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M R Starling

Publications and source records attributed to M R Starling.

At least 73 records · Page 4Linked to original sources
PubMed1984

Estimates of left-ventricular volumes by equilibrium radionuclide angiography: importance of attenuation correction.

To compare the accuracy of attenuated and attenuation-corrected equilibrium radionuclide angiographic (RNA) left ventricular (LV) volume estimates, we studied 23 consecutive patients with biplane contrast cineangiography (CINE). Attenuated RNA end-diastolic (ED) and end-systolic (ES) volumes were calculated from background-corrected ED and ES counts obtained from hand-drawn regions of interest that were normalized to cardiac cycles processed, frame rate, and blood activity. A simple, geometric attenuation correction was performed to obtain attenuation-corrected RNA LV volumes. The attenuated and attenuation-corrected RNA LV EDV estimates correlated with the CINE LV EDVs ; however, the attenuation-corrected RNA LV EDV estimates correlated more closely. Also, the average attenuation-corrected RNA LV EDV did not differ significantly from the mean CINE LV EDV. Attenuated and attenuation-corrected RNA LV ESV estimates also correlated with the CINE LV ESVs , but the attenuation-corrected RNA LV ESV estimates correlated more closely. Also, the average attenuation-corrected RNA LV ESV did not differ significantly from the mean biplane CINE LV ESV.

Adult↗
PubMed1983

Value of noninvasive techniques for predicting early complications in patients with clinical class II acute myocardial infarction.

Twenty-six consecutive patients with acute clinical class II myocardial infarction were prospectively evaluated to assess the ability of two-dimensional echocardiography and gated equilibrium radionuclide angiography to predict early morbidity and mortality. Within 48 hours of the onset of symptoms, right heart catheterization, two-dimensional echocardiography and radionuclide angiography were performed. Serious in-hospital complications developed in 7 patients (27%, Group I), while the remaining 19 patients (Group II) had no complications. Mean left ventricular stroke work index was the only hemodynamic variable that differed significantly between Group I and Group II (28 +/- 8 [standard deviation] vs. 39 +/- 13 g-m/m2, respectively, p less than 0.02). Also, Group I compared with Group II had a significantly lower mean left ventricular ejection fraction by two-dimensional echocardiography (26 +/- 5 vs. 51 +/- 10%, p less than 0.001) or by radionuclide angiography (29 +/- 9 vs. 46 +/- 12%, p less than 0.001). Similarly, Group I had a higher average wall motion index than Group II by both techniques (2.2 +/- 0.2 vs. 1.7 +/- 0.3, p less than 0.001 by two-dimensional echocardiography, and 2.1 +/- 0.3 vs. 1.7 +/- 0.3, p less than 0.001 by radionuclide angiography). Selected stepwise multiple regression analysis demonstrated that left ventricular ejection fraction or wall motion index, by two-dimensional echocardiography or radionuclide angiography, had additional value to a history of prior myocardial infarction for predicting in-hospital complications in patients with class II infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

Physical examination for exclusion of hemodynamically important right ventricular infarction.

Fifty-three consecutive patients with inferior myocardial infarction were evaluated prospectively, by physical examination and right heart catheterization within 36 hours of the onset of symptoms, to determine whether physical findings can separate such patients into those with and without associated right ventricular infarction. Hemodynamic findings consistent with right ventricular infarction were defined as right atrial pressure of 10 mm Hg or greater and a right atrial: pulmonary artery wedge pressure ratio of 0.80 or greater. Eight patients (Group 1) had hemodynamic evidence of right ventricular infarction, whereas 45 patients (Group 2) did not meet these criteria. Group 1, compared with Group 2, had a lower cardiac index (1.8 +/- 0.3 versus 2.6 +/- 0.6 L/min X m2, p less than 0.001), and a lower right ventricular stroke work index (4.1 +/- 3.6 versus 7.3 +/- 3.2 g X m/m2, p less than 0.05). An elevated jugular venous pressure of 8 cm H2O or more was seen in 7 of 8 Group 1 and 14 of 45 Group 2 patients (p less than 0.01). In addition, a Kussmaul's sign, substantiated by hemodynamic findings, was seen in all 8 Group 1 and in no Group 2 patients (p less than 0.001). The absence of both an elevated jugular venous pressure and a Kussmaul's sign in patients with inferior myocardial infarction makes the presence of a hemodynamically significant right ventricular infarction highly unlikely.

