Electrocardiographic detection of left ventricular hypertrophy using echocardiographic determination of left ventricular mass as the reference standard. Comparison of standard criteria, computer diagnosis and physician interpretation.

Electrocardiographic findings of left ventricular hypertrophy were compared with echocardiographic left ventricular mass in 148 patients to assess performance of standard electrocardiographic criteria, the IBM Bonner program and physician interpretation. On echocardiography, 43% of the patients had left ventricular hypertrophy (left ventricular mass greater than 215 g). Sokolow-Lyon voltage-(S in V1 + R in V5 or V6) and Romhilt-Estes point score correlated modestly with left ventricular mass (r = 0.40, p less than 0.001 and r = 0.55, p less than 0.001, respectively). Sensitivity of Sokolow-Lyon voltage greater than 3.5 mV for left ventricular hypertrophy was only 22%, but specificity was 93%. Point score for probable left ventricular hypertrophy (greater than or equal to 4 points) had 48% sensitivity and 85% specificity, whereas definite hypertrophy (greater than or equal to 5 points) had 34% sensitivity and 98% specificity. Computer analysis resulted in 45% sensitivity and 83% specificity. Overall diagnostic accuracy of the IBM Bonner program (67%) was better than that of Sokolow-Lyon voltage (62%), but worse than the Romhilt-Estes point score (69% for greater than or equal to 4 points or 70% for greater than or equal to 5 points). Three cardiologists interpreted electrocardiograms independently and in a blinded fashion. Physician sensitivity was 56%, specificity 92% and accuracy 76%. Correlation with left ventricular hypertrophy was good (r = 0.70, p less than 0.001). It is concluded that: 1) computer diagnosis of left ventricular hypertrophy by the IBM Bonner program is no more accurate than diagnosis by Sokolow-Lyon or Romhilt-Estes criteria, and 2) physician recognition of left ventricular hypertrophy is more accurate.(ABSTRACT TRUNCATED AT 250 WORDS)

Patients treated by cardiologists have a lower in-hospital mortality for acute myocardial infarction.

OBJECTIVES: We sought to determine the effect of specialty care on in-hospital mortality in patients with acute myocardial infarction. BACKGROUND: There has been increasing pressure to limit access to specialists as a method to reduce the cost of health care. There is little known about the effect on outcome of this shift in the care of acutely ill patients. METHODS: We analyzed the data from 30,715 direct hospital admissions for the treatment of acute myocardial infarction in Pennsylvania in 1993. A risk-adjusted in-hospital mortality model was developed in which 12 of 20 clinical variables were significant independent predictors of in-hospital mortality. To determine whether there were factors other than patient risk that significantly influenced in-hospital mortality, multiple logistic regression analysis was performed on physician, hospital and payer variables. RESULTS: After adjustment for patient characteristics, a multiple logistic regression analysis identified treatment by a cardiologist (odds ratio=0.83 [confidence interval ¿CI¿=0.74 to 0.94] p < 0.003) and physicians treating a high volume of acute myocardial infarction patients (odds ratio=0.89 [CI=0.80 to 0.99] p < 0.03) as independent predictors of lower in-hospital mortality. Treatment by a cardiologist as compared to primary care physicians was also associated with a significantly lower length of stay for both medically treated patients (p < 0.01) and those undergoing revascularization (p < 0.01). CONCLUSIONS: Treatment by a cardiologist is associated with approximately a 17% reduction in hospital mortality in acute myocardial infarction patients. In addition, patients of physicians treating a high volume of patients have approximately an 11% reduction in mortality. This has important implications for the optimal treatment of acute myocardial infarction in the current transformation of the health care delivery system.

Transesophageal Doppler echocardiography of pulmonary venous flow: a new marker of mitral regurgitation severity.

