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In experiments to assess mental work load the effect of the central choice making system being the weakest link is demonstrated, using a binary choice generator. It was found that increasing the number of binary choices per minute diminished the irregularity of the rest pattern (Sinus Arrhythmia) without affecting the level of heart rate.
A simple scoring method for the use of sinus arrhythmia is put forward and different tasks are scaled according to the progressive suppression of sinus arrhythmia. Referring to experiments showing that the central choice making mechanisms are operating as a single channel, the "method of distraction stress" is introduced. The deterioration of experimental performance by this method is described and compared with the deterioration caused by other sources of stress.
Finally the concepts of reserve-capacity and "willing-to-spend" capacity are discussed. [ABSTRACT FROM AUTHOR]

20 consecutive patients who underwent aorto-coronary saphenous vein graft were studied regarding arrhythmias and the preventive aspects, 17 of which were done on cardiopulmonary bypass. Urine was measured for 3 consecutive days for volume, osmolality, urea, sodium and potassium. Two patients developed ventricular fibrillation in the control group, on the day of surgery. Controlled patients did not receive any diuretics or potassium. K excretion was independent of volume. K excretion was twice higher than normal even in control group. Hence, we feel supplement therapy of potassium is important to prevent cardiac arrhythmias. [ABSTRACT FROM AUTHOR]

A multiform variant of accelerated idioventricular rhythm (MAIVR) was detected in three elderly patients with long-standing heart disease, digitalis toxicity, abnormal blood gases, electrolyte imbalance and renal insufficiency. All three died in heart failure despite medical therapy. The clinical and electrocardiographic features of MAIVR must be recognized and distinguished from the more common and benign, unifocal form of the arrhythmia. [ABSTRACT FROM AUTHOR]

The effects of treadmill exercise on cardiac mechanism were studied in 34 dogs, two to eight days following ligation of the anterior descending coronary artery. Physical exercise abolished all ventricular arrhythmias which were present at rest. Some of the animals displayed return of ventricular rhythm disorders towards the end of exercise when studied as early as 48 hours after the coronary occlusion. In experiments carried out on the second and third days, a transient intensification of ventricular arrhythmias during recovery was ob- served. Physical exertion beyond the third day after infarction did not provoke ventricular arrhythmias during or after the exercise. However, isoproterenol and epinephrine infusions resulted in reappearance of ventricular arrhythmias up to four days after coronary ligation. The effects of exercise on cardiac mechanism are probably a result of diverse factors; the faster rate during exercise tends to abolish ventricular arrhythmias whereas other unidentified factors, perhaps related to myocardial oxygen requirement, catecholamines or the appearance of left heart, failure, tend to provoke ventricular arrhythmias especially after the exercise as the sinus rate slows. These results may have implications in the interpretation of exercise tests and in assessing the role of physical activity in patients with ischemic heart disease. [ABSTRACT FROM AUTHOR]

Two syndromes with coexisting cardiac and bone malformations have been identified.' In ventrkuloradinl dysplasia, congenital alterations of the radius occur together with ventricular septal defect.2 The Holl-Oram syndrome consists of atrial septal defect, cardiac arrthymias, and nialforinations of one or both thumbs.3 This report describes four cases of the Holt-Oram syndrome studied at the Instituto Nacional de Cardiologia de Mexico. [ABSTRACT FROM AUTHOR]

Presents comments and corrections on articles about medical conditions and treatments. Quality of experiments on carbon monoxide and angina pectoris; Role of tape recorders in detecting arrhythmia; Description of the elevation of alpha-lipoprotein cholesterol due to heavy alcohol ingestion.

Presents a study which assessed the effects of procainamide on recurrent arrhythmias occurring during maximal exercise stress. Patients and methods; Results; Discussion.

Presents a study which correlated the presence of exercise-related ventricular premature complexes with both ST-segment depression and coronary arteriographic and ventricular findings in patients evaluated for chest pain. Clinical significance of exercise-related ventricular premature complexes; Methods used in the study; Results.