Adult↗
PubMed1982

Superiority of selected treadmill exercise protocols predischarge and six weeks postinfarction for detecting ischemic abnormalities.

We evaluated 29 uncomplicated post-myocardial infarction patients with heart rate-limited and symptom-limited modified Naughton treadmill exercise tests predischarge and 31 similar patients with symptom-limited modified Naughton and standard Bruce stress tests at 6 weeks following infarction to determine their comparative value for detecting unsuspected ischemic abnormalities. Predischarge, the symptom-limited modified Naughton test identified a significantly greater number of patients with ECG ST segment depression or angina than did the heart rate-limited test (21 vs 13 patients, p less than 0.05). This resulted from a significantly longer average maximal exercise duration (10.5 +/- 4.9 vs 7.9 +/- 4.2 minutes, P less than 0.001) and higher maximal rate-pressure product (21.9 +/- 5.8 vs 19.2 +/- 4.6 X 10(3), p less than 0.001) during the symptom-limited test. At 6 weeks following infarction, the standard Bruce stress test identified a significantly higher frequency of ischemic abnormalities than did the symptom-limited modified Naughton test (20 vs 13 patients, p less than 0.05). This resulted from a higher average maximal rate-pressure product (23.1 +/- 7.3 vs 21.0 +/- 6.2 X 10(3), p less than 0.02), despite a shorter maximal exercise duration (6.9 +/- 1.2 vs 10.7 +/- 4.4 minutes, p less than 0.001) during the Bruce stress test. We conclude that: (1) symptom-limited exercise is superior to heart rate-limited exercise predischarge and (2) the standard Bruce stress test is superior to the symptom-limited modified Naughton exercise test at 6 weeks following infarction for the detection of unsuspected ischemic abnormalities in uncomplicated postinfarction patients.

Adult↗
PubMed1982

Diltiazem: effects on exercise performance in patients with coronary artery disease.

We evaluated a new slow-channel calcium-blocking agent, diltiazem hydrochloride, in 10 patients with documented fixed coronary artery disease who had reproducible angina and greater than or equal to 0.1 mV ST segment depression on ECG treadmill exercise testing after 1 week of single-blind placebo administration. Subsequently, over the next 6 weeks, either diltiazem (30 mg/tablet) or placebo were administered for 1 week each in a randomized double-blind triple crossover design, as one tablet four times a day, two tablets three times a day or two tablets four times a day, for a total diltiazem dose of 120, 180 and 240 mg/day, respectively. Treadmill (electrocardiogram) exercise testing was performed at the end of each week. Only diltiazem at 240 mg/day increased significantly the time to angina pectoris (P less than 0.05), time to ST segment depression (P = 0.01), time to maximal exercise (P less than 0.02), and heart rate at maximal exercise (P less than 0.05) without effecting significantly the maximal rate-pressure product compared to the corresponding placebo values. In addition, using only the diltiazem data, a significant high dose response was observed for time to angina (P less than 0.05), ST segment depression (P less than 0.005), and maximal exercise (P less than 0.025). No adverse reactions were reported during the study. Therefore, we conclude that 240 mg/day of diltiazem improves significantly exercise performance in patients with angina pectoris due to fixed coronary artery disease and adverse effects, rarely, if ever, occur at this dosage.

Adult↗
PubMed1982

A new two-dimensional echocardiographic technique for evaluating right ventricular size and performance in patients with obstructive lung disease.

To compare two-dimensional (2-D) echocardiographic estimates of right ventricular size and performance to similar determinations from equilibrium radionuclide angiography (RNA) before and after isosorbide dinitrate, we evaluated 19 patients with severe chronic obstructive pulmonary disease. The end-diastolic and end-systolic volumes estimated from subcostal 2-D echocardiographic views of the right ventricle correlated with the RNA end-diastolic and end-systolic counts (r = 0.76 and 0.82, respectively). The 2-D echocardiographic and RNA right ventricular ejection fraction (EF) estimates also correlated (r = 0.80), and the average right ventricular EF measures of 42 +/- 11% and 40 +/- 12%, respectively, did not differ significantly. Nitrate administration produced a significant increase in heart rate (99 +/- 11 to 108 +/- 14 beats/min, p less than 0.001) and a decrease in systolic arterial pressure (139 +/- 23 to 120 +/- 22 mm Hg, p less than 0.001). Nitrates also significantly decreased the average 2-D echocardiographic end-diastolic and end-systolic volumes (22 +/- 16% and 18 +/- 12%, p less than 0.001), as well as RNA end-diastolic and end-systolic counts (33 +/- 17% and 32 +/- 22%, p less than 0.001), but did not significantly decrease the average right ventricular EF values (4 +/- 12% and 4 +/- 24%, respectively). Nevertheless, after isosorbide dinitrate, the 2-D echocardiographic right ventricular end-diastolic and end-systolic volume estimates continued to correlate with the corresponding RNA count measures (r = 0.76 and 0.79, respectively), as did the 2-D echocardiographic and RNA right ventricular EF values (r = 0.75). We conclude that 2-D echocardiographic evaluation of right ventricular size and performance is feasible in selected patients with chronic obstructive pulmonary disease, and that 2-D echocardiographic measures of right ventricular size and performance compare favorably with similar determinations by RNA at rest and after nitrate administration.