Pulmonary venous flow varies with different cardiac conditions. Flow patterns in response to mitral regurgitation have not been well studied, but flows may vary enough to differentiate among different grades of regurgitation. Accordingly, pulmonary venous flow velocities were recorded in 50 consecutive patients referred for outpatient (n = 26) or intraoperative (mitral valve repair; n = 24) echocardiographic examination for mitral regurgitation. Recordings were made of right and left upper pulmonary veins with pulsed wave Doppler transesophageal echocardiography. Mitral regurgitation was graded from 1+ to 4+ by an independent observer using transesophageal color flow mapping. The results of cardiac catheterization performed 5 weeks earlier in 43 of the patients were also graded for mitral regurgitation by an independent observer. Pulmonary venous flow patterns, the presence of reversed systolic flow and peak systolic and diastolic flow velocities were compared with the severity of mitral regurgitation indicated by each technique. Of the 28 patients with 4+ regurgitation by transesophageal color flow mapping, 26 (93%) had reversed systolic flow. The sensitivity of reversed systolic flow in detecting 4+ mitral regurgitation by transesophageal color flow mapping was 93% and the specificity was 100%. The sensitivity and specificity of reversed systolic flow in detecting 4+ mitral regurgitation by cardiac catheterization were 86% and 81%, respectively. Discordant flows were observed in 9 (24%) of 38 patients; the left vein usually showed blunted systolic flow and the right showed reversed systolic flow. In 22 intraoperative patients, there was "normalization" of pulmonary venous systolic flow after mitral valve repair in the postcardiopulmonary bypass study compared with the prebypass study after the mitral regurgitant leak was corrected.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiographic detection of left ventricular hypertrophy: development and prospective validation of improved criteria.

To develop improved electrocardiographic criteria of left ventricular hypertrophy, individual electrocardiographic voltage measurements were compared with echocardiographic left ventricular mass in a "learning series" of 414 subjects. The strongest independent relations with left ventricular mass were exhibited by the S wave in lead V3, the R wave in lead a VL and the T wave in lead V1 (each p less than 0.001), and by age and sex. Better electrocardiographic detection of left ventricular hypertrophy was achieved by new criteria that stratified QRS voltage and repolarization findings in sex and age subsets. For men, at all ages, left ventricular hypertrophy is suggested by QRS voltage alone when the R wave in lead aVL and the S wave in lead V3 total more than 35 mm. When this voltage exceeds 22 mm, left ventricular hypertrophy is suggested in men under age 40 years when the T wave in lead V1 is positive (greater than or equal to 0 mm), and in men 40 years or older when the T wave in lead V1 is at least 2 mm. For women, at all ages, left ventricular hypertrophy is suggested when the R wave in lead a VL and the S wave in lead V3 total more than 25 mm. When this voltage exceeds 12 mm, left ventricular hypertrophy is suggested in women under 40 when the T wave in lead V1 is positive (greater than or equal to 0 mm), and in women over 40 when the T wave in lead V1 is 2 mm or greater.(ABSTRACT TRUNCATED AT 250 WORDS)

Standardization of M-mode echocardiographic left ventricular anatomic measurements.

To improve standardization of echocardiographic left ventricular anatomic measurements, echographic left ventricular dimensions and mass were related to body size indexes, sex, age and blood pressure. Independent normal populations comprised 92 hospital-based subjects (64 women, 28 men) and 133 subjects from a population sample (55 women, 78 men). All measurements of chamber size, wall thickness and mass differed between men and women in both series (p less than 0.01 to p less than 0.001). Left ventricular mass was related most closely to body surface area among measurements of body size (r = 0.37, p less than 0.01 to r = 0.57, p less than 0.001) in all four groups. Indexation by body surface area eliminated sex differences in wall thicknesses and internal dimension, but a significant sex difference in left ventricular mass index persisted (89 +/- 21 g/m2 in men versus 69 + 19 g/m2 in women in the entire series, p less than 0.0001). The 97th percentile of left ventricular mass index was identical in both groups of men (136 and 132 g/m2) and women (112 and 109 g/m2). A highly significant difference in lean body mass, estimated from 24 hour urine creatine excretion, was observed between men and women (58 +/- 15 versus 40 +/- 13 kg, p less than 0.001) and no sex difference existed in left ventricular mass indexed by lean body mass (3.4 +/- 1.3 versus 3.5 +/- 1.5 g/kg). Weak correlations were observed between left ventricular mass/lean body mass and systolic or diastolic blood pressure (r = 0.25, p less than 0.05 and r = 0.28, p less than 0.01, respectively) but not age (18 to 72 years).(ABSTRACT TRUNCATED AT 250 WORDS)

Cost-effectiveness of echocardiography and electrocardiography for detection of left ventricular hypertrophy in patients with systemic hypertension.