An in vivo study of skeletal muscle paralysis induced by intravenous barium chloride has been made in curarized and non-curarized rats. The influence of potassium and calcium chlorides, propranolol, ouabain, and prior adrenalectomy on the paralysis has also been studied. Paralysis is found to be due to a direct effect on skeletal muscle, and to correlate well with the development of hypokalaemia. Possible mechanisms of action of barium are discussed, and attention is drawn to the similarity between barium poisoning and hypokalaemic familial periodic paralysis. [ABSTRACT FROM AUTHOR]

Heart rate was recorded on a SETAR (Serial Event Tinter and Recorder) This gave a digital reading on punched paper tape for each R-R interval. A computer program for the analysis of cyclic cardiac activity, which identifies the troughs and peaks in a series of heart beats, is described. These readings are cast into frequency distributions, as are differences between successive troughs and peaks, both in terms of amplitude and elapsed time. [ABSTRACT FROM AUTHOR]

Ten psychotic and 10 normal children, paired for age and sex, were compared for respiratory sinus arrhythmia differences under conditions of spontaneous and 5, 10, and 15 sec interval breathing. Cardiac rate and respiratory changes were simultaneously recorded. Parameters of degree of change and timing for each respiratorycardiac cycle and its associated changes in heart rate were measured and compared statistically. Results show significant differences between psychotics and normal controis as follows: 1. The psychotics did not sustain the acceleratory phase of the cardiac cycle as did the controls. 2. The lag intervals (interval between onset of inspiration and onset of cardiac acceleration, interval between onset of expiration and onset of cardiac deceleration) were more consistent for the normal controls than for the psychotics. 3. At maximum respiratory depths the psychotics no longer demonstrated a direct relationship between depth of respiration and degree of cardiac rate change as did the controls. We conclude that there is a different or less well-coordinated combination of operative forces in the sinus arrhythmia mechanism of the psychotics as compared to the controls. [ABSTRACT FROM AUTHOR]

The electrocardiographic patterns of 152 adolescents at rest and at maximal exercise were obtained. This included both sexes in approximately equal numbers. At rest, most exhibited sinus arrhythmia, a mean QRS frontal plane vector from 0 to +90°, and a resting rate from 80 to 90 per minute. The response to exercise was consistently that of tachycardia, reaching a rate from 180 to 220 per minute. All subjects did not attain a rate of 200 per minute, but several exceeded this. Changes in the T wave morphology with exercise were common and consisted of an increase in amplitude with peaking. Sex differences were noted in that girls had a slightly faster resting rate. required a shorter time to reach maximal exercise, had more rapid duration of exercise, and had faster recovery rates. Also, more girls than boys had an electrical axis of greater than 90°. [ABSTRACT FROM AUTHOR]

Focuses on the reactions of drugs to lichenoid eruptions. Treatment of rheumatoid arthritis; Difference between lichenoid drug eruption and lichen planus; Prevention and control of cardiac arrhythmias.

The antihistaminic clemizole was studied as an antiarrhythmic in a preparation in which two arrhythmias of different nature and mechanism were produced in the right atrium of anesthetized dogs. One of the arrhythmias was a circus movement flutter induced by the method of Rosenblueth and García Ramos; the other, an ectopic focus induced by local application of aconitine in the auricular appendage, electrically isolated from the rest of the atrium. Clemizole selectively converted the flutter to sinus rhythm with little action on the coexistent aconitine dysrhythmia. It did not modify arterial pressure. In effective doses the wave length of the impulse was increased by prolongation of the refractory period without significant reduction in conduction velocity. Similarly, in subendocardial cells of isolated rat atria, clemizole in appropriate concentrations retards repolarization with little effect on the rate of depolarization. These results afford pharmacological evidence for the existence of atrial circus movement arrhythmias which can respond to prolongation of the refractory period unaccompanied by effects on other properties of the tissue. Other arrhythmias, self-sustained by the discharge of an ectopic focus, such as the tachysystole produced by aconitine, are not suppressed by similar increase in the refractory period. [ABSTRACT FROM AUTHOR]

