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Biomedical subjects

P Kligfield

Publications and source records attributed to P Kligfield.

At least 37 records · Page 2Linked to original sources
PubMed1996

Chronotropic response to exercise. Improved performance of ST-segment depression criteria after adjustment for heart rate reserve.

BACKGROUND: Heart rate (HR) response to exercise plays an important role in the diagnosis of coronary artery disease (CAD). Adjustment of ST-segment depression for the change in HR with exercise increases the accuracy of the exercise ECG in the detection of CAD. In addition, an attenuated HR response to exercise, a manifestation of chronotropic incompetence, may have independent diagnostic value for CAD. METHODS AND RESULTS: The diagnostic value of adjusting the magnitude of ST-segment depression, the ST-segment (ST)/HR index, and the ST/HR slope for chronotropic response to exercise was assessed in 283 control subjects and 337 patients with CAD by dividing each ST measurement by the fraction of HR reserve achieved. At a matched specificity of 96%, ST-segment depression of > 160 microV identified CAD with a sensitivity of 52%, an ST/HR index of > 1.69 microV/bpm identified CAD with a sensitivity of 90%, and an ST/HR slope of > 2.96 microV/bpm identified CAD with a sensitivity of 88%. Adjustment for HR reserve improved the sensitivity of each method: adjusted ST-segment depression of > 176 had a sensitivity of 87% (P < .0001), an adjusted ST/HR index of > 2.14 had a sensitivity of 94% (P = .005), and an adjusted ST/HR slope of > 3.47 had a sensitivity of 93% (P = .0001). In addition, the 94% and 93% sensitivities of the adjusted ST/HR index and ST/HR slope were significantly greater than the 87% sensitivity of adjusted ST-segment depression (P < .0001). CONCLUSIONS: Correction for an attenuated HR response to exercise improves performance of the simple and HR-adjusted ST-segment depression criteria for the identification of CAD. These findings support assessment of the degree of chronotropic reserve in routine evaluation of the exercise ECG.

Coronary Disease↗
PubMed1996

QT interval-heart rate relation during exercise in normal men and women: definition by linear regression analysis.

OBJECTIVES: This study sought to develop a regression-based method for characterization of QT interval behavior during exercise and to define the normal range of the resulting "dynamic" measures of repolarization during submaximal treadmill testing in men and women. BACKGROUND: The Bazett-corrected QT (QTc) interval during exercise has been used as a marker for ischemic disease, arrhythmogenic substrate and the long QT syndrome. However, recent studies indicate that the QTc interval is nonlinear with respect to heart rate during exercise, making the end-exercise QTc interval dependent on peak work load achieved. In contrast, the unadjusted QT interval measured from QRS onset to T wave offset (QTo) and from QRS onset to T wave peak (QTm) appears to vary linearly with heart rate during gently graded effort. METHODS: The QT interval relation to heart rate and cycle length was examined by linear regression in 50 normal men (mean age 48 years) and 30 normal women (mean age 51 years), all of whom had normal rest electrocardiograms. The QTo and QTm measurements were made from digitized lead V5 complexes averaged by computer over 20-s periods, at upright control and after seven 2-min stages of the Cornell modification of the Bruce treadmill protocol (work load equivalent to Bruce stage 3). RESULTS: For each subject, regression of QTo (ms) versus heart rate (beats/min) resulted in a slope (reflecting the "dynamic" change in QTo during effort), an adjusted intercept (reflecting QTo extrapolated to a heart rate of 60 beats/min) and a significant correlation coefficient (r) value. Under these conditions, mean +/- SD (5th to 95th percentile) values for men were -1.45 +/- 0.34 ms/beat per min (-0.90, "less dynamic" to -1.96, "more dynamic") for the slope; 403 +/- 21 ms (365 to 431) for the adjusted intercept; and -0.93 +/- 0.06 (-0.81 to -0.99) for r. Values for women were more dynamic, with a mean slope of -1.74 +/- 0.32 ms/beat per min (-1.23 to -2.18, p < 0.0005 vs. men) and higher adjusted intercept of 426 +/- 23 ms (392 to 462, p < 0.0001 vs. men) at similar strength of correlation (r = -0.95 +/- 0.06). Corresponding normal data were also tabulated for QTm behavior and QT-RR interval behavior during exercise. CONCLUSIONS: These data provide a "dynamic" definition of normal and abnormal repolarization and describe normal limits for the linear relations of the QTo and QTm intervals with respect to heart rate and cycle length during submaximal exercise in normal men and women.

