Prevalence of ventricular late potentials in patients with obstructive sleep apnea syndrome

BACKGROUND: It is known from various cardiac disorders that the presence of ventricular late potentials (VLP) in the signal-averaged electrocardiogram (ECG) is associated with an increased risk of sudden cardiac death. HYPOTHESIS: In view of the increased cardiovascular mortality of patients with obstructive sleep apnea syndrome (OSAS), we assessed the prevalence of VLP in these patients. METHODS: In all, 118 consecutive patients with polysomnographically verified OSAS were prospectively studied; 21 snorers without evidence of a sleep-related breathing disorder served as a control group. Signal-averaged ECG and 24-h Holter ECG were performed in all patients and controls, and left ventricular function was determined by radionuclide ventriculography in the OSAS group. Furthermore, patients and controls were followed for up to 45.5 months for arrhythmic events, syncopes, or sudden cardiac death. RESULTS: An abnormal signal-averaged ECG was seen in seven patients (5.9%) and in one snorer (4.8%). Patients with and without VLP did not differ with respect to age, body mass index, left ventricular ejection fraction, or ectopic activity in the 24-h Holter ECG, but the former had significantly higher mean (standard deviation) apnea/hypopnea indices [55.4 (25.2)/h vs. 37.4 (22.6)/h; p < 0.05]. Of the 118 patients, 110 could be followed for 26.7 (7.9) months. During this period, two patients had syncopes and one patient had sudden cardiac death. The seven patients with VLP remained free of events during the follow-up period, as did the 21 snorers. CONCLUSIONS: Patients with OSAS have a low prevalence of VLP in the signal-averaged ECG, not exceeding that in normal subjects. Moreover, abnormal signal-averaged ECGs do not appear to be useful as a prognostic marker.     

The prognostic significance of quantitative signal-averaged variables relative to clinical variables, site of myocardial infarction, ejection fraction and ventricular premature beats: a prospective study

A prospective study was undertaken of the prognostic significance of quantitative signal-averaged electrocardiographic (ECG) variables relative to clinical variables, site of myocardial infarction, left ventricular ejection fraction and characteristics of ventricular premature beats in 115 patients (mean age 62 +/- 12 years) studied 10 +/- 6 days after myocardial infarction. Signal-averaged variables included the root mean square voltage of the terminal 40 ms, the duration of the filtered signal-averaged QRS complex and low amplitude signals less than 40 microV determined at 25 and 40 Hz high pass filtering in all patients. Of the 115 patients, 51 (44%) had an abnormal signal-averaged ECG (one or more abnormal signal-averaged variables), 51 (44%) at 25 Hz and 48 (42%) at 40 Hz high pass filtering. A higher proportion of patients with an inferior wall infarction had an abnormal signal-averaged ECG as compared with patients with anterior wall infarction (58% versus 31%). Over a 14 +/- 8 month follow-up period 16 patients (14%) had an arrhythmic event. An abnormal signal-averaged ECG at 40 Hz high pass filtering had a higher sensitivity (81% versus 75%) and specificity (65% versus 61%) than at 25 Hz high pass filtering. The predictive value of the signal-averaged ECG was superior to that of the ejection fraction (40% versus 20%) in anterior wall myocardial infarction, whereas in patients with inferior wall infarction, the predictive values of the two tests were equivalent. The prognostic power of 27 clinical and noninvasive variables was determined with the Cox proportional hazards regression model.(ABSTRACT TRUNCATED AT 250 WORDS)     