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‘Abnormal’ ventricular end-diastolic pressures (RVEDP, LVEDP) have been observed in patients with bradycardia. In order to assess the effect of heart rate (HR) on R and LVEDP in the absence of demonstrable heart disease, the data recorded from 97 patients adjudged to have no significant heart disease after routine right and left heart catheterization were reviewed. Nine patients had ‘abnormal’ elevations of R or R and LVEDP. These patients did not differ significantly from the other eighteen in terms of age, cardiac index (CI), arterio-venous oxygen difference or oxygen consumption. There was a significant difference in HR (P = 0.005 - 0.001) and pulmonary artery pres- sure (P = 0.005 - 0.001). The combination of a normal CI and relative bradycardia caused a significantly larger stroke index (60.9 versus 45.8 cc, P < 0.001) in the nine patients with elevated VEDP's. [ABSTRACT FROM AUTHOR]

Postmortem examination revealed a severe Ebstein's anomaly in a 66 year old woman with Stokes-Adams syndrome associated with complete heart block and fatal ventricular arrhythmias. Inability to pace the ventricle effectively was probably related to the bizarre deformity of the tricuspid valve and marked ‘atrialization’ of most of the inflow portion of the right ventricle. The association of Ebstein's anomaly and symptomatic complete heart block in an elderly woman is unique. [ABSTRACT FROM AUTHOR]

The electrocardiograms of 30 patients with TIA were reviewed. Twenty-seven (90%) of the patients had ECG changes; they include sinus bradycardia in 15, supraventricular premature beats in 3, atrial fibrillation in 2, first degree of atrioventricular block in one, and abnormalities of QRS complex and ST-T wave in 19 patients. Cardiac arrhythmia as a cause of TIA is discussed. [ABSTRACT FROM AUTHOR]

Circulatory arrest due to ventricular fibrillation occurred in two patients with subarachnoid hemorrhage. Their ECO showed the typical abnormalities previously described in patients with central nervous system disease. Prompt recognition of the arrhythmia and initiation of resuscitative measures led to their complete recovery. [ABSTRACT FROM AUTHOR]

The effect of aconitine induced arrhythmia and of bleeding on the coronary flow pattern was studied in open chest dogs. A parallel change of the aortic-left ventricular pressure difference and the coronary arterial flow pattern was observed when the aortic valve was closed. With an open aortic valve, during ejection, the aortic pressure-left ventricular pressure difference became negative, while the coronary flow pattern exhibited a positive systolic wave. The following correlations were observed between the height of the systolic wave (peak systolic coronary arterial flow-PSCAF) and other parameters: a) a direct relationship between peak left ventricular pressure and PSCAF. This relationship was inverse for beats producing the same peak aortic flow, b) an inverse relationship between aortic end diastolic pressure and PSCAF. c) a direct relationship between peak aortic flow and PSCAF, and d) an inverse relationship between peak dP/dt and PSCAF. These correlations are in agreement with the mathematical derivations from a mathematical model of the coronary circulation. [ABSTRACT FROM AUTHOR]

Two techniques have been used to study further the diving reflex in man using eight male volunteer subjects. First is a method which allows diving to be simulated by a cold wet cloth placed on the face of an apneic subject. Second is a ballistocardiogram-analog computer system which permits a beat-to-beat determination of cardiac output and other cardiovascular measurements. A marked decrease in the heart, rates resulted during simulated diving. Associated with these decreases in heart rate were decreases in cardiac output, left ventricular work and mean forearm blood flow with an increase in the mean arterial pressure. Our observations all confirm that the diving reflex in man is qualitatively similar to that in marine mammals although considerably attenuated. Our results with the ballistocardiogram are consistent with the well described integrated oxygen conserving reflex which slows the heart, maintains central arterial pressure and redistributes blood flow. [ABSTRACT FROM AUTHOR]

The article focuses on the newer inotropic agents in the management of arrythmias associated with cardiac failure. A significant percentage of arrhythmias, primarily ventricular, were controlled by the agents as was the underlying heart failure. Side effects were minimal, primarily vomiting, hypotension and hyperglycemia with hypokalemia. Definite usefulness for these agents was noted in patients with arrhythmias associated with heart failure in whom digitalis can not safely be used.

