Serial changes in response of hibernating myocardium to inotropic stimulation after revascularization: a dobutamine echocardiographic study.

OBJECTIVES: We sought to evaluate the serial changes in the response of the hibernating myocardium to dobutamine stimulation after revascularization. BACKGROUND: An improvement in myocardial contraction during dobutamine stress echocardiography (DSE), particularly a biphasic response, predicts recovery of rest function. However, little is known about the changes in the response of the myocardium to dobutamine after revascularization. METHODS: Thirty-four patients with stable coronary artery disease and regional left ventricular dysfunction underwent DSE before, early (within 1 week) and late (>6 weeks) after coronary angioplasty. Dobutamine was given in incremental doses from 2.5 to 40 microg/kg body weight per min. RESULTS: Of 180 revascularized segments with severe rest dysfunction, recovery of rest function was seen in 56 segments (31%) late after angioplasty, 80% of which had early recovery. Ventricular function during DSE was similar early and late after revascularization. Patients who showed a biphasic response to DSE before revascularization (n = 12) had the most improvement in function at rest (mean [+/-SD] wall motion score index [WMSI] 1.98 +/- 0.75 vs. 1.35 +/- 0.54, p < 0.05) and during DSE (2.11 +/- 0.67 vs. 1.21 +/- 0.41, p < 0.05) late after revascularization. Patients with sustained improvement during DSE before revascularization had no significant change in wall motion during DSE after angioplasty. However, patients without improvement in function at low dose DSE, who demonstrated worsening of function at a high dose, had significant augmentation in wall motion during DSE after revascularization (WMSI 2.16 +/- 0.50 vs. 1.60 +/- 0.57, p < 0.05). Patients who had no recovery of rest function had significant improvement in wall motion response to DSE, particularly when ischemia was inducible before revascularization. CONCLUSIONS: In myocardial hibernation, the majority of recovery of rest function occurs early after revascularization. Although patients who recover rest function show the most marked improvement in wall motion during DSE, those without recovery of rest function also have improved function during DSE, particularly when there is evidence of ischemia before revascularization.

Ethics in cardiovascular medicine. Task Force II: The relation of cardiovascular specialists to patients, other physicians and physician-owned organizations.

1. The American College of Cardiology acknowledges the continuum of changing societal, medical and economic perspectives affecting traditional medical ethics. Primacy of patient responsibility remains paramount to the cardiovascular specialist who at the same time should participate in the development of broader societal programs. 2. Medical decisions should be freely and jointly formulated by the patient and the cardiovascular specialist with appropriate sensitivity to such matters as mental competence, pertinent medical information and standards of care, sufficient time for contemplation, informed consent, patient right of refusal, physician right to refuse to provide inappropriate care and the right of patient, physician or third party payer to seek consultation or additional opinions. 3. The cardiovascular specialist should make a special effort to clarify and document patient preferences regarding end-of-life treatment through some form of advance directive. 4. The cardiovascular specialist bears a moral obligation to provide medical care to any patient who is HIV positive or has AIDS. 5. A conflict of interest occurs when a cardiovascular specialist places personal or financial interest ahead of the welfare and health of a patient. Professional accountability should be established through local or regional peer review. 6. The American College of Cardiology encourages and supports a renewed dedication to the principles of medical ethics, particularly in the field of cardiovascular disease. Cardiovascular specialists are encouraged to participate in the promulgation of medical ethics by teaching and by example, individually and with others.

Identification of hibernating myocardium: comparative accuracy of myocardial contrast echocardiography, rest-redistribution thallium-201 tomography and dobutamine echocardiography.

OBJECTIVES: We sought to evaluate the comparative accuracