Search

Objective The aim of this study was to determine whether resting ST-T wave abnormalities (ST-Ta) provide incremental prognostic information in patients with no history of coronary artery disease undergoing dobutamine stress echocardiography (DSE). Methods We evaluated 1308 consecutive patients without previous myocardial infarction (MI) or revascularization who underwent DSE. Ischemia was defined as new or worsening wall motion abnormalities. End points during follow-up were all-cause death and cardiac death/nonfatal MI. Results ST-Ta were detected in 162 (12%) patients. The incidence of ischemia was higher in patients with baseline ST-Ta than patients without [74 (46%) vs. 327 (28%), P = 0.00001]. During a follow-up of 4.6 +/- 3 years, cardiac death/nonfatal MI occurred in 42 (26%) patients with resting ST-Ta and in 157 (14%) patients without resting ST-Ta (P < 0.001). Patients with ST-Ta had a higher annual cardiac death/nonfatal MI rate compared with patients without, both in the presence of normal DSE (3.2 vs. 1.4%, P = 0.01) as well as abnormal DSE (5.3 vs. 3%, P < 0.001). In a Cox proportional modeling, resting ST-Ta added incremental value over clinical and stress echocardiographic data for the prediction of death (global chi(2) 125, 140, 150, respectively; P < 0.05) and cardiac death/nonfatal MI (global chi(2) 79, 100, 111, respectively; P < 0.05). Conclusion Baseline ST-Ta are associated with an increased risk of cardiac death/nonfatal MI and all-cause mortality, incremental to clinical data and DSE results. The associated risk is persistent among patients with normal DSE. Coron Artery Dis 22:559-564 (C) 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Objective To investigate the association between (cardiac) mortality and spatial QRS-T angle in patients undergoing dobutamine - atropine stress echocardiography (DSE) for evaluation of known or suspected coronary disease. Methods Between 1990 and 2003, 2347 patients underwent DSE for evaluation of coronary disease at the Erasmus Medical Center. Echocardiographic images were analyzed offline using a 16-segment, 5-point scoring model for regional function. Twelve-lead resting ECGs were analyzed and patients were grouped in three categories according to their spatial QRS-T angle: normal (0-105 degrees), borderline (105-135 degrees), and abnormal (135-180 degrees). Results Mean age was 61 +/- 13 years, 66% were male, 32% had hypertension, 26% had hypercholesterolemia, 28% were smokers, and 12% were diabetic. During a mean follow-up of 7 +/- 3.4 years, 26.5% (623) of the patients died; 15.3% (359) died due to a cardiac cause. Abnormal QRS-T angle (135-180 degrees) was present in 21% of the patients. Abnormal QRS-T angle was a predictor of cardiac death [ hazard ratio: 3.2 (2.6-4.1)] and all-cause mortality [hazard ratio: 2.2 (1.8-2.6)]. After multivariate analysis abnormal and borderline QRS-T angle, peak wall motion score, age, male sex, history of diabetes, history of heart failure, smoking, and hypertension were independent predictors of (cardiac) death. Conclusion Abnormal QRS-T angle is an independent predictor of (cardiac) death in patients undergoing DSE. Abnormal QRS-T angle should be considered as a risk factor in stable patients evaluated for coronary disease. Coron Artery Dis 21:26-32 (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT center dot A large number of drugs can prolong the QTc interval on the electrocardiogram (ECG). center dot Clinical decision support systems may generate drug safety alerts on QTc prolongation. center dot Drug safety alerts are frequently overridden. WHAT THIS STUDY ADDS center dot QTc alert overriding does rarely result in ECG recordings. center dot ECGs before and after QTc overrides reveal clinically relevant QTc prolongation. To investigate whether, in patients in whom drug-drug interaction (DDI) alerts on QTc prolongation were overridden, the physician had requested an electrocardiogram (ECG), and if these ECGs showed clinically relevant QTc prolongation. For all patients with overridden DDI alerts on QTc prolongation during 6 months, data on risk factors for QT prolongation, drug class and ECGs were collected from the medical record. Patients with ventricular pacemakers, patients treated on an outpatient basis, and patients using the low-risk combination of cotrimoxazole and tacrolimus were excluded. The magnitude of the effect on the QTc interval was calculated if ECGs before and after overriding were available. Changes of the QTc interval in these cases were compared with those of a control group using one QTc-prolonging drug. In 33% of all patients with overridden QTc alerts an ECG was recorded within 1 month. ECGs were more often recorded in patients with more risk factors for QTc prolongation and with more QTc overrides. ECGs before and after the QTc override were available in 29% of patients. Thirty-one percent of patients in this group showed clinically relevant QTc prolongation with increased risk of torsades de pointes or ventricular arrhythmias. The average change in QTc interval was +31 ms for cases and -4 ms for controls. Overriding the high-level DDI alerts on QTc prolongation rarely resulted in the preferred approach to subsequently record an ECG. If ECGs were recorded before and after QTc overrides, clinically relevant QTc prolongation was found in one-third of cases. ECG recording after overriding QTc alerts should be encouraged to prevent adverse events.