Blood Pressure↗
PubMed1982

Noninvasive quantitation of right-ventricular volume overload in adults by gated equilibrium radionuclide angiography.

R-wave-synchronized equilibrium radionuclide angiography (RNA) is a noninvasive method whose time-activity curves provide count information that is proportional to ventricular volume. We have performed resting gated RNA in nine consecutive adult patients undergoing cardiac catheterization for evaluation of left-to-right shunting. Pulmonary/systemic flow ratios (Qp/Qs) calculated from RNA correlated well with Qp/Qs defined by oximetry (r = 0.87, y = 0.85x + 0.11, sy . x = 0.46). In five patients imaged before, and within 1 mo after, successful surgical repair, RNA Qp/Qs declined from a mean (+/- s.d.) of 2.9 +/- 1.0 to 1.1 +/- 0.2. Right/left ventricular end-diastolic volume ratios declined from 3.1 +/- 1.3 to 1.7 +/- 0.2. Although left-ventricular ejection fraction did not change, right-ventricular ejection fraction declined in these patients. Imaging in nine patients with right-ventricular dysfunction, but without shunt or regurgitation, yielded a mean Qp/Qs of 0.94 +/- 0.27. We conclude that Qp/Qs, right-ventricular ejection fraction, and relative ventricular enlargement may be accurately quantitated and followed serially after therapeutic intervention using gated RNA.

Adult↗
PubMed1981

Predictive value of early postmyocardial infarction modified treadmill exercise testing in multivessel coronary artery disease detection.

We evaluated 57 patients with modified treadmill exercise testing and angiography early post-infarction (MI) to determine the predictive value of ST segment depression, angina, and an inadequate blood pressure response for multivessel coronary artery disease (MVCAD). ST segment depression alone identified MVCAD stenoses (greater than or equal to 70% diameter narrowing in two or more vessels) with sensitivity 54%, specificity 75%, and accuracy 60%. When ST segment depression and angina were considered a positive treadmill test result, a significant improvement in sensitivity (88%, p less than 0.01) and accuracy (82%, p less than 0.05) for MVCAD was observed. An inadequate blood pressure response was associated with MVCAD (12 of 13 patients) and a significantly reduced average left ventricular (LV) ejection fraction of 39 plus or minus 13% compared to 58 plus or minus 14% for patients without this treadmill abnormality (p less than 0.01). Therefore, we conclude that (1) ST segment depression and angina on early post-MI modified treadmill exercise testing are superior predictors of MVCAD compared to ST segment depression alone and (2) an inadequate blood pressure response during modified exercise testing early following MI is observed in patients with MVCAD and reduced LV performance.

Adult↗
PubMed1981

Comparative accuracy of electrocardiographic and vectorcardiographic criteria for inferior myocardial infarction.

Numerous criteria for the diagnosis of inferior wall myocardial infarction by electrocardiogram (ECG) and vectorcardiogram (VCG) have been published, but they have not been subjected to a systematic, independent evaluation. Accordingly, we studied 146 patients undergoing cardiac catheterization; 63 were normal and 83 had a history of infarction, a significant right coronary lesion and an inferior wall motion abnormality (inferior infarction group). No ECG or VCG criteria were considered in the designation of the two groups; rather, three sets of ECG and VCG criteria were evaluated for this purpose. Specificity was excellent (98-100%) and sensitivity was poor (4-34%) by all three sets of ECG criteria, but the 1949 ECG criteria of Meyers et al. are the least sensitive (4%, p less than 0.001). Specificity (90-100%) and sensitivity (82-84%) were very good by all three VCG criteria. The VCG criteria of Starr et al. gave no false-positive results in our normal group. Because of enhanced sensitivity, the overall accuracy of the VCG was higher than that of the ECG for the diagnosis of inferior infarction (90% vs 62%, p less than 0.001). We conclude that more recent ECG criteria for the diagnosis of inferior wall myocardial infarction are highly specific, but insensitive compared with VCG criteria.

