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Aims: Predischarge identification of viable myocardium with a spontaneous recovery over time can be helpful in decision-making process following acute myocardial infarction (AMI). An intriguing hypothesis is that identification of viability in myocardial asynergic segments with or without spontaneous recovery over time may require an inotropic stimulus of a different intensity. To test this we used post-extrasystolic potentiation (PESP), which represents an inotropic stimulation of a different intensity as a function of coupling interval., Methods and Results: Myocardial viability was assessed by PESP echocardiography in 86 patients with a first uncomplicated AMI. Spontenous changes in contractile function of viable but asynergic segments at predischarge were evaluated by a follow-up resting echocardiogram 1 month later. Viable myocardium of left ventricular asxynergic segments with spontaneous recovery or persistence of dysfunction showed its first significant improvement for different values of coupling interval during PESP (409+/-18 vs 336+/-23ms (milliseconds), P<0.0001). An arbitrary cut-off value for RR interval >or=380ms, correctly identified 91% of myocardial segments undergoing spontaneous recovery, while 99% of asynergic myocardial segments with spontaneous recovery had a threshold coupling interval >or=380ms., Conclusion: At predischarge following AMI, asynergic but viable myocardial segments by PESP with spontaneous recovery of contraction over time require an inotropic stimulus of lesser intensity to acutely improve contraction pattern than viable and asynergic segments without this favourable outcome., (Copyright 2003 The European Society of Cardiology. Published by Elsevier Science Ltd.)

Measurement of baroreflex sensitivity is a new method to identify patients after myocardial infarction with a high risk for sudden cardiac death, ventricular tachycardia or ventricular fibrillation. In this retrospective study the baroreflex sensitivity was obtained noninvasively by measuring the systolic blood pressure blood pressure with a FINAPRES-device and correlating this with the R-R intervals of the ECG after raising blood pressure with an intravenous dose of Norfenefrin-hydrochloride (Novadral). According to other investigators a correlation of > 0.7 with a significance of p < 0.05 was recommended for evaluable results with a baroreflex sensitivity < 3 ms/mm Hg being judged as decreased. We investigated 302 patients (mean age 59 +/- 17 years, 224 males, 78 females). 75% of the investigations showed acceptable results. In 77 cases (25%) reasonable results could not be achieved. We found premature ventricular beats to be responsible in 18 investigations (6% of all investigations). 41 (13.1%) of all investigations were not evaluable because of bad correlation for unknown reason. When we looked closely at these nonevaluable results, we found a significantly higher number of patients with impaired left ventricular ejection fraction (< 40%), diabetes or inducible sustained ventricular tachyarrhythmia in the electrophysiologic study in this group. During all investigations no severe side effects were observed. We conclude that the noninvasive measuring of the baroreflex sensitivity is a save method and leads to reasonable results in 75% of the investigations. In 13.1% it is not possible for unknown reason to achieve sufficiently correlating values. These measurements cannot be evaluated from nowadays' standards and have to be further investigated as they may indicate a population at high risk.

Objectives: To establish a score or arrhythmic pattern for the prediction of long-term cardiac deaths on patients who have survived to the first acute myocardial infarction., Patients and Methods: We studied prospectively 200 patients that survived at a first myocardial infarction and in whom ambulatory ECG monitoring during 24 hours between days 7th and 18th (mean 12th) from the infarction was performed. The mean follow-up time was 51 +/- 18 months. The number and type of ventricular arrhythmias were analyzed and a score was measured, accordingly with Castellanos and Lown's classifications. An "arrhythmic pattern" or "total punctuation" was defined and compared among two groups: group 1 > 65 points and group 2 < 65 points., Results: The differential characteristics of both groups were: age (60 +/- 9 versus 56 +/- 10 years old; p = 0.004); hypertension (63% versus 29%; p < 0.001); clinic stage II-III (23% versus 11%; p = 0.02); echocardiographic ejection fraction (45 +/- 11% versus 50 +/- 10%; p = 0.04); positive exercise testing (73% versus 56%; p = 0.01); arrhythmias on the exercise test (15% versus 25%; p = 0.006). The long-term cardiac mortality was 25% versus 6% (p = 0.01), with an incidence of sudden death of 11% versus 3% (p < 0.05). Specificity, sensibility, positive predictive value and negative predictive value (reference cut point of 100) were 94, 65, 71 and 91%, respectively., Conclusions: The use of a score of arrhythmic pattern may identify 2 groups of patients with different clinic profiles that probably justify a different long-term prognosis after a first acute myocardial infarction.