In an open, crossover study of six months' duration, clonidine given alone and with chlorthalidone was compared in 37 patients completing the study. Significant blood pressure lowering was achieved following both clonidine and clonidine with chlorthalidone. The response was highly significant following the combination. While there was a systolic orthostatic effect, tolerance developed only after clonidine alone in this study. Adverse effects were frequently reported. They were an annoying feature of the drug, but no major toxic effects were seen, and the only significant laboratory abnormalities were those associated with diuretic therapy. Bradycardia was a common finding. Based on the findings of this study, clonidine is a valuable additional tool for the management of hypertensive vascular disease. The combination with chlorthalidone provides a much more predictable means of controlling blood pressure than clonidine alone. [ABSTRACT FROM AUTHOR]

1. The dosage of propranolol needed in the treatment of patients with cardiac arrhythmias or angina poctoris in our study, has depended upon the relief of symptoms, the heart, rate, the degree of fatigue and the blood level attained. 2. A reduction in total dose was not necessary, in the absence of symptoms, unless the heart rate was sustained below 52 beats per minute. 3. Fatigue, in the absence of clinical heart failure, need not signal a reduction in dose unless sustained for two weeks. 4. In this study, a propranolol blood level of .03 μg/ml or higher was associated with the best symptom relief. 5. An increment dose of propranolol every three hours was needed to sustain a blood level of .03 μg/ml or higher in most patients studied. The smallest total daily dose on the q3h schedule for good relief of anginal pain was 80 mgs daily. The average daily dose required for relief of pain was 218 mgs. 6. The apparent half-life of propranolol hydrochloride after the ingestion of one 40 mg tablet is between two and three hours. [ABSTRACT FROM AUTHOR]

The transvenous system of permanent pacemaking is both simple and safe and is recommended, especially for older patients. The standby (demand) pacemaker functions in all types of symptomatic bradycardia, virtually eliminating the danger of competitive pacing, and is, therefore, recommended in preference to the asynchronous (fixed rate) pacemaker. The continuously functioning synchronous standby R.S. pacemaker is currently preferred to the intermittently functioning R.I. type, because of the possibility of pacer inhibition by stray electrical fields in the latter. With better protection against external electrical fields by improved circuit design, the R.I. type of demand pacemaker will be the preferred unit because it does not distort the QRS complex and should have longer battery life. [ABSTRACT FROM AUTHOR]

This study describes the application of the Valsalva maneuver in the electrocardiogram for the differentiation between functional and organic T-wave abnormalities. The study comprised no patients who were arbitrarily assigned to 5 different groups: Groups 1 and 2 consisted of groups of patients with postviral autonomic disturbances with and without EKG abnormalities; group 3 consisted of neuropsychiatric patients with autonomic disturbances; group 4 were patients with clinically proven arteriosclerotic heart disease and group 5 consisted of healthy controls. Patients with abnormal EKG and a false-positive exercise electrocardiogram due to neurovegetative disturbance resulting from either viral infection or neuropsychiatric disorders were observed. The Valsalva-EKG test was able to assist in the differentiation of nonspecific T-wave abnormalities due to an organic cause from those resulting from autonomic disturbance. Under these circumytanoes, functional T-wave abnormalities were magnified by the Valsaiva test while the ones due to organic heart disease were not affected. Other potential uses of this test are in the electrocardiographic diagnosis of cardiac arrhythmias and as a test for the early detection of digitalis toxicity. Criteria for the appropriate interpretation of the test are formulated. Attention is called to potential pitfalls and complications which can be associated with the use of the Valsalva maneuver. Possible mechanisms involved are discussed. [ABSTRACT FROM AUTHOR]

Presents a study on the frequent and variable effect of sustained diaphragmatic inspiration on 160 electrocardiograms. Effect of inspiration on a standard electrocardiogram; Method of diaphragmatic inspiration; Reported cardiac arrhythmias and abolition of left and right bundle-branch block following deep inspiration.

