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Dive into the research topics where Allan S. Lew is active.

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Featured researches published by Allan S. Lew.


Journal of the American College of Cardiology | 1987

Transient ischemic dilation of the left ventricle on stress thallium-201 scintigraphy: a marker of severe and extensive coronary artery disease.

A. Teddy Weiss; Daniel S. Berman; Allan S. Lew; Jan M. Nielsen; Benjamin N. Potkin; H.J.C. Swan; Alan D. Waxman; Jamshid Maddahi

On exercise thallium-201 scintigraphy, it has been noted that the size of the left ventricle is sometimes larger on the immediate poststress image than on the 4 hour redistribution image; this phenomenon has been termed transient ischemic dilation of the left ventricle. The angiographic correlates of this finding were assessed in 89 consecutive patients who underwent both stress-redistribution thallium-201 scintigraphy and coronary arteriography. A transient dilation ratio was determined by dividing the computer-derived left ventricular area of the immediate postexercise anterior image by the area of the 4 hour redistribution image. In patients with a normal coronary arteriogram or nonsignificant coronary stenoses (less than 50%), the transient dilation ratio was 1.02 +/- 0.05 and, therefore, an abnormal transient dilation ratio was defined as greater than 1.12 (mean + 2SD). The transient dilation ratio was insignificantly elevated in patients with noncritical coronary artery disease (50 to 89% stenosis) (1.05 +/- 0.05) and in patients with critical stenosis (greater than or equal to 90%) of only one coronary artery (1.05 +/- 0.05). In contrast, in patients with critical stenoses in two or three vessels, the transient dilation ratio was significantly elevated (1.12 +/- 0.08 and 1.17 +/- 0.09, respectively; p less than 0.05 compared with all other patient groups). An abnormal transient dilation ratio had a sensitivity of 60% and a specificity of 95% for identifying patients with multivessel critical stenosis and was more specific (p less than 0.05) than were other known markers of severe and extensive coronary artery disease, such as the presence of multiple perfusion defects or washout abnormalities, or both.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of the American College of Cardiology | 1993

Angiographic validation of bedside markers of reperfusion

Prediman K. Shah; Bojan Cercek; Allan S. Lew; William Ganz

OBJECTIVES We sought to validate with coronary angiography several primary and ancillary markers of reperfusion. BACKGROUND The availability of bedside markers of reperfusion is of major importance in the thrombolytic therapy of acute myocardial infarction. However, the reliability of current markers is still controversial. METHODS Changes in chest pain, ST segment elevation and heart rate and rhythm were assessed every 5 to 10 min for up to 3 h after initiation of recombinant tissue-type plasminogen activator therapy in 82 patients with acute myocardial infarction. Coronary angiography was performed within 24 h. RESULTS At angiography, 69 of the 82 patients had a patent infarct-related artery with Thrombolysis in Myocardial Infarction trial (TIMI) grade 3 flow and a rapid and progressive decrease in chest pain and ST elevation. The pain resolved in 24 +/- 23 min (range 3 to 50). The ST elevation decreased by > or = 50% within 16 +/- 14 min (range 5 to 41). Accelerated idioventricular rhythm developed in 49% of patients and sinus bradycardia in 23%; conduction abnormalities and atrial fibrillation resolved. All markers appeared in close temporal proximity to the onset of an abrupt increase in plasma creatine kinase (CK) and CK-MB isoenzyme activity, a previously validated marker of the time of reperfusion. Before its final resolution, ST elevation transiently decreased and increased in 58% of patients. Comparison of one pretreatment and one posttreatment electrocardiogram significantly reduced the reliability of ST segment change as a marker of reperfusion. In 13 of 82 patients, the infarct-related artery demonstrated TIMI grade < or = 2 flow; in 9, pain and ST elevation did not lessen and CK and CK-MB activity showed no abrupt increase. The remaining four patients initially demonstrated a decrease in pain and ST elevation; however, within 3 h and before angiography, the recurrence of pain and ST elevation suggested reocclusion. CONCLUSIONS A rapid and progressive decrease in pain and ST elevation is a reliable marker of reperfusion with TIMI grade 3 flow. Because ST elevation and pain often fluctuate before undergoing final resolution with reperfusion, frequent or continuous monitoring of ST elevation is essential for reliable recognition of the fact and time of reperfusion. Accelerated idioventricular rhythm and episodes of sudden sinus bradycardia, although specific to reperfusion, do not occur in all patients with reperfusion.


Journal of the American College of Cardiology | 1986

Reverse redistribution of thallium-201: a sign of nontransmural myocardial infarction with patency of the infarct-related coronary artery.