This study was designed to compare the prognostic value of predischarge ambulatory electrocardiographic monitoring for 1, 6 and 24 hours in 188 patients surviving a first acute myocardial infarction. Ventricular premature complexes (VPCs) were considered as a mean hourly rate or classified using Lown and Moss grading systems. During the 1-year follow-up 20 cardiac deaths occurred. For all 3 monitoring times, a higher number of VPCs/hour and a higher Moss grade were associated with mortality, whereas a Lown grading system gave prognostic information only for the first hour of recording. Monitoring time did not influence specificity or sensitivity in predicting mortality; > or = 3 VPCs/hour showed a higher sensitivity than > or = 10 VPCs/hour (p < 0.05) with a comparable specificity. After 1-hour data entered the model, neither the 6- or the 24-hour data entry improved the overall likelihood ratio statistic, regardless of what VPC grading system was used. These results demonstrate that continuous electrocardiographic recordings of > 1 hour are unnecessary when they are to be used for detecting ventricular arrhythmia as a predictor of mortality in patients surviving a first acute myocardial infarction.

The objective of this study was to relate the number of ventricular arrhythmias (VA) to the normalization time of the ST segment during thrombolysis for acute myocardial infarction. The 24 h Holter recordings, begun on start of intravenous thrombolytic therapy, and the 12-lead electrocardiograms of 41 patients with a patent infarct-related artery according to coronary angiography were analysed. The mean time from onset of chest pain to angiography was 30.5 +/- 3.1 h, < or = 24 h in 59%. The normalization time of the ST segment, assessed by the time of decrease of ST segment elevation from start of Holter recording to normal or steady state was < or = 60 min in 13 patients (group 1), 60 to 180 min in 15 patients (group 2) and > 180 min in 13 patients (group 3). The incidence of VA was similar in all groups, except for ventricular tachycardias (VT) > 15 beats (group 1:69%, group 2:13%, group 3:15%, P = 0.002). The frequency of accelerated idioventricular rhythms (AIVR), early AIVR (< or = 6 h) and of VT was significantly higher in group 1 than in group 3 with a 8-, 30- and 6-fold increase, respectively (back transformed mean). We conclude that the number of VAs is related to the normalization time of the ST segment during reperfusion. This may suggest that faster reflow is more arrhythmogenic.

In this study, the QTc interval was determined in 51 patients of acute myocardial infarction and the incidence of ventricular arrhythmias in them was noted. It was found that the QTc interval was prolonged (more than 0.44 sec) in all the 33 patients who developed ventricular arrhythmias, while it was below 0.44 sec in all the 18 patients who did not develop ventricular arrhythmia.

Frequent and recurrent ventricular premature beats (VPB's) are considered to be associated with a higher risk of sudden cardiac death, particularly for survivors of myocardial infarction (MI). The distribution of VPB's has a large probability mass at zero, and a very heavy right hand tail. In this research, we fitted a model to VPB for patients for which VPB was present. The model was fitted on the basis of a relatively large data set on MI survivors in Israel. The model was fitted by a method which is based on the generalized linear model. This method, which was introduced by Zeger and Liang, is designed for longitudinal data and uses the quasi-likelihood concept. No specific assumptions are required on the shape of the distribution of the dependent variable. The results indicate that the model fits the data quite well but underestimates the very extreme high values. This research demonstrates the applicability of generalized linear models for longitudinal non-Gaussian data. Such data often arise in medical studies. The study also points out the distributional properties of VPB counts. In particular, it shows their associations with simple clinical and epidemiological variables, and with certain time periods during the day.

