Biomedical subjects

G S Wagner

Publications and source records attributed to G S Wagner.

At least 19 recordsLinked to original sources

PubMed1999

Terminal QRS distortion on admission is better than ST-segment measurements in predicting final infarct size and assessing the Potential effect of thrombolytic therapy in anterior wall acute myocardial infarction.

We assessed predicting final infarct size (using predischarge Selvester score) by 3 electrocardiographic variables in 267 patients with first anterior wall acute myocardial infarction (AMI) undergoing (n = 86) or not undergoing (n = 181) thrombolysis. Patients with previous AMI or inverted T waves in leads with ST elevation were excluded. The sum (sigma) of ST elevation, the number of leads with ST elevation, and the initial electrocardiographic pattern were determined on the admission electrocardiogram (absence (QRS-) or presence (QRS+) of distortion of the terminal portion of the QRS in > or =2 leads (J point > or =0.5 of the R-wave amplitude in leads I, aVL, V4 to V6, or presence of ST elevation without S waves in leads V1 to V3). There was no association between sigmaST elevation and final infarct size in patients who did or did not receive thrombolytic therapy. Analysis of covariance showed that the number of leads with ST elevation (F = 19.6), thrombolysis (F = 25.2), and QRS+ initial pattern (F = 19.5) were all associated with final infarct size (p <0.0001 for all). Among patients who did not receive thrombolytic therapy, the average Selvester score was 19.7+/-9.9 for the QRS- patients and 26.1+/-10.4 for the QRS+ patients (p = 0.02). Among patients who received thrombolytic therapy, the average Selvester score was 11.7+/-9.8 for the QRS- patients and 24.2+/-10.1 for the QRS+ patients (p <0.0001). Thrombolysis reduced final Selvester score only in the QRS- group (p <0.00001), but not in the QRS+ group (p = 0.45). It is concluded that (1) final Selvester score in anterior wall AMI can be predicted by the number of leads with ST elevation, the initial electrocardiographic pattern, and thrombolysis, and (2) thrombolysis reduces final Selvester score only in patients with QRS- pattern.

Adult↗

PubMed1999

Comparison of the roles of the C1a and C1b domains of protein kinase C alpha in ligand induced translocation in NIH 3T3 cells.

To explore the relative roles of the two C1 domains of protein kinase C alpha (PKC alpha) in the response to phorbol esters and related analogs, we mutated the individual C1 domains, expressed the mutated PKC alpha in NIH 3T3 cells, and then examined the ability of ligands to induce its translocation to the membrane. The C1a and C1b domains play equivalent roles for translocation in response to phorbol 12-myristate 13-acetate, mezerein, and (-)octylindolactam V. These results contrast with those previously reported for PKC delta, suggesting that the domains play different roles in different PKC isoforms.

3T3 Cells↗

PubMed1999

Combined historical and electrocardiographic timing of acute anterior and inferior myocardial infarcts for prediction of reperfusion achievable size limitation.

The historical time of acute symptom onset is not always an accurate indication of the timing of onset of an acute myocardial infarction (AMI). Consideration of electrocardiographic (ECG) timing parameters could supplement historical timing alone as a clinical guide for decisions regarding the use of reperfusion therapy. Three hundred ninety-five patients from 4 trials of thrombolytic therapy conducted in the northwestern United States and western Canada are included in the present study. A total of 316 patients received either streptokinase or tissue plasminogen activator, and 79 received no reperfusion therapy. Historical time of symptom onset was acquired by emergency or cardiology department personnel and recorded on patient report forms. An ECG method for estimating the timing of the AMI, the Anderson-Wilkins (AW) acuteness score, was calculated from the initial standard 12-lead recording by investigators blinded to the knowledge of symptom duration or any other study variables. Tomographic thallium-201 imaging 7 weeks after hospital admission was used to measure final AMI size. The ECG timing method achieved a relation with final AMI size similar to that previously reported for historical timing. The AW acuteness score proved most useful for anterior AMI location when there was a > or = 2 hour delay following symptom onset, but was most useful for the inferior AMI location when there was a < 2 hour delay. Despite a longer delay, patients with high AW acuteness scores had 50% lower final anterior AMI size than those with low scores; and despite a shorter delay, those with low ECG acuteness scores had 50% greater final inferior AMI size than those with high scores. The AW acuteness score combined with the historical estimation of symptom duration should provide a more accurate basis for predicting the potential for limitation of final AMI size than either method alone. These results could potentially provide the basis for developing a new method for noninvasive guidance of clinical decisions regarding administration of reperfusion therapy in the initial evaluation of patients with AMI.