Electrocardiography↗
PubMed1996

Rhythm annotation and interobserver reproducibility of measures of heart rate variability.

Interobserver reproducibility is high for time domain and power spectral measures of heart rate variability, with greater reproducibility for low-frequency measures, and especially for the standard deviation of the 5-minute RR intervals over 24 hours, than for high-frequency measures. Overall interobserver variability of < 8% for these measures is largely (50% to 75%) explained by interobserver differences in annotation of supraventricular ectopy and sinus arrhythmia.

Adult↗
PubMed1996

The Sir James Mackenzie Cardiological Society and the American College of Cardiology.

Documents have recently been discovered that detail the origin and emergence of the New York Cardiological Society in 1928 from an earlier local organization that was founded in 1926 and named in honor of the Scottish cardiologist Sir James Mackenzie. These documents shed light on the earliest evolution of antecedent societies to the present American College of Cardiology and provide important insight into the early professional organization of clinical cardiology in the United States.

Cardiology↗
PubMed1996

Electrocardiographic identification of left ventricular hypertrophy: test performance in relation to definition of hypertrophy and presence of obesity.

OBJECTIVES: This study sought to assess a test performance of the electrocardiogram (ECG) in relation to 1) varying definitions of left ventricular hypertrophy based on different methods of adjusting left ventricular mass for body size, and 2) the presence or absence of obesity. BACKGROUND: Although left ventricular mass is most commonly indexed for body surface area or height when defining left ventricular hypertrophy, recent work suggests that normalization for height to the power of 2.7 (height2.7) may decrease variability among normal subjects and correctly identify the impact of obesity on hypertrophy. METHODS: The product of Cornell voltage and QRS duration (Cornell product) and Framingham-adjusted Cornell voltage were determined from 12-lead ECGs in 212 patients. Left ventricular hypertrophy was defined on the basis of left ventricular mass indexed to body surface area, height and height2.7. RESULTS: Using partitions with matched specificity of 95%, the sensitivity of ECG criteria varied with the definition of hypertrophy, ranging from 39% to 52% for the Cornell product and from 24% to 33% for adjusted Cornell voltage. When left ventricular mass was indexed to body surface area or to height2.7, the 52% and 39% sensitivities of the Cornell product were significantly greater than the 24% (p < 0.001) and 29% (p < 0.05) sensitivities of adjusted Cornell voltage, with a similar trend when left ventricular mass was indexed to height (43% vs. 33%, p = 0.10). Comparison of receiver operating characteristic curves confirmed the superior overall performance of the Cornell product relative to adjusted Cornell voltage for hypertrophy defined by body surface area and height2.7 and demonstrated greater reproducibility of overall performance, as measured by the coefficient of variability, for the Cornell product (1.7%) than for adjusted Cornell voltage (5.8%). Sensitivity of adjusted Cornell voltage was significantly greater in obese than in nonobese subjects (50% to 59% vs. 18% to 24%, p < 0.01), but the Cornell product had only minimally higher sensitivity in nonobese than in obese subjects (40% to 54% vs. 32% to 44%, p = NS). CONCLUSIONS: The ability of ECG criteria to detect left ventricular hypertrophy differs depending on the method of indexing left ventricular mass for body size and with the presence or absence of obesity. Further, the Cornell product provides the best combination of overall accuracy and low variability of performance between definitions of hypertrophy. These findings have important implications for the clinical and epidemiologic use of 12-lead ECG criteria for the detection of left ventricular hypertrophy.

