of day, the day of the week, and a recent meal, especially if accompanied by alcohol, were also significantly related. Very strenuous exercise, the season of the year, the environmental temperature or recent change of it, and chronic psychological stress were not so related. Neither were the actual smoking of a cigarette nor the composition of the meal immediately preceding death. Compared with previous series of proved acute myocardial infarction the necropsies in these cases showed that the right coronary artery had been recently occluded by a thrombus more often than the left anterior descending. Stenosis or occlusion of the right coronary artery bore a significant relation to the suddenness of death. Special analysis of the 52 cases in which neither recent thrombus nor infarction were found did not disclose any circumstances attending death which differed from the remainder. Some comparisons are made with the circumstances attending the onset of symptoms in 100 men studied while recovering from an acute myocardial infarct.

Dual atrioventricular nodal pathways. A common electrophysiological response.

Abstract: Evidence of dual atrioventricular nodal pathwats (a sudden jump in H1-H2 at critical A1-A2 coupling intervals) was shown in 41 out of 397 patients studied with atrial extrastimulus techniques. In 27 of these 41, dual pathways were demonstrable during sinus rhythm, or at a cycle length close to sinus rhythm (CL1). In the remaining 14, dual pathways were only demonstrated at a shorter cycle length (CL2). All patients with dual pathways at cycle length who were also tested at cycle length (11 patients) had dual pathways demonstrable at both cycle lengths. In these 11 patients both fast and slow pathway effective refractory periods increased with decrease in cycle length. Twenth-two of the patients (54%) had either an aetiological factor strongly associated with atrioventricular nodal dysfunction or one or more abnormalities suggesting depressed atrioventricular nodal function. Dvaluation of fast pathway properties suggested that this pathway was intranodal. Seventeen of the patients had previously documented paroxysmal supraventricular tachycardia (group 1). Eight patients had recurrent palpitation without documented paroxysmal supraventricular tachycardia (group 2), and 16 patients had neither palpitation nor paroxysmal supraventricular tachycardia (group 3). Echo zones were demonstrated in 15 patients (88%) in group 1, no patients in group 2, and 2 patients (13%) in group 3.

RR interval variations in young male diabetics.

Abstract: The beat-to-beat (RR interval) variation in resting heart rate was used to detect possible autonomic nerve damage in a group of 42 young asymptomatic male diabetics, employing a sensitive electrocardiographic computer technique. Compared with 25 age-matched controls, the diabetics showed both a significantly smaller mean RR interval (P less than 0.005) and less RR interval variation (P less than 0.001). Whereas only 4 of the diabetic subjects had shorter mean RR intervals, 22 (52%) of the diabetics had RR interval variations that were less than any of the normal subjects. This reduction in heart rate variation has not been previously reported in diabetics without clinical features of autonomic neuropathy and might provide a sensitive method of assessing early autonomic nerve involvement in diabetes.

Relation between infarct size and ventricular arrhythmia.

Abstract: In order to determine whether ventricular arrhythmia is quantitatively related to infarct size estimated enzymatically we studied 31 patients with acute myocardial infarction without cargiogenic shock. Infarct size index was estimated from hourly serum creatine kinase (CK) changes during periods of 48 to 72 hours. Ventricular arrhythmia was quantified by automated analysis of continuous electrocardiographic recordings over a period of 20 hours with the use of the Argus/H computer system. Patients were classified into three groups according to infarct size index. Patients in all groups had similar average heart rate, blood pressure, serum potassium, and arterial pH and PCO2 values during the first 10 hours after admission. The total number of ventricular ectopic beats (VEB), frequency of couplets, and ventricular tachycardia, and peak rate of ventricular ectopic beats during the first 10 hours after admission were all related to infarct size index. For example, patients with small, medium, and large estimated infarct size averaged 26, 104, and 405 ventricular ectopic beats, respectively. These results suggest that the severity of ventricular arrhythmia early after myocardial infarction is related to the extent of myocardial injury as estimated enzymatically. Thus the apparent efficacy and therefore the evaluation of antiarrhythmic agents early after myocardial infarction may be influenced by the magnitude of injury sustained by the heart.