Holter monitoring was performed on days 1-2, 6-9 of the disease and on days 30-60 before their discharge from hospital in 54 patients with acute gross myocardial infarction. The presence of cardiac rhythm and conduction disturbances and ischemic ST-segment depression or elevation was evaluated. The patients having frequent and prolonged (more than 3 hours during a 2-day follow-up) showed a complicated course of the disease: recurrent pain syndrome, signs of heart failure, prolonged cardiac arrhythmias, and fatal outcomes. The patients with uncomplicated acute myocardial infarction had no long-term episodes of ischemic ST-segment depression or elevation, as recorded by Holter monitoring in the first 2 days of the disease. On days 6-9 no cardiac rhythm and conduction disturbances that had been observed in them were recorded. The patients in whom the episodes of silent myocardial infarction remained on their discharge exhibited a high (35%) incidence of myocardial infarction recurrence within a year.

The author analyzes the effect of postextrasystolic potentiation of contraction of the asynergic regions of the myocardium in 18 of 34 patients with postinfarction aneurysm of the left ventricle evaluated by contrast ventriculography. There was a statistically valid increase of the extension of the zones of hypokinesia due to reduction of the relative length of akinetic regions as compared with data of control contractions, a significant rise of reduction of the sizes of hypokinetic zones, increase of the fraction of ejection of the contractile segment in the general fraction of ejection. It is recommended to use the effect of postextrasystolic potentiation of contraction on the function of asynergic regions of the myocardium with the purpose of assessment of their vitality, determination of resection borders and expediency of their revascularization in the course of aneurysmectomy.

This study was performed to determine the relationships among angiographic, hemodynamic, clinical, and electrocardiographic data and premature ventricular contractions (PVCs). Arrhythmias were analyzed by 24 hour Holter monitor in 244 patients evaluated for chest pain by coronary angiography and left ventriculography. Using a categorical linear model, the presence of myocardial fibrosis as indicated by both abnormal left ventricular contraction (LVC) and abnormal initial QRS on electrocardiogram was found to be the only independent predictor of both frequent and complex ventricular arrhythmias (P less than .0001). All other descriptors, including the number of diseased vessels (greater than or equal to 75% obstruction), were dependent upon abnormal LVC in their association with PVCs. When the right anterior oblique view of the left ventriculogram was divided into nine segments to allow automated quantiative analysis of LVC, the prevalence of frequent PVCs was directly related to the number of abnormally contracting segments. Of patients with 0 abnormal segments, 11% had greater than or equal to 2 PVC/hr, in contrast to 44%, 73% and 100% of patients with 1-3, 4-6, and 7-9 abnormal wall segments, respectively (P less than 0.01). A similar quantitative relationship was found between premature ventricular contractions and abnormal initial forces indicating previous myocardial infarction on the electrocardiogram.

Changes in ventricular extrasystole were examined using 3 sessions of 24-hour Holter ECG monitoring in 304 myocardial infarction survivors. The highest reproducibility was shown by the maximum ventricular extrasystole gradations 1, 3, 4b, according to the Lown-Wolff classification. Evidence of possible transformation of the maximum ventricular extrasystole gradations at repeated prolonged ECG monitoring sessions is presented.

Left ventricular (LV) ejection fraction (EF) is known to be related to prognosis after acute myocardial infarction (AMI), but its role alone and in combination with other factors in the definition of a high-risk group has not been adequately specified. Several recent multicenter studies emphasize that LVEF together with features of ventricular ectopic activity during ambulatory electrocardiography define a group at high risk for death for up to 3 years. However, these high-risk groups comprised only a small fraction of the population (less than 7.5%) and failed to include 75% or more (less than 25% specificity) of observed events. In our study, LVEF was determined close to the time of hospital discharge in 750 patients with AMI enrolled in a collaborative study. Used alone, an LVEF of less than 0.45 best defined a high-risk group (39% of the population) yielding 62% sensitivity and 64% specificity for total cardiac mortality by 1 year; it was 77% sensitive for sudden death alone. In a multivariate analysis together with other factors, LVEF was an independent predictor, but other markers of LV dysfunction entered before LVEF with similar sensitivity for total cardiac deaths, but with increased specificity (75%). When an LVEF of less than 0.45 was used together with the presence of complex arrhythmias to define a high-risk group (19% of the population), sensitivity decreased to 39% and specificity increased to 84%. Thus, LVEF is a simple and effective alternative to multivariate analysis for risk assessment after AMI.(ABSTRACT TRUNCATED AT 250 WORDS)

