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Accuracy of echocardiography versus electrocardiography in detecting left ventricular hypertrophy: comparison with postmortem mass measurements.

The accuracy of electrocardiography, M-mode echocardiography and two-dimensional echocardiography in predicting left ventricular hypertrophy was compared in 50 patients who came to autopsy within 6 months after the studies were performed. Several methods for determining left ventricular hypertrophy were examined for each of the three techniques. M-mode echocardiography was technically adequate to evaluate the presence or absence of left ventricular hypertrophy more often than either electrocardiography or two-dimensional echocardiography. Measurements from M-mode echocardiography also correlated best with autopsy measurements. Both echocardiographic techniques had a higher sensitivity than electrocardiographic criteria in diagnosing left ventricular hypertrophy. Two-dimensional echocardiography was not shown to improve the M-mode assessment of left ventricular hypertrophy. In an attempt to simplify both M-mode left ventricular mass calculations and the diagnosis of left ventricular hypertrophy for the clinician, a left ventricular mass nomogram was constructed, enabling quick insertion of standard M-mode echocardiographic measurements.

Adult↗

Noninvasive diagnostic test choices for the evaluation of coronary artery disease in women: a multivariate comparison of cardiac fluoroscopy, exercise electrocardiography and exercise thallium myocardial perfusion scintigraphy.

Several diagnostic noninvasive tests to detect coronary and multivessel coronary disease are available for women. However, all are imperfect and it is not yet clear whether one particular test provides substantially more information than others. The aim of this study was to evaluate clinical findings, exercise electrocardiography, exercise thallium myocardial scintigraphy and cardiac fluoroscopy in 92 symptomatic women without previous infarction and determine which tests were most useful in determining the presence of coronary disease and its severity. Univariate analysis revealed two clinical, eight exercise electrocardiographic, seven myocardial scintigraphic and seven fluoroscopic variables predictive of coronary or multivessel disease with 70% or greater stenosis. The multivariate discriminant function analysis selected a reversible thallium defect, coronary calcification and character of chest pain syndrome (p less than 0.05) as the variables most predictive of presence or absence of coronary disease. The ranked order of variables most predictive of multivessel disease were cardiac fluoroscopy score, thallium score and extent of ST segment depression in 14 electrocardiographic leads. Each provided statistically significant information to the model. The estimate of predictive accuracy was 89% for coronary disease and 97% for multivessel coronary disease. The results suggest that cardiac fluoroscopy or thallium scintigraphy provide significantly more diagnostic information than exercise electrocardiography in women over a wide range of clinical patient subsets.

Adult↗

Assessment of single vessel coronary artery disease: results of exercise electrocardiography, thallium-201 myocardial perfusion imaging and radionuclide angiography.

The sensitivity of the commonly used stress tests for the diagnosis of coronary artery disease was analyzed in 46 patients with significant occlusion (greater than or equal to 70% luminal diameter obstruction) of only one major coronary artery and no prior myocardial infarction. In all patients, thallium-201 perfusion imaging (both planar and seven-pinhole tomographic) and 12 lead electrocardiography were performed during the same graded treadmill exercise test and radionuclide angiography was performed during upright bicycle exercise. Exercise rate-pressure (double) product was 22,307 +/- 6,750 on the treadmill compared with 22,995 +/- 5,622 on the bicycle (p = NS). Exercise electrocardiograms were unequivocally abnormal in 24 patients (52%). Qualitative planar thallium images were abnormal in 42 patients (91%). Quantitative analysis of the tomographic thallium images were abnormal in 41 patients (89%). An exercise ejection fraction of less than 0.56 or a new wall motion abnormality was seen in 30 patients (65%). Results were similar for the right (n = 11) and left anterior descending (n = 28) coronary arteries while all tests but the planar thallium imaging showed a lower sensitivity for isolated circumflex artery disease (n = 7). The specificity of the tests was 72, 83, 89 and 72% for electrocardiography, planar thallium imaging, tomographic thallium imaging and radionuclide angiography, respectively. The results suggest that exercise thallium-201 perfusion imaging is the most sensitive noninvasive stress test for the diagnosis of single vessel coronary artery disease.

Adult↗

Prevalence and distribution of coronary disease in claudicants using 12-lead precordial stress electrocardiography.