A seventy-seven-year old woman is presented with a questionable history of rheumatic fever in childhood. When first seen 20 years ago, she revealed mitral stenosis and a regular sinus rhythm. Eleven years later auricular fibrillation was first noted and this arrhythmia persisted for eight years. Spontaneous conversion to regular sinus rhythm was then observed and has persisted until the present, 36 months later. No quinidine or other antiarrhythmia drugs had been used. [ABSTRACT FROM AUTHOR]

Anterior septal artery ligation was performed on 1(X) healthy dogs in which normal sinus rhythm was present preoperatively. The effects of sustained-action pentaerythritol tetranitrate (PETN) administered orally, beginning before and beginning after ligation, were determined in animals developing electrocardiographic evidence of atrioventricular conduction disturbances (partial and complete A-V block, A-V dissociation, A-V nodal rhythm, and idioventricular rhythm) by one day post-ligation and who survived the full eight-day experimental period. These effects were compared with those obtained in a control group of animals which did not receive PETN. Administration of PETN beginning on the first day post-ligation (post-operative-PETN group), and after the development of the arrhythmias, resulted in no significant change in the course of recovery from the arrhythmias. Administration of PETN beginning two days prior to anterior septal artery ligation (preoperative-PETN group) demonstrated: (1) No effect on the incidence of development of arrhythmias by the first day post-ligation. (2) No effect on total per cent recovery from arrhythmias from the fourth to eighth days post-ligation. (3) A statistically significantly increase in the cumulative per cent recovery from arrhythmias by the second day post-ligation when compared to those animals not receiving PETN preoperatively. [ABSTRACT FROM AUTHOR]

Two hundred and nineteen nonsynchronized d.c. countershocks were delivered across the intact chest of 100 unanesthetized patients and abolished 92 episodes of a variety of arrhythmias. Rhythm and conduction disturbances were observed rather frequently after countershock, especially at energy levels of 300 joules or more. Some interesting observations were the complete abolishment of ventricular multifocal activity in 7 cases and marked reduction of this activity in 4; the marked but reversible ST segment elevations at the site of application of the anterior paddle electrode (leads V2 to V3) in 36 cases and the disappearance of 4 cases of complete right bundle branch block with the restoration of normal sinoatrial mechanism. [ABSTRACT FROM AUTHOR]

Reports on another group of patients undergoing major surgery of which 1.4 percent demonstrated electrocardiographic abnormalities. Omission of cardiac surgery from those studied; Majority of patients asymptomatic; Various types of arrhythmias, conduction disturbances and patterns of myocardial ischemia and infarction.

1. Physical conditioning would appear to be no protector against atherosclerosis, especially where adverse, genetic, or metabolic factors are present. 2. Aging athletes discovered to have arrhythmias should be examined electrocardiographically at high work loads to differentiate vagal from organic causes of the arrhythmias. 3. Lifetime conditioned athletes have markedly increased heart voltage as manifested by high R-waves in their electrocardiographic complexes. 4. T-wave and J-wave increases with exercises appear to be normal physiological phenomena. 5. On unrestricted diets, this special group under study generally revealed elevated triglycerides at all age levels, and elevated cholesterol and triglyceride values above 60 years of age, suggesting different dietary habits than the general population. 6. Some of these athletes perform very well at high work loads in spite of the presence of advanced ischemic heart disease, often even better at higher work loads than lower loads, suggesting a reserve of collateral circulation acting at maximum effort. [ABSTRACT FROM AUTHOR]

The significant therapeutic problems of coronary heart disease and the current controversy involving the value of nitrate compounds therein has prompted an evaluation of a long-acting form of pentaerythritol tetranitrate. Eighty-four per cent of 56 patients with angina were improved with this type of therapy. Additional benefits in the clinical status of the patients were also noted. These included their sense of well being, energy and exercise tolerance. A small number of patients showed a striking remission of cardiac arrhythmias, which seemed directly related to the nitrate therapy. [ABSTRACT FROM AUTHOR]