Bidirectional tachycardia in a child. A study using His bundle electrography.

Abstract: This is a report of a case of bidirectional tachycardia in a 6-year-old girl with no evidence of any structural abnormality of the heart. The patient had never received digitalis. The arrhythmia appeared to be precipitated by effort and emotional stress, and could be induced by increasing the heart rate by atrial pacing or isoprenaline administration. His bundle electrography showed that the arrhythmia was ventricular in origin. This emphasizes the importance of recording an effort electrocardiogram in all children with unexplained syncopal episodes, even when the resting electrocardiogram is normal.

Effect of quinidine on maintaining sinus rhythm after conversion of atrial fibrillation or flutter. A multicentre study from Stockholm.

Abstract: In a controlled study comprising 176 patients, quinidine in the form of Kinidin Durules was found to reduced significantly the recurrence of the atrial fibrillation during a 1-year follow-up period after successful electric shock conversion. After one year, 51 per cent (52/101) of the patients in the quinidine group, and 28 per cent (21/75) in the control group remained in sinus rhythm (P smaller than 0.001). No less than 43 per cent of the patients converted to sinus rhythm during treatment with maintenance doses of quinidine sulphate before intended DC conversion. Gastrointestinal side-effects were not uncommon, and caused interruption of quinidine treatment in some cases.

Idiopathic giant cell myocarditis--a distinctive clinico-pathological entity.

Abstract: Eleven cases of idiopathic giant cell myocarditis are described, The pathological features are unmistakable with serpiginous areas of myocardial necrosis, at the margins of which giant cells can be seen on histological examination. The aetiology of the condition remains obscure but associated pathology suggests that altered immunity may be a factor. The rapid clinical course is, however, highly suggestive of an infective cause though none has been found.

Surgical treatment of ventricular tachycardia after epicardial mapping studies.

Abstract: Two patients with intractable life-threatening ventricular tachycardias have been studied using intracardiac electrograms and programmed electrical stimulation of the heart. Both patients have shown to have an underlying re-entry mechanism in the ventricles as the basis for the tachycardias. Both patients underwent epicardial mapping studies at cardiac surgery, and the site of re-entry was established. In one patient the re-entry front was found to start in the posterobasal region of the left ventricle and in the other patient the re-entry front was found in the anterobasal region of the right ventricle. In both patients surgical interruption of the re-entry front was carried out. Both patients are alive and free from tachycardias at the time of writing.

Arteriographic patterns early in the onset of the coronary syndromes.

Abstract: Coronary arteriography in 300 patients within one year of onset of symptoms of coronary arterial disease revealed already severe anatomical coronary disease in three patient groups: those with angina pectoris alone (164 patients), with subendocardial myocardial infarction (63 patients), and with transmural myocardial infarction (73 patients). The number of vessels diseased (larger than or equal to 50% obstruction), distribution of obstruction, and degree of stenosis were similar in the three groups. However, total occlusion of at least one artery was much more common in transmural myocardial infarction and in subendocardial myocardial infarction with elevation of enzyme levels. We suggest that such occlusions occurred at the time of the infarction. Similarities in coronary anatomy between patient subgroups with angina (on exercise or at rest and nocturnal) indicate that factors other than coronary anatomy intervene in precipitating the different types of angina. Vessel disease was not related to smoking, hyperlipidaemia, or hypertension but coronary disease was manifest earlier in life in smokers or those with hyperlipidaemia.

Left and right heart haemodynamics during spontaneous angina pectoris. Comparison between angina with ST segment depression and angina with ST segment elevation.

