Traditional Electrocardiographic Research Articles

Prevalence of electrocardiographic abnormalities in a middle-aged, biracial population: Coronary Artery Risk Development in Young Adults study

BackgroundFew studies to date have described the prevalence of electrocardiographic (ECG) abnormalities in a biracial middle-aged cohort. Methods and ResultsParticipants underwent measurement of traditional risk factors and 12-lead ECGs coded using both Minnesota Code and Novacode criteria. Among 2585 participants, of whom 57% were women and 44% were black (mean age 45 years), the prevalence of major and minor abnormalities was significantly higher (all P < .001) among black men and women compared to whites. These differences were primarily due to higher QRS voltage and ST/T-wave abnormalities among blacks. There was also a higher prevalence of Q waves (Minnesota Code 1-1, 1-2, 1-3) than described by previous studies. These racial differences remained after multivariate adjustment for traditional cardiovascular (CV) risk factors. ConclusionsBlack men and women have a significantly higher prevalence of ECG abnormalities, independent of traditional cardiovascular risk factors, than whites in a contemporary cohort of middle-aged participants.

Relation of Electrocardiographic Criteria for Left Atrial Enlargement to Two-Dimensional Echocardiographic Left Atrial Volume Measurements

Left atrial (LA) enlargement by 2-dimensional (2-D) echocardiography predicts adverse cardiovascular outcomes. Electrocardiographic (ECG) criteria for LA enlargement are based on M-mode echocardiographic LA diameter, which is inferior to 2-D-derived LA volumes. This study compared established ECG criteria for LA enlargement with atrial volume obtained by 2-D echocardiography to determine if traditional ECG criteria accurately represent LA chamber enlargement, therefore offering a low-cost screening tool. A total of 261 randomly selected patients who underwent electrocardiography and 2-D echocardiography were enrolled. ECG parameters and electronically derived P-wave medians were analyzed with electronic calipers for maximal accuracy. LA volumes by 2-D echocardiography were measured with Simpson's method of discs, with enlargement defined as 32 ml/m(2). Sensitivity and specificity tables and receiver-operating characteristic curves were constructed for each criterion. Univariate and multivariate analyses were performed for predictors of 2-D echocardiographic LA enlargement. LA enlargement was present in 43% of patients. ECG P-wave duration was the most sensitive for the detection of LA enlargement (69%) but had low specificity (49%). Conversely, a biphasic P wave was the most specific (92%) but had low sensitivity (12%). The maximum area under the receiver-operating characteristic curve for any criterion was 0.64, too low to be of clinical utility. In conclusion, established ECG criteria for LA enlargement do not reliably reflect LA enlargement and lack sufficient predictive value to be useful clinically. These results suggest that P-wave abnormalities should be noted as nonspecific LA abnormalities, with the term "LA enlargement" no longer used.

Evaluation of electrocardiographic criteria for right atrial enlargement by quantitative two-dimensional echocardiography

Objectives. This study was conducted to evaluate the sensitivity and specificity of traditional electrocardiographic (ECG) criteria for right atrial enlargement and identify improved criteria, using quantitative two-dimensional echocardiography.Background. Traditional ECG criteria for right atrial enlargement, such as P pulmonale, have been increasingly criticized as insensitive and nonspecific. Quantitative two-dimensional echocardiography has been shown to be a useful method for evaluating atrial size.Methods. Hospitalized patients with mild, moderate and severe right atrial enlargement were selected from our laboratory's data base and compared with age- and gender-correlated hospitalized control subjects. After exclusions, 100 patients with right atrial enlargement and 25 control patients remained. Planimetric measurement of right atrial volumes was accomplished by two independent observers using the single-plane method of discs algorithm. Electrocardiograms were independently evaluated for current and newly proposed right atrial enlargement criteria.Results. Fifty-two patients (52%) were in sinus rhythm, 41 were in atrial fibrillation, 5 were in atrial flutter, and 2 were in ectopic atrial rhythm. All control subjects were in sinus rhythm. The right atrial volume for the control group was 35.0 ± 7.4 ml (mean ± SD), with a narrow, roughly normal distribution. The right atrial volume for the patient group was 147.6 ± 69.1 ml (median 127.2) in a wide, skewed distribution. The difference of mean values was highly significant (p = 0.0001). Right ventricular enlargement was found to some degree in all patients with right atrial enlargement. The most powerful predictors of right atrial enlargement were a QRS axis >90 °, a P wave height in lead V2>1.5 mm and an R/S ratio >1 in lead V2in the absence of complete right bundle branch block. The combined sensitivity of these three criteria was 49%, with preservation of 100% specificity. P pulmonale detected only 6% of patients with right atrial enlargement.Conclusions. Using quantitative two-dimensional echocardiography, we found that most previously reported ECG criteria for right atrial enlargement have low predictive power. The best predictors of right atrial enlargement were a P wave height >1.5 mm in lead V2and, as new criteria, a QRS axis >90 ° and an R/S ratio >1 in lead V1in the absence of complete right bundle branch block. The combined sensitivity of these three criteria was 49%, with preservation of 100% specificity. Further studies are needed to prospectively validate these findings.

Electrocardiomultigraphimeter using a home computer

The drop in hardware costs has fostered the widespread use of home-computer systems. Because of this situation, the home computer can be profitably employed in some highly specialized fields. We belive electrocardiographic instrumentation to be one such field. We have built an electrocardiomultigraphimeter (ECXGM), which can be considered as a development of the traditional electrocardiograph that performs some additional functions. Our prototype features vectorcardiography, polar coodrdinate tracing, automatic measurements between foducial points selected by the user with a joystick and screen cursor and trace filing by patient on labelled floppy disks. The standard hardware consists of a Commodore 64 console, a monitor, two floppy disk drives and an Epson HI-80 plotter, all of which are readily available. The special hardware consists of an A/D converter, which recieves the electrocardiographic signal downstream of the amplifying stage, which is a standard feature of any electrocardiograph. Prototype development mostly involved the software. Difficulties were posed by the limited resources available on home computers, an important point in view of the problem to be tackled. The solutions adopted are based ont he use of assembler language and overloading techniques and minimizing the interconnections among the software modules defined in a compactly built program. The result is an instrument with significantly advanced clinico-scientific capabilities as compared to current electrocardiographic instruments. This fact, and the class of the hardware used and special software built, confer originally to this work. The new instrument ought to be especially suitable for the offices of cardiologists who have an interest in such capabilities, and for schools of electrocardiography.

Electrocardiographic criteria for the diagnosis of combined inferior myocardial infarction and left anterior hemiblock

New electrocardiographic (ECG) criteria for diagnosing the combination of inferior myocardial infarction and left anterior hemiblock are proposed. The proposed criteria are based upon the relations between portions of the vectorcardiographic QRS loop in the frontal plane and the corresponding portions of the QRS complexes recorded by the limb leads. The application of the proposed criteria requires that the tracings be obtained with 3-channel ECG machines. The proposed criteria for the diagnosis of inferior myocardial infarction and left anterior hemiblock are as follows: (1) leads aVR and aVL both end in R waves, with the peak of the terminal R wave in lead aVR occurring later than the peak of the terminal R wave in lead aVL, and (2) a Q wave of any magnitude is present in lead II. The performance of the proposed criteria was superior to that of 10 combinations of traditional ECG criteria for inferior myocardial infarction and left anterior hemiblock.