Aim: The aim of the study was to simultaneously test the EASI lead system and two other derived ECG methods against the standard 12-lead ECG during percutaneous coronary intervention (PCI). Methods: During 44 percutaneous coronary interventions, a simultaneously recorded 12-lead and EASI ECG were marked at the start of the PCI (baseline) and at known ischemia caused by balloon inflation (peak). ST deviations were measured 60 ms after the J point at baseline and peak in all leads and were summated (SUMST) to assess overall changes. For regional changes, the lead with the highest ST deviation (PEAKST) was marked. For each patient, derived 12-lead ECGs were computed from the EASI leads and a lead subset using patient-specific coefficients (PS) and coefficients based on a patient population (GEN). Absolute differences were computed between each derived and routine ECG for SUMST and PEAKST. Results: SUMST was at baseline 567 mu V (range: 150-1707) and increased at peak to 871 mu V (range: 350-2101). SUMST difference at peak was for EASI: 163 mu V (CI: 90-236, P

This study was designed to assess the functional and prognostic significance of left anterior hemiblock (LAHB) in patients with no history of myocardial infarction referred for dobutamine stress echocardiography (DSE). BACKGROUND: The significance of isolated LAHB in patients with suspected coronary artery disease (CAD) is unclear. METHODS: We studied 1,187 patients with suspected CAD and no history of myocardial infarction who underwent DSE and were followed for occurrence of cardiac death. RESULTS: Left anterior hemiblock was detected on baseline electrocardiogram in 159 patients (13%). Ischemia occurred more frequently in patients with LAHB (43% vs. 33%, p = 0.02). During a mean follow-up of 5.0 +/- 2.5 years, 125 patients (11%) died of cardiac causes. The annual cardiac death rate was 4.9% in patients with LAHB and 1.9% for patients without (p < 0.0001). Patients with both LAHB and an abnormal DSE had the highest annual cardiac death rate (6.3%). In a Cox multivariable analysis, independent predictors of cardiac death were age, smoking, history of heart failure, diabetes, and ischemia. Left anterior hemiblock was independently associated with increased risk of cardiac death among patients with normal DSE (hazard ratio 1.8, 95% confidence interval 1.1 to 3.8) and in patients with abnormal DSE (hazard ratio 1.7, 95% confidence interval 1.1 to 2.7). CONCLUSIONS: In patients with suspected CAD referred for stress testing, LAHB is associated with increased risk of cardiac death. This risk is persistent after adjustment for major clinical data and abnormalities on the stress echocardiogram. Therefore, isolated LAHB should not be considered a benign electrocardiographic abnormality in these patients.

Twelve-lead ST-segment monitoring is a widely used tool for capturing focal ischemia and transient intermittent episodes. However, continuous registration of all 10 electrodes is impractical in clinical settings. This study investigated the accuracy of 2 derived 12-lead strategies that required 6 electrodes, including all limb leads, and 2 precordial leads by using population-based (generalized) and individualized (patient-specific) reconstruction coefficients to derive the additional 4 chest leads. A total of 26,880 simultaneous digital conventional 12-lead generalized and patient-specific electrocardiograms were monitored over 112 hours in 39 patients during percutaneous coronary intervention, including 159 balloon occlusions in 63 arteries, to test accuracy at rest and during ischemia. Occlusion duration was 78 seconds (range 42 to 96) in the left main coronary in 2 patients, the left anterior descending artery in 15, the right coronary artery in 10, the circumflex artery in 2, and graft segments in 5 patients. Average summated 12-lead ST deviation over the study population at baseline was 377 microV (range 104 to 1,718), which increased at peak ischemia to an average of 1,086 microV (range 282 to 4,099). Median absolute differences at peak ischemic ST deviation were 25 microV in lead V(1), 0 microV in lead V(2), 35 microV in lead V(3), 34 microV in lead V(4), 0 microV in lead V(5), 11 microV in lead V(6), and 114 microV for summated 12-lead ST deviation with the generalized method and 7 microV in lead V(1), 4 microV in lead V(2), 1 muV in lead V(3), 5 microV in lead V(4), 4 microV in lead V(5), 9 microV in lead V(6), and 83 microV for the summated 12-lead ST deviation with the patient-specific method. Limb leads (I, II, III, aVR, aVL, and aVF) were identical in all patients. Thus, generalized and patient-specific methods derived from 12-lead electrocardiography using actual limb and 2 precordial electrodes accurately derived the additional chest leads at rest and during ischemia. These approaches appear to be more practical than conventional 10-electrode monitoring but preserve high accuracy.