Abstract: The function of both right and left sides of the heart was studied during spontaneous attacks of angina pectoris at rest in 7 patients showing ST depression (type I) and 4 showing ST elevation (type II) during the attack. In none of the 44 type I attacks and 29 type II attacks which were recorded did circulatory changes; the latter were different in the two groups. Type I attacks showed: a) a brief fall in arterial pressure, accompanied by b) a rise of right atrial and pulmonary wedge pressures and c) a decrease of cardiac output, right and left stroke work, the mean rate of systolic ejection, and indirect left ventricular pre-ejection dP/dt. In the course of the attack a hypertensive phase followed, which was paralleled by an increase of heart rate, cardiac output, left and right stroke work, and mean systolic ejection rate, left dP/dt; right atrial pressure and wedge pressure remained raised. All of the circulatory functions started to revert towards the pre-attack levels coincident with the waning phase of the electrocardiographic alteration, the latter occurring either spontaneously or after nitroglycerin. Type II attacks for the entire duration of the electrocardiographic changes showed: a) a reduction of arterial pressure, cardiac output, right and left stroke work, mean systolic ejection rate, and left dP/dt, b) a rise of right atrial and wedge pressures, and c) quite small changes of heart rate. When the electrocardiogram started to revert to the pre-attack aspect, the cardiac function rapidly improved and, after a supernormal phase, returned to the basal levels in about 2 minutes. It is concluded: 1) that no circulatory factor interfering with the mechanical effort of the heart is responsible for eliciting spontaneous angina: 2) that in type I attacks right and left ventricular impairment occurs which recovers rapidly, possibly through a sympathetic compensation; 3) that in type II attachs dysfunction of both sides of the heart occurs and persists throughout the episode of electrocardiographic alteration; 4) that the dynamic impairment is probably more severe in type I than in type II angina.

Atrio-His bundle tracts.

Abstract: The atrio-His bundle tracts are very rare; only two have been found in 687 hearts studied histologically. These tracts have a similar appearance to those of the atrioventricular bundle and form a complete bypass of the atrioventricular node. In their presence the electrocardiogram may show a short or normal PR interval. They may be responsible for some cases of very rapid ventricular response to supraventricular arrhythmias.

Quantitation of infarct size in man by means of plasma enzyme levels.

Abstract: A method is described in which the extent of myocardial infarction in man is assessed by mathematical analysis of the rise in plasma enzyme levels after infarction. Five enzymes are used in this study: lactate dehydrogenase (LDH); alpha-hydroxybutyrate dehydrogenase (alpha-HBDH); aspartate aminotransferase (GOT); creatine phosphokinase (CPK); and phosphohexoseisomerase (PHI). It is shown that a reasonable assessment of the total enzyme release, reflecting the extent of the infarcted area, can be made when a sufficient number of blood samples are taken after infarction. This could provide a method by which to judge therapeutic effects of intervention in the course of a myocardial infarction, as demonstrated in this study by the assessment of the effect of urokinase on the enzyme release after an infarct.

Effects of amiodarone on thyroid function in patients with ischaemic heart disease.

Abstract: Thyroid function was evaluated clinically and biochemically in 12 patients with ischaemic heart disease receiving 200 mg oral amiodarone three times daily for periods up to 6 weeks. During drug administration, no patient developed clinical or laboratory evidence of hypothyroidism, but serum levels of T3 tended to fall and those of T4 increased but not to levels outside the normal range. Amiodarone produced a significant reduction in heart rate with prolongation of the QTc interval of the electrocardiogram without altering either the PR interval or the QRS duration. These effects of the drug were still present 4 weeks after cessation of treatment. In spite of the high iodine content, amiodarone does not, therefore, depress thyroid function to any important degree during chronic administration and its antianginal action does not appear to be caused by the production of generalized hypothyroidism.

Continuous assessment of left ventricular shape in man.

Abstract: Frame by frame analysis of left ventriculograms has been performed in 10 normal subjects and 40 patients with heart disease. Left ventricular shape index was derived as 4 pi (cavity area)/(perimeter)2, which has a maximum value of 1 when the outline is circular. In normal subjects systole was always associated with progressive reduction in shape index, indicating that the cavity projection had become less circular. This change was smaller in patients with low ejection fraction and also when inferior or anterior hypokinesia was present, even though ejection fraction was normal. During early diastole shape index rose rapidly due to an increase in minor diameter occurring throughout the period of rapid filling. In some cases this preceded any change in long axis, which was due to upward movement of the aortic root as well as outward movement of the apex. These results have functional implications, suggesting in particular that wall movement during filling may be non-uniform and that assumptions about cavity shape used in the derivation of wall properties from estimates of ventricular volume may require modification.