A.Teddy Weiss; Jamshid Maddahi; Allan S. Lew; Prediman K. Shah; William Ganz; H.J.C. Swan; D. S. Berman

The pattern of reverse redistribution on the day 10 poststreptokinase resting thallium-201 myocardial scintigrams is a common finding in patients who have undergone streptokinase therapy in evolving myocardial infarction. To investigate this phenomenon, 67 patients who underwent streptokinase therapy were studied pre- and 10 days poststreptokinase therapy resting thallium-201 studies, poststreptokinase therapy resting radionuclide ventriculography and coronary arteriography (60 of the 67 patients). Of the 67 patients, 50 (75%) showed the reverse redistribution pattern on the day 10 thallium-201 study (Group I), 9 (13%) had a nonreversible defect (Group II) and the remaining 8 (12%) had a normal study or showed a reversible defect (Group III). The reverse redistribution pattern was associated with patency of the infarct-related artery (100%), quantitative improvement in resting thallium-201 defect size from day 1 to day 10 study (94%) and normal or near normal wall motion on day 10 radionuclide ventriculography (80% of segments with marked and 54% of those with mild reverse redistribution). In contrast, nonreversible defects were associated with significantly less frequent patency of the infarct-related artery (67%, p = 0.01), improvement in defect size (11%, p less than 0.001) and normal or near normal wall motion (21%, p less than 0.05). Group III patients were similar to Group I with respect to these variables. The quantitated thallium-201 percent washout was higher in the regions with the reverse redistribution pattern (49 +/- 15%) compared with the contralateral normal zone (24 +/- 15%, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)


American Journal of Cardiology | 1987

Electrocardiographic differentiation of occlusion of the left circumflex versus the right coronary artery as a cause of inferior acute myocardial infarction

C. Noel Bairey; Prediman K. Shah; Allan S. Lew; Sharon Hulse

To determine whether the admission electrocardiogram can identify left circumflex or right coronary artery occlusion as the cause of an inferior acute myocardial infarction (AMI), findings from electrocardiography and coronary angiography performed within 12 hours of each other were retrospectively assessed in 41 consecutive patients with inferior AMI. All patients had ST-segment elevation in 1 or more inferior leads (II, III or aVF). Of the 12 patients with circumflex coronary artery occlusion, 10 (83%) had ST-segment elevation in 1 or more lateral leads (aVL, V5 or V6) without ST-segment depression in lead I. Similar electrocardiographic findings were noted in only 1 of 29 patients (4%) with right coronary occlusion (p less than 0.001). ST-segment depression in precordial leads V1-V3 was equally prevalent in both groups. Thus, the presence of both ST-segment elevation in 2 or more inferior leads and ST-segment elevation in 1 or more lateral leads with an isoelectric or elevated ST segment in lead I identified circumflex coronary occlusion with a sensitivity of 83%, specificity of 96%, positive predictive accuracy of 91% and negative predictive accuracy of 93%. When these criteria were prospectively applied to an additional cohort of 19 consecutive patients with inferior AMI (5 with left circumflex and 14 with right coronary artery occlusion), presence of left circumflex coronary artery occlusion was predicted with a sensitivity of 80%, specificity of 93%, positive predictive accuracy of 100% and negative predictive accuracy of 93%. Thus, the admission 12-lead electrocardiogram can assist in differentiating left circumflex from right coronary artery occlusion in patients with inferior AMI.


American Journal of Cardiology | 1987

Mortality and morbidity rates of patients older and younger than 75 years with acute myocardial infarction treated with intravenous streptokinase

Allan S. Lew; Hanoch Hod; Bojan Cercek; Prediman K. Shah; William Ganz

The influence of patient age on mortality risk and on the incidence of serious hemorrhagic complications after treatment of acute myocardial infarction (AMI) with intravenous streptokinase (SK) and heparin was examined in 120 consecutive patients. No upper age limit was set for patient inclusion. The mortality rate increased abruptly in patients aged 75 years or older such that the 24 patients in that age group had a 10-fold higher in-hospital mortality rate (33% vs 3%) and 1-year mortality rate (42% vs 4%) than the 96 patients younger than 75 years. This increased mortality rate in the elderly patients was related to a 2-fold higher incidence of major hemorrhagic complications (24% vs 11%) and an increased incidence of anterior AMI, healed prior AMI, multiple-vessel coronary artery disease and extensive myocardial necrosis estimated by peak creatine kinase-MB. Hemorrhagic complications were more frequent in women than in men and in patients with diabetes mellitus or systemic hypertension; all of these conditions were more prevalent in patients aged 75 years and older than in those younger than 75 years. In contrast, the incidence of hemorrhagic complications in nondiabetic elderly men (1 of 12) was similar to the incidence of bleeding in the patients younger than 75 years. Based on our data and those from other studies reporting no reduction in mortality in elderly patients with AMI who are treated with intravenous SK, it is recommended that patients aged 75 years or older should not be routinely treated with intravenous SK.(ABSTRACT TRUNCATED AT 250 WORDS)


American Journal of Cardiology | 1988

Usefulness of a rapid initial increase in plasma creatine kinase activity as a marker of reperfusion during thrombolytic therapy for acute myocardial infarction

Basil S. Lewis; William Ganz; Pierre Laramee; Bojan Cercek; Hanoch Hod; Prediman K. Shah; Allan S. Lew

This study evaluates a new nonangiographic marker of reperfusion--a rapid initial increase in plasma creatine kinase (CK) and CK-MB activity--in 50 patients receiving intracoronary streptokinase. Blood for CK and CK-MB activity was sampled at 30-minute intervals and angiography performed at 15-minute intervals or earlier if there were clinical signs suggestive of reperfusion. An absolute first-hour increase in CK activity of 480 +/- 345 IU/liter (range 54 to 1,440 IU/liter), or a relative first-hour increase of 34 +/- 18% (range 13 to 67% of the peak rise), or an absolute first-hour increase in CK-MB activity of 48 +/- 36 IU/liter (range 10 to 144 IU/liter) or a relative first-hour increase of 27 +/- 13% (range 13 to 57%) was found in patients immediately after reperfusion with Thrombolysis In Myocardial Infarction (TIMI) grade 3 perfusion of the artery of infarction. The onset of rapid increase in CK and CK-MB activity closely reflected the time of angiographic documentation of reperfusion. In contrast, in the absence of reperfusion, the absolute rate of increase in CK activity measured in the last hour of the 2 1/2-hour period beginning with the start of treatment was only 15 +/- 9 IU/liter on the average (range 2 to 30 IU/liter) and the relative rate of rise was 3 +/- 2% on the average (range 1 to 6%).(ABSTRACT TRUNCATED AT 250 WORDS)


American Journal of Cardiology | 1985

Factors that determine the direction and magnitude of precordial ST-segment deviations during inferior wall acute myocardial infarction

Allan S. Lew; Jamshid Maddahi; Prediman K. Shah; A.Teddy Weiss; Thomas Peter; Daniel S. Berman; William Ganz

Sixty-one patients with inferior acute myocardial infarction (AMI) and no evidence of prior AMI were studied to determine which factors influence the magnitude of precordial ST-segment depression. In the total study group, there was a significant but weak correlation between the magnitude of precordial ST-segment depression and the magnitude of inferior ST-segment elevation (r = -0.46, p less than 0.001). In the 29 patients with evidence of concomitant right ventricular (RV) involvement, precordial ST-segment depression was significantly smaller both in absolute terms (-1.3 +/- 1.8 vs -2.8 +/- 1.9 mm, p less than 0.01) and relative to the magnitude of inferior ST-segment elevation (ratio of -0.2 +/- 1.0 vs -1.1 +/- 0.5, p less than 0.01), whereas in the 15 patients with lateral ST-segment elevation (greater than or equal to 1 mm in lead V6), precordial ST-segment depression was significantly greater both in absolute terms (-3.5 +/- 2.3 vs -1.6 +/- 1.7 mm, p less than 0.01) and relative to the magnitude of inferior ST-segment elevation (ratio of -1.1 +/- 0.8 vs -0.5 +/- 0.9, p less than 0.02). Consistent with these findings, the correlation between the magnitudes of precordial and inferior ST-segment deviations was considerably improved when only the 24 patients with neither evidence of RV involvement nor lateral ST-segment elevation were analyzed (r = 0.89, p less than 0.001, n = 24). These data suggest that in patients with inferior AMI, there is a reciprocal relation between precordial and inferior ST-segment deviations, which is distorted by concomitant RV involvement and by concomitant lateral left ventricular wall involvement.