Signal-averaged electrocardiography in hypertrophic cardiomyopathy

A major goal in the management of patients with hypertrophic cardiomyopathy is the prediction of sudden death. To evaluate the high gain signal-averaged electrocardiogram (ECG) in this setting, 64 patients with hypertrophic cardiomyopathy and 50 age- and gender-matched control subjects were studied. An abnormal signal-averaged ECG was more common in patients than in control subjects: 13 (20%) of 64 patients with hypertrophic cardiomyopathy had abnormalities compared with 2 (4%) of the 50 control subjects (p less than 0.001). There was a significant association between the presence of nonsustained ventricular tachycardia on 48 h ECG Holter monitoring and the presence of an abnormal signal-averaged ECG: 8 (47%) of the 17 patients with nonsustained ventricular tachycardia and 6 (86%) of 7 patients with more than three episodes of nonsustained ventricular tachycardia per 24 h had signal-averaged ECG abnormalities. There was no association between an abnormal signal-averaged ECG and a family history of premature sudden cardiac death, a history of syncope, symptomatic status, maximal left ventricular wall thickness, the presence of systolic anterior motion of the mitral valve or maximal rate of oxygen uptake on exercise. However, of four patients with a history of cardiac arrest, three had an abnormal signal-averaged ECG. Sensitivity was 50%; specificity was 93% and positive predictive accuracy was 77% for the signal-averaged ECG in detecting patients with electrical instability (defined as a history of cardiac arrest or the presence of nonsustained ventricular tachycardia, or both).(ABSTRACT TRUNCATED AT 250 WORDS)     

A new noninvasive index to predict sustained ventricular tachycardia and sudden death in the first year after myocardial infarction: based on signal-averaged electrocardiogram, radionuclide ejection fraction and Holter monitoring

A prospective study of the prognostic significance of the signal-averaged electrocardiogram (ECG), left ventricular function and 24 hour Holter ECG monitoring was performed in 102 patients (age 63 +/- 11 years) after myocardial infarction. The signal-averaged ECG (40 Hz high pass bidirectional filtering) was obtained 10 +/- 6 days after the acute myocardial infarction and all three tests were performed within 72 hours of each other. Ejection fraction was determined by radionuclide ventriculography. An abnormal signal-averaged ECG was seen in 44% of patients; abnormal ejection fraction (less than 40%) in 52% and high grade ectopic activity (greater than or equal to 10 ventricular premature depolarizations/h or couplets, or nonsustained ventricular tachycardia, or a combination of these) in 62%. During a 12 +/- 6 month follow-up period, 15 patients (14.7%) had an arrhythmic event defined as sustained ventricular tachycardia or sudden cardiac death, or both. The event rates were higher in patients with an abnormal versus a normal signal-averaged ECG (29 versus 3.5%, p = 0.003), an abnormal versus a normal ejection fraction (24 versus 6%, p = 0.001) and the presence versus the absence of high grade ectopic activity (23 versus 9%, p = 0.09). Patients with an abnormal signal-averaged ECG and an abnormal ejection fraction had a significantly higher (p = 0.0007) event rate than did patients in whom both the tests were normal (36 versus 0%; odds ratio 30.1).(ABSTRACT TRUNCATED AT 250 WORDS)     

Prognostic value of an abnormal signal-averaged electrocardiogram in patients with nonischemic dilated cardiomyopathy

The usefulness of an abnormal signal-averaged ECG (SAECG) for the risk stratification of patients with dilated cardiomyopathy was studied prospectively in 76 patients. Multiple analysis showed that an abnormal SAECG predicted cardiac mortality (p = 0.0046), sudden cardiac death, and the need for resuscitation (p = 0.003); however, it did not predict death from heart failure and heart transplantation.     