Noninvasive visualization of acute myocardial infarction in man with thallium-201.

Abstract: Myocardial imaging using 201Tl was performed in 10 patients with supposedly normal myocardial perfusion and in 11 patients with acute myocardial infarction. In all patients with acute myocardial infarction the scintiscan showed an area with diminished radioactivity at the site corresponding the electrocardiographic localization of the infarction. 210Tl seems to be of diagnostic value for recognizing acute myocardial infarction in the very first hours after its onset and for visualizing infarction in patients in whom pre-existing electrocardiographic abnormalities prevent its diagnosis and/or localization.

Effects of disopyramide on electrophysiological properties of specialized conduction system in man and on accessory atrioventricular pathway in Wolff-Parkinson-White syndrome.

Abstract: Seven patients with normal specialized conduction system and three patients with the Wolff-Parkinson-White (WPW) syndrome were studied using programmed stimulation of the heart before and after the administration of intravenous disopyramide. The principal effect of this drug was to prolong the effective refractory period of the atria and ventricles, and to prolong the effective refractory period of the anomalous pathway in the WPW syndrome. In addition, it prolonged the conduction time in the anomalous pathway in the WPW syndrome. These findings suggest that disopyramide would be a useful and safe drug in the management of certain atrial and ventricular arrhythmias and in the management of the Wolff-Parkinson-White syndrome with atrial fibrillation.

Extreme pulmonary hypertension caused by mitral valve disease. Natural history and results of surgery.

Abstract: Five hundred and eighty six patients with mitral valve disease were studied with cardiac catheterization between 1961 and 1972; 48 (8.2%) had extreme pulmonary hypertension (resting systolic pulmonary artery pressure of 80 mmHg or above and pulmonary vascular resistance of 10 units or greater) and of these patients, 27 underwent cardiac surgery. The operative mortality for mitral valvotomy was 11 per cent and for mitral valve replacement 56 per cent. The overall mortality was 31 per cent. The risks of operation were increased in those with a long history of cardiac symptoms, those over 50 years of age, and in the presence of associated aortic valve disease. The mean survival for those patients not having operation was only 2.4 plus or minus 0.5 years. The mean follow-up period for those surviving operation has been 5.8 plus or minus 0.6 years, and symptomatic improvement has been good.

Clinical, haemodynamic, and coronary angiographic correlates of angina pectoris in patients with severe aortic valve disease.

Abstract: Of 88 consecutive patients aged 20 to 77 years with severe symptomatic aortic valve disease requiring surgery, 51 patients had angina pectoris; of these 51, 41 had predominant aortic stenosis and 10 had severe aortic regurgitation. All patients with angina pectoris underwent coronary angiography; significant coronary arterial disease was encounted in 24 per cent of those with aortic stenosis and 20 per cent of those with aortic regurgitation. By contrast, of 37 patients without angina pectoris 19 underwent coronary arteriography; none showed significant coronary artery disease (P smaller than 0.05). Among patients with angina pectoris, 17 per cent of those with aortic stenosis experienced prolonged, rest or nocturnal pain, compared to 70 per cent of those with aortic regurgitation (P smaller than 0.005). At the time of onset of angina pectoris, there were features of heart failure in 34 per cent of those with aortic stenosis, and in 90 per cent of those with aortic regurgitation (P smaller than 0.005). Nitroglycerin promptly relieved angina pectoris in 56 percent of patients with aortic stenosis and in 50 per cent of those with aortic regurgitation (P smaller than 0.05). Neither the pattern of angina pectoris nor the response to nitroglycerin was dependent upon the coexistence of significant coronary artery disease. In patients with aortic stenosis, there was not significant difference between those with angina pectoris, and those without angina with regard to left ventricular end-diastolic volume, end-diastolic pressure, ejection fraction, peak systolic pressure, wall thickness, cardiac index, or the product of these factors. In patients with aortic regurgitation, cardiac index was significantly lower (P smaller than 0.05), left ventricular end-diastolic volume tended to be larger, and ejection fraction tended to be lower in patients with angina pectoris as opposed to those without angina pectoris.