Although echocardiography is more accurate than electrocardiography for detection of left ventricular hypertrophy, it is also more expensive, making it uncertain whether echocardiography is cost-effective for detection of this abnormality in hypertensive patients. Accordingly, the sensitivity of M-mode echocardiographic and electrocardiographic criteria for left ventricular hypertrophy was determined in necropsied patients with anatomic hypertrophy of mild (n = 26), moderate (n = 21) or severe (n = 46) degree, and the prevalence of each degree of hypertrophy was determined in 561 hypertensive adults drawn from clinical and employed population samples. The sensitivity of echocardiographic left ventricular mass index criteria was 57% in necropsied patients with mild hypertrophy and 98% in patients with moderate or severe hypertrophy. All electrocardiographic criteria exhibited lower sensitivity: 15 to 42% for mild, 10 to 38% for moderate, and 30 to 57% for severe hypertrophy. Cost estimates from three sources were $160 for M-mode echocardiography and $48 to $64 for 12-lead electrocardiography. In populations with a 12 to 40% prevalence of hypertrophy, echocardiography was calculated to cost less than electrocardiography per instance of hypertrophy detected ($390-$1013 vs $800-$1829), yielded better separation in predicted incidence of morbid events between hypertensive patients with or without hypertrophy (3.4-4.7 vs 1.5-2.1 per 100 patient-years as opposed to 3.0-4.4 vs 1.9-2.9 per 100 patient-years), and required smaller case and control samples for hypothetical research studies (n = 254-309 vs 397-3478).(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous low level treadmill exercise and intravenous dipyridamole stress thallium imaging.

Intravenous dipyridamole-thallium imaging unmasks ischemia in patients unable to exercise adequately. However, some of these patients can perform limited exercise, which, if added, may provide useful information. Treadmill exercise combined with dipyridamole-thallium imaging was performed in 100 patients and results compared with those of 100 other blindly age- and sex-matched patients who received dipyridamole alone. Exercise began after completion of the dipyridamole infusion. Mean +/- 1 standard deviation peak heart rate (109 +/- 19 vs 83 +/- 12 beats/min, p less than 0.0001) and peak systolic and diastolic blood pressure (146 +/- 28/77 +/- 14 vs 125 +/- 24/68 +/- 11 mm Hg, p less than 0.0001) were higher in the exercise group compared with the nonexercise group. There was no difference in the occurrence of chest pain, but more patients in the exercise group developed ST-segment depression (26 vs 12%, p less than 0.0001). The exercise group had fewer noncardiac side effects (4 vs 12%, p less than 0.01) and a higher target (heart) to background (liver) count ratio (2.1 +/- 0.7 vs 1.2 +/- 0.3; p less than 0.01), due to fewer liver counts. There were no deaths, myocardial infarctions or sustained arrhythmias in either group. Combined treadmill exercise and dipyridamole testing is safe, associated with fewer noncardiac side effects, a higher target to background ratio and a higher incidence of clinical electrocardiographic ischemia than dipyridamole alone. Therefore, it is recommended whenever possible.

Effects of dobutamine on Gorlin and continuity equation valve areas and valve resistance in valvular aortic stenosis.

Previous studies demonstrated changes in aortic valve area calculated by the Gorlin equation under conditions of varying transvalvular flow in patients with valvular aortic stenosis (AS). To distinguish between flow-dependence of the Gorlin formula and changes in actual orifice area, the Gorlin valve area and 2 other measures of severity of AS, continuity equation valve area and valve resistance, were calculated under 2 flow conditions in 12 patients with AS. Transvalvular flow rate was varied by administration of dobutamine. During dobutamine infusion, right atrial and left ventricular end-diastolic pressures decreased, left ventricular peak systolic pressure and stroke volume increased, and systolic arterial pressure did not change. Heart rate increased by 19%, cardiac output by 38% and mean aortic valve gradient by 25%. The Gorlin valve area increased in all 12 patients by 0.03 to 0.30 cm2. The average Gorlin valve area increased from 0.67 +/- 0.05 to 0.79 +/- 0.06 cm2 (p < 0.001). In contrast, the continuity equation valve area (calculated in a subset of 6 patients) and valve resistance did not change with dobutamine. The data support the conclusion that flow-dependence of the Gorlin aortic valve area, rather than an increase in actual orifice area, is responsible for the finding that greater valve areas are calculated at greater transvalvular flow rates. Valve resistance is a less flow-dependent means of assessing severity of AS.

Performance of primary and derived M-mode echocardiographic measurements for detection of left ventricular hypertrophy in necropsied subjects and in patients with systemic hypertension, mitral regurgitation and dilated cardiomyopathy.

To determine which M-mode echocardiographic (echo) measurement best detects left ventricular (LV) hypertrophy, the sensitivity and specificity of upper normal limits of echo LV anatomic measurements (previously shown to have 97% specificity in living normal subjects) were tested in 60 necropsied patients with anatomic hypertrophy and in 28 necropsied patients with normal left ventricles. The prevalence of hypertrophy by each echo criterion was determined in 165 living patients with systemic hypertension, mitral regurgitation or dilated cardiomyopathy. The best separation between patients with normal vs increased necropsy LV mass was obtained using sex-specific echo LV mass index criteria (overall accuracy = 73 of 88 patients, 83%). Lower overall accuracies for separation of patients with and without hypertrophy were observed for echo cross-sectional area (59 of 88 patients, 67%; p less than 0.05 vs LV mass index) and indexes of LV wall thickness (39 to 51%, p less than 0.001). Among 113 living patients with moderate or severe hypertension, mitral regurgitation or dilated cardiomyopathy, LV mass index was increased in 73%, cross-sectional area index in 58% (p less than 0.02 vs LV mass index), and posterior wall thickness, septal thickness and relative wall thickness in only 11 to 32% (all p less than 0.001 vs LV mass index). Thus, an M-mode echo LV mass index of more than 134 g/m2 in men and more than 110 g/m2 in women detects concentric and eccentric LV hypertrophy accurately by comparison with necropsy and clinical reference standards; cross-sectional area is slightly less useful; and other M-mode echo criteria of LV hypertrophy perform too poorly to be clinically applicable.

Echocardiographic score as a predictor of in-hospital cost in patients undergoing percutaneous balloon mitral valvuloplasty.

Percutaneous balloon mitral valvuloplasty (PBMV) is an effective means of palliating mitral stenosis, but it sometimes leads to adverse clinical outcomes and exorbitant in-hospital costs. Because echocardiographic score is known to be predictive of clinical outcome in patients undergoing PBMV, we examined whether it could also be used to predict in-hospital cost. Preprocedure echocardiographic scores, baseline clinical characteristics, and total in-hospital costs were examined among 45 patients who underwent PBMV between January 1, 1992, and January 1, 1994. Patients ranged in age from 18 to 71 years and had preprocedure echocardiographic scores that ranged from 4 to 12. Following PBMV, mean mitral valve area increased from 1.1 +/- 0.3 to 2.4 +/- 0.6 cm2 (p = 0.0001), and mean pressure gradient decreased from 18.3 +/- 5.9 to 6.7 +/- 2.7 mm Hg (p = 0.0001). In-hospital cost for the 45 patients ranged from $3,591 to $70,975 (mean $9,417; median $5,311). Univariate and multiple linear regression analyses demonstrated that among the variables examined, echocardiographic score (p = 0.0007), age (p = 0.01), and preprocedure mitral valve gradient (p = 0.03) were associated with in-hospital cost. Regression modeling suggested that every increase in preprocedure echocardiographic score of one grade was associated with an increase in in-hospital cost of $2,663. Because echocardiographic score is predictive of both clinical outcome and in-hospital cost, we conclude that patients with elevated scores should be considered for alternative therapy.

Percutaneous balloon valvotomy for the treatment of isolated tricuspid stenosis.

A 46-year-old woman with isolated tricuspid stenosis complained of increasing fatigue and dyspnea on exertion. Exercise Doppler echocardiography reproduced her symptoms and revealed a marked increase in trans-tricuspid gradient. Successful percutaneous balloon tricuspid valvotomy was performed, with resolution of her symptoms.

Transesophageal echocardiographic guidance of closed mitral commissurotomy.

We describe the utility of transesophageal echocardiography in a patient undergoing emergent closed mitral commissurotomy. Two-dimensional images provided an assessment of valve morphology and mobility while Doppler echocardiography was used to monitor the occurrence of mitral regurgitation and changes in valve gradient and area.

Transesophageal echocardiography in percutaneous balloon valvuloplasty for mitral stenosis.

As percutaneous mitral valvuloplasty gains wider acceptance, appropriate selection of patients for this procedure continues to be important. The presence of atrial thrombus is a contraindication, and transesophageal echocardiography provides optimal visualization of the left atrium and atrial appendage to assess for the presence of thrombus. This case report describes a patient in whom left atrial thrombus was suspected based on standard precordial echocardiography. After transesophageal echocardiography demonstrated the structure in question to be a normal portion of the left atrial wall, the patient underwent successful uncomplicated percutaneous mitral valvuloplasty. We recommend transesophageal echocardiography in all patients being considered for percutaneous valvuloplasty for mitral stenosis.

Percutaneous balloon valvotomy for patients with mitral stenosis: initial and follow-up results.

Percutaneous double balloon mitral valvotomy (PMV) was performed in 25 patients with severe mitral stenosis who were followed for at least 6 months after the procedure. There were 22 women and 3 men, with a mean age of 51 +/- 14 years (range, 27 to 74). Hemodynamic and angiographic findings were evaluated before and after PMV and clinical status was assessed at follow-up. There was a significant decrease in mitral gradient following PMV, from 15.4 +/- 5.1 to 5.0 +/- 2.6 mm Hg (p less than .0001); an increase in cardiac output, from 4.6 +/- 1.1 to 5.2 +/- 1.1 L/min (p less than .01); and an increase in calculated mitral valve area, from 0.9 +/- 0.2 to 2.2 +/- 0.6 cm2 (p less than 0.0001). Mitral regurgitation developed or increased in severity in six patients (24%). At the time of follow-up (mean, 12 +/- 5 months), three patients required elective mitral valve replacement for symptomatic mitral regurgitation and 91% (20 of 22) of the remaining patients had continued improvement in functional class. PMV can safely be performed in properly selected patients with symptomatic mitral stenosis with good immediate and follow-up results.

Pericardial effusion: relation of clinical echocardiographic and electrocardiographic findings.

To evaluate the effects of pericardial effusion on the ECG, we compared clinical, echocardiographic and ECG findings in 459 patients. The prevalence of echocardiographic effusion ranged from 1% (1/79) among normal subjects, to 28% (32/114) among patients with valvular disease, 30% (27/90) in patients with hypertension, and 86% (18/21) in patients with pericardial disease. No relationship existed between left ventricular function and the prevalence of effusion, but a strong inverse relationship was found between LV function and effusion size (r = -0.63, p less than 0.01). Small and moderate sized effusions had a progressive damping effect on ECG voltage, displacing the regression lines between Sokolow -Lyon voltage and left ventricular mass downward by 1.2 and 4.4 mm respectively. Standard ECG criteria for low voltage (leads I, II, III each less than 0.5 mV, or V1 to V6 each less than 1.0 mV) were extremely insensitive for detection of effusions (12%), although highly specific (94%). Other ECG criteria which improved sensitivity resulted in an unacceptably high prevalence of false-positive diagnoses of pericardial effusion. Thus, echocardiographic effusions occur in only 1% of normal subjects but in more than 25% of patients with hemodynamic loading conditions, with a strong relationship between worsening left ventricular function and increasing effusion size. In contrast to the close relationship between echocardiographic pericardial effusions and clinical findings, low electrocardiographic QRS voltage is a weak predictor of the presence of pericardial effusion.