Electrocardiography↗
PubMed1981

Aorto-coronary vein fistula. A complication of coronary artery bypass graft surgery.

We report two cases of the inadvertent insertion of a saphenous vein bypass graft into the anterior cardiac vein creating an aortocoronary vein fistula. The clinical recognition, evaluation, and management are discussed. Suggestions on surgical technique to help minimize or eliminate this potential complication during saphenous vein bypass surgery are proposed.

Aged↗
PubMed1981

Treadmill exercise tests predischarge and six weeks post-myocardial infarction to detect abnormalities of known prognostic value.

We evaluated 89 patients with predischarge and 6-week post-myocardial infarction treadmill exercise tests to determine the importance of doing repeat tests to identify abnormalities of known prognostic value, and assess the individual variability of treadmill abnormality responses. Nineteen patients (21%) completed only a predischarge exercise test, nine of whom experienced an early cardiac event precluding repeat testing. All nine had a prognostically important treadmill abnormality during the predischarge test. Electrocardiographic ST segment depression was highly reproducible between the early and 6-week tests (k = 0.968). However, angina, inadequate blood pressure response, and ventricular arrhythmias showed limited reproducibility (k = 0.344, 0.50, and 0.166, respectively) and substantial individual variability. Thus, we concluded that: a predischarge treadmill exercise test is important for determining the immediate short-term prognosis of patients after myocardial infarction; and ST segment depression is highly reproducible, whereas other treadmill abnormality responses show substantial variability between the predischarge and 6-week tests.

Adult↗
PubMed1980

Exercise testing early after myocardial infarction: predictive value for subsequent unstable angina and death.

Recently, modified treadmill exercise testing before hospital discharge has been reported to be safe in patients after uncomplicated myocardial infarction. Accordingly, the frequency of treadmill exercise-induced abnormalities and their prognostic value were evaluated in 130 patients with uncomplicated myocardial infarction. Seventy-eight patients (60 percent) had one or more treadmill exercise-induced abnormalities; 42 had S-T segment depression, 35 had angina and 17 had an inadequate blood pressure response. During the mean follow-up period of 11 months, 27 patients experienced unstable angina, 12 had a recurrent myocardial infarction and 10 died of cardiac causes. Compared with patients with no exercise-induced abnormality, patients with S-T segment depression, angina pectoris or an inadequate blood pressure response had a significantly greater (p < 0.001) incidence of all cardiac events during the follow-up period. Furthermore, unstable angina pectoris was significantly more frequent (p < 0.005) in patients with S-T segment depression or angina pectoris. Finally, when the patients with ischemic treadmill abnormalities were combined with the patients exhibiting an inadequate blood pressure response, they had a statistically greater (p < 0.005) incidence of cardiac death than that of patients with no treadmill abnormalities. Therefore, these three abnormalities during modified treadmill exercise testing before hospital discharge identify patients with uncomplicated myocardial infarction who are at risk for a future cardiac event.

Adult↗
PubMed1980

Accuracy and reproducibility of new M-mode echocardiographic recommendations for measuring left ventricular dimensions.

In order to assess the accuracy and reproducibility of the proposed American Society of Echocardiography (ASE) method for measuring left ventricular dimensions on M-mode echocardiograms, we measured the end-diastolic (Dd) and end-systolic (Ds) dimensions by the ASE method and our current technique in 50 normal subjects and 24 patients without coronary artery disease who had symmetrically contracting ventricles on cineangiography. Dd and Ds were significantly greater by the proposed ASE method than by our current technique (p less than 0.001), but the correlation between the two was good (r = 0.93 and 0.83, respectively). In 10 of the normal subjects, the interobserver variability of both methods was excellent. In the 24 patients, the proposed method consistently overestimated the angiographic left ventricular volumes compared with our current technique and occasionally the discrepancies were quite large. Therefore, the proposed ASE method for measuring left ventricular dimensions is not clearly superior to other currently available techniques.

Adult↗