In the course of 1 year 130 patients were examined who had survived myocardial infarction and were alive 2 months after the onset of the disease and were included into the Myocardial Infarction Registry. After 2,3,6,9 and 12 months ECG of various duration was recorded. The prolongation of ECG recording permits to give a more precise characteristics of the incidence and nature of the rhythm disorders observed in chronic ischaemic heart disease patients. Repeated heart rhythm examinations at rest during 1 hour, or during physical exercises (bicycle test) permitted to reveal rhythm disorders in 72.2--66.7% of the patients, and among them ventricular extrasystole in 62.6--66.7% of those examined, respectively. The appearance of ventricular extrasystoles correlates with the state of the patients surviving myocardial infarction A higher incidence of ventricular extrasystoles is observed in pateints with distinct tecg changes, with angina pectoris and elevated blood pressure (larger than or equal to140/90mm Hg).

The arrhythmia profile has been studied in 40 patients (pts) with acute myocardial infarction (MI) resuscitated early (less than 24 hours post MI, group I) and late (4-12 weeks post MI, group II) using 24 h Holter monitoring (HM) at the time of LV- and coronary angiography (HM A) with an average follow-up of 27 months (7-61) (HM B). Forty pts with an acute MI without resuscitation served as controls (group III). Mortality for sudden cardiac death (scd) (death within 24 hours after beginning of symptoms) was significantly higher in group II (6/14 or 42.9%; 13% per year) than in group I (4/26 or 15.4%; 5.9% per year) (p less than 0.05) or in group III (3/40 or 7.5%; 1.8% per year) (p less than 0.001). In HM A there were no significant differences with regard to PVCs and complex arrhythmias using qualitative and quantitative analysis in groups I-III as well as between survivors and scd-pts. In HM B survivors in group II had significantly more PVCs (mean = 1347), couplets (mean = 29) and salvos (mean = 11) than in group I (PVC, mean = 355; couplets, mean = 3; salvos, mean = 0.1; p less than 0.05) or in group III (PVC, mean = 455; couplets, mean = 4; salvos, mean = 0.8; p less than 0.05). They also showed significantly more PVCs (mean = 1480), couplets (mean = 35) and salvos (mean = 15) than in HM A (PVC, mean = 1347; couplets, mean = 3; salvos, mean = 0; p less than 0.05). There were no significant differences between HM A and HM B in groups I and III. It can be concluded that the risk of sudden cardiac death was increased in pts resuscitated 4-12 weeks post MI in comparison to pts with early resuscitation or without resuscitation post MI. In these high risk pts repeated studies using Holter monitoring were helpful in estimating the further risk of sudden cardiac death.

Unlabelled: Ventricular premature beats are probably important in the prognostic evaluation after acute myocardial infarction and may allow a better management of these patients. The purpose of this study was to compare the sensitivity of two methods exercise testing - ET - and ambulatory electrocardiographic monitoring - AM - detecting potentially dangerous ventricular arrhythmias and to evaluate their prognostic value. Sixty-four patients have been studied (53 males and 11 females); their mean age was 61 years. They underwent ET and AM before discharge (mean 13.9 days) and were followed for a period of 12 months., Conclusions: -- ET and AM are useful to detect ventricular arrhythmias; -- AM is the most sensitive method; -- there are no significant differences between the two methods in the diagnosis of major arrhythmias; -- the combined use of the two methods has a greater sensitivity; -- late mortality is not higher in the patients who have suffered from major arrhythmias in the acute phase of the disease.

To assess the correlates of supraventricular arrhythmia (SA) in the late hospital phase of acute Q-wave myocardial infarction (MI), continuous 24-h ambulatory electrocardiographic monitoring, gated cardiac pool scan, modified exercise test, and chest x-ray were reviewed in 102 patients. Supraventricular tachyarrhythmias were seen in 11 patients, atrial premature beats in 42 patients; 49 patients did not have SA. Multiple discriminant analysis was used to determine the important variables contributing to the occurrence of SA. Variable included age, sex, history of previous MI, hypertension, location of MI, moist rales at time of admission, cardiothoracic ratio, ejection fraction, wall motion abnormality, exercise test result, duration of exercise and use of digitalis. Moist rales, digitalis, age and cardiothoracic ratio were the predictors of SA. Aging, hemodynamic change imposed on the left ventricle, and arrhythmic effects of digitalis are the major factors associated with SA in the late hospital phase of acute MI.

