Clinical significance of supraventricular tachyarrhythmias after acute myocardial infarction

160 survivors of acute myocardial infarction (AMI) were evaluatedto assess the clinical significance of supraventricular tachyarrhythmias(SVTA) occurring at discharge from the hospital after the acuteevent. the variables considered for the study were estimatedbefore hospital discharge; arrhythmias were quantified witha 24 h Hotter ECG monitoring system. SVTA occurred in 88 patients(55%). Single or repetitive supraventricular premature beatswere found in 65 (41%), paroxysmal atrial orjunctional tachycardiasin 20 (12%), bouts of atrial flutter or fibrillation in 3 (2%).Bivariate statistical analysis showed no relationship betweensex, previous cardiovascular history, type, and location ofAMI and SVTA occurrence. A close positive relationship was foundbetween age, left atrial dimension (LAD), cardio-thoracic ratio(CTR) and SVTA occurrence; an inverse relationship was foundfor left ventricular ejection fraction (LVEF). The presenceof SVTA appeared significantly related to age above 55 years,to LAD greater than 40 mm, to LVEF less than 45%, to serum creatinekinase peak levels over 1400 U l–¹ and to CTR over 0.49.Multivariate statistical analysis showed that five variablesare important in discriminating patients suffering from SVTA:age, LAD, LVEF, left ventricular fractional shortening, andCTR. SVTA occurring at discharge from hospital after AMI areindicative of impaired left ventricular pump function.     

Incidence and significance of inducible supraventricular tachyarrhythmias in patients with chronic myocardial infarction

In order to evaluate the incidence and significance of inducible supra-ventricular (SVTA) in patients with chronic myocardial infarction (MI), the results of systematic programmed atrial stimulation were compared in two groups of patients: 150 patients (group I) without MI or underlying heart disease, studied for syncope or conduction disturbances, 296 patients (group II) studied after an acute Mi (greater than 1 month). None of them had spontaneous SVTA, and 24-h Holter monitoring showed no SVTA. The atrial stimulation programme used one and two extra stimuli delivered during sinus rhythm and atrial pacing (600 ms and 10% less than the sinus cycle length). A sustained (S) (greater than 30 s) supraventricular tachycardia (SVT) (atrial flutter, fibrillation, tachycardia) was induced in 17 patients in group I (11%) and in 120 patients in group II (40.5%). In group II inducible SVTA could not be correlated with the occurrence of a SVT during acute MI, the location of MI, the value of LV ejection fraction (EF), the incidence of inducible sustained ventricular tachycardia (VT), or fibrillation (VF). However, inducible SVTA could be correlated with a significantly shorter effective atrial refractory period (197 +/- 23 ms vs 220 +/- 35 ms, P less than 0.001) and a shorter retrograde block cycle length (518 +/- 215 vs 585 +/- 215 ms, P less than 0.03). The patients in group II were followed-up for at least 6 months; 12 of them developed sustained episodes of supraventricular tachycardia; 11 of them had inducible SVTA (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Incidence, predictive factors, and prognostic significance of supraventricular tachyarrhythmias in congestive heart failure