Echocardiographic left ventricular dimensions in pressure and volume overload. Their use in assessing aortic stenosis.

Abstract: Left ventricular 'relative wall thickness', determined from the ratio between echocardiographic measurements of end-systolic wall thickness and cavity transverse dimension, was related to peak systolic intraventricular pressure in 15 normal subjects, in 15 patients with left ventricular volume or pressure overload without aortic stenosis, and in 23 patients with aortic stenosis. All these patients had a mean rate of circumferential fibre shortening greater than 1.0 circumference per second and were regarded as having good ventricular function. Relative wall thickness was found to be normal in cases of volume overload and to be increased in pressure overload, being proportional to the systolic intraventricular pressure. Values for the ratio of systolic intraventricular pressure to relative wall thickness in the normal subjects and patients without aortic stenosis were similar (mean 30 +/- 2.5). Based on this relation, estimates of peak systolic intraventricular pressure were made in the cases of aortic stenosis using the formula: systolic intraventricular pressure (kPa) equals 30 x wall thicknes divided by transverse dimension. Peak systolic aortic value gradients derived by subtracting brachial artery systolic pressure, measured by sphygmomanometer, from the echocardiographic estimates of intraventricular pressure compared favourably with the gradients measured at left heart catheterization (r equals 0.87, P less than 0.001). Aortic value orifice areas, derived from echocardiographic estimates of stroke volume, ejection time, and value gradient, ranged from 0.21 to 3.16 cm2 and appeared to correlate with the severity of aortic stenosis. All patients with aortic stenosis, with or without coexistent mild aortic regurgitation, who were recommended for aortic valve surgery, had estimated valve orifice areas of less than 0.8 cm2. A further 10 patients with pressure or volume overload had mean rates of circumferential fibre shortening of less than 1.0 circumference per second and were regarded as having poor ventricular function. In these cases values for relative wall thickness were lower than in those with good ventricular function and were not proportional to systolic intraventricular pressure. In patients with good left ventricular function systolic intraventricular pressure is proportional to, and can be estimated from, echocardiographic measurement of relative wall thickness.

Measurement of peak rates of left ventricular wall movement in man. Comparison of echocardiography with angiography.

Abstract: Estimates of peak systolic and diastolic rates of left ventricular wall movement were made in 23 patients by echocardiography and angiocardiography. Echocardiographic measurements were calculated as the rate of change of the transverse left ventricular dimension, derived continuously throughout the cardiac cycle. These were compared with similar plots of transverse left ventricular diameter, in the same patients, derived from digitized cineangiograms taken within 10 minutes of echocardiograms. The results indicate close correlation between the two methods, and suggest that either can be used to measure peak rates of left ventricular wall movements in patients with heart disease.

Myocardial infarction in young men. Study of risk factors in nine countries.

Abstract: In order to determine whether the development of myocardial infarction in different countries is associated with different risk factors, 240 male survivors, aged 40 or less, were studied in nine countries. In the seven centres in developed countries (Auckland, Melbourne, Los Angles/Atlanta, Cape Town, Tel Avic, Heidelberg, and Edinburgh) there was a high procedure of risk factors, particularly of hyperlipidaemia and cigarette smoking. The prevalence of hypertension, obesity, hyperglycaemia, and hyperuricaemia varied from centre to centre. Risk factors were less prevalent in Bombay and Singapore: the most common risks operating in Bombay seemed to be cigarette smoking and hyperglycaemia, while in Singpore cigarette smoking was the commonest. The mean age of the whole group was 35.4 years. Serum cholesterol levels of 7.25 mmol/l (280 mg/dl) or more were present in 25 per cent of all patients, serum triglyceride levels of 2.26 mmol/l )l200 mg/dl) or more in 35 per cent. 80 per cent of the patients were smokers, and 15 per cent were either for hypertension before myocardial infarction or had a raised blood pressure after myocardial infarction. Obesity was found in 19 per cent of all patients and serum uric acid levels over 0.5 mmol/l (8.5 mg/dl) in 17 per cent. 10 per cent of all patients were either treated for diabetes mellitus before myocardial infarction or showed an abnormal glucose tolerance after myocardial infarction. This collaborative study may help, by showing differences in the prevalence of risk factors, to indicate to each centre and to national and to international organizations, the direction for their future studies into the causation and prevention of myocardial infarction in young men.