Adult↗
PubMed1996

Prognostic value of heart rate adjustment of exercise-induced ST segment depression in the multiple risk factor intervention trial.

OBJECTIVES: We sought to assess the effect of heart rate adjustment of ST segment depression on risk stratification for the prediction of death from coronary artery disease. BACKGROUND: Standard analysis of the ST segment response to exercise based on a fixed magnitude of horizontal or downsloping ST segment depression has demonstrated only limited diagnostic sensitivity for the detection of coronary artery disease and has variable test performance in predicting coronary artery disease mortality. Heart rate adjustment of the magnitude of ST segment depression has been proposed as an alternative approach to increase the diagnostic and prognostic accuracy of the exercise electrocardiogram (ECG). METHODS: Exercise ECGs were performed in 5,940 men from the Usual Care Group of the Multiple Risk Factor Intervention Trial at entry into the study. An abnormal ST segment response to exercise was defined according to standard criteria as > or = 100 micro V of additional horizontal or downsloping ST segment depression at peak exercise. The ST segment/heart rate index was calculated by dividing the change in ST segment depression from rest to peak exercise by the exercise-induced change in heart rate. An abnormal ST segment/heart rate index was defined as >1.60 micro V/beats per min. RESULTS: After a mean follow-up of 7 years there were 109 coronary artery disease deaths. Using a Cox proportional hazards model, a positive exercise ECG by standard criteria was not predictive of coronary mortality (age-adjusted relative risk [RR] 1.5, 95% confidence interval [CI] 0.6 to 3.6, p = 0.39). In contrast, an abnormal ST segment/heart rate index significantly increased the risk of death from coronary artery disease (age-adjusted RR 4.1, 95% CI 2.7 to 6.0, p < 0.0001). Excess risk of death was confined to the highest quintile of ST segment/heart rate index values, and within this quintile, risk was directly related to the magnitude of test abnormality. After multivariate adjustment for age, diastolic blood pressure, serum cholesterol and cigarettes smoked per day, the ST segment/heart rate index remained a significant independent predictor of coronary death (RR 3.6, 95% CI 2.4 to 5.4, p < 0.001). CONCLUSIONS: Simple heart rate adjustment of the magnitude of ST segment depression improves the prediction of death from coronary artery disease in relatively high risk, asymptomatic men. These findings strongly support the use of heart rate-adjusted indexes of ST segment depression to improve the predictive value of the exercise ECG.

Coronary Disease↗
PubMed1996

Combined rest and exercise electrocardiographic repolarization findings in relation to structural and functional abnormalities in asymptomatic aortic regurgitation.

The relationship of combined rest and exercise electrocardiographic (ECG) repolarization abnormalities to left ventricular geometry and function was examined in 48 patients with asymptomatic chronic pure aortic regurgitation and no recent use of digitalis. Echocardiographic and radionuclide cineangiographic findings were compared in groups defined by the presence or absence of the "strain" pattern of repolarization abnormality on the resting ECG and also by the presence or absence of standard positive repolarization changes during upright treadmill exercise ( > 0.1 mV additional horizontal or downsloping ST depression). These hierarchic groups demonstrated trends toward progressively abnormal left ventricular dimensions, mass, wall stress, and change in ejection fraction with exercise. Although the presence of the strain pattern on the resting ECG alone was most strongly correlated with underlying functional and geometric abnormalities, an abnormal exercise test response was independently associated with abnormal left ventricular systolic dimension. The large group of patients with no symptoms and normal resting repolarization had only 0% to 4% prevalences of markedly increased systolic dimension (> 55 mm), reduced ejection fraction at rest (< 45%), or reduced ejection fraction during exercise (< 40%), whereas the small group of patients with abnormal resting repolarization and a positive exercise test response had 50% to 83% prevalences of these findings. These data suggest a possible role for rest and exercise ECG in the serial evaluation of patients with aortic regurgitation.