BACKGROUND: The incidence, predictive factors, morbidity, and mortality associated with the development of supraventricular tachyarrhythmias (SVTs) in patients with congestive heart failure (CHF) are poorly defined. METHODS: In the Digitalis Investigation Group trial, patients with CHF who were in sinus rhythm were randomly assigned to digoxin (n = 3,889) or placebo (n = 3,899) and followed up for a mean of 37 months. Baseline factors that predicted the occurrence of SVT and the effects of SVT on total mortality, stroke, and hospitalization for worsening CHF were determined. RESULTS: Eight hundred sixty-six patients (11.1%) had SVT during the study period. Older age (odds ratio [OR], 1.029 for each year increase in age; p = 0.0001), male sex (OR, 1.270; p = 0.0075), increasing duration of CHF (OR, 1.003 for each month increase in duration of CHF; p = 0.0021), and a cardiothoracic ratio of > 0.50 (OR, 1.403; p = 0.0001) predicted an increased risk of experiencing SVT. Left ventricular ejection fraction, New York Heart Association functional class, and treatment with digoxin vs placebo were not related to the occurrence of SVT. After adjustment for other risk factors, development of SVT predicted a greater risk of subsequent total mortality (risk ratio [RR] = 2.451; p = 0.0001), stroke (RR = 2.352; p = 0.0001), and hospitalization for worsening CHF (RR = 3. 004; p = 0.0001). CONCLUSION: In CHF patients in sinus rhythm, older age, male sex, longer duration of CHF, and increased cardiothoracic ratio predict an increased risk for experiencing SVT. Development of SVT is a strong independent predictor of mortality, stroke, and hospitalization for CHF in this population. Prevention of SVT may prolong survival and reduce morbidity in CHF patients.     

Incidence and prognostic significance of silent atrial fibrillation in acute myocardial infarction

Background

Silent atrial fibrillation (AF) has been suggested to be frequent after acute myocardial infarction (MI). Continuous ECG monitoring (CEM) has been shown to improve AF screening in patients at risk of stroke.

Objectives

We aimed to assess the incidence and prognosis of silent AF in patients with acute MI.

Methods

All the consecutive patients with acute MI were prospectively analyzed by CEM ≥ 48 h after admission. Silent AF was defined as asymptomatic episodes lasting at least 30 s. The population was divided into three groups: no-AF, silent AF and symptomatic AF.

Results

Among the 849 patients, 135 (16%) developed silent AF and 45 (5%) symptomatic AF. Compared with the no-AF group, patients with silent AF were markedly older (80 vs. 62 y, p < 0.001), more frequently women (43% vs. 30%, p = 0.006) and less likely to be smokers (20% vs. 36%, p < 0.001). They had impaired left ventricular ejection fraction (LVEF) and left atrial (LA) enlargement. By multivariate analysis, age, history of AF, indexed LA area and LVEF were identified as independent predictors of silent AF. In-hospital heart failure and death rates were markedly higher in silent AF group when compared with no-AF patients (41.8% vs 21.0% and 10.4% vs. 1.3%, respectively).

Conclusion

Our large prospective study showed for the first time that silent AF is more frequent than symptomatic AF after MI. Our work suggests that indexed LA area could help to predict the risk of developing silent AF. Moreover, the onset of silent AF is associated with worse hospital prognosis.     

Incidence and prognostic significance of intraventricular block in acute myocardial infarction.

In 404 consecutively admitted patients with their first myocardial infarction (MI), intraventricular block (IV) was a complication in 124 (31%). The following types of block were encountered: 21 (5%) had left bundle-branch block (LBBB), 73 (18%) left anterior hemiblock (LAH), 13 (3%) left posterior hemiblock (LPH); 7 (2%) right bundle-branch block (RBBB); 9 (2%) RBBB + LAH, and 1 (0.3%) RBBB + LPH. Patients with IV block at the time of admission did not develop total atrioventricular block more frequently in the acute phase of MI (0-30 days) or in the follow-up period (3-5 years) than patients without IV block. During the acute phase, only patients with RBBB with or without hemiblock showed significantly higher mortality than patients without IV blocks. The other types of IV block did not influence the short-term prognosis. Among patients who survived the acute phase, significantly lower long-term survival rates were found in patients with LBBB compared to patients without IV block, whereas the presence of LAH did not affect the long-term prognosis.     