Signal-Averaged ECG in Noninvasive Assessment of Reperfusion in the Acute Phase of Myocardial Infarction

Background: Coronary artery patency after thrombolytic therapy has important prognostic implications for survival after acute myocardial infarction (Ml). Several noninvasive methods have been tested to assess the effectiveness of thrombolytic therapy. However, the value late potential (LP) analysis from the signal-averaged ECG for assessment of reperfusion has not been established. Methods: In 50 patients (34 males, 16 females, mean age 59 ± 12 years, range, 35 years to 84 years) with acute Ml, signal-averaged ECG recordings were performed using the FD-3 solid-state Holter recorder and analyzed prior to and 1, 2, and 3 hours from the initiation of thrombolytic treatment. Reduction in ST elevation of > 50% compared with baseline values was taken as a marker of successful reperfusion. Results: At 2 hours, 28 (56 %) patients were considered to have successful reperfusion: LPS were not present in any patient with successful reperfusion compared with 8 (36%) patients without reperfusion (P = 0.002). At 3 hours 31 (62 %) patients were considered to have successful reperfusion: 1 (3%) had abnormal signal-averaged ECG versus 6 (35%) patients without reperfusion (P = 0.01). An abnormal signal-averaged ECG identified patients with failed reperfusion with very high specificity and positive predictive value (100% and 100% at 2 hours; 97% and 86% at 3 hours, respectively). Conclusions: Patients with failed reperfusion have abnormal signal-averaged ECGs more frequently than patients with successful reperfusion. Thus, signal-averaged ECG may be helpful for identification of patients without reperfusion who may urgently need invasive treatment or rethrombolysis to restore blood flow in the infarct-related artery. A.N.E. 1999;4(3):301–308     

Prevalence and prognostic significance of exercise-induced silent myocardial ischemia in apparently healthy subjects.

The addition of thallium-201 (201Tl) scintigraphy to traditional exercise electrocardiography (ECG) was assessed to determine whether the combination was a more accurate predictor of future coronary events than exercise ECG alone in an apparently healthy population. There were 407 participants enrolled in the Baltimore Longitudinal Study of Aging. The participants, who had no clinical or resting ECG evidence of coronary artery disease, underwent 201Tl scintigraphy immediately following maximal treadmill exercise. Four subsets of subjects were derived: (1) negative ECG and negative 201Tl; (2) positive ECG and negative 201Tl; (3) negative ECT and positive 201Tl; (4) positive ECG and positive 201Tl. A total of 66 individuals (16%) had positive ECGs and 55 (14%) had positive 201Tl scans. Concordant positive results in both tests were seen in 23 subjects (6%), with a 7-fold increase in prevalence from ages 40-59 years to greater than 80 years. Over a mean follow-up of 4.6 years, cardiac events (angina pectoris, myocardial infarction, or cardiac death) occurred in 40 of 407 volunteers (9.8%). Analysis revealed a 48% incidence of cardiac events in the subset with concordant abnormal ECG and 201Tl test results versus an event rate of 3-12% for the other 3 groups (p less than 0.001). By proportional hazards analysis, age, hypertension, exercise duration, and a concordant positive ECG and 201Tl scan were independent predictors of future coronary events. A concordant abnormal ECG and 201Tl response imparted a 3.6-fold relative event risk. Although not practical for screening the general population, combined exercise ECG and 201Tl scintigraphy warrants further investigation as a diagnostic strategy in high-risk subsets with additional coronary risk factors.     

Spectrum of cardiac involvement in Friedreich's ataxia: Clinical,electrocardiographic and echocardiographic observations

Combined 2-dimensional and M-mode echocardiography was used to assess the cardiac status of 22 patients with Friedreich's ataxia, and the findings were correlated with the clinical and electrocardiographic (ECG) data. Mean age at onset of Friedreich's ataxia was 8 years (range 3 to 18); mean age at echocardiography was 18 years (range 8 to 39). Echocardiographic findings were abnormal in 19 patients (86%). The 3 patients with normal echocardiographic findings did not have cardiac symptoms, but 1 had ECG repolarization abnormalities. Concentric left ventricular (LV) thickening, the most common echocardiographic finding, was found in 15 patients (68%) and in all 15 the papillary muscles were thickened. These 15 patients had ECG repolarization abnormalities and 5 had left-axis deviation; however, only 3 satisfied ECG criteria for LV or right ventricular hypertrophy. Two of the 15 patients (9%) had symptoms of heart failure. Two patients had asymmetric septal thickening without clinical evidence of LV outflow tract obstruction; neither had cardiac symptoms, but both had ECG repolarization abnormalities. Two patients showed a dilated cardiomyopathy pattern; both had heart failure and atrial flutter. One of these patients died, and necropsy revealed 4-chamber cardiac dilatation, biventricular hypertrophy and histologic findings of diffuse interstitial fibrosis, myocellular hypertrophy and necrosis. This study revealed a wide spectrum of cardiac abnormalities in patients with Friedreich's ataxia.     

Postinfarction risk assessment for sudden cardiac death using late potential analysis of the digital Holter electrocardiogram

INTRODUCTION: Noninvasive postinfarction risk assessment for sudden cardiac death is limited. Standard analysis of the signal-averaged QRS complex can identify patients at risk for monomorphic ventricular tachycardia, but its value for discriminating patients at risk for sudden death is low. METHODS AND RESULTS: The aim of this study was to prospectively investigate repeated late potential analysis of digital Holter ECG and compare it with standard analysis of the signal-averaged QRS complex within a short ECG period and with common clinical risk factors for sudden cardiac death in 756 consecutive patients after acute myocardial infarction. Digital Holter ECG were subdivided into 5-minute segments, and late potential analysis was performed on each 5-minute segment. During follow-up of 32 +/- 15 months, 35 patients died of sudden cardiac death and 50 patients died of nonsudden cardiac death. Sudden cardiac death was associated with ejection fraction < 40%, nonsustained ventricular tachycardia, creatine kinase > 1,000 IU/L, and late potentials in > 75% of analyzed Holter ECGs (abnormal LP75), but not with late potentials determined by only a short ECG period. According to multivariate analysis, the best independent significant predictor of sudden cardiac death was abnormal LP75 (P = 0.002, sensitivity 29%, specificity 96%, positive predictive value 40%, negative predictive value 97%). Nonsudden cardiac death was associated with ejection fraction < 40% (P = 0.001). CONCLUSIONS: Late potential analysis of digital Holter ECG is a powerful tool that can be used to determine postinfarction patients at risk for sudden cardiac death and is optimized when combined with determination of ejection fraction.     

Noninvasive predictors of cardiac events after myocardial infarction. Complementary value of exercise testing and signal-averaged electrocardiography

Signal-averaged electrocardiography, resting radionuclide ventriculography and Holter monitoring were performed prior to hospital discharge, to assess their value in predicting recurrent cardiac events in 210 survivors of acute myocardial infarction. In addition, 153 of these patients also underwent exercise radionuclide ventriculographic assessment. During median follow-up of 14 months (6-24 months), there were 16 cardiac deaths, 15 patients had recurrent infarction and 7 patients represented with symptomatic ventricular tachycardia. Cox regression analysis identified independent predictors of 'ischemic events' (death or re-infarction) as a previous history of infarction (p = 0.01), Killip class III-IV (p = 0.03) and an abnormal exercise radionuclide study (p = 0.04); and predictors of 'arrhythmic events' (sustained ventricular tachycardia or sudden death) as an abnormal signal-averaged electrocardiograph (p = 0.01) and left ventricular ejection fraction less than 40% (p = 0.03). Patients with an abnormal signal-averaged electrocardiograph and reduced left ventricular ejection fraction had a 34% incidence of arrhythmic events during the first 6 months compared with a 4% incidence among patients without late potentials. In those patients who underwent exercise testing and signal averaging, 85% of total cardiac events and all cardiac deaths were predicted by an abnormality of either noninvasive test. In addition, exercise testing and signal-averaged ECG were independent predictors of outcome. Hence, using a combination of noninvasive tests, patients can be stratified according to the risk of recurrent life-threatening cardiac events after myocardial infarction; such patients may be suitable for intensive investigation and considered for trials involving active intervention.     

Clinical significance of abnormal electrocardiographic patterns in trained athletes

BACKGROUND-The prevalence, clinical significance, and determinants of abnormal ECG patterns in trained athletes remain largely unresolved. METHODS AND RESULTS-We compared ECG patterns with cardiac morphology (as assessed by echocardiography) in 1005 consecutive athletes (aged 24+/-6 years; 75% male) who were participating in 38 sporting disciplines. ECG patterns were distinctly abnormal in 145 athletes (14%), mildly abnormal in 257 (26%), and normal or with minor alterations in 603 (60%). Structural cardiovascular abnormalities were identified in only 53 athletes (5%). Larger cardiac dimensions were associated with abnormal ECG patterns: left ventricular end-diastolic cavity dimensions were 56. 0+/-5.6, 55.4+/-5.7, and 53.7+/-5.7 mm (P<0.001) and maximum wall thicknesses were 10.1+/-1.4, 9.8+/-1.3, and 9.3+/-1.4 mm (P<0.001) in distinctly abnormal, mildly abnormal, and normal ECGs, respectively. Abnormal ECGs were also most associated with male sex, younger age (<20 years), and endurance sports (cycling, rowing/canoeing, and cross-country skiing). A subset of athletes (5% of the 1005) showed particularly abnormal or bizarre ECG patterns, but no evidence of structural cardiovascular abnormalities or an increase in cardiac dimensions. CONCLUSIONS-Most athletes (60%) in this large cohort had ECGs that were completely normal or showed only minor alterations. A variety of abnormal ECG patterns occurred in 40%; this was usually indicative of physiological cardiac remodeling. A small but important subgroup of athletes without cardiac morphological changes showed striking ECG abnormalities that suggested cardiovascular disease; however, these changes were likely an innocent consequence of long-term, intense athletic training and, therefore, another component of athlete heart syndrome. Such false-positive ECGs represent a potential limitation to routine ECG testing as part of preparticipation screening.     

Noninvasive detection of patients with ischemic and nonischemic heart disease prone to ventricular fibrillation

Abnormalities in the fast Fourier transforms of signal-averaged electrocardiograms (ECGs) obtained during sinus rhythm appear to distinguish patients with ischemic heart disease and sustained monomorphic ventricular tachycardia from those without ventricular tachycardia. This study was performed to determine the power of frequency analysis to detect patients with a history of ventricular fibrillation, to determine the extent to which spectra of signal-averaged ECGs from patients with ischemic and nonischemic heart disease are comparable and to compare results of signal-averaged ECG analysis in patients with ventricular fibrillation with results of programmed ventricular stimulation. Signal-averaged ECGs were obtained during sinus rhythm from 60 patients with sustained ventricular tachycardia (Group I) and 34 patients with ventricular fibrillation (Group II). Results of signal-averaged ECG analysis were abnormal in 92% of patients with ventricular tachycardia and 85% of patients with ventricular fibrillation (p = NS). Abnormal spectra were detected in the signal-averaged ECGs from 90% of patients with ischemic and from 86% of patients with nonischemic heart disease (p = NS). In contrast, the results of programmed stimulation differed markedly between the two patient groups. Sustained ventricular arrhythmias were induced in 91% of the patients with ventricular tachycardia compared with only 46% of those with ventricular fibrillation (p less than 0.0001). Moreover, ventricular tachycardia was inducible in 81% of patients with ischemic heart disease compared with only 50% of those with nonischemic heart disease (p less than 0.02). Thus, abnormalities in the spectra of signal-averaged ECGs were found in the majority of patients with ventricular fibrillation and were detectable even in those whose arrhythmia was not inducible by programmed stimulation. These results broaden the potential clinical application of noninvasive interrogation of signal-averaged ECGs to include the prospective identification of patients with ischemic or nonischemic heart disease prone to ventricular tachycardia or ventricular fibrillation.     