The authors present their experiences in the application of the Lown-Cardioverter in surgical conditions. This instrument is used for the. termination of ectopic arrhythmias, such as atrial fibrillation or ventricular tachycardia. By delivering a synchronized direct current counter-shock, a complete depolarization of the heart is accomplished and sinus rhythm restored, The procedure was used as an adjuvant to surgical therapy in mitral stenosis with atrial fibrillation, postcommissurotomy, tachyarrhythmia, arteriosclerotic heart disease with repeated embolizations, and ventricular tachycardia occurring during open heart surgery. The results were satisfactory and no complications occurred. [ABSTRACT FROM AUTHOR]

1. A discussion of the theoretic concepts presently used to explain the mechanism of coupled and of independent (parasystolic) premature beats is presented. 2. The electrocardiogram and case record of a patient manifesting an atrial arrhythmia intermediate between coupled and parasystolic in diagnostic criteria are described. 3. The implications of the analysis of this tracing on the single focus theory of the etiology of premature impulse formation is outlined. [ABSTRACT FROM AUTHOR]

Twenty-five patients with various cardiac arrhythmias were treated with a new quinidine salt, quinidine polygalacturonate. The usual daily dosage was one 275-mg tablet. Duration of therapy averaged 133 days In 50 per cent of the patients, quinidine polygalacturonate provided more satisfactory control than previous quinidine sulfate therapy, and in 42 per cent of the patients the new agent was equally as effective In 2 patients, transient side effects made it necessary to discontinue therapy. It was striking that single-tablet dosages (275 trig) of quinidine polygalacturonate were sufficient to provide maintenance control of the arrhythmia or to reduce the ventricular rate in patients who previously had required 400 to 2400 mg of quinidine sulfate each day. This study showed quinidine polygalacturonate to be effective and convenient for the control of a variety of cardiac arrhythmias. Its use in relatively small dosages provided therapeutic efficacy comparable to that obtained with quinidine sulfate with less risk of the aide effects attending the use of conventional quinidine preparations. [ABSTRACT FROM AUTHOR]

In open chest anesthetized dogs the heart was driven at rates from 90 to 210 per minute with the sinuaurieular node intact or crushed. A second pulse produced a premature systole measuring the refractory period of the normal cyclic systole. A third pulse was applied producing a second premature systole so as to measure the refractory period of the first premature systole. Latency of response to the second and third pulses was also measured. It was found that in all heart rates studied, the refractory period and latency were much shorter for the premature systole as compared to the previous cyclic systole. In nodal rhythm the same results were obtained. Latency was progressively shorter for the premature systoles induced in successive cycles. The results substantiate the view that a single premature systole may make the heart muscle more susceptible to rapid ventricular rhythms. [ABSTRACT FROM AUTHOR]

1. A series of investigations utilizing several hundred patient observations wore carried out to determine the effects of defecation on circulatory function in presumably normal individuals and persons with chronic constipation. 2. It appears that during bowel function of apparently normal individuals, approximately 12 per cent of the straining episodes are of sufficient intensity and duration to satisfy the accepted criteria for the Valsalva maneuver, and that by substituting a bedpan for the commode, this incidence is more than doubled (28.0 per cent). Constipation, it may be noted, increases this frequency approximately fivefold (57.9 per cent). From the results of research presently underway, the use of a constipation corrective, Senokot, favorably modifies the magnitude and duration of straining among constipated individuals. 3. The established sequential changes in blood pressure of the Valsalva maneuver were found to occur during defecation in response to those strains meeting this criteria. While the height of the initial blood pressure rise was roughly proportional to the intensity of the effort in both groups, the constipated group had twice as many peaks above 60 mm Hg than did the normal group and conversely, the normals had three times as many peaks below 20 mm Hg as did the constipated series. 4. The peaks of the phase IV overshoot were not found to be related to the height of the original straining pressures exerted. The distribution of these peaks was comparable in both groups, when they occurred. 5. The Valsalva maneuver initiated electrocardiographic changes in approximately 20 JXT cent of the normal subjects studied. These changes included (1) ST depression, (2) flattening of the T wave, (3) poststraining arrhythmia, and (4) the reversal of a previously al)normal T wave to one which became fiat to upright. These abnormalities are generally associated with physiologic myocardial insufficiency. No significant abnormalities of the electrocardiogram were detected in the remaining 80.4 per cent of the over-all group performing the Valsalva maneuver. 6. The presence of either a tachycardia or a bradycardia occurring in connection with certain of the straining efforts of defecation was confirmed. These alterations of the rate arc reflexes principally associated with the Valsalva phenomenon. 7. It becomes apparent, therefore, that the physician must seriously consider the volatile effects and potential hazards of .stool-straining in his cardiac patients. Our data indicates that physiologic changes following straining at stool may result in serious consequences, and if tragic episodes are to be avoided, the immediate correction of constipation becomes of special importance to the patient with cardiovascular disease. [ABSTRACT FROM AUTHOR]