Frequency, characteristics and significance of supraventricular tachyarrhythmias detected by 24-hour electrocardiographic recording in the late hospital phase of acute myocardial infarction

The incidence, characteristics and clinical significance of supraventricular tachyarrhythmias occurring in the late hospital phase of acute myocardial infarction (AMI) were assessed in 209 consecutive patients. Arrhythmias were quantified by 24-hour electrocardiographic recording 16 +/- 3 days after AMI, and were classified according to the degree of complexity in 5 classes. Class 0 = less than 5 premature beats/hr; class 1 = between 5 and 100/hr; class 2 = greater than 100/hr or repetitive premature beats; class 3 = atrial-junctional tachycardia; class 4 = atrial flutter-fibrillation. Supraventricular tachyarrhythmias classes 1 to 2 always occurred in the absence of symptoms in 86 patients (41%); supraventricular tachyarrhythmias classes 3 to 4 (paroxysmal, self-limiting, brief) occurred in 27 patients (13%), symptomatically in 6. The presence of supraventricular tachyarrhythmias classes 2 to 3 was related to age over 55 years and complex ventricular tachyarrhythmias (greater than 20 premature beats/hr, ventricular tachycardia) (both p less than 0.05). Increasing complexity of supraventricular tachyarrhythmias was significantly associated with presence and entity of cardiac enlargement and left ventricular dysfunction (both p less than 0.01). Patients with class 4 showed the most severe cardiac deterioration. During the 2 years after AMI, patients with classes 2, 3 and 4 had a higher incidence of acute pulmonary edema, New York Heart Association functional classes III to IV for congestive heart failure (both p less than 0.005) and a greater need of digitalis and diuretics (p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)     

The relation between supraventricular tachyarrhythmias and left ventricular dysfunction after acute myocardial infarction

The clinical characteristics of supraventricular tachyarrhythmias (SVTA) and their relation to left ventricular dysfunction were assessed in 208 consecutive patients with recent myocardial infarction. Arrhythmias were quantified on hospital discharge by 24 hour electrocardiographic recording. All the variables were evaluated between the second and the fourth week after infarction. SVTA occurred in 113 (54%) patients: Supraventricular premature beats (SVPB) in 49 (24%), frequent or repetitive SVPB in 37 (18%), atrial or junctional tachycardia in 23 (11%), atrial flutter or fibrillation in 4 (2%). Most of these arrhythmias occurred in the absence of symptoms, and the most complex forms were always selflimiting. No relation was found among the presence of different forms of SVTA and sex, coronary risk factors, previous history of ischemic heart disease, type or site of acute myocardial infarction, NYHA functional class. Age, left atrial dimension (LAD), cardio-thoracic ratio (CTR) and left ventricular ejection fraction (LVEF) at rest differed significantly among three groups of patients: those without SVTA, those with SVPB less than 100 per hour and those with frequent-repetitive SVPB or atrial-junctional tachycardia. The more SVTA complexity, the worse LAD, CTR, LVEF and the higher the age. Multivariate discriminant analysis showed that CTR was directly and LVEF inversely related to the occurrence of SVPB less than 100 per hour, while the presence of frequent-repetitive SVPB or supraventricular tachycardia was closely related to increasing age, LAD, CTR and decreasing LVEF. Patients with atrial fibrillation always showed the worst values of LAD, CTR, LVEF and age. The results of the present study show that different types of SVTA occurring at discharge from hospital after myocardial infarction are clinically benign, but always suggestive of different degrees of left ventricular dysfunction.     

Atrial tachyarrhythmias in acute myocardial infarction

Causative factors, clinical consequences and treatment of atrial tachyarrhythmias were reviewed in 917 monitored patients with definite acute myocardial infarction. Significant atrial tachyarrhythmias were found in 104 (11 per cent) of them and included atrial fibrillation in 67, atrial flutter in 29 and paroxysmal atrial tachycardia in 33. These episodes were single in 79 patients and multiple in 25, and began within the first four days of acute myocardial infarction in 90 per cent of the patients. Fifty per cent of these atrial tachyarrhythmias were heralded by premature atrial contractions.

The incidence of atrial tachyarrhythmia was not related to the location of the acute myocardial infarction or to the presence or degree of power failure; however, atrial tachyarrhythmias were significantly more frequent in patients with pericarditis. Atrial tachyarrhythmias were well tolerated in almost one fifth of the patients, caused marginal compromise in almost two thirds and led to severe clinical deterioration in one fifth. Paroxysmal atrial tachycardia rarely required specific treatment, atrial fibrillation was best managed with intravenous administration of digoxin except when associated with severe clinical compromise, and atrial flutter generally required cardioversion or rapid intravenous therapy and usually caused severe clinical deterioration.

Over-all, atrial tachyarrhythmia was not associated with a significantly increased mortality, and in those who died, death was not related specifically to the atrial tachyarrhythmia but rather to the severity of the underlying acute myocardial infarction. However, persisting atrial tachyarrhythmias, particularly atrial flutter which tends to be refractory to both heart rate control and cardioversion, may contribute indirectly to morbidity and mortality.     

Incidence and prognostic significance of atrial fibrillation in acute myocardial infarction: the GISSI-3 data

OBJECTIVE—To assess the relations between early filling deceleration time, left ventricular remodelling, and cardiac mortality in an unselected group of postinfarction patients.
DESIGN AND PATIENTS—Prospective evaluation of 131 consecutive patients with first acute myocardial infarction. Echocardiography was performed on day 1, day 2, day 3, day 7, at three and six weeks, and at three, six, and 12 months after infarction. According to deceleration time on day 1, patients were divided into groups with short (< 150 ms) and normal deceleration time ( 150 ms).
SETTING—Tertiary care centre.
RESULTS—Patients with a short deceleration time had higher end systolic and end diastolic volume indices and a higher wall motion score index, but a lower ejection fraction, in the year after infarction. These patients also showed a significant increase in end diastolic (p < 0.001) and end systolic volume indices (p = 0.007) during the follow up period, while ejection fraction and wall motion score index remained unchanged. In the group with normal deceleration time, end diastolic volume index increased (p < 0.001) but end systolic volume index did not change; in addition, the ejection fraction increased (p = 0.002) and the wall motion score index decreased (p < 0.001). One year and five year survival analysis showed greater cardiac mortality in patients with a short deceleration time (p = 0.04 and p = 0.02, respectively). In a Cox model, which included initial ejection fraction, infarct location, and infarct size, deceleration time on day 1 was the only significant predictor of five year mortality.
CONCLUSIONS—A short deceleration time on day 1 after acute myocardial infarction can identify patients who are likely to undergo left ventricular remodelling in the following year. These patients have a higher one year and five year cardiac mortality.


Keywords: deceleration time; left ventricular remodelling; acute myocardial infarction     

Pericardial effusion in acute myocardial infarction: clinical feature and significance]

To determine the incidence and clinical significance of pericardial effusion after acute myocardial infarction, two-dimensional echocardiography was serially performed in 137 consecutive patients. Pericardial effusion was observed in 45 patients (33%), of whom 22 were followed until they recovered and were discharged. Pericardial effusion was more frequent in patients with anterior acute infarction than those with inferior acute infarction, and so it was in non-recanalized patients than in recanalized ones. Patients with pericardial effusion had higher peak levels of creatine kinase, higher wall motion score indices, and higher defect scores of thallium imagings. The improvement of regional wall motion at an infarct zone in patients with pericardial effusion was less regardless of the successful early recanalization. These results show that pericardial effusion is a common event in patients with acute myocardial infarction and observation of transition of pericardial effusion is important for predicting prognosis.     