High-resolution ECG in assessment of myocardial functional state in patients with ischemic heart disease and resultant cardiac dilatation

High resolution signal-averaged ECG (SAECG), echocardiography and 24-hour Holter ECG monitoring were used in the study of 30 patients (mean age 56-/+2 years) with coronary heart disease and stable class II-IV angina (group 1) and 66 patients (mean age 45-/+1 years) with dilated cardiomyopathy of ischemic origin (group II). SAECG was used for detection of late ventricular potentials and calculation of time-voltage and velocity parameters of P-waves. Disturbances of myocardial de- and repolarization indicative of pronounced hemodynamic left atrial overload associated with elevated left ventricular end diastolic pressure were revealed. These disturbances were more pronounced in patients of group II. Late ventricular potentials and arrhythmias were more frequent in patients with more severe cardiac failure. Sensitivity of SAECG for detection of arrhythmogenic substrate in the myocardium was 70 and 90% in groups I and II, respectively. Positive predictive power of ventricular late potentials for occurrence of ventricular arrhythmias in these groups was 86 and 91%, respectively.     

Yield of Serial Evaluation in At-Risk Family Members of Patients With ARVD/C

Background

Incomplete penetrance and variable expressivity of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) complicate family screening.

Objectives

The objective of the present study was to determine the optimal approach to longitudinal follow-up regarding: 1) screening interval; and 2) testing strategy in at-risk relatives of ARVD/C patients.

Methods

We included 117 relatives (45% male, age 33.3 ± 16.3 years) from 64 families who were at risk of developing ARVD/C by virtue of their familial predisposition (72% mutation carriers [92% plakophilin-2]; 28% first-degree relatives of a mutation-negative proband). Subjects were evaluated by electrocardiography (ECG), Holter monitoring, signal-averaged ECG, and cardiac magnetic resonance (CMR). Disease progression was defined as the development of a new criterion by the 2010 Task Force Criteria (not the “Hamid criteria”) at last follow-up that was absent at enrollment.

Results

At first evaluation, 43 subjects (37%) fulfilled an ARVD/C diagnosis according to the 2010 Task Force Criteria. Among the remaining 74 subjects (63%), 11 of 37 (30%) with complete re-evaluation experienced disease progression during 4.1 ± 2.3 years of follow-up. Electrical progression (n = 10 [27%], including by ECG [14%], Holter monitoring [11%], or signal-averaged ECG [14%]) was more frequently observed than structural progression (n = 1 [3%] on CMR). All 5 patients (14%) with clinical ARVD/C diagnosis at last follow-up had an abnormal ECG or Holter monitor recording, and the only patient with an abnormal CMR already had an abnormal ECG at enrollment.

Conclusions

Over a mean follow-up of 4 years, our study showed that: 1) almost one-third of at-risk relatives have electrical progression; 2) structural progression is rare; and 3) electrical abnormalities precede detectable structural changes. This information could be valuable in determining family screening protocols.     

Late potentials are unaltered by ventricular filling pressure reduction in heart failure.

Exacerbation of heart failure may increase susceptibility to arrhythmias. Therefore tests to assess the risk of arrhythmia, performed after hemodynamic improvement, may be of limited value. To determine whether hemodynamic improvement alters ventricular late potentials detected by signal-averaged ECG, we studied 27 consecutive patients with dilated heart failure (left ventricular ejection fraction 0.20 +/- 0.06, 15 with coronary artery disease) before and 3 +/- 2 days after tailored vasodilator and diuretic therapy reduced ventricular filling pressures. QRS duration, terminal QRS amplitude (root mean square [RMS]), and low-amplitude (less than 40 microV) signal (LAS) duration were determined by an automated algorithm from the vector magnitude of the QRS high-pass filtered at 25 Hz and at 40 Hz. Despite marked decreases in pulmonary capillary wedge (27 +/- 7 to 16 +/- 5 mm Hg, p less than 0.001) and right atrial (13 +/- 7 to 7 +/- 4 mm Hg, p less than 0.001) pressures and a 20% increase in cardiac output, there was not a significant change in QRS duration, RMS, or LAS. Before and after therapy late potentials, defined as abnormal QRS duration RMS, or LAS, were present in 14 (52%) patients with filtering at 25 Hz and in 22 (81%) patients with filtering at 40 Hz. The signal-averaged ECG after hemodynamic improvement predicted the results during exacerbation of heart failure in all patients. Thus in patients with advanced heart failure the signal-averaged ECG obtained after hemodynamic improvement reflects the findings during exacerbation of heart failure.     