To determine the diagnostic value of Q-waves (greater than or equal to 0.04 seconds duration) in premature ventricular complexes (PVC's) for the presence of myocardial scar, we examined 12-lead electrocardiograms and multiple lead rhythm strips obtained before and after exercise at the time of thallium-201 myocardial imaging in 970 patients. PVC's were found in 233 patients, 112 of whom had fixed thallium-201 perfusion defects indicative of myocardial scar. PVC's occurring during exercise were excluded from the analysis. Twenty-one patients had Q-wave PVC's in one or more electrocardiographic leads. Of those, 14 patients (67%) had myocardial scar in the suggested location. Myocardial scar was more common among patients with Q-wave PVC's than in patients without (67% vs. 36%, p less than 0.01). However, only 6 of 13 patients (46%) with Q-wave PVC's but no diagnostic sinus beats actually had myocardial scar. The remaining seven patients had Q-wave PVC's, no myocardial scar, and no evidence of myocardial ischemia suggested by angina during exercise, exercise electrocardiogram or thallium-201 imaging. We conclude that although Q-wave PVC's indicate the presence of myocardial scar in 67% of patients, they yield little or no additional diagnostic information to that obtained from the sinus beats

Prognostic value of ventricular extrasystoles was assessed by round-the-clock Holter's ECG monitoring at different dates after myocardial infarction. Correlation between complex ventricular arrhythmias and poor vital prognosis was more obvious 1 month after myocardial infarction than it was 12 months after the infarction. Recurrent ventricular arrhythmias were associated with the poorest vital prognosis.

The time course and characteristics of ventricular arrhythmias were studied in 45 consecutive patients with acute myocardial infarction who received intravenous streptokinase and underwent 24-hour Holter monitoring both after admission and before discharge 8 +/- 3 days later. In 41 of the 45 patients, thrombolytic treatment resulted in reperfusion as determined by characteristic clinical signs, i.e., rapid relief of pain associated with rapid resolution of ST-segment elevation and simultaneous abrupt increase in serum creatine kinase-MB activity. During the first 24 hours after reperfusion, the prevalence of ventricular premature complexes (VPCs) and couplets was nearly 100%, with an average frequency of 67 VPCs (range 1 to 1,336, median 44) and 6 couplets per hour per patient (range 1 to 97, median 4). Ninety percent of patients had an average of 8 runs of accelerated idioventricular rhythm per hour per patient (range 1 to 226, median 5) and 23% of the patients had an average of 2 runs of ventricular tachycardia per hour per patient (range 1 to 22, median 2) during the first 24 hours after reperfusion. The frequency of arrhythmias began to decrease 8 to 12 hours after reperfusion. Except for VPCs, ventricular arrhythmias were rare during the predischarge Holter study. Arrhythmias after reperfusion did not produce clinical symptoms and did not degenerate into ventricular fibrillation even though the patients were not receiving antiarrhythmic therapy. In the 4 patients without signs of reperfusion, the prevalence and frequency of all ventricular arrhythmias during the 24 hours after treatment was lower than in patients with reperfusion, and none had an accelerated idioventricular rhythm.(ABSTRACT TRUNCATED AT 250 WORDS)