Incidence and clinical significance of involvement of the right ventricle in acute inferior myocardial infarction

The purpose of our study was to evaluate, with noninvasive procedures, the incidence and the clinical picture of right ventricular involvement in patients with acute transmural inferior myocardial infarction. Our study group was constituted of 107 consecutive patients admitted to our Coronary Care Unit within 10 hours from the onset of symptoms; in every patient a standard 12-leads ECG and the precordial leads V3R and V4R were obtained at admission in CCU and then every 12 hours. 80 patients underwent B-mode echocardiographic evaluation within 36 hours and in 93 patients a myocardial scintigraphy was performed, between the 48th and 72nd hour from the onset of chest pain, 1-2 hours after injection of Tc-99m-pyrophosphate. Results: 45 patients (42.1%) had ECG positive for right ventricular infarction, 49 patients (51.6%) had positive Tc-99m-pyrophosphate scintigraphy and 24 patients (30%) positive echocardiography. By using the positivity of ECG and another method at least, patients were separated into 2 groups: group A (associated inferior and right infarction) was constituted of 45 patients, and group B (isolated inferior infarction) was constituted of 62 patients. In group A we noted a higher incidence of hypotension (systolic blood pressure less than 100 mmHg) and oliguria (less than 30 ml/h)- p less than 0.01-, of 2nd and 3rd A-V blocks-p less than 0.001- and primary ventricular fibrillation -p less than 0.01. The incidence of parossistic atrial fibrillation, severe bradycardia or SA blocks and of mortality was not statistically different between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Variability, prediction and prognostic significance of chest pain in acute myocardial infarction

The variability of chest pain is described in 389 patients with acute myocardial infarction. Whereas 17% were free from severe pain after arrival in hospital, 11% required more than 10 analgesic injections. In 27% of the series analgesics were given more than 24 h after arrival in hospital. Predictors for the severity of chest pain were the rate-pressure product and degree of chest pain soon after arrival in hospital as well as electrocardiographic signs of myocardial infarction at entry. Patients with more severe chest pain had a higher 2-year mortality rate and a higher incidence of ventricular fibrillation and congestive heart failure during hospitalization.     

Silent myocardial ischemia in myocardial infarction patients: its prognostic significance]

To evaluate the prognostic and clinical significance of silent myocardial ischemia (SMI), we examined cardiac events in 160 patients with old myocardial infarction who underwent ambulatory Holter monitoring, treadmill exercise testing and coronary angiography. Using the Cox's proportional hazard regression model and the survival curves with the Kaplan-Meier method, we identified the predictors of cardiac events. The incidence of cardiac events for all the patients during the 44-month follow-up period was 18%. The significant predictors of unfavorable outcomes were severe coronary lesions and SMI. The incidence of SMI was 38%. The cardiac event rate in patients with SMI was higher than in those without SMI (32 vs 9%, p < 0.05). The most frequent cardiac event in patients with SMI was reinfarction, and the significant predictors of cardiac events for these SMI patients were lower ejection fraction and maximum ST depression on Holter monitoring. In conclusion, SMI proved to be a significant predictor of unfavorable outcome in patients with old myocardial infarction. It was, therefore, suggested that revascularization (PTCA/CABG) should be used as early as possible in patients with SMI whether anginal symptoms are present or not.     

Incidence and clinical significance of distal embolization during primary angioplasty for acute myocardial infarction.

AIMS: Although recognized as an important feature of atherosclerotic coronary disease, little is known about the frequency and prognostic importance of distal embolization during primary angioplasty for acute myocardial infarction. METHODS AND RESULTS: As part of a randomized trial of thrombolysis vs primary angioplasty, 178 patients with acute myocardial infarction were treated with primary angioplasty. In these patients the occurrence of distal embolization after angioplasty was assessed. Embolization was defined as a distal filling defect with an abrupt 'cutoff' in one of the peripheral coronary artery branches of the infarct-related vessel, distal to the site of angioplasty. We analysed myocardial blush grade, ST-T segment elevation resolution, enzymatic infarct size and left ventricular ejection fraction in patients with and without distal embolization. Clinical information was collected for a mean of 5 years. Distal embolization was present in 27 patients (15.2%). Mean age and gender were not different from patients without distal embolization. Angiographic success (thrombolyis in myocardial infarction flow grade 3 and residual stenosis <50%) after primary angioplasty was less frequently observed in patients with distal embolization (70% vs 90%, P<0.01). Myocardial blush and ST-T segment elevation resolution after angioplasty were reduced when distal embolization was present. Patients with distal embolization had a larger enzymatic infarct size (mean cumulative lactate dehydrogenase measured over 72 h, 1612 vs 847, P<0.05) and a lower left ventricle ejection fraction at discharge (42% vs 51%, P<0.01). Long-term mortality was higher in patients with distal embolization (44% vs 9%, P<0.001). CONCLUSION: Distal embolization in patients treated with primary angioplasty is visible on the coronary angiogram in 15.2% of patients. It is related to reduced myocardial reperfusion, more extensive myocardial damage and a poor prognosis. Additional pharmacological interventions and/ or mechanical devices should be studied to prevent and/or treat distal embolization.     