Chronic Chagas' heart disease in the elderly: a clinicopathologic study

A retrospective study of the medical records of our hospital from 1965 to 1985 was carried out to characterize for the first time chronic Chagas' heart disease in the elderly (more than 70 years old). A total of 25 patients (mean age = 76) were suitable for the study. Congestive heart failure, sudden cardiac death, thromboembolism and atypical chest pain were found in 68, 16, 8 and 8% of cases, respectively. Ventricular premature contractions (60%), right bundle branch block (32%), left anterior hemiblock (28%), atrial fibrillation (28%) and right bundle branch block associated with left anterior hemiblock (20%) were the ECG changes most frequently found. A morphological study was performed on 8 (32%) patients. All of them showed cardiac abnormalities, with apical aneurism being detected in 100% of cases. At autopsy, pulmonary embolism was observed in 3(37%) of these patients who presented with congestive heart failure, ventricular premature contractions and/or intraventricular conduction defect and/or atrial fibrillation. Thus, the characteristics of chronic Chagas' heart disease in the elderly are similar to those found in middle-aged patients. We suggest that these patients are important for the study of the pathogenesis of chronic Chagas' heart disease because they may have less aggressive pathophysiologic mechanisms than middle-aged patients.     

The signal-averaged electrocardiogram and ventricular arrhythmias after thrombolysis for acute myocardial infarction

The prevalence of an abnormal signal-averaged electrocardiogram (ECG) and ventricular arrhythmias on 24 h ambulatory electrocardiography was evaluated in 118 patients 13 +/- 2 days after acute myocardial infarction. Group 1 (46 patients) underwent intravenous thrombolysis within 6 h of the onset of symptoms, whereas Group 2 (72 patients) did not. An abnormal signal-averaged ECG was seen in 15% of patients in Group 1 and 21% of those in Group 2 (difference not significant). The number of ventricular premature complexes/h was lower in Group 1 than in Group 2: 2.58 +/- 1.63 versus 7.91 +/- 10.75 (p less than 0.01). However, complex arrhythmias (greater than or equal to 10 ventricular premature complexes/h or ventricular tachycardia) were equally common in Groups 1 and 2 (20% versus 22%, respectively). Their prevalence was similar in patients with or without an abnormal signal-averaged ECG (29% versus 18%, respectively, in Group 1 and 27% versus 21%, respectively, in Group 2). Comparison between patients with (n = 26) or without (n = 20) angiographic patency of the infarct-related coronary artery after thrombolysis showed no significant difference in the prevalence of an abnormal signal-averaged ECG (8% versus 25%, respectively) and complex ventricular arrhythmias (19% versus 20%, respectively). These data suggest that thrombolysis does not affect the prevalence of complex ventricular arrhythmias and an abnormal signal-averaged ECG or their relation after acute myocardial infarction.     