AIMS: to evaluate the prevalence of coronary artery disease (CAD) by means of modified stress electrocardiography in patients presenting with intermittent claudication. METHODS: three hundred consecutive patients (188 male) with intermittent claudication (post-exercise ankle brachial index <0.8), and 100 age and sex-matched controls, were assessed for CAD with resting and stress 12-lead-precordial ECG. A history of angina and previous myocardial infarction (MI) was recorded. EXCLUSION CRITERIA: recent (<1 month) MI; unstable angina; prior coronary intervention; arrhythmias; conduction abnormalities; uncontrolled hypertension; heart failure, digoxin therapy, and inability to perform tests. RESULTS: based on antecedent angina, MI and abnormal resting ECG, CAD prevalence was 47% in claudicants and 6% in controls; on 12-lead-precordial ECG stress testing, CAD prevalence was 46% (95% CI: 40.1-51.7%) in claudicants and 11% (95% CI: 4.8-17.2%) in controls (both p <0.0001). Only 67% of claudicants (n=141) with antecedent angina, MI or an abnormal resting ECG, met the criteria of CAD on stress testing; also 28% of claudicants without antecedent angina, MI and a normal resting ECG (n=159) had evidence of CAD. The odds ratio for CAD in claudicants was 6.9. Based on 12-lead-precordial ECG stress testing we detected the presence of: one-, two- and three-vessel disease in 14.7% (95% CI: 10.6-18.7%), 19% (95% CI: 14.5-23.5%) and in 12.3% (95% CI: 8.6-16%) of claudicants; and in 8, 3 and 0% of controls, respectively. CONCLUSIONS: forty six percent of patients with intermittent claudication had concomitant CAD, and 31% two- or three-vessel disease. In the presence of claudication the odds ratio for CAD is 6.9 (95% CI: 3.5-13.4) and for two- or three-vessel disease 14.8. Non-invasive modified stress electrocardiography by enabling identification of those with multi-vessel CAD and thus by providing cardiac risk stratification may help bridge the gap between clinical evaluation and invasive coronary imaging.

Adult↗

Differences in foetal heart rate variability from phonocardiography and abdominal electrocardiography.

The agreement of the phonocardiographic method to provide foetal heart rate variability (FHRV) indices equivalent to those derived from abdominal electrocardiography was tested. 15 pregnant women were recruited in order to obtain antepartum foetal phonocardiograms and abdominal electrocardiograms three minutes long. From the respective sound (SS) and electric (RR) time series, typical temporal and spectral indices of FHRV were computed and compared. Means of the SS and RR intervals were not significant (P> 0.05) and these showed a correlation r=0.98. However, the temporal indices, P(TOT), HF and LF/HF presented differences (P< 0.05), since SS values were higher. Spectral coherence decreased below 0.5 for frequencies above 0.28+ 0.07 Hz, where bands resembling maternal and foetal breathing movements were noted. Particularly above 0.28Hz, temporal and spectral FHRV indices derived from phonocardiography and electrocardiography show differences. Quality of the signal, processing techniques, and maternal and foetal respiratory factors could account to explain these.

Adult↗

Detection of restenosis after coronary angioplasty for single-vessel disease: how reliable are exercise electrocardiography and scintigraphy in asymptomatic patients?

The diagnostic value of exercise electrocardiography and thallium myocardial scintigraphy for the detection of restenosis was assessed in 111 patients undergoing control angiography 6 months after successful coronary angioplasty. All patients were free of symptoms at the time of the study. A diameter reduction of 70% or more at the site of angioplasty was considered restenosis. The sensitivity of exercise electrocardiography is low (64%). Exercise ECG and scintigraphy are highly specific (respectively 90% and 93%). The predictive value of a positive ECG or thallium scintigraphy is poor (respectively 53% and 63%). The value of a negative scintigraphic result is slightly better than the predictive value of a negative ECG (98% vs 95%; NS). A negative exercise scintigraphy almost excludes severe restenosis. These non-invasive tests seem suitable for the detection of asymptomatic restenosis.

Angioplasty, Balloon, Coronary↗

Ambulatory electrocardiography strategies used in assessing silent myocardial ischaemia.

Ambulatory electrocardiography is increasingly used as a noninvasive diagnostic cardiologic test to detect symptomatic or silent myocardial ischaemia. Several clinical and technical factors effect the accurate interpretation of ambulatory electrocardiography myocardial ischaemia and are reviewed. The current state of ambulatory ECG technical strategies used in assessing myocardial ischaemia are presented with a viewpoint towards their advantages and disadvantages.

Coronary Disease↗

Effects of antianginal therapy with a calcium antagonist and nitrates on dobutamine-atropine stress echocardiography. Comparison with exercise electrocardiography.