Electrocardiography↗

PubMed1999

Effects of revascularization after first acute myocardial infarction on the evolution of QRS complex changes (the DANAMI trial). DANish Trial in Acute Myocardial Infarction.

The changes in QRS complex morphology associated with acute myocardial infarction (AMI) can resolve spontaneously over time. Whether complete revascularization of the infarct-related myocardial territory after AMI affects this QRS resolution has not been studied adequately. The present study compares the evolution of the changes in the QRS complex associated with AMI during 1-year follow-up in patients treated with or without revascularization after their first thrombolyzed AMI. The study is a substudy of the DANish Trial in Acute Myocardial Infarction (DANAMI) (n = 1,008) that randomized patients with inducible ischemia after their first AMI, treated with intravenous thrombolytic therapy, to conservative treatment or coronary angiography followed by the appropriate revascularization strategy. A total of 817 patients had complete sets of evaluable electrocardiograms. Electrocardiograms were obtained at randomization, and at 3, 6, and 12 months of follow-up and subjected to blinded core-laboratory evaluation according to the Selvester QRS scoring method. This score considers Q-, R-, and S-wave duration and ratios to provide a semiquantitative estimate of AMI size. The median electrocardiographic estimated infarct size in the entire population was 15% of the left ventricle at randomization. At the end of the follow-up period this estimate had decreased to 12% (p < 0.00001). There was no difference in the rate of QRS resolution whether the patients were subgrouped according to randomization or subgrouped according to actual treatment with or without revascularization. The present study confirms the findings from previous studies conducted in the prethrombolytic era, that considerable normalization of the QRS complex also occurs after AMI treated with thrombolytic therapy. This QRS normalization seems unaffected by an aggressive treatment strategy with revascularization via balloon angioplasty or bypass surgery.

Adult↗

PubMed1999

Correlation of angiographic findings and right (V1 to V3) versus left (V4 to V6) precordial ST-segment depression in inferior wall acute myocardial infarction.

This study assessed whether differences in the underlying mechanisms for various patterns of precordial ST-segment depression with inferior acute myocardial infarction (AMI) are associated with poorer prognoses. We studied 1,155 patients with inferior AMI who underwent thrombolysis in the Global Utilization of Streptokinase and TPA for Occluded arteries (GUSTO-I) angiographic substudy: those without precordial ST depression (n = 412; 35.7%), those with maximum ST depression in leads V1 to V3 (n = 547; 47.4%), and those with maximum ST depression in leads V4 to V6 (n = 196; 17.0%) on admission electrocardiogram. We compared the infarct-related artery, presence of left anterior descending or multivessel coronary artery disease, and left ventricular function among groups. Patients with maximum ST depression in leads V4 to V6 more often had 3-vessel disease (26.0%) than those without precordial ST depression (13.5%) or those with ST depression in leads V1 to V3 (15.7%; p = 0.002), and they had a lower ejection fraction (median 54% vs 60% and 55%, respectively; p <0.001). Patients with maximum ST depression in leads V1 to V3 less often had AMIs due to proximal right coronary artery obstruction (23.9%) than patients without precordial ST depression (35.2%) or those with ST depression in leads V4 to V6 (40.0%; p = 0.001) and had larger AMIs as estimated by peak creatine kinase. Different patterns of precordial ST depression are associated with distinctive coronary anatomy. ST depression in leads V4 to V6, but not V1 to V3, confers a greater likelihood of multivessel coronary artery disease.

Acute Disease↗

PubMed1999

Evaluation of the efficacy of hand-held computer screens for cardiologists' interpretations of 12-lead electrocardiograms.

BACKGROUND: Newly designed computer-based applications and the development of wireless technology have allowed the transmission of 12-lead electrocardiogram (ECG) waveforms from remote locations to the hand-held computers of cardiologists. If these computer ECGs can be reliably interpreted, then the time to treatment for cardiac patients may be reduced. METHODS AND RESULTS: Twenty classic examples of cardiac abnormalities were chosen to test the efficacy of the hand-held computer's liquid crystal display (LCD) screen in the interpretation of 12-lead ECGs. Ten cardiologists interpreted these 20 ECGs on the hand-held computers and then twice later on traditional printed paper. The control intraobserver agreement between the sets of paper-displayed ECGs was measured against the agreement between each of the paper sets and the LCD-displayed set of ECGs. Eighty-nine percent (178/200) of the ECGs were interpreted identically by the participants between the 2 paper sets. When comparing the interpretations of the LCD-displayed ECGs with those of each of the paper sets of ECGs, 88.0% (176/200) and 87.5% (175/200) of identical diagnoses were noted. These differences of 1.0% and 1.5% in intraobserver agreement between paper-to-paper and each of the 2 paper-to-LCD comparisons were not significant (P =.75 and P =.88, respectively). CONCLUSIONS: The strong intraobserver agreement shows that cardiologists make the same diagnoses when viewing LCD-displayed ECGs as they do when viewing paper-displayed ECGs. A study to measure the intraobserver agreement of the decision regarding administration of reperfusion therapy after interpretation of ECGs of patients with acute chest pain is now underway.

Data Display↗

PubMed1999

Attribution of responsibility for injury and long-term outcome of patients with paralytic spinal cord trauma.

STUDY DESIGN: Survey. OBJECTIVE: To assess the association between patients' perceptions of responsibility for the injury and long term outcomes. SETTING: Duke University Medical Center Spinal Injury Service. METHODS: One hundred and forty patients, who suffered spinal cord injuries between 1985 and 1990, were selected to participate in the study, and 26 (19%), including eight with quadriplegia, completed a telephone interview. The mean age at interview was 39+/-12 years and 12% were women. The mean time from injury to completion of the study was 8.7+/-1.5 years. Attribution of cause of injury, the Craig Handicap Assessment Reporting Technique, and the SF36 mental health depression/vitality surveyed instruments attribution of responsibility for the injury, functional capacity, mental health depression, and vitality. RESULTS: The majority (18/26) of patients either totally blamed themselves or others for their injuries. Overall, there was no statistically significant association between attribution of injury and long-term outcomes. Outcomes were similar in patients who either totally blamed themselves or others for their predicament. CONCLUSION: In this study, long-term outcomes were not influenced by whether patients perceived themselves as being responsible for their injuries.

Activities of Daily Living↗

PubMed1999

Reduction of myocardial damage by prolonged treatment with subcutaneous low molecular weight heparin in unstable coronary artery disease. FRISC study group. Fragmin during Instability in Coronary Artery Disease.

AIMS: Several studies have proved heparin useful in treating patients with unstable coronary artery disease. The present study investigates whether Selvester QRS scoring for estimation of myocardial infarct size increases the incidence of detection of acute myocardial infarction during follow-up in a trial of patients with unstable angina/non-Q wave myocardial infarction treated with low molecular weight heparin or placebo. Finally it will be discussed how the QRS score, used for end-point identification, impacts on the power calculation in clinical trials. METHODS AND RESULTS: Electrocardiographic data on 1276 patients (644 in the placebo group, 632 in the low molecular weight heparin treatment group) were available. All ECGs were scored according to the Selvester QRS scoring method. At 40 days, more patients in the placebo than in the heparin group had achieved a threshold level of QRS score (25.9% vs 21.1%, P=0.05). Myocardial infarction, diagnosed as per the classic Q wave criteria, occurred in 3.7% of patients in the placebo group and in 0.9% in the low molecular weight heparin group at 6 days (P=0.002). At 40 days, the rates were 8.2% (placebo) and 5.7% (low molecular weight heparin, P=0.2). By combining the classic criteria with the Selvester method the myocardial infarction end-point rate in both groups was almost doubled (8.2% to 14.4% in the placebo group and 5.7% to 11.1% in the low molecular weight heparin group, P=0.07). The 216 patients with non-evaluable electrocardiograms did not differ from the 1276 patients as regards baseline characteristics; however, they had a significantly poorer prognosis, with a death/myocardial infarction rate of 20% at 40 days, compared with 8% among the patients with evaluable electrocardiograms (P<0.00001). CONCLUSION: Long-term subcutaneous treatment with low molecular weight heparin decreases the number of subsequent myocardial infarctions - determined both conventionally and by an increase in QRS score - in patients with unstable coronary artery disease. Silent myocardial infarctions detected by QRS score, as well as clinical myocardial infarctions, could be used as end-points in clinical trials of ischaemic heart disease and thus lower the population needed for obtaining statistical power.

Aged↗

PubMed1998

Predictors of in-hospital bundle branch block reversion after presenting with acute myocardial infarction and bundle branch block. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries.

Patients with acute myocardial infarction and bundle branch block have a higher mortality rate and more in-hospital complications than patients with normal intraventricular conduction. Patients whose conduction defects revert have an improved prognosis (with outcomes similar to patients who never develop bundle branch block); thus, we analyzed potential predictors of bundle branch block reversion.

Aged↗

PubMed1998

Higher T-wave amplitude associated with better prognosis in patients receiving thrombolytic therapy for acute myocardial infarction (a GUSTO-I substudy). Global Utilization of Streptokinase and Tissue plasminogen Activator for Occluded Coronary Arteries.

Increased T-wave amplitude is one of the earliest electrocardiographic (ECG) changes following coronary artery occlusion. Therefore, higher T waves in the presenting electrocardiogram should represent earlier time to treatment and thus be associated with lower mortality following thrombolytic therapy. However, T-wave amplitude has never been evaluated as a prognostic marker in this setting. We examined clinical outcomes in 3,317 patients with acute myocardial infarction (AMI) who underwent thrombolysis in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) Study. Patients were classified as either those with high T waves or those with low T waves. Higher T waves were defined as those >98th percentile of the upper limit of normal. T-wave amplitude was also evaluated as a continuous variable according to infarct location (maximum T-wave amplitude) and as the amount of excess T-wave amplitude above normal (excess T-wave amplitude). Patients with higher T waves had lower 30-day mortality than those without (5.2% vs 8.6%, p = 0.001) and were less likely to develop congestive heart failure (15% vs 24%, p <0.001) or cardiogenic shock (6.1% vs 8.6%, p = 0.023). Higher maximum T-wave amplitude and excess T-wave amplitude were predictive of lower 30-day mortality (chi-square = 67, p <0.001 and chi-square = 33, p <0.001, respectively). These differences remain significant after controlling for other prognostic baseline ECG variables. In addition, T-wave amplitude added prognostic significance after controlling for time to treatment. T-wave amplitude, an often-overlooked component of the electrocardiogram, can add significant prognostic information in initial evaluation of patients with AMI.

Aged↗

PubMed1998

Comparison of the various electrocardiographic scoring codes for estimating anatomically documented sizes of single and multiple infarcts of the left ventricle.

It is clinically important to estimate the size of a myocardial infarction (MI) to predict patient prognosis, to determine the ability of a therapy to limit its size, and to evaluate its effect on left ventricular function. Various electrocardiographic methods have been used for these purposes but their accuracies have not been compared with each other using an identical reference population of anatomically measured infarcts. The capability of 4 electrocardiographic scoring methods (the Selvester score, the Minnesota code, the Novacode, and the Cardiac Infarction Injury Score) to estimate MI size was compared using anatomic MI size in a group of 100 deceased patients. All patients had a standard 12-lead electrocardiogram of sufficient quality to perform manual waveform measurements and without confounding factors such as ventricular hypertrophy, fascicular block, or bundle branch block. The location and size of the left ventricular infarction was measured postmortem using the anatomic method of Ideker et al. All methods' size estimates correlated best with anatomic MI size in the anterior location (r = 0.65 to 0.89). The Selvester score was superior in estimating the sizes of inferior (r = 0.70) and posterolateral (r = 0.74) infarcts. For multiple infarcts all methods performed poorly (r = 0.18 to 0.44).

Electrocardiography↗

PubMed1998

Differential selectivity of ligands for the C1a and C1b phorbol ester binding domains of protein kinase Cdelta: possible correlation with tumor-promoting activity.

Protein kinase C (PKC) represents the major, high-affinity receptor for the phorbol esters as well as for a series of structurally diverse natural products. The phorbol esters function by binding to the tandem C1a and C1b domains in PKC, leading to enzyme activation. Although the typical phorbol esters represent the paradigm for tumor promoters in mouse skin, it is now clear that different high affinity ligands for PKC have distinct biological effects. Thus, the daphnane analogue mezerein is a second-stage promoter, the macrolide bryostatin 1 is a partial antagonist, and certain 12-deoxyphorbol 13-monoesters also function as partial antagonists but with a different pattern of activity. The biochemical basis for these differences is an area of active investigation. In this report, we have examined the relative interaction of ligands differing in structure and pattern of biological response with the C1a and C1b domains of PKCdelta. We mutated either or both of the C1 domains of PKCdelta, expressed the constructs in NIH 3T3 cells, and monitored the interaction of the ligands by their ability to induce translocation of the mutated PKCdelta from the cytosol to the particulate fraction. We found that different ligands showed different dependence on the C1a and C1b domains for translocation. Whereas phorbol 12-myristate 13-acetate and the indole alkaloids indolactam and octylindolactam were selectively dependent on the C1b domain, selectivity was not observed for mezerein, for the 12-deoxyphorbol 13-monoesters prostratin or 12-deoxyphorbol 13-phenylacetate, or for the macrocyclic lactone bryostatin 1. Provocatively, the pattern of response corresponds with the activity of the compounds as complete tumor promoters.

3T3 Cells↗

PubMed1998

Non-Q-wave versus Q-wave myocardial infarction after thrombolytic therapy: angiographic and prognostic insights from the global utilization of streptokinase and tissue plasminogen activator for occluded coronary arteries-I angiographic substudy. GUSTO-I Angiographic Investigators.

BACKGROUND: Although the stratification of patients with myocardial infarction into ECG subsets based on the presence or absence of new Q waves has important clinical and prognostic utility, systematic evaluation of the impact of thrombolytic therapy on the subsequent development and prognosis of non-Q-wave infarction has been limited to date. METHODS AND RESULTS: We examined 12-lead ECG, coronary anatomy, left ventricular function, and mortality among 2046 patients with ST-segment elevation infarction from the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries angiographic subset to gain further insight into the pathophysiology and prognosis of Q- versus non-Q-wave infarction in the thrombolytic era. Non-Q-wave infarction developed in 409 patients (20%) after thrombolytic therapy. Compared with Q-wave patients, non-Q-wave patients were more likely to present with lesser ST-segment elevation in a nonanterior location. The infarct-related artery in non-Q-wave patients was more likely to be nonanterior (67% versus 58%, P=.012) and distally located (33% versus 39%, P=.021). Early (90-minute, 77% versus 65%, P=.001) and complete (54% versus 44%, P<.001) infarct-related artery patency was greater among the non-Q-wave group. Non-Q-wave patients had better global (ejection fraction, 66% versus 57%; P<.0001) and regional left ventricular function (10 versus 24 abnormal chords, P=.0001). In-hospital, 30-day, 1-year, and 2-year (6.3% versus 10.1%, P=.02) mortality rates were lower among non-Q-wave patients. CONCLUSIONS: The excellent prognosis among the subgroup of patients who develop non-Q-wave infarction after thrombolysis is related to early, complete, and sustained infarct-related artery patency with resultant limitation of left ventricular infarction and dysfunction.

Aged↗

PubMed1998

Prognostic significance of the initial electrocardiogram in patients with acute myocardial infarction. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries.

CONTEXT: Early risk stratification of patients with myocardial infarction is critical to determine optimum treatment strategies and enhance outcomes, but knowledge of the prognostic importance of the initial electrocardiogram (ECG) is limited. OBJECTIVE: To assess the independent value of the initial ECG for short-term risk stratification after acute myocardial infarction. DESIGN: Retrospective analysis of the Global Utilization of Streptokinase and t-PA (alteplase) for Occluded Coronary Arteries (GUSTO-I) clinical trial database. SETTING: A total of 1081 hospitals in 15 countries. PATIENTS: From the 41 021 patients enrolled in the overall study, we selected those who presented within 6 hours of chest pain onset with ST-segment elevation and no confounding factors (paced rhythms, ventricular rhythms, or left bundle-branch block) on the ECG performed before thrombolysis was administered (n=34 166). MAIN OUTCOME MEASURE: Ability of initial ECG to predict all-cause mortality at 30 days. RESULTS: Most ECG variables were associated with 30-day mortality in a univariable analysis. In a multivariable analysis combining the initial ECG variables and clinical predictors of mortality, the sum of the absolute ST-segment deviation (both ST elevation and ST depression: odds ratio [OR], 1.53; 95% confidence interval [CI], 1.38-1.69), ECG, heart rate (OR, 1.49; 95% CI, 1.41-1.59), QRS duration (for anterior infarct: OR, 1.55; 95% CI, 1.43-1.68), and ECG evidence of prior infarction (for new inferior infarct: OR, 2.47; 95% CI, 2.02-3.00) were the strongest ECG predictors of mortality. A nomogram based on the multivariable model produced excellent discrimination of 30-day mortality (C-index, 0.830). CONCLUSIONS: In patients presenting with myocardial infarction accompanied by ST-segment elevation, components of the initial ECG help predict 30-day mortality. This information should be valuable in early risk stratification, when the opportunity to reduce mortality is greatest, and may help in assessing outcomes adjusted for patient risk.

Aged↗

PubMed1998

Implementation of a computerized cardiovascular information system in a private hospital setting.

BACKGROUND: The use of clinical databases improves quality of care, reduces operating costs, helps secure managed care contracts, and assists in clinical research. Because of the large physician input required to maintain these systems, private institutions have often found them difficult to implement. At LDS Hospital in Salt Lake City, Utah, we developed a cardiovascular information system (LDS-CIS) patterned after the Duke University Cardiovascular Database and designed for ease of use in a private hospital setting. METHODS: Features of the LDS-CIS include concise single-page report forms, a relational database engine that is easily queried, automatic generation of final procedure reports, and merging of all data with the hospital's existing information system. So far, data from more than 14,000 patients have been entered. RESULTS: LDS-CIS provides access to data for research to improve patient care. For example, by using data generated by LDS-CIS, the policy requiring surgical backup during percutaneous transluminal coronary angioplasty was eliminated, resulting in no increased patient risk while saving nearly $1 million in 1 year. LDS-CIS generates physician feedback reports documenting performance compared with peers. This physician self-evaluation has standardized and improved care. Information from LDS-CIS has been instrumental in securing and maintaining managed care contracts. LDS-CIS risk analysis provides physicians with outcomes data specific to their current patient's demographics and level of disease to assist in point of care decisions. CONCLUSION: The use of LDS-CIS in the routine operations of LDS Hospital heart services has been found to be feasible, beneficial, and cost-effective.

Cardiac Catheterization↗

PubMed1998

Acute myocardial infarction and complete bundle branch block at hospital admission: clinical characteristics and outcome in the thrombolytic era. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for Occluded Coronary Arteries.

OBJECTIVES: We sought to assess the outcome of patients with acute myocardial infarction (MI) and bundle branch block in the thrombolytic era. BACKGROUND: Studies of patients with acute MI and bundle branch block have reported high mortality rates and poor overall prognosis. METHODS: The North American population with acute MI and bundle branch block enrolled in the Global Utilization of Streptokinase and t-PA [tissue-type plasminogen activator] for Occluded Coronary Arteries (GUSTO-I) trial was matched by age and Killip class with an equal number of GUSTO-I patients without conduction defects. RESULTS: Of all 26,003 North American patients in GUSTO-I, 420 (1.6%) had left (n = 131) or right (n = 289) bundle branch block. These patients had higher 30-day mortality rates than matched control subjects (18% vs. 11%, p = 0.003, odds ratio [OR] 1.8) and were more likely to experience cardiogenic shock (19% vs. 11%, p = 0.008, OR 1.78) or atrioventricular block/asystole (30% vs. 19%, p < 0.012, OR 1.57) and to require ventricular pacing (18% vs. 11%, p = 0.006, OR 1.73). Bundle branch block also carried an independent 53% higher risk for 30-day mortality. Thirty-day mortality rates for patients with complete, partial and no reversion of the bundle branch block were 8%, 12% and 20%, respectively (two-tailed chi-square test for trend 5.61, p = 0.02, OR 0.34 for complete reversion, OR 0.55 for partial reversion). CONCLUSIONS: Bundle branch block at hospital admission in patients with acute MI predicts in-hospital complications and poor short-term survival.

Aged↗

PubMed1998

Electrocardiographic changes during prolonged coronary artery occlusion in man: comparison of standard and high-frequency recordings.

Detection of acute myocardial ischaemia using electrocardiographic methods is generally based on assessment of the ST segments in the standard 12-lead electrocardiogram (ECG). Several studies have also shown changes in high-frequency QRS components during acute ischaemia. The purpose of the present study was to determine the changes in high-frequency QRS components during prolonged percutaneous transluminal coronary angioplasty (PTCA) and to compare these changes with ST-segment deviations in the standard 12-lead ECG. The study population consisted of 19 patients receiving prolonged PTCA. Standard and high-resolution signal-averaged ECGs were recorded before and during balloon inflation. The high-resolution recordings were performed using bipolar X, Y and Z leads. The QRS complexes in the high-resolution signal-averaged ECGs were analysed within a bandwidth of 150-250 Hz. During inflation, significant reductions in high-frequency QRS components were observed (12-72%). Changes in the high-frequency QRS components were seen in four of the patients without ST-segments deviation in the standard ECG. The correlation between the ST-segment deviation and the reduction in high-frequency QRS components was weak (r = 0.27). Acute coronary artery occlusion produces changes in high-frequency QRS components, even in the absence of ST-segment deviation in the standard ECG. Further studies need to be carried out to evaluate whether analysis of high-frequency QRS components could provide a method for detecting myocardial ischaemia and give additional information to that available in the ST segment in the standard ECG.

Adult↗

PubMed1998

Specificity of electrocardiographic myocardial infarction screening criteria in patients with nonischemic cardiomyopathies.

BACKGROUND: The 32-point, 54-criteria Selvester QRS scoring system has been successfully used to estimate the size of nonacute myocardial infarction (MI). Three criteria of the system have been shown to be sensitive for the identification of nonacute MI and specific in normal control subjects. The validity of the system has not been tested in patients with cardiomyopathy of nonischemic origin. The purpose of this study was to examine the electrocardiographs (ECGs) of patients with abnormal left ventricular function but no presence of coronary disease to determine the diagnostic specificity of the MI screening criteria subset of the Selvester QRS scoring system. METHODS AND RESULTS: Six hundred ninety patients were considered. Exclusion criteria included age <10 years, cardiac transplantation, thrombolytic therapy, any angiographic evidence of coronary disease, left ventricular ejection fraction (LVEF) >60%, or history of myocardial revascularization. ECG exclusion criteria included left ventricular hypertrophy, right ventricular hypertrophy, left bundle branch block, right bundle branch block, ventricular pacing, left anterior fascicular block, left posterior fascicular block, ventricular preexcitation, and low voltage, because these confounding factors could mimic an infarct on the ECG. The 261 remaining patients were then examined for the presence of the MI screening criteria subset: (1) inferior location: Q > or =30 msec in aVF, (2) anterior location: either any Q or R< or =0.1 mV and < or =10 msec in V2, and (3) posterior location: R> or =40 msec in V1. Thirty-two of the 261 patients falsely met at least 1 of the 3 MI screening criteria, resulting in an overall specificity of 88% (vs 95% in normal control subjects, P=.0006). A specificity of 98% (n = 256) was achieved for the inferior MI screening criterion alone, whereas the anterior and posterior MI screening criteria alone achieved significantly lower specificities: 94% (n = 245) and 95% (n = 249), respectively. When the patient population was divided into LVEF <30% and LVEF > or =30%, no significant association was found between MI screening criteria and LVEF with specificities of 87% and 88%, respectively, for the 2 groups (P= .34). CONCLUSIONS: The MI screening criteria subset is relatively specific in patients with nonischemic cardiomyopathy, falsely identifying only 12% with nonacute MI. However, this specificity is lower than the 95% achieved in normal subjects. Regional accumulation of scarring caused by cardiomyopathy could result in false-positive indication of MI in the present population. Another possibility could be that some patients could have hypertrophy of the myocardium insufficient to produce positive ECG criteria for left ventricular hypertrophy or right ventricular hypertrophy but sufficient to mimic infarction.

Adult↗