24小时动态心电图在老年心律失常诊断中的应用

目的:分析24小时动态心电图(DCG)在60岁以上老年心律失常诊断中的诊断价值。方法:回顾性分析我院2010年12月~2013年1月,981例老年患者的DCG与常规12导联心电图(ECG)检查结果,对二者结果进行对比分析,评估DCG在心律失常方面的诊断价值。结果:在各种心律失常的总检出率DCG明显高于ECG;在各种心律失常中,房性期前收缩最常见,发生率为90.2%,其次为室性期前收缩,占77.3%。结论:在老年患者心律失常诊断中DCG优于ECG。     

Amyloidosis and cardiac involvement

BACKGROUND: Amyloidosis is a rare disease characterized by the extracellular accumulation of a protein polysaccharide complex: amyloid. Cardiac involvement may occur with or without clinical manifestations, and is considered as a major prognostic factor. AIM OF THE STUDY: Firstly, to analyze the clinical, electrocardiographic, radiological and echocardiographic features in a group of patients with extracardiac biopsy-proven amyloid infiltration and evidence of echocardiographic amyloid heart disease. Secondly, to compare the survival of amyloidosis patients, with or without cardiac involvement. PATIENTS AND METHODS: We retrospectively analyzed the main echocardiographic features of 47 patients with biopsy proven amyloidosis. No clinical, electrocardiographic, radiological or scintigraphic criterium were selective for cardiac involvement. Thirty patients with echographic features of amyloid heart disease were identified and compared to 17 patients without echographic features of amyloid heart disease. RESULTS: Amyloid disease with heart involvement was AL in 25/30 (83%) patients and occurred more commonly in middle age men (mean age: 53+/-11 years). The main clinical presentation was congestive heart failure (59%), but 37% of patients had no clinical cardiac features. The electrocardiogram was abnormal in 86% and the cardiac silhouette was enlarged on chest roentgenogram in 27% of patients. The main echocardiographic findings were: diffuse ventricular wall thickening in 21 patients (70%) and isolated septal wall thickening in 9 patients (30%); restrictive pattern of left ventricular (LV) diastolic function in 17 patients (57%); pericardial effusion in 12 patients (40%); impaired LV systolic function in 8 patients (27%); atrial enlargement in 8 patients (27%); characteristic granular sparkling of LV myocardium in 8 patients (27%); mitral and/or aortic valve thickening in 4 patients (13%). Cardiac symptoms developed in 72% of the non symptomatic patients having echocardiographic evidence of cardiac involvement. Twenty-five patients died during the study period and the death was due to cardiac disease in 76%. Median survival time was 36 months from time of amyloidosis diagnosis, and it was 23 months from time of amyloid myocardiopathy diagnosis. It shortened to 6 months when congestive heart failure appeared. CONCLUSION: Patients with a histologically proven amyloidosis should be examined by echocardiography, because cardiac involvement is frequently found in patients with no clinical symptoms, and non symptomatic patients having echocardiographic evidence of cardiac involvement will almost always develop cardiac symptoms. Survival actuarial study confirms the significant adverse influence of cardiac involvement in amyloidosis.     

Prediction of coronary artery disease in a population of insulin-requiring diabetic patients: results of an 8-year follow-up study

To identify predictors of clinical coronary artery disease, 110 insulin-requiring diabetic patients with no symptoms suggestive of cardiac disease and with a normal resting ECG underwent metabolic and noninvasive cardiovascular screening including a history and physical examination, exercise ECG, M-mode echocardiography, and chemical laboratory testing. During a median follow-up interval of 100 months, 14 of these patients had clinical evidence of coronary artery disease consisting of acute myocardial infarction, sudden cardiac death, or anginal chest pain with angiographic documentation of occlusive coronary artery disease. Baseline variables that were univariately predictive of subsequent clinical coronary disease included age, peak treadmill heart rate, and retinal neovascularization. According to multivariate analysis the peak treadmill heart rate was the single most important predictor of subsequent development of clinical coronary disease. A treadmill ECG result that was either abnormal or inconclusive because of failure to achieve 90% of predicted maximal heart rate identified each patient in whom clinical coronary artery disease developed within 50 months after entry testing. Thus the entry treadmill ECG provided prognostic information not available from the history and physical examination results, but little further prognostic information was provided after the first 50 months of follow-up, suggesting the need for serial testing.