The carotid sinus serves as an accessible and versatile structure in diagnosis and treatment. Its practical application in the diagnosis of carotid sinus hypersensitivity, embolism or thrombosis of the bifurcation, certain arrhythmias, and many other clinical conditions has been discussed. Its therapeutic value in acute left ventricular failure, anginal pains, and arrhythmias has also been presented. [ABSTRACT FROM AUTHOR]

Direct current cardioversion has been used in 87 patients either before or after cardiac surgery at the University of Minnesota Medical Center. Forty per cent of the preoperative patients and 48 per cent of the postoperative patients were restored to a sinus rhythm for more than 1 month. In preoperative patients, restoration of a sinus rhythm improved the cardiac reserve and facilitated preparation of poor-risk patients for surgery. It also aided in differentiating functional from organic tricuspid valvular disease. In the postoperative patient, conversion to a sinus rhythm appeared to improve cardiac function. The incidence of successful cardioversion was 66 per cent if attempted 6 or more months after surgery, whereas it was only 33 per cent when carried out earlier. We now consider d.c. cardioversion the method of choice in the management of atrial flutter in the postoperative period and have been successful in converting 90 per cent of patients with this arrhythmia. Anticoagulant therapy before cardioversion does not appear to protect against thromboembolic complications after conversion, Procaineamide and quinidine sulfate appear to be equally effective as anti-arrhythmia drugs when used in association with d.c. cardioversion. [ABSTRACT FROM AUTHOR]

, , 448-452. Thirty-seven children with transposition of the great arteries have undergone Mustard's operation in Birmingham Children's Hospital from May 1968 to December 1971. Thirtythree of these had simple transposition of the great arteries and four were complicated. All but two had some previous palliative procedures. Ten patients died before discharge from hospital and there were two late deaths, one after three months and the other after eight months. Bleeding, dysrhythmia, and hypotension were common immediate postoperative complications, while recurrent heart failure and persistent atrioventricular block occurred in five and four patients respectively. [ABSTRACT FROM PUBLISHER]

The surgical approach to myocardial revascularization has been undertaken on the same basis as in peripheral vascular surgery. Aorta to coronary saphenous vein bypass has been found to be one of the best methods of providing immediate augmentation of coronary blood flow. Thirty-eight patients have been operated upon. The hospital mortality was 5.3% and the total mortality has been 13.2% in a follow-up extending one month to two years. Among the survivors, 90% had excellent initial results with complete disappearance of symptoms and marked improvement in exercise tolerance. The authors advocate the saphenous vein bypass as the procedure of choice for elective coronary revascularization. [ABSTRACT FROM PUBLISHER]

A series of 260 patients who underwent pneumonectomy for cancer of the lung was analysed for post-operative arrhythmias. Of these patients 28% developed such arrhythmias, usually in the form of atrial fibrillation, on the first to third post-operative day, rapidly yielding to fast-acting digitalis preparations. Possible aetiological factors were investigated, but no single cause was demonstrable. The indication for pre-operative digitalization, if any, is discussed. [ABSTRACT FROM PUBLISHER]