BACKGROUND: Anti-ischaemic therapy with nitrates and/or calcium channel blockers profoundly affects the results of pharmacological stress echocardiography with coronary vasodilators but the influence on catecholamine stress testing remains unsettled. AIMS: The present study aimed to assess the effects of non-beta-blocker antianginal therapy on dobutamine (up to 40 micrograms.kg-1.min-1)-atropine (up to 1 mg) stress. echo-cardiography and to evaluate whether drug-induced changes in the dobutamine atropine stress echocardiography response may predict variations in exercise tolerance. METHODS: Twenty six patients with angiographically assessed coronary artery disease (seven patients with single-, 10 with double-, and nine with triple-vessel disease) performed a dobutamine atropine stress echocardiography and an exercise electrocardiography test in random order both off and on antianginal drugs (nitrates and calcium antagonists). In doubtamine-atropine stress echocardiography, we evaluated: dobutamine time (i.e. the time from initiation of the dobutamine infusion to obvious dyssynergy), wall motion score index (in a 16-segment model of the left ventricle, each segment ranging from 1 = normal, to 4 = dyskinetic), and rate-pressure product at peak stress. RESULTS: Dobutamine-atropine stress echocardiography positivity occurred in 26 out of 26 patients off and in 23 patients on therapy (100 vs 88%, P = ns). Atropine coadministration was needed to evoke echo positivity in no patient off and in five out of 26 on therapy (0 vs 19% P < 0.01). The achieved rate pressure product during dobutamine-atropine stress echocardiography was comparable on and off therapy (17 +/- 4 vs 19 +/- 5 x 10(3) mmHg x heart rate. min-1, P = ns). Therapy induced an increase in dobutamine time (on = 16 +/- 3 vs of = 13 +/- 3 min, P < 0.01) and a decrease in peak wall motion score index (on = 1.3 +/- 0.2 vs off = 1.5 +/- 0.3, P < 0.01). The therapy induced changes in exercise time during the exercise electrocardiography test were not significantly correlated to dobutamine-atropine stress echocardiography variations in either dobutamine time (r = 0.07, P = ns), or peak rate pressure product (r = 0.24, P = ns), or peak wall motion score index (r = 0.02, P = ns). CONCLUSIONS: (1) non-beta-blocker antianginal therapy only modestly reduces dobutamine-atropine stress echocardiography sensitivity, although atropine coadministration is more often required to reach stress echo positivity under therapy; (2) therapy reduces the severity of dobutamine atropine stress echocardiography ischaemia stratified in the time and space domain, but these changes are only poorly correlated to variations in exercise tolerance.

Atropine↗

Protective effect of nisoldipine on dipyridamole-induced myocardial ischemia: correlation with exercise electrocardiography.

BACKGROUND: Nisoldipine, a dihydropyridine calcium channel blocker with strong coronary dilatative action, is commonly used in the treatment of myocardial ischaemia; its beneficial effect on effort angina has been demonstrated by several previous reports. Infusion of dipyridamole in doses sufficient to provoke myocardial ischaemia in patients with significant coronary artery disease is used safely in imaging studies for diagnostic purposes. OBJECTIVE: To evaluate the potential effect of nisoldipine on dipyridamole-induced ischaemia and to compare the results with the effect of nisoldipine on exercise-induced ischaemia. METHOD: Twelve patients (10 men and two women, mean age 62 +/- 8 years) with significant coronary artery disease (at least 70% lumen reduction in at least one major coronary vessel) were selected for inclusion in the study. In accordance with the inclusion criteria, the patients exhibited an ischaemic diagnostic response to a multistage exercise electrocardiography stress test (> 0.15 mV ST segment depression compared with the resting electrocardiographic tracing) and to a dipyridamole-echocardiography test (transient left ventricular dyssynergy of contraction during infusion of dipyridamole up to 0.84 mg/kg over 10 min), after 3 days' cessation of antianginal treatment. After treatment with oral nisoldipine (10 mg twice daily) was introduced, the patients repeated the two tests, within 18 days of the first evaluation. RESULTS: The dipyridamole-echocardiography test was positive for ischaemia in 12 patients who were not receiving nisoldipine and in eight patients who were receiving the drug (100% and 67% respectively, P < 0.05). In the eight patients who gave positive dipyridamole-echocardiography tests both with and without treatment, dipyridamole time (time to onset of dyssynergy during the test) increased from 7.9 +/- 2.9 min to 10.2 +/- 3.1 min (P < 0.01). In these patients, no significant changes were observed, at ischaemia, in the severity and extent of induced dyssynergy, evaluated as wall motion score index (each of 16 left ventricular segments scored from 1 = normal to 4 = dyskinetic) after treatment (score variations from baseline to ischaemia: 0.20 +/- 0.11 without nisoldipine and 0.16 +/- 0.06 with nisoldipine; NS). Variations in dipyridamole time (arbitrarily considered to be 15 min in the negative dipyridamole-echocardiography test) were significantly correlated with variations in exercise time (duration of exercise to exhaustion or diagnostic positive response on the electrocardiogram): r = 0.75 (P < 0.01). No significant differences were recorded in rate-pressure product (beats/min x mmHg x 100) at peak ischaemia between patients who were or were not receiving nisoldipine, during either the exercise electrocardiography stress test (233 +/- 36 with nisoldipine and 244 +/- 39 without nisoldipine; NS) or the dipyridamole-echocardiography test (147 +/- 21 with nisoldipine and 133 +/- 30 without nisoldipine; NS). CONCLUSION: Nisoldipine treatment can protect from dipyridamole-induced ischaemia, being associated with a longer stress time, and completely preventing the development of ischaemia in some patients. The therapy-induced changes in ischaemic threshold during the dipyridamole-echocardiography test correlate with variations in exercise tolerance.

Calcium Channel Blockers↗

Solving the inverse problem of electrocardiography using a Duncan and Horn formulation of the Kalman filter.

Numeric regularization methods most often used to solve the ill-posed inverse problem of electrocardiography are spatial and ignore the temporal nature of the problem. In this paper, a Kalman filter reformulation incorporated temporal information to regularize the inverse problem, and was applied to reconstruct left ventricular endocardial electrograms based on cavitary electrograms measured by a noncontact, multielectrode probe. These results were validated against in situ electrograms measured with an integrated, multielectrode basket-catheter. A three-dimensional, probe-endocardium model was determined from multiplane fluoroscopic images. The boundary element method was applied to solve the boundary value problem and determine a linear relationship between endocardial and probe potentials. The Duncan and Horn formulation of the Kalman filter was employed and was compared to the commonly used zero- and first-order Tikhonov spatial regularization as well as the Twomey temporal regularization method. Endocardial electrograms were reconstructed during both sinus and paced rhythms. The Paige and Saunders solution of the Duncan and Horn formulation reconstructed endocardial electrograms at an amplitude relative error of 13% (potential amplitude) which was superior to solutions obtained with zero-order Tikhonov (relative error, 31%), first-order Tikhonov (relative error, 19%), and Twomey regularization (relative error, 44%). Likewise, activation time error in the inverse solution using the Duncan and Horn formulation (2.9 ms) was smaller than that of zero-order Tikhonov (4.8 ms), first-order Tikhonov (5.4 ms), and Twomey regularization (5.8 ms). Therefore, temporal regularization based on the Duncan and Horn formulation of the Kalman filter improves the solution of the inverse problem of electrocardiography.

Algorithms↗

The influence of beta-adrenoceptor blockers with and without intrinsic sympathomimetic activity on heart rate, arrhythmias and ST-T segments, using ambulatory electrocardiography.

1. Ambulatory electrocardiography was used to compare the effects of propranolol and pindolol on symptoms, heart rate, arrhythmias and ST segments. Seventeen males (mean age 54 years) with a diagnosis of chronic stable angina pectoris (New York Heart Association Class II-III) were studied. Patients were treated on a double-blind cross-over basis with propranolol 80 mg three times daily or pindolol 5 mg three times daily for 14 days each. During the last 48 h of each treatment period ambulatory electrocardiography was performed. 2. Propranolol resulted in a significantly lower mean hourly, mean 24 h and minimum heart rate. Likewise propranolol caused a lower mean daytime and nocturnal heart rate. There was no significant difference in the frequency of angina between the treatments. The number of episodes of ST segment depression was not significantly different between the two drugs, although there was a trend in favour of propranolol. 3. Both the mean 24 h ST level and the maximum ST segment depression were lower during treatment with pindolol. Propranolol was associated with a total of 117 nocturnal pauses or episodes of asystole ranging in length from 1.5 to 2.8 s. During treatment with pindolol only one such period occurred. The number of premature ventricular contractions occurring during treatment with pindolol (1316 beats) was less than on propranolol (2010) and the mean hourly frequency of premature ventricular contractions was significantly lower during pindolol administration. 4. Pindolol is not significantly different from propranolol in the control of symptomatic and asymptomatic myocardial ischaemia and is associated with fewer premature ventricular contractions. However, there is no advantage in using pindolol in chronic stable angina.

Adult↗

Transesophageal electrocardiography and atrial pacing in acute cardiac care: diagnostic and therapeutic value.

The utility of transesophageal electrocardiography using a bipolar 'pill electrode' was assessed in 17 consecutive patients with tachycardia presenting to our casualty department. Standard 12-lead electrocardiography showed regular narrow QRS tachycardia in 12 patients, and five patients had wide QRS tachycardia. Esophageal atrial electrogram recordings were obtained in 14 patients (82%), and these were helpful in determining the mechanism of tachycardia in 11 patients (78%). Of these 11, seven patients fulfilled criteria for atrioventricular junctional (AVJ) tachycardia based on measurement of the minimum interval between the onset of ventricular depolarisation and earliest atrial (esophageal) activity. One of these patients had presented with a wide QRS tachycardia. The other four patients were diagnosed as having ventricular tachycardia (VT) following diagnosis of AV dissociation. Atrial overdrive pacing, via the pill electrode, successfully reverted four of the nine patients (44%) with narrow QRS tachycardia but no patient with VT. Esophageal recording during tachycardia is a simple, relatively non-invasive technique which is helpful in suggesting the mechanism of tachycardia both in patients with narrow and wide QRS tachycardia, and may have a therapeutic role in patients with AVJ tachycardia.

Adolescent↗

Three-dimensional electrocardiography of cardiac pacing.

Electrocardiographic evaluation of modern pacing systems requires sustained documentation during iterative programming procedures, exercise testing or Holter monitoring. Documentation of a prolonged period of time in standard electrocardiography is based on horizontal compression. The value and limitations of a vertical compression with no change in horizontal chronology and waveform morphology are evaluated. The signal taken from a selected surface lead is introduced into an oscilloscope triggered by an electrocardiographic event along the horizontal axis. A continuous vertical monitoring provides a vertical superimposition of the consecutive cycles. The brightness is proportional to the amplitude of the signal and introduces a third dimension. The three-dimensional technique results in an original image allowing report miniaturization at standard 25 or 50 mm/sec paper speed. Appropriate lead selection and use of the brightness as a marker event allow reliable atrial activity identification. In rate responsive pacing evaluation, the procedure is specifically convenient to full disclosure of the chronotropic response. The main limitation is a high sensitivity to noise during recording. Further developments are to be expected based on computer-assisted electrocardiography.

Cardiac Pacing, Artificial↗

Signal-averaged electrocardiography in elderly subjects with and without heart disease.

Prevalence of abnormal signal-averaged electrocardiography in normal populations appears to be low, but has not been studied previously in an asymptomatic elderly population. To study the prevalence of abnormal ventricular late potentials in an elderly population, a group of 51 subjects with no evidence of cardiac disease and ranging in age from 62 to 102 years underwent signal-averaged electrocardiography. Results were compared to a group of 179 patients similar in age but with complex ventricular arrhythmias, and to a group of 25 asymptomatic volunteers under the age of 50. The prevalence of an abnormal signal-averaged ECG was 14% in the normal elderly subjects, and 31% in the patients (P = 0.01), and 4% in the young subjects (P = NS). We conclude that the prevalence of abnormal ventricular late potentials in elderly patients without heart disease is similar to levels reported in other populations of normal controls, but elderly patients with cardiac disease have a significantly higher prevalence of abnormal signal-averaged ECG studies than the normals.

Action Potentials↗

Diagnostic value of chest radiography and electrocardiography in the evaluation of asymptomatic children with a cardiac murmur.

We investigated the diagnostic value of the chest radiograph and ECG in the evaluation of whether asymptomatic children with a cardiac murmur had a heart disease as defined by echocardiography. One hundred children aged 1 month to 15 years (median 30.1 months) were included. After physical examination, a tentative diagnosis was made: 53 children had no heart disease, 24 had a probable heart disease and 23 children were thought to have heart disease on the basis of clinical assessment alone. After information from chest radiography and electrocardiography was obtained, the diagnoses were re-evaluated. This resulted in a change of the tentative diagnosis in three children. However, the diagnosis in relation to the definite diagnosis by colour Doppler echocardiography was not changed to the correct diagnosis in any of these cases. In 24 cases, radiography suggested the presence of heart disease; however, only 10 of these had heart abnormalities on the colour Doppler echocardiogram (CDE). Three children had an abnormal ECG; all of these had abnormalities on the CDE, but they were already diagnosed as having heart disease by physical examination. We conclude that chest radiography and electrocardiography is of no help in the discrimination between heart disease and no heart disease in asymptomatic children referred for a cardiac murmur.

Adolescent↗

Ambulatory electrocardiography in squash players.

Ambulatory electrocardiography was carried out in 21 healthy, fit, male squash players (aged 23-43 years) before, during, and after match play. Resulting electrocardiograms were analysed with respect to heart rate and changes in rhythm. The results indicate that squash increases the heart rate to 80% of an individual's predicted maximum heart rate for the duration of a game. Ventricular arrhythmias were detected in seven of the subjects during play and in seven in the immediate post-exercise period, an incidence which was not reproduced on subsequent maximal treadmill exercise testing. This study indicates that squash is a physiologically demanding sport which places a severe strain on the myocardium for considerable periods of time and is capable of generating cardiac arrhythmias. These findings are particularly important for an individual already at risk of sudden death from coronary artery disease or structural cardiovascular abnormalities. Medical advice before participation in the game will identify those at high risk of cardiovascular disease. Subjects in this study who developed arrhythmias were not, however, identified by history, examination, or exercise electrocardiography. Thus, it seems unwise to begin playing squash after the age of 40 years. Whether subjects in this age group already participating in the game should continue to play remains a matter for individual judgment.

Adult↗

Technician run open access exercise electrocardiography.

OBJECTIVE: To evaluate the safety, efficacy, and feasibility of the technician run open access exercise electrocardiography service at Freeman Hospital. DESIGN: Questionnaire analysis of the responses of the general practitioners of randomly selected patients who used the service. SETTING: A tertiary care cardiac centre, providing an open access service to general practitioners in the community. PATIENTS: 269 patients randomly selected from 552 who underwent open access exercise electrocardiography over a 2.5 year period. OUTCOME MEASURES: Utilisation of service: the reasons for referral, whether the service was optimally used by the general practitioners, and its effect on their management practice; effect on number of cardiology referrals; benefit to the patients; safety, efficacy, and feasibility of a technician run service; general practitioners' assessment of the service. RESULTS: 147 of 178 general practitioners (82.6%) responded to the questionnaire, on 247 of 269 patients (91. 8%). General practitioners used the service for diagnosing ischaemic heart disease in 72.5% of cases, for prognostic purposes in 17.8%, or both in 5.3%. In 197 cases (79.8%), the general practitioners felt that the service had changed the way they managed their patients. The exercise test was positive in 90 patients (36.5%) and identified 38 as at high risk. The service was effective in optimising the cardiology service by reducing referrals by 47%. CONCLUSIONS: The service was used by general practitioners primarily for diagnosing ischaemic heart disease and not so often for prognosis. The utilisation of the service was optimal as assessed by the high positivity rate. The service meets its primary objective of assisting general practitioners in the management of patients with suspected ischaemic heart disease, and may have helped to optimise resources by reducing the number of referrals to cardiologists. It has helped prioritize patient management and may have benefited high risk patients by facilitating rapid identification and referral. It can be run safely and effectively by trained technicians.

Adult↗

Intraoperative detection of myocardial ischemia in high-risk patients: electrocardiography versus two-dimensional transesophageal echocardiography.

Because acute segmental wall motion abnormalities (SWMAs) of the left ventricle are highly sensitive and specific indicators of myocardial ischemia, this study compared the incidence and significance of ischemia, as detected by two-dimensional transesophageal echocardiography and surface electrocardiography, during anesthesia and surgery in patients at high risk of myocardial ischemia. During surgery, 24 of the 50 patients studied had new SWMAs, whereas only six had ST segment changes. All patients with ST segment changes also had new SWMAs: in three instances, SWMAs occurred before the ST segment change, and in three instances, they occurred simultaneously. All three patients who had intraoperative myocardial infarctions also had persistent intraoperative SWMAs, whereas only one patient had ST segment changes. Ten healthy patients requiring noncardiovascular surgery were monitored similarly; none of these had SWMAs, ST segment changes, or myocardial infarction. This study demonstrates the superiority of two-dimensional transesophageal echocardiography over electrocardiography for the intraoperative detection of myocardial ischemia. Furthermore, when new SWMAs persist to the conclusion of surgery, myocardial infarction is likely to have occurred.

Echocardiography↗