Factors influenceing long-term prognosis in male patients surviving a first coronary attack.

Abstract: Three hundred and sixty-four men who survived a first episode of acute coronary insufficiency or myocardial infarction for 28 days were admitted to a coronary heart disease secondary programme between 1 January 1961 and 31 December 1971 Of these, 252 have been followed for at least 4 years The 4-year mortality was 135 per cent (34 patients) The average mortality was 34 per cent but an excess of deaths occurred during the first year of follow-up Of 11 characteristics measured during the acute attack, only severity of the attack was significantly associated with poor 4-year survival Cigarette consumption after infarction was significantly less among those surviving the 4-year period when compared with decedents Follow-up systolic and diastolic blood pressure levels were significantly lower among decedents No significant differences were noted in serum cholesterol levels and in mean weight, The presence of post-infarction angina did not affect the prognosis

Haemodynamic effects of a new inotropic agent (dobutamine) in chronic cardiac failure.

Abstract: The haemodynamic effects of dobutamine were studied in 14 patients with chronic congestive cardiac failure. Heart rate, central venous, pulmonary arterial, pulmonary wedge, and aortic pressures, aortic dp/dt, cardiac output, cardiac index, stroke volume, and pulmonary and systemic vascular resistances were measured or derived. Dose-response curves were obtained by recording all measurements before and after intravenous infusion of dobutamine at rates of 2.5, 5, and 10 mug/kg per min for periods of 30 minutes each. Significant increases in mean values were observed for cardiac output from 3.7 to 6.4 l/min (82%), for stroke volume from 44 to 64 ml (39%), and aortic dp/dt from 692 to 1414 mmHg/s (92.0 to 188.1 kPa/s (76%). Heart rate increased only moderately from 86 to 101 per minute (31%). Significant reduction occurred in pulmonary wedge and central venous pressures. Mean aortic and pulmonary pressures did not change significantly, as a measure of decreased vascular resistances. The drug was uniformly well tolerated. The predominant inotropic effects of dobutamine without tachycardia or arrhythmias may be valuable in severe heart failure.

Effect of propranolol on left ventricular function, segmental wall motion, and diastolic pressure-volume relation in man.

Abstract: Precise quantitation of the effects of the non-selective beta adrenergic blocking drug propranolol (3.15 mg/kg body weight) on left ventricular function, segmental wall motion, and diastolic pressure-volume relation in man has been performed. High fidelity left ventricular pressure measurements and simultaneous single-plane angiocardiograms were recorded on a video disc and volumes calculated by a light-pen computer system. Systolic segmental wall motion was computer analysed using the long axis-quadrasection method. Patients were transvenously atrially paced to maintain a constant heart rate. The haemodynamic effects of propranolol may vary depending upon the extent of pre-existing myocardial disease. In some patients ventricular function, as measured by ejection fraction, may be reduced. This reduction in ejection fraction appears to result from overall reduction in segmental wall motion, but also from accentuation of segmental wall abnormalities. These results are consistent with the thesis that beta adrenergic blocking drugs may inhibit compensatory sympathetic mechanisms. The diastolic effects of propranolol may include quite substantial increases in ventricular volumes in those patients with impaired cardiac function. With respect to the intact human ventricle, propranolol may increase diastolic volume for a given level of ventricular pressure. Thus, in a static sense, the ventricle in these patients could be viewed as being more compliant after propranolol administration. However, the fact that the length-tension relation, as measured by the slope of the logarithmic pressure versus volume plot is unaltered by propranolol, suggests that the muscle comprising the ventricle itself exhibits no alteration in its passive elastic properties.

Infective endocarditis in the billowing mitral leaflet syndrome.