Unlabelled: To assess incidence of ventricular premature beats (VPB) and correlate ECGraphic and hemodynamic data of parameters at rest and during exercise, 176 oligo or asymptomatic patients (167 males and 9 females) with recent myocardial infarction (RMI) (20-60 days after AMI) underwent a maximal symptom limited exercise test in supine position during hemodynamic monitoring (Swan-Ganz cath. 7F placed in pulmonary artery) without medical therapy. During the following 24 hours the patients underwent a continuous ambulatory ECG. 71 patients (40%) had no VPB (class 0), 56 patients (32%) had less than 1 VPB/hour (class 1), 35 patients (20%) had less than 6 VPB/minute and less than 30 VPB/hour (class 2) and 14 patients (8%) had greater than 6 VPB/minute and greater than 30 VPB/hour (class 3). Patients with VPB were then divided into qualitative classes: class A: 57 patients (54%) with isolated and unifocal VPB; class B: 38 patients (36%) with polifocal, bigeminal and paired VPB; class C: 10 patients (10%) with R on T or consecutive beats (3 or more). 28% of the patients had complex VPB (class B and C). 20% of all the patients (36/176) had VPB during exercise, 8 patients had VPB only during exercise, increasing the percentage of arrhythmias from 60% to 64%. VPB were more frequent and complex in patients with inferior or anterior + inferior MI than in patients with anterior MI and patients aged more than 60. Patients with complex VPB had cardiac volume index higher (p less than 0.05) than patients without VPB or with isolated VPB. Patients of different classes showed work capacity of 75-80 watts with 75-80% of maximal theoretic heart rate. Infarct size (NQ) was not correlated with number of VPB. Arrhythmias were slightly more frequent in patients with exercise ST depression (66%) than in patients without exercise ST depression (57%) (NS). No significant difference was found between ST elevation at rest and during exercise and VPB. PWP was, on the average, normal at rest (10 mmHg in the different classes) and slightly pathological during exercise with no differences between patients without VPB (class 0 = 21.7 mmHg) and patients with VPB (class 1 = 22.4 mmHg, Class 2 = 24.4 mmHg, Class 3 = 20.8 mmHg)., In Conclusion: in oligo or asymptomatic patients with RMI: a) exercise slightly increased the sensitivity of continuous ambulatory ECG to reveal VPB b) poor correlations were found between VPB and ECGraphic and hemodynamic parameters both at rest and during exercise.

A 6-hour taped electrocardiogram recording was obtained prior to hospital discharge on 193 patients less than 66 years of age with a definite or probable myocardial infarction. All ventricular premature beats (VPBs) were identified on the 6-hour recording, and the various VPB characteristics were related to a complicated course (CC) defined as cardiac death or myocardial reinfarction within 4 months after hospital discharge. Only three univariate VPB characteristics (multiform pattern, bigeminal rhythm, and frequency greater than or equal to 20/hr) were significantly associated with a 4-month posthospital CC. By use of bivariate and multivariate combinations of these three VPB characteristics, a two-grade prognostic stratification system was derived: Grade I VPBs (CC = 8%) included patients with less than 20 VPB/hr but with neither multiform nor bigeminal beats: Grade II VPBs (CC = 31%, P less than 0.001) contained patients with greater than or equal to 20 VPBs/hr or with multiform or bigeminal beats or both. Patients with Grade II VPBs had more severe cardiac disease, but when patients were stratified by the clinical severity of their cardiac disease, Grade II VPBs identified patients with higher CC rates. The clinical significance of these findings together with a critical analysis of the prognostic stratification method are discussed.

The results of repeated 24-hour ECG monitoring in 81 patients with documented transmural and macrofocal myocardial infarction are reported. The occurrence and pattern of heart rhythm disorders, including high-grade ventricular extrasystoles within the first day of the attack, were determined, as was the correlation between the infarction site and the occurrence of arrhythmia. The frequency and number of extrasystoles were the highest in recurrent myocardial infarction with developing left-ventricular insufficiency. High diagnostic value of 24-hour ECG monitoring, as compared to routine recordings, is demonstrated. The monitoring showed a significant drop in the frequency and number of extrasystoles by the end of the acute phase, including cases where no antiarrhythmic drugs were administered, and a significant rise in those in the subacute phase of myocardial infarction. It is suggested that the latter fact may be due to increased patient's physical activity in the course of convalescence, and myocardial autoimmune processes developing in the subacute phase.