Adult↗
PubMed1996

ECG identification of left ventricular hypertrophy. Relationship of test performance to body habitus.

Obesity is associated with the presence of left ventricular hypertrophy (LVH) and, conversely, with decreased sensitivity of the electrocardiogram (ECG) for LVH due to attenuating effects on QRS amplitudes. Although the Framingham-adjusted Cornell voltage, incorporating age, sex, and body mass index (BMI), was developed to correct for the effects of obesity on the accuracy of the ECG, the impact of body habitus on ECG detection of LVH for newer, more accurate ECG criteria based on the time-voltage area under the QRS complex has not been determined. The authors examined the test accuracy of the Sokolow-Lyon voltage, Cornell voltage, Cornell product (product of QRS duration and Cornell voltage), Framingham-adjusted Cornell voltage, and time-voltage area of the horizontal plane vector QRS for the detection of echocardiographic LVH in relation to body habitus in 250 patients. Normal-weight or overweight status was based on sex-specific population-based BMI partitions. Using partitions with a matched specificity of 98% in the overall population without LVH, the sensitivity of standard ECG criteria varied according to body habitus. Sensitivity of the Framingham-adjusted Cornell voltage was less in normal-weight than in overweight patients (49 vs 59%, P = .0004); there were also trends toward lower sensitivity in normal-weight patients for the Cornell voltage (40 vs 65%, P = .10) and the Cornell product (43 vs 65%, P = NS), but sensitivity of the Sokolow-Lyon voltage was lower in obese than in nonobese patients (18 vs 50%, P = .025). In contrast, the horizontal plane vector area had similar sensitivity in obese and normal-weight patients (76 vs 74%, P = NS). Specificity varied with body habitus only for the Framingham-adjusted Cornell voltage: 100% in normal-weight vs 95% in overweight patients (P < .05). Thus, accuracy of the Framingham-adjusted Cornell voltage and Sokolow-Lyon voltage varies significantly with body habitus. In contrast, accuracy of the Cornell voltage and the Cornell product appears less dependent on BMI, and the time-voltage area of the QRS minimizes the effects of obesity on the accuracy of the ECG for LVH.

Body Mass Index↗
PubMed1996

Variability of precordial electrode placement during routine electrocardiography.

Placement of precordial electrodes by 30 experienced technicians during routine electrocardiography was compared with anatomically ascertained sites marked by ink visible only under ultraviolet "black light" in three men and five women. The distance and direction from each marked site to the center of the applied electrode was measured to allow calculation of both the linear magnitude of difference (derived from the square root of the sum of the squares of rise and run) and also the direction of difference (in quadrants) between the anatomically established location and the electrode at each precordial site. The average difference from the applied electrodes to the corresponding marked sites was 1.14 inches, ranging from a mean of 1.31 inches at lead V1 to 0.98 inches at lead V4. Overall, 64% of precordial electrodes were placed within a radius of 1.25 inch, ranging from 56% for lead V6 to 74% for lead V4, and 27% of precordial electrodes were placed within a radius of 0.625 inch. There was superior quadrant displacement of more than 0.625 inch in more than 50% of routine applications of leads V1 and V2, indicating that these electrodes are commonly placed both high and wide of their anatomically defined precordial sites. Similarly, there was an inferior and left-ward displacement of more than 0.625 inch in 30-50% leads of routine applications of V4 through V6, indicating that these lateral precordial electrodes are commonly placed both low and wide of their respective anatomic sites.

Body Constitution↗
PubMed1996

Time-voltage area of the QRS for the identification of left ventricular hypertrophy.