Abstract: Ten patients with the billowing mitral leaflet syndrome complicated by infective endocarditis are reported. Two patients had a non-ejection systolic click and 8 had both a non-ejection systolic click and a late systolic murmur. These auscultatory features were difficult to detect in 4 instances in that they were intermittent, soft, or brought out only with postural change. Seven patients were unaware of their cardiac lesions. A low grade pyrexia was present in all 10 patients. Four patients presented with clinical features caused by reversible neurological lesions. Blood cultures were positive in all patients, with Staphylococcus albus the infecting organism in 6. Antibiotic therapy was successful with significant mitral regurgitation supervening in only one instance. The importance of the billowing leaflet as a potential site of infective endocarditis is emphasized. It seems that antibiotic prophylaxis is indicated at times of increased risk of infection in subjects with a non-ejection systolic click or a late systolic murmur.

Creatine kinase release in acute myocardial infarction: correlation with clinical, electrocardiographic, and pathological findings.

Abstract: Creatine kinase (CK) release curves were analysed in 40 patients with acute myocardial infarction. Three groups could be identified. Group A (duration of CK release less than 30 hours) comprised 15 patients whose CK release was completed within 22.8 hours. In these patients chest pain was noted on the first hospital day and necropsy in three showed a homogeneous myocardial infarction. Group B (duration of CK release greater then 30 hours) comprised 16 patients who had a significantly longer CK release time of 42.2 hours (P less than or equal to 0.05). Their chest pain persisted for two to three days and pathological examination in five patients showed a heterogeneous composition of the infarcted myocardium. Group C comprised nine patients who had a second rise of serum CK. This was always associated with chest pain. It reflected an extension of the infarct which accounted on average for 24 per cent of the size of the final infarct. We concluded that a CK release of short duration indicated infarction without extension, CK release of longer duration indicated a gradual extension of infarction, and a repeated CK release resulted from a sudden extension of an infarct. According to these criteria an extension of the infarct occurred in 62 per cent of our patients.

Contribution of cardiac pacing to our understanding of the Wolff-Parkinson-White syndrome.

Abstract: This review discusses the information which can be obtained by cardiac pacing in patients with the Wolff-Parkinson-White syndrome. Programmed electrical stimulation when combined with the recording of intracardiac electrograms and surface electrocardiograph leads, can be extremely useful in the following areas. 1) Determining the type of the accessory atrioventricular connexions; 2) determining the electrophysiological properties of the accessory atrioventricular pathway; 3) localizing the position of the accessory atrioventricular pathway; 4) determining the mechanisms of any tachycardia; 5) assessing effect of drugs; 6) identifying patients likely to be at high risk; and 7)evaluating postoperative conduction.

Quantitative structural analysis of pulmonary vessels in isolated ventricular septal defect in infancy.

Abstract: Structural changes in the pulmonary circulation were studied in the lungs of 5 infants dying with ventricular septal defect. Applying precise quantitative morphological techniques to the pulmonary vessels, it was possible to correlate pathological change with clinical and haemodynamic findings, and to identify two patterns of response. Three of the infants (group I) ppresnted in cardiac failure with a large pulmonary blood flow, dilated and tortuous pulmonary arteries, and fewer intra-acinar vessels than normal. Medial hypertrophy was moderate and affected chiefly the larger arteries, i.e. those with a diameter greater than 200 mum. The other 2 infants (group 2) had a high pulmonary vascular resistance with an intermittent right-to-left shunt. The pulmonary arteries were of normal size and the reduction in the number of the arteries was less striking. Medial hypertrophy was greater than in the first group and affected all sizes of artery including those less than 200 mum in diameter. In both groups, muscle extended further along the axial pathway. Muscular hypertrophy was found also in the vein wall in most cases and, as with the arteries, was more severe in those with a higher pulmonary vascular resistance. The findings illustrate the variation in pulmonary vascular response in infants with a ventricular septal defect. It is suggested that in patients with a ventricular septal defect, arterial muscularity usually regresses after birth and a left-to-right shunt develops; secondary hypertrophy of the media then develops in reaponse to the shunt. Our findings also suggest, however, that in some infants arterial muscle fails to regress postnatally so that pulmonary blood flow is never high and a right-to-left shunt develops soon after birth.