In this study we evaluate limited lead sets for the reconstruction of 12-lead ECGs and body surface potential maps (BSPMs). For 12-lead ECG reconstruction, we focused on four available limited lead systems (V2, V1V5, V1V6, V2V5) to derive the standard 12-lead ECG and the EASI lead system as an alternative to the existing 12-lead ECG. We used a data set of 44 continuous 16-lead balloon inflation ECG registrations during percutaneous coronary interventions. For reconstruction of BSPMs an optimal lead selection algorithm was applied to a set of 744 BSPMs, consisting of recordings from subjects with myocardial infarction, left ventricular hypertrophy, and no apparent disease.Median root mean square (RMS) error for 12-lead ECG reconstruction were in decreasing order: V1V6: 165 muV, V2 131 muV, V1V5: 124 muV, EASI: 96 muV, and V2V5: 87 muV. In the BSPM reconstruction experiments, it was shown that by repositioning the six precordial leads the RMS error decreased from 35.4 muV to 26.7 muV. In summary, the results from this study have indicated that limited lead systems offer potential in all forms of cardiac monitoring and assessment, but certain lead sets show higher reconstruction errors.

In emergency care situations, recording all leads of the 12-lead ECG is often not possible due io technical and organizational restrictions. The recording of a subset of leads and subsequent synthesis of rhe absent leads might be a solution to these problems. The goal of this study was to evaluate the efficacy of a reduced lead set, consisting of leads I, 11, V2, and V5. The lead subset was derived from a data set of 12-lead ECGs recorded from parients with a suspected acute myocardial infarction prior to hospitalization. Performance was evaluated by comparing the originally recorded leads and reconstructed leads using correlation coeflcients and STdigerences. Several clinically important decision rules for detection and pre-hospital treatment were evaluated on the original and reconstructed 12-lead ECGs and accuracy was determined. This study shows that high agreement, correlation coeflcients and small STdifferences can be obtained between the original and reconstructed leads.

Objective: To investigate whether the orientation of the electrical T-axis and the spatial QRS-T angle provide independent diagnostic and prognostic information in patients presenting with acute chest pain. Methods: Patients with symptoms suggestive of acute cardiac pathology, who were seen by a general practitioner and for whom a prehospital electrocardiogram (ECG) was recorded by the ambulance service between 1992 and 1994 were investigated. The ECGs (n = 2,261) for our study population were stored for off-line analysis by the Modular ECG Analysis System. QRS- and T-axes were computed from the reconstructed vectorcardiographic X, Y and Z leads. During the year 2000, a follow-up of the entire cohort was performed, and the vital status of the patients was determined via the civil registrar’s office. Cox multivariable regression analyses were performed to evaluate the relation between the orientation of the T-axis, the spatial QRS-T angle and long-term mortality. Results: An abnormal orientation of the T-axis and the spatial QRS-T angle were associated with an increased likelihood of cardiac diseases and an increased risk of all-cause mortality during short- and long-term follow-up. Conclusions: We conclude that the frontal T-axis and the spatial QRS-T angle are important determinants of diagnosis and prognosis in patients presenting with acute chest pain. The reintroduction of vectorcardiography in routine clinical practice might therefore be reconsidered.

A complete cardiology information system is under development. This system should provide to physicians, nurses and others not only access to all patient data but also to the appropriate guideline information, as well as background material (journals, textbooks). The different "building blocks" of the system have been developed or will be developed by different organisations. The integration of the different blocks (systems) provides the physician access all to patient related information, for a specific difficult patient problem with the knowledge base related to his specific problem (what is the appropriate course of action) as well as registry/survey/information (what do my colleagues do in practice). This article describes the following main characteristics of this system more extensively: interactive guideline-based decision support; general report generator; unique unambiguous relation between images, results and reports.

It is well known that changes in the body position (BPC) can have marked changes on the electrical axis of the heart. This may cause ST-segment shifts and/or T-wave inversions, triggering false alarms during continuous ECG monitoring. To investigate the effects in the CCU setting, a body position test (BPT) has been set up to measure the effect during controlled BPC. The ECG obtained in the supine position was used as reference. A scalar and spatial approaches were used. The scalar approach uses linear regression analysis, the supine position being the reference mapping all measurements to the supine position. The spatial approach uses the derived VCG by applying the inverse Dower transformation. This paper describes the results of the first 54 patients done so far. Marked ST-changes (>100 /spl mu/V) were observed in 11 patients out of the 54 when turning to their left side. Other positions appear to have much less effect. A concomitant axis shift in the frontal plane of more than 15 degrees was present in 5 of these 11 patients with ST-changes. Two patients showed T-wave inversion when turning from supine to the left side.

Many Cardiology guidelines have been widely distributed by the professional societies (European Society of Cardiology, American College of Cardiology, American Heart Association, and the national Cardiology societies). In order tu improve accessibility to problemspecific content from guidelines, we have developed a set of tools, methodologies and deployment strategies that provide quick and intuitive access to the clinically relevant section of European practice guidelines at appropriute moments of care delivery. We have developed two guideline delivery systems, one as a stand-done interactive system and one integrated into a patient infomation system. Both a PDA version and a PC web based version of rhe srand-alone'system have been developed to support the cardiologist in the medical decision process. The usability of the system have been tested by staff members of the Cardiology departments in Rotterdam and Cork (Ireland) in a very structured way. The users had an overall positive impression of the system. Moreover they considered the systems as very useful.