It is estimated that an unknown, yet possibly large, number of patients would benefit from transplantation of the heart and both lungs if technically, physiologically, and immunologically feasible. In this paper we attempt to explore the main non-immunological areas in which we feel that cardiopulmonary transplantation requires further evaluation. A technique is described by which the heart and lungs, as one unit, can be removed from a donor animal, and viability of these organs can be maintained for several hours by autoperfusion (circulation being through the coronary and pulmonary vessels) with positive pressure ventilation via the trachea. This simple heart-lung preparation preserves the organs concerned for sufficient time to allow preparation of the recipient, transport of the donor organs, and tissue typing to be carried out. Our technique of implanting these donor organs into the recipient is also described. We have carried out this operation on approximately 100 dogs and have been impressed by the good cardiac function obtained, but spontaneous respiratory function has been either absent or inadequate to sustain life for more than a few hours. It would appear that dogs cannot tolerate bilateral pulmonary denervation, and our findings are discussed in the light of other work on this subject. Work on primates suggests that man would be able to undergo this procedure successfully. The organizational and ethical problems involved in cardiac and cardiopulmonary transplantation are briefly discussed. [ABSTRACT FROM PUBLISHER]

Transplantation of the heart and both lungs is being considered as a clinical possibility in several surgical centres today. This paper reviews the experimental development of surgical techniques in this field. In the 1940s Demikhov in the U.S.S.R. succeeded in developing a technique by which he could carry out cardiopulmonary transplantation without the use of any artificial means of recipient support during the procedure. He obtained survivors for up to six days; late deaths occurred mainly from pulmonary complications. The techniques and results of subsequent workers using hypothermia or pump-oxygenator support are reviewed. Recent work has focused on the problem of the return of spontaneous respiration following denervation of the lungs which, of necessity, occurs during this procedure. [ABSTRACT FROM PUBLISHER]

The article reports on the case of a patient who had cardiac arrest with apnea and convulsions after electroconvulsive therapy (ECT). A 29-year-old patient was readmitted in a hospital due to a recurrence of depressive psychosis, identified with ideas of reference and delusions involving cancer. She was scheduled for a series of ECT after reassessing her clinical state. After the treatments, causes of apnea and cardiac arrest have overlapped. It has been suggested to not give repeated shocks to patients with cardiac arrhythmia.

Mice were anaesthetized by a maximal narcotic but not lethal dose of ethyl urethane. Continuous electronic computing of their ECG's shows marked sinus bradycardia from 30 min to 7 h after injection. After 7 h bradycardia is reduced more and more, but the initial frequency is not yet reestablished 12 h after injection. There occur arrhythmias in a similar time course. Heart rhythm shows a very marked periodic shift: Pronounced bradycardia with increased arrhythmia is followed by faster and more regular heart beats. This shifting is produced regularly by nearly all the mice for several hours. Its main period is 7.6 min and its main frequency alteration is 0.83 c.p.s. The PR interval remains nearly unaffected. All frequency effects are mainly brought about by changing correspondingly the TP-intervals of the ECG. Thus the origin of the frequency alterations is to be found within the CNS or its autonomic pathways to the sinus node, within the sinus node itself, or in the sinauricular conduction system. Urethane is not suitable for immobilizing mice in order to measure their heart function because of its strong effects on heart rhythm. [ABSTRACT FROM AUTHOR]

Discusses office electrocardiography (ECG) after cardiac surgery in general pediatrics. ECG changes, such as rhythm disturbances and intraventricular conduction delay; Postoperative rhythm disturbances; Premature beats in tachycardia; Indication of antiarrhythmic drugs or cardioversion for ectopic disturbances, but never for sinus tachycardia; Arrhythmias After Atrial Surgery; Association of surgery of the atria and the intra-atrial seitum with a high incidence rhythm disturbances.

This article focuses on the abnormalities of cardiac rhythm. Abnormalities of cardiac rhythm are more common in infants and children than is generally appreciated. Physicians tend to take particular note only of those arrhythmias which are causing immediate symptoms. Asymptomatic arrhythmias may be noted in the medical record butt considered no further if the precise diagnosis and possible significance are not evident. Some arrhythmias pass unnoticed due to the low level of interest of the observer. The pediatric significance of arrhythmias lies not only in the immediate symptoms but also in the forewarning or more serious rhythm disturbances and the implications by association that heart disease is present.