To determine whether morphologic analysis of ventricular premature beats (VPBs) can aid in the electrocardiographic diagnosis of myocardial infarction (MI), 12-lead electrocardiograms were evaluated in 760 consecutive patients who underwent cardiac catheterization, and 2-minute multiple-lead rhythm strips were evaluated in 515 of these patients. VPBs occurred in 58 patients; 21 had prior MI diagnosed by regional akinesia or dyskinesia on left ventricular cineangiography. Standard criteria were used to diagnose prior MI from the sinus beats of the electrocardiogram. Infarction was diagnosed from the morphology of a VPB when it had a QR or QRS pattern with Q wave greater than or equal to 0.04 second. Morphologic analysis of VPBs had a low sensitivity (29%) but high specificity (97%) and high predictive value (86%) for the diagnosis of MI. Sinus beats diagnosed MI with higher sensitivity (52%, and 69% if patients with left bundle branch block and left ventricular hypertrophy were excluded from analysis) than VPB morphologic analysis (p less than 0.05), but with similar specificity (97%) and predictive value (92%). Two patients with angiographic MI had no MI according to standard electrocardiographic criteria, but did have an MI manifest by VPB morphologic analysis. Despite low sensitivity, analysis of the morphology of VPBs may be useful for the diagnosis of MI when the morphology of sinus beats is not diagnostic. Therefore, VPB analysis is complementary to the standard electrocardiographic diagnosis of MI.

For one year 215 patients were followed up who had been taken into the register of patients with myocardial infarction and had survived three months after the incident. At intervals of 3, 6, 9, and 12 months their electrocardiograms of various durations were recorded. Prolongation of the ECG tracing time eases the assessment of the frequencies and nature of heart rhythm disturbances in patients with ischaemic heart disease. Exercise test helps reveal more complicated types of ventricular extrasystoles better than one-hour recording of resting ECG does. Ventricular ectopic activity is more frequently found in patients with unequivocal ECG changes (p less than 0.025), in patients with enlarged heart volume (p less than 0.05), and in men vs. women (p less than 0.05). Presence of ventricular extrasystoles, especially of complicated ones (polytopic, couplets, early) enhances the risk of death of ischaemic heart disease.

Patients with acute myocardial infarction were monitored for ventricular arrhythmias in the first 48 hours. Idioventricular rhythm (rate less than 100/minute) occurred in 35 out of 224 patients (15.6%) during the first day and in 13 out of 192 patients not receiving treatment on the second day (6.8%). This arrhythmia was frequently preceded by late ventricular extrasystoles, which often showed variation of their coupling intervals to the preceding QRS. Double ventricular extrasystoles separated by larger than or equal to 600 ms were also precursors of idioventricular rhythm. Idioventricular rhythm at times could be described as an escape rhythm, but on other occasions it was undoubtedly an accelerated rhythm. Spontaneous changes in the idioventricular cycle length were frequent on single one-minute electrocardiographic recordings. The rate of the dominant rhythm in patients with episodes of idioventricular rhythm was significantly slower than the heart rate of patients without this arrhythmia. Idioventricular rhythm was more frequent in patients with inferior infarction. Idioventricular rhythm sometimes preceded ventricular tachycardia but there was only a significant association between ventricular tachycardia and idioventricular rhythms with rates of over 75/minute. Irregular idioventricular rhythm frequently accelerated to ventricular tachycardia. It is suggested that the term benign idioventricular rhythm be reserved for those rhythms below 75/minute, and that the term rapid idioventricular rhythm should be used for rhythms between 75 and 120/minute. The rate of idioventricular rhythm is related to the probability of development of life-threatening ventricular arrhythmias during the first 48 hours after myocardial infarction.

Ventricular arrhythmias were recorded in 233 patients in a prospective study of patients with acute myocardial infarction. In over 95% of patients antiarrhythmic therapy was not given until the onset of ventricular tachycardia, ventricular fibrillation, or persistent idioventricular rhythm. There was a mortality of 18% during the patients' stay in hospital. The most important features of ventricular ectopic activity, which preceded these severe ventricular arrhythmias in the first 48 hr, were multiformity, variation of coupling intervals of larger or equal to 0-1 sec, the R-on-T phenomenon, double ventricular extrasystoles and ventricular bigeminy. The number of a single ventricular extrasystoles per minute was related to the probability of these severe ventricular arrhythmias but to a lesser degree. It was found that if all the patients with the first two prognostic features that if all the patients with the first two prognostic features were removed, the number of single ventricular extrasystoles was not of significant import and the other features were less important. Three-quarters of the severe arrhythmias occurred in the first 24 hr and during this period 60% were preceded by either multiform ventricular extrasystoles or extrasystoles with variable coupling. The importance of these findings in relation to prophylactic therapy is discussed.