Journal of the American College of Cardiology | 1985

Precordial ST segment depression during acute inferior myocardial infarction: Early thallium-201 scintigraphic evidence of adjacent posterolateral or inferoseptal involvement

Allan S. Lew; A.Teddy Weiss; Prediman K. Shah; Jamshid Maddahi; Thomas Peter; William Ganz; H.J.C. Swan; Daniel S. Berman

To investigate the myocardial perfusion correlates of precordial ST segment depression during acute inferior myocardial infarction, a rest thallium-201 scintigram and a closely timed 12 lead electrocardiogram were obtained within 6 hours of the onset of infarction in 44 patients admitted with their first acute inferior myocardial infarction. Thirty-six patients demonstrated precordial ST segment depression (group 1) and eight did not (group 2). A perfusion defect involving the inferior wall was present in all 44 patients. Additional perfusion defects of the adjacent posterolateral wall (n = 20), the ventricular septum (n = 9) or both (n = 6) were present in 35 of 36 patients from group 1 compared with only 1 of 8 patients from group 2 (p less than 0.001). There was no significant difference in the frequency of multivessel coronary artery disease or disease of the left anterior descending artery between group 1 and group 2 or between patients with and those without a thallium-201 perfusion defect involving the ventricular septum. Thus, precordial ST segment depression during an acute inferior myocardial infarction is associated with thallium-201 scintigraphic evidence of more extensive involvement of the adjacent posterolateral or inferoseptal myocardial segments, which probably reflects the extent and pattern of distribution of the artery of infarction, rather than the presence of coexistent multivessel coronary artery disease or disease of the left anterior descending artery.


Journal of the American College of Cardiology | 1987

Inferior ST segment changes during acute anterior myocardial infarction: A marker of the presence or absence of concomitant inferior wall ischemia

Allan S. Lew; Hanoch Hod; Bojan Cercek; Prediman K. Shah; William Ganz

The significance of inferior ST segment changes during acute anterior myocardial infarction was studied in 60 patients with acute anterior infarction who had angiographic visualization of the entire distribution of the left anterior descending artery after thrombolytic therapy with streptokinase. In 34 patients (Group 1) this artery supplied the anterior wall of the left ventricle up to or including the apex but did not reach the inferior wall; in 16 patients (Group 2) it continued beyond the apex onto the inferior wall of the left ventricle; and in 10 patients with prior inferior infarction (Group 3) it partially supplied the inferior wall of the left ventricle through collateral channels to an occluded right or dominant circumflex coronary artery. Consistent with this anatomy, evidence of inferior wall ischemia was significantly more frequent in Groups 2 and 3 than in Group 1 by thallium-201 scintigraphy (91 versus 7%) and by contrast left ventriculography (91 versus 13%). There was no difference in the magnitude of precordial ST segment elevation among the three groups but the inferior ST segment depression was significantly smaller in Groups 2 and 3 with concomitant inferior wall ischemia than in Group 1 (aVF: -0.5 +/- 0.7; -0.5 +/- 1.0; -1.8 +/- 0.8 mm, respectively; p less than 0.001) with 10 of the 26 patients in Groups 2 and 3 having an elevated or isoelectric ST segment in aVF compared with none of the 34 patients in Group 1 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)


American Heart Journal | 1986

Utility of echocardiography for the early assessment of patients with nondiagnostic chest pain

Hiroyuki Sasaki; Yzhar Charuzi; Clain Beeder; Yuji Sugiki; Allan S. Lew

A two-dimensional (2D) echocardiogram was recorded shortly after admission in 46 patients with nondiagnostic chest pain. Eighteen patients were studied during chest pain and 28 were studied following the resolution of chest pain. Of the 18 patients studied during chest pain, six of the eight patients who had a regional wall motion abnormality (RWMA) evolved an acute infarction and the remaining two patients had evidence of significant coronary artery disease. Only 1 of 10 patients without a RWMA evolved an infarction and none had significant coronary artery disease. Of the 28 patients studied following the resolution of chest pain, 8 of the 10 patients with a RWMA evolved an acute infarction and one patient had evidence of significant coronary artery disease, whereas of 18 patients without a RWMA, none evolved an acute infarction and five had evidence of significant coronary artery disease. These data suggest that in patients presenting with nondiagnostic chest pain, an early assessment of regional wall motion by 2D echocardiography can reliably differentiate patients with myocardial ischemia or early infarction from patients with nonischemic chest pain when performed during an episode of chest pain; can also identify those patients with early acute myocardial infarction, even when performed following the resolution of chest pain; but is not useful for the detection of patients with significant coronary artery disease without infarction when performed following the resolution of chest pain.

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William Ganz

Cedars-Sinai Medical Center

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Prediman K. Shah

Cedars-Sinai Medical Center

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Daniel S. Berman

Cedars-Sinai Medical Center

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Bojan Cercek

Cedars-Sinai Medical Center

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H.J.C. Swan

University of California

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Hanoch Hod

Cedars-Sinai Medical Center

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J. Maddahi

Cedars-Sinai Medical Center

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A.Teddy Weiss

University of California

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Thomas Peter

University of California

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