Geometric determinants of electrocardiographic left ventricular hypertrophy.

Experimental studies have suggested that electrocardiographic recognition of left ventricular hypertrophy depends on geometric relationships involving wall thickness and chamber size. To determine the clinical significance of these observations, we studied the effects of echocardiographic LV mass (LVM), posterior wall thickness (PWT), interventricular septal thickness (IVST) and internal dimension (LVID) on ECG voltage in 360 patients. Standard voltage and nonvoltage manifestations of LVH correlated modestly with LVM (r = 0.33-0.44, p less than 0.001). Sokolow-Lyon precordial voltage (SLV) (SV1 + RV5 or V6) correlated moderately with LVM (r = 0.41, p less than 0.001), but correlated less well with IVST (r = 0.26), PWT (r = 0.24) or LVID (r = 0.22). Stepwise regression revealed that there was no relation, independent of LVM, between SLV and IVST (r = 0.03), PWT (r = 0.03) or LVID (r = 0.01). The 90 patients with increased LVM (greater than 215 g) but without LVH by SLV (false negatives) were compared with the 48 identified by SLV (true positives). False negatives differed from true positives in LVM (298 +/- 72 vs 339 +/- 98 g, p less than 0.01), age (55 +/- 18 vs 44 +/- 19 years, p less than 0.001), weight (70 +/- 16 vs 63 +/- 14 kg, p less than 0.02), and distance from skin to the interventricular septum (42 +/- 10 vs 38 +/- 8 mm, p less than 0.02). Thus, for a given LVM, ECG voltage criteria of LVH are independent of LV chamber dilatation or other geometric variables, but depend on age, weight and LV depth in the chest, suggesting that stratification of subjects by clinical variables has promise for improved electrocardiographic recognition of LVH.

Improved sex-specific criteria of left ventricular hypertrophy for clinical and computer interpretation of electrocardiograms: validation with autopsy findings.

In a previous study of 543 patients we developed, using echocardiographic left ventricular mass as the reference standard, two new sets of criteria that improve the electrocardiographic diagnosis of left ventricular hypertrophy (LVH). One set of criteria, which is suitable for routine clinical use, detects LVH when the sum of voltage in RaVL + SV3 (Cornell voltage) exceeds 2.8 mV in men and 2.0 mV in women. The second set of criteria, suitable for use in interpretation of the computerized electrocardiogram, uses logistic regression models based on electrocardiographic and demographic variables with independent predictive value for LVH, with separate equations for patients in sinus rhythm and atrial fibrillation. To test these criteria prospectively with use of a different reference standard, antemortem electrocardiograms were compared with left ventricular muscle mass measured at autopsy in 135 patients. Sensitivity of standard Sokolow-Lyon voltage (SLV) criteria (SV1 + RV5 or RV6 greater than 3.5 mV) for LVH was only 22%, but specificity was 100%. The Cornell voltage criteria improved sensitivity to 42%, while maintaining high specificity at 96%. Higher sensitivity (62%) was achieved by use of the new regression criteria, with a specificity of 92%. Overall test accuracy was 60% for SLV criteria, 68% for the Cornell voltage criteria, and 77% for the new regression criteria (p less than .005 vs SLV). We conclude that the Cornell voltage criteria improve the sensitivity of the electrocardiogram for detection of LVH and are easily applicable in clinical practice.(ABSTRACT TRUNCATED AT 250 WORDS)