Standard electrocardiographic criteria have exhibited poor sensitivity for left ventricular hypertrophy at acceptable levels of specificity and perform less well in women than men, even when sex-specific criteria are used. The time-voltage integral of the horizontal plane vector QRS complex can improve identification of hypertrophy in men, but performance of this approach in women and the effect of sex-specific criteria on accuracy have not been examined. To evaluate the accuracy of the time-voltage integral of the QRS complex for the identification of left ventricular hypertrophy in women and to examine the effect of sex-and non-sex-specific criteria on test performance, we obtained standard 12-lead and orthogonal-lead signal-averaged electrocardiograms and echocardiograms in 175 control subjects without hypertrophy (43 women and 132 men) and 75 patients with hypertrophy (26 women and 49 men) defined by echocardiographic criteria (indexed left ventricular mass > 110 g/m2 in women and > 125 g/m2 in men). Voltage of the QRS complex was integrated over the total QRS duration in leads X and Z for calculation of the time-voltage integral of the horizontal plane vector complex. With the use of a partition of 99.2 microV.s with a specificity of 98% in the entire normal group, sensitivity of the horizontal plane vector integral was significantly lower in women than men (31% versus 71%, P < .001). In contrast, use of sex-specific partitions of 75.4 microV.s in women and 99.2 microV.s in men with matched 98% specificity significantly improved sensitivity in women to 81% (P < .001), with no change in sensitivity in men (71%). Comparison of receiver operating characteristic curves with the use of sex-specific criteria demonstrated no significant difference in overall performance of the horizontal plane vector integral between men and women. The 81% and 71% sensitivities of the sex-specific horizontal plane vector integral were significantly greater than the 27% to 58% sensitivities of sex-specific 12-lead electrocardiographic criteria in this population. Thus, sex-specific criteria significantly improve performance of the time-voltage integral of the QRS for the identification of left ventricular hypertrophy in women, with no loss of accuracy in men. Use of the time-voltage integral can improve the accuracy of the electrocardiogram for the identification of left ventricular hypertrophy in both women and men.

Analysis of Variance↗
PubMed1996

Association of carotid atherosclerosis with electrocardiographic myocardial ischemia and left ventricular hypertrophy.

Patients with carotid atherosclerosis have an increased risk of coronary events and an increased prevalence of echocardiographic left ventricular hypertrophy. However, little is known regarding the association between electrocardiographic abnormalities and carotid atherosclerosis. The relationship of electrocardiographic evidence of myocardial ischemia and left ventricular hypertrophy to the presence of carotid atherosclerosis was prospectively studied in 349 asymptomatic subjects who underwent echocardiography and carotid ultrasonography. Myocardial ischemia on the electrocardiogram was defined by the presence of localized T-wave inversions, and electrocardiographic hypertrophy was defined by the product of Cornell voltage and QRS duration. Carotid atherosclerosis was present in 21% (72/ 349) of subjects and was associated with older age, higher systolic and pulse pressures, and greater left ventricular mass. Both ischemia and hypertrophy on the electrocardiogram were strongly associated with carotid plaque. Carotid atherosclerosis was more than three times more prevalent in subjects with electrocardiographic ischemia (69% [11/16] versus 18% [61/333], P < .0001) or electrocardiographic left ventricular hypertrophy (78% [7/9] versus 19% [65/340], P = .0003) than in subjects without these findings. Logistic regression analysis, including standard risk factors, revealed that both ischemia and hypertrophy on the electrocardiogram remained significant independent predictors of the presence of carotid atherosclerosis, along with age and echocardiographic left ventricular mass. These findings suggest that the associations of ischemia and left ventricular hypertrophy with carotid atherosclerosis may contribute to the increased incidence of coronary events in patients with carotid atherosclerosis.

Adult↗
PubMed1995

Gender-specific criteria and performance of the exercise electrocardiogram.

BACKGROUND: Significant gender differences have been found in performance of the exercise ECG for the identification of coronary artery disease. However, identical exercise ECG ST segment criteria have been used in men and women, which might contribute to the lower accuracy of these methods in women than in men. METHODS AND RESULTS: To assess the effect of gender-specific test partitions on relative performance of standard and heart rate-adjusted ST segment depression criteria in men and women, the exercise ECGs of 143 women and 477 men were examined. Non-gender-specific test partitions, selected to have matched specificities of 96% for each test method, were determined in all 283 normal subjects, and gender-specific test partitions with identical specificity were determined separately in the 52 normal women and 231 normal men; sensitivity of these criteria was then examined in the 91 women and 246 men with coronary disease. Standard ST segment depression criteria (0.1 mV of additional horizontal or downsloping ST segment depression at end exercise) with identical 96% specificity in the entire group of normal subjects and separately in women and men had a significantly lower sensitivity of 51% in women compared with 67% in men (P < .01). Among women, performance of the ST segment/heart rate (ST/HR) slope was more improved than that of the ST/HR index by the use of gender-specific criteria. Compared with the performance of non-gender-specific criteria, application of gender-specific ST/HR slope partitions with matched specificity of 96% resulted in a significant increase in sensitivity in women from 84% to 91% (P < .01), with no significant change in sensitivity in men (89% to 88%) and with no residual difference in sensitivity between men and women. Although the use of gender-specific ST/HR slope criteria significantly improved sensitivity in both men and women with respect to standard criteria (each P < .0001), the relative increase in sensitivity provided by heart rate adjustment was significantly greater in women than in men (40% versus 21%, P < .001). Similar gender differences in improvement in performance using gender-specific criteria for the ST/HR slope were observed when analysis of test performance was restricted to the detection of three-vessel coronary disease (50% versus 9%, P = .002). CONCLUSIONS: At high specificity, gender-specific test partitions improve sensitivity of the ST/HR slope for the identification of coronary disease in women, with no decrease in sensitivity in men. In contrast, gender-specific partitions do not change performance of standard test criteria, which is lower in women than in men. Accordingly, the relative benefit of heart rate adjustment by the ST/HR slope method is greater in women than in men. These findings support use of the ST/HR slope with use of gender-specific partitions for the identification and quantification of coronary artery disease in both men and women.

Angina Pectoris↗
PubMed1995

Fractal clustering of ventricular ectopy correlates with sympathetic tone preceding ectopic beats.

BACKGROUND: Fractal geometric analysis of ventricular ectopy yields a fractal dimension, which can range from zero to one and is inversely related to clustering of ventricular premature contractions (VPCs). Low values of this fractal dimension, which reflect significantly nonuniform distributions of ventricular ectopy, are found in patients with life-threatening ventricular arrhythmias and predict adverse outcomes in selected patients with congestive heart failure and with mitral regurgitation. However, the physiological mechanism and correlates of the fractal dimension are unknown. METHODS AND RESULTS: To explore the physiological correlates of clustered ventricular ectopy, we studied 30 patients with a history of sustained ventricular tachycardia or ventricular fibrillation who had inducible sustained monomorphic ventricular tachycardia during electrophysiological study and also underwent drug-free 24-hour ambulatory ECG. In addition to fractal dimension (determined by use of our previously described algorithm), we measured the mean RR interval (+/- SD) for all sinus beats preceding a sinus beat and for all sinus beats preceding a single VPC and the mean root-mean-square difference (RMSSD) of all windows of 15 successive RR intervals (excluding ectopic beats) preceding a sinus beat and preceding a single VPC. Based on the directional changes of mean RR (a measure of both sympathetic and parasympathetic tone) and of RMSSD (a measure of parasympathetic tone), each patient's inferred relative sympathetic tone preceding ventricular ectopy was classified as increased, unchanged, or decreased. If these values changed concordantly, relative sympathetic tone was indeterminate. Fractal dimension did not correlate with the mean RR interval, SD of the RR interval, or RMSSD preceding sinus beats or preceding VPCs (all P > .10). In 20 patients, fractal dimension was significantly lower among those with increased relative sympathetic tone (n = 14) than those with unchanged or decreased sympathetic tone (n = 6, P = .008). Ten patients had indeterminate relative sympathetic tone. CONCLUSIONS: Clustering of ventricular ectopy, as measured by the fractal dimension, is observed in patients at increased risk of sudden cardiac death. A low fractal dimension (clustered ventricular ectopy) is related to changes in heart rate and heart rate variability that are consistent with transient increases in cardiac sympathetic tone.