Pericarditis in the acute phase of myocardial infarction: incidence and clinical significance]

STUDY OBJECTIVE: To evaluate the incidence and the clinical significance of pericarditis in the acute myocardial infarction. DESIGN: Retrospective study. SETTING: The Coronary Care Unit of a University Hospital. PATIENTS AND METHODS: We have studied 668 consecutive patients with their first acute myocardial infarction admitted at the Coronary Care Unit, Hospital General de Galicia, Santiago de Compostela, Spain, in the years 1983 to 1988. Pericarditis was defined as the presence of a pericardial friction rub on auscultation during the hospital course. Pericarditis was noted in 86 patients (12.8%), who were considered as group A. The remain 582 patients were considered as group B. Statistical analysis was carried out using the BMDP statistical package. MAIN RESULTS: Pericarditis occurred in 12.8% of the patients. Patients with, compared to those without, pericarditis had a lower age (59.0 +/- 12.4 years; p = .0005), and a higher percentage of males (86.1% versus 75.6%; p = .038), an a higher percentage of smokers (63.9% versus 48.6%; p = .01). The delay to the hospital admission was greater in group A (12.6 +/- 18.5 hours versus 8.0 +/- 11.7 hours; p = .0024). Pericarditis more often occurred in the setting of anterior wall myocardial infarction and in Q-wave infarct. The group A had a higher CPK peak (1877.5 +/- 1548.9 UI/L versus 1240.2 +/- 961.5 UI/I; p = .001) and a higher peak of CK-MB (213.7 +/- 134.7 UI/L versus 160.8 +/- 112.9 UI/L; p = .001). In-hospital mortality was significantly lower in group A (6.9% versus 17.2%; p = .016). The multivariate analysis by stepwise logistic regression identified the Q- wave myocardial infarct, the age, the delay to the hospital admission, the peak of MB creatine kinase and location of infarct as the only independent predictive variables for the pericarditis occurrence. CONCLUSIONS: We conclude that the pericarditis in the setting of Q-wave myocardial infarction, with anterior wall location, and is related to transmural extension of the myocardial necrosis.     

Long-term prognostic significance of atrioventricular block in inferior acute myocardial infarction

Among 477 consecutive patients admitted for inferior acute myocardial infarction (AMI), 2nd or 3rd degree atrioventricular (AV) block developed in 88 (20%). Compared with the 359 without AV block, these 88 patients presented a higher incidence of Killip class greater than 1 (52% vs 28%, P less than 0.001), pericarditis (30% vs 17%, P less than 0.01), atrial fibrillation (26% vs 11%, P less than 0.01), complete bundle branch block (12% vs 4%, P less than 0.01) and in-hospital mortality (24% vs 4%, P less than 0.001). The 3-year post-hospital mortality was not significantly different in the two groups (12% vs 15%). Among the 88 patients with AV block, those who died at hospital were older (66 +/- 11 vs 59 +/- 11 years, P less than 0.05), had a higher incidence of Killip class greater than 1 (86% vs 42%, P less than 0.001) and bundle branch block (29% vs 7%, P less than 0.05). Thus, patients with inferior AMI who developed AV block had a poor hospital outcome but long-term prognosis was similar in hospital survivors who had AV block and in those without this complication.