[Emergency coronary care--successful, but unequaly distributed]. / Akut kranskärlsvård--framgångsrik, men ojämlik.

The need of acute coronary care is increasing because of an increase in the incidence of severe angina pectoris, and despite a reduction in that of acute myocardial infarction. Patients with acute myocardial infarction are characterised by continuously increasing age, lower mortality, and shorter hospitalisation. The improvement in acute care is related to increased use of expensive drugs, new diagnostic methods, and an increasing coronary revascularisation rate. However, there is still inequality in the utilisation of cardiac care, and in order to further enhance its quality and equality of utilisation, there is an emphatic need of common registries.

Atrial and ventricular function after cardioversion of atrial fibrillation.

OBJECTIVE: Previous studies on atrial recovery after cardioversion of atrial fibrillation have not taken into account new knowledge about the pathophysiology of transmitral and transtricuspid flow velocity patterns. It is possible to shed further light on this problem if atrioventricular inflow velocity, venous filling pattern, and atrioventricular annulus motion are recorded and interpreted together. DESIGN: Prospective examinations of mitral and tricuspid transvalvar flow velocities, superior caval and pulmonary venous filling, and mitral and tricuspid annulus motion were recorded using Doppler echocardiography. Examinations were performed before and 24 hours, 1 month, and 20 months after cardioversion. SETTING: Tertiary referral centre for cardiac disease with facilities for invasive and non-invasive investigation. PATIENTS: 16 patients undergoing cardioversion of atrial fibrillation in whom sinus rhythm had persisted for 24 hours or more. RESULTS: Before conversion there was no identifiable A wave in transvalvar flow recordings. The total motion of the tricuspid and mitral annulus was subnormal and there was no identifiable atrial component. Venous flow patterns in general showed a low systolic velocity. After conversion, A waves and atrial components were seen in all patients and increased significantly (P < 0.01) with time. There was a similar time course for the amplitude of annulus atrial components, an increased systolic component of venous inflow, an increased A wave velocity, and a decreased E/A ratio of the transvalvar velocity curves. The ventricular component of annulus motion was unchanged. Changes in general occurred earlier on the right side than the left. CONCLUSIONS: This study indicates that, in addition to the previously known electromechanical dissociation of atrial recovery that exists after cardioversion of atrial fibrillation, there may also be a transient deterioration of ventricular function modulating the transvalvar inflow velocity recordings. Function on the right side generally becomes normal earlier than on the left. Integration of information from transvalvar inflow curves, annulus motion, and venous filling patterns gives additional insight into cardiac function.

Arm-ankle systolic blood pressure difference at rest and after exercise in the assessment of aortic coarctation.

OBJECTIVE: To evaluate the difference in systolic blood pressure at the arm and ankle at rest and after various exercise tests for the assessment of aortic coarctation. METHODS: 22 patients (mean age 33 years, range 17-66) were investigated on the suspicion of having haemodynamically significant aortic coarctation. Eight had undergone previous coarctation surgery, of whom five had received vascular grafts and three end to end anastomoses. The patients exercised submaximally while supine, seated on a bicycle, and walking on a treadmill, as well as exercising maximally on a treadmill. Arm and ankle blood pressure were measured with a cuff at rest and 1-10 minutes after exercise. Invasive pressures and cardiac output by thermodilution were recorded during catheterisation while patients were at rest and during and after supine bicycle exercise. The degree of constriction was assessed by angiography. Twelve healthy volunteers (mean age 32 years, range 17-56) provided reference values for cuff pressures after exercise. RESULTS: All patients with a difference in cuff pressure at rest of 35 mm Hg or more had a difference in invasive pressure of 35 mm Hg or more. Increasing severity of constriction on angiography correlated with larger pressure gradients at rest and during exercise (P < 0.0001). When cuff measurements after exercise were considered singly or combined to form a predictor they did not improve the prediction of the invasive pressure gradients at rest or after maximal exercise. A pressure gradient between arm and ankle also developed in normal subjects after maximal but not after submaximal exercise. CONCLUSION: In most patients with suspected haemodynamically significant coarctation the difference in cuff pressure between arm and ankle at rest is sufficient to select patients in need of further evaluation. If exercise is performed submaximal exercise is preferable.

The value of exercise test, Holter monitoring, and programmed electrical stimulation in detection of ventricular arrhythmias in patients with hypertrophic cardiomyopathy.