Aged↗
PubMed1995

Performance of the signal-averaged electrocardiogram: relation to baseline QRS duration.

Analysis of the duration and terminal components of the filtered QRS complex on the signal-averaged electrocardiogram (ECG) has been widely used for the detection of late potentials. Although filtered QRS duration is strongly related to 12-lead QRS duration, the relation of performance of the signal-averaged ECG to baseline QRS duration has not been critically examined. To examine the relation of test performance of the signal-averaged ECG to 12-lead QRS duration and to test the hypothesis that the difference between filtered and baseline 12-lead QRS duration would reflect more accurately the presence of late potentials than would analysis of the filtered QRS alone, we evaluated signal-averaged and 12-lead ECGs in 144 normal subjects and in 132 patients who were examined by electrophysiologic study and of whom 45 had inducible sustained monomorphic ventricular tachycardia. The signal-averaged ECG was considered positive by standard late potential criteria when the filtered vector QRS duration was > 114 msec and either the root-mean-square voltage of the terminal 40 msec of the filtered QRS was < 20 microV or the low-amplitude signal of the terminal filtered QRS was > 38 msec. A new signal-averaged ECG criterion for the presence of late potentials was developed in the 144 normal subjects on the basis of the difference between the longest filtered QRS duration in any of the orthogonal leads and QRS duration on the baseline 12-lead ECG ("the QRS difference"), which was adjusted by regression analysis for the decreasing QRS difference found with increasing baseline QRS duration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Electrocardiographic identification of increased left ventricular mass by simple voltage-duration products.

OBJECTIVES: This study was conducted to validate the hypothesis that the product of QRS voltage and duration, as an approximation of the time-voltage area of the QRS complex, can improve the electrocardiographic (ECG) detection of echocardiographically determined left ventricular hypertrophy and to further assess the relative contribution of QRS duration to the ECG detection of hypertrophy. BACKGROUND: The ECG identification of left ventricular hypertrophy has been limited by the poor sensitivity of standard voltage criteria alone. However, increases in left ventricular mass can be more accurately related to increases in the time-voltage area of the QRS complex than to changes in QRS voltage or duration alone. METHODS: Standard 12-lead ECGs and echocardiograms were obtained for 389 patients, including 116 patients with left ventricular hypertrophy. Simple voltage-duration products were calculated by multiplying Cornell voltage by QRS duration (Cornell product) and the 12-lead sum of voltage by QRS duration (12-lead product). RESULTS: In a stepwise logistic regression model that also included Cornell voltage, Sokolow-Lyon voltage, age and gender, QRS duration remained a highly significant predictor of the presence of left ventricular hypertrophy (chi-square 26.9, p < 0.0001). At a matched specificity of 96%, each voltage-duration product significantly improved sensitivity for the detection of left ventricular hypertrophy compared with simple voltage criteria alone (Cornell product 37% vs. Cornell voltage 28%, p < 0.02, and 12-lead product 50% vs. 12-lead voltage 43%, p < 0.005). Sensitivities of both the Cornell product and the 12-lead product were significantly greater than the 27% sensitivity of QRS duration alone (p < 0.01 vs. p < 0.001), the 20% sensitivity of a Romhilt-Estes point score > 4 (p < 0.001) and the 33% sensitivity of the best-fit logistic regression model in this cohort (p < 0.05 vs. p < 0.001). CONCLUSIONS: QRS duration is an independent ECG predictor of the presence of left ventricular hypertrophy, and the simple product of either Cornell voltage or 12-lead voltage and QRS duration significantly improves identification of left ventricular hypertrophy relative to other ECG criteria that use QRS duration and voltages in linear combinations.

Echocardiography↗