To determine the best way to detect serious ventricular arrhythmia in patients with hypertrophic cardiomyopathy (HCM), 15 patients with HCM performed an exercise test, had Holter monitoring during 24 hours, and programmed electrical stimulation (PES) in a randomized order, and the presence and type of ventricular arrhythmia was noted. During exercise testing, only one patient demonstrated ventricular tachycardia (VT) just prior to the test. By Holter monitoring, four patients had short episodes of asymptomatic VT. PES, using up to three extrastimuli induced VT or ventricular fibrillation (VF) in ten patients including those with VT during exercise testing and Holter monitoring. There were no differences between patients with and without ventricular arrhythmia during PES regarding age, left ventricular outflow obstruction, thickness of interventricular septum, interventricular septum/posterior wall thickness ratio, corrected QT interval, or the amplitude of the R wave in lead aVR in electrocardiography. Our results indicate that inducible VT/VF during PES is a common finding in patients with HCM. Twenty-four hour Holter monitoring was superior to exercise testing in revealing serious ventricular arrhythmia in those patients.

Long-term efficacy of flecainide in paroxysmal atrial fibrillation.

The efficacy and safety of flecainide for long-term prevention of paroxysmal atrial fibrillation (AF) were studied in an open trial. Twenty patients with very frequent attacks (mean 13 per month) of paroxysmal AF for many years (mean 8 years) participated. Before inclusion, the patients had unsuccessfully been treated with an average of 3.3 antiarrhythmic drugs. Efficacy was jugded from a carefully kept diary in which the patients made daily notes of any AF attacks and possible side-effects from 1 month before treatment until the end of a follow-up period of 6 months. Twelve patients (60%) were completely free from AF and 11 of these are still successfully treated with flecainide after 11-38 months (mean 24 months). Flecainide plasma levels did not differ between responders and non-responders. Eleven patients (55%) had adverse effects but these were usually mild and well tolerated, necessitating withdrawal or dose reduction resulting in relapse of AF only in three patients (15%). No proarrhythmic events were seen.

Tachycardias initiated by automatic antitachycardia pacemakers.

Available automatic tachycardia-terminating pacemakers cannot distinguish between physiological and pathological tachycardia and, consequently, electrical stimulation during sinus tachycardia can occur. In order to evaluate whether this might be an arrhythmogenic problem or not, the cardiac response in eight patients having paroxysmal supraventricular tachycardia treated with tachycardia-terminating pacemakers was studied during exercise. After tachycardia recognition, the implanted pulse generator automatically emits single or double critically timed premature stimuli for termination of the arrhythmia. Post-implantation examinations revealed successful tachycardia termination by the pacemaker at rest, without the addition of any antiarrhythmic drugs, in all eight patients. During exercise tests, the sinus rate in seven patients exceeded the programmed tachycardia trigger rate resulting in triggered pacemaker stimulation. The native supraventricular tachycardia was initiated in four cases. In one of these patients, two short episodes of probable ventricular tachycardia were also recorded. This study demonstrates the clinical value of post-implantation assessments with exercise tests concerning the problem of pacemaker-initiated tachyarrhythmias. Tachycardia-terminating devices can induce tachycardias, and individual precautions must be taken in order to prevent or minimize the risk of pacemaker reversion of sinus rhythm to paroxysmal tachycardia or hazardous arrhythmias.

Comparative antiarrhythmic efficacy of intravenous N-acetylprocainamide and procainamide.

Ten patients with persistent ventricular arrhythmia were studied in a comparison of the antiarrhythmic efficacy of N-acetylprocainamide (NAPA) and procainamide (PA). Each patient performed three exercise tests for 40 min., on different days, with submaximal and fixed work loads. During the first exercise test no drug was administered. During the following two tests PA and NAPA, respectively, were administered by intravenous infusion. The electrocardiogram was continously recorded and was analyzed minute by minute. Blood samples for determination of plasma drug concentration were frequently collected. Exercise alone did not significantly change the incidence of arrhythmia. Both PA and NAPA showed a similar and significant antiarrhythmic effect. A blood pressure fall was seen in two patients after administration of each drug. No other adverse reaction was observed.

Procainamide-induced lupus erythematosus-like syndrome in relation to acetylator phenotype and plasma levels of procainamide.

To investigate the relationship between acetylator phenotype and the development of procainamide (PA)-induced systemic lupus erythematosus (SLE-like syndrome, 28 patients with chronic ventricular arrhythmias treated with PA were followed for one year. The therapy was guided by plasma monitoring in all patients in order to obtain the proposed therapeutic plasma level of PA. Nine patients (30%), both slow and rapid acetylators, developed the SLE-like syndrome within one year. PA plasma levels were similar in both slow and rapid acetylators and there was no difference in total dose or duration of therapy before development of the syndrome. Thus, the acetylator phenotype is probably of no or minor predictive importance when PA therapy is guided by plasma monitoring. On the other hand, the antinuclear antibodies appeared significantly more rapidly in patients developing the syndrome and could possible be used as an indicator of the risk. The results support the hypothesis that the primary amino group structure of PA may be of importance in the induction of the SLE-like syndrome.

Lidocaine and the quarternary ammonium compound QX-572 in acute myocardial infarction. A comparative study.

Patients with suspected or proven acute myocardial infarction complicated by ventricular arrhythmias not corrected by lidocaine therapy (bolus dose 100 mg followed by infusion 2 mg/min) were treated either with an increased dose of lidocaine (bolus dose 50 mg followed by infusion 3 mg/min) or with 600 mg N,N-bis dimethylammonium chloride (QX-572, Astra, Sweden) as an i.v. infusion during 30 min (3 patients) or 60 min (13 patients). In the lidocaine group the arrhythmias were controlled in 6 out of 15 patients, in the QZ-572 group in 12 out of 16, a difference that is not statistically significant. However, the frequency of side-effects was significantly higher (p less than 0.001) in the QX-572 group (15 out of 16 patients). They were also more severe, including pronounced tachycardia and hypertension. It is concluded that despite the high antiarrhythmic effect of QX-572, an increase of the lidocaine dose would be safer and preferable in the clinical situation studied.

Ventricular arrhythmias in acute myocardial infarction. A comparative study on some tests for ventricular arrhythmias.

A continuous ECG recording has been made in 31 myocardial infarction patients during the first 24 hours after admission to hospital. The number and severity of ventricular arrhythmias were recorded in great detail. Before discharge from hospital the patients were submitted to 20 hours of ECG tape recording, an exercise test on a bicycle ergometer and a static work test (handgrip). Another exercise test was performed one month after discharge. During the first day in the Coronary Care Unit (CCU) all 31 patients had ventricular arrhythmias and in 27 of them the arrhythmia was classified as major (calling for treatment according to Lown's criteria). At the exercise tests 23 patients showed ventricular arrhythmias, 12 of them considered as major. No antiarrhythmic therapy was given during the investigation. No correlation was found between the degree of arrhythmia during the first day in the CCU and during the exercise tests. Tape-recorded ECG's appeared to be inferior to dynamic exercise tests in the ability to disclose a latent tendency to ventricular arrhythmia. Static work did not provoke any ventricular arrhythmias. At a 2-year follow-up 5 patients had died, 4 of them suddenly. Examination of additional material on 11 patients with ventricular tachycardia or ventricular fibrillation during the CCU stay, showed that 2 had died, but only one suddenly. Frequency and severity of arrhythmias during the first day after the infarction seemed to correlate poorly to a persistent tendency to arrhythmias during the first day after the infarction seemed to correlate poorly to a persistent tendency to arrhythmias or to the risk of sudden death during the following 2 years. A dynamic exercise test performed before discharge would appear to be more effective in selecting patients in need of long-term prophylaxis. However, very few patients seem to need such a specific antiarrhythmic prophylaxis.

Comparative evaluation of intravenous phenytoin, procainamide and practolol in the acute treatment of ventricular arrhythmias.

Ten patients with a persistent ventricular arrhythmia, but no other sign of heart disease, were studied by means of an exercise test performed 4 times with a fixed work load, over 30--40 min. No drug was given in the first exercise test and in the others phenytoin, procainamide or practolol were chosen at random for i.v. administration. Blood samples for determination of plasma concentration were frequently collected. The ECG was recorded continuously during the exercise test and was analysed minute by minute. Despite plasma levels within the suggested therapeutic range, only procainamide showed a statistically significant antiarrhythmic effect in this group of patients.

Hemodynamic effects of two cardioselective beta-adrenoceptive antagonists, metoprolol and H 87/07, in coronary insufficiency.

Nineteen patients with ischemic heart disease were randomized into two groups and received either metoprolol or H 87/07. Heart catheterization was performed, and the groups were studied at rest and during exercise--before and after intravenous drug administration. During work metoprolol gave a statistically significant reduction in left ventricular work (expressed as pressure-rate product) of about 20%, mainly depending on a reduction in heart rate. Cardiac output decreased by 21%. Stroke volume was almost unchanged. The abnormal increase in left ventricular filling pressure during work was slightly, but not significantly, reduced by the drug. For H 87/07 no significant changes were found in the corresponding variables. This seems, however, to depend on an inadequate dosage, since not even the heart rate during work was significantly reduced. In conclusion, in the doses used metoprolol has been shown to be a potent beta-adrenoceptive antagonist in contrast to H 87/07.

Haemodynamic effects of procainamide and phenytoin at apparent therapeutic plasma levels.

The haemodynamic effects of procainamide and phenytoin after intravenous administration to 19 patients with suspected congenital heart lesions were studied. The drugs were injected into the pulmonary artery in a dose of 5 mg per kg bodyweight, at an infusion rate of 50 mg per minute, thus giving plasma concentrations within the suggested therapeutic ranges. The diastolic pressures in the pulmonary artery and the right ventricle were reduced by procainamide and the converse effect was noted after phenytoin. The heart rate was significantly increased by both drugs but with phenytoin this effect was only transitory. The latter drug also caused a small and transient fall in cardiac output and mean arterial pressure. It was concluded that of the two drugs phenytoin seemed to have the most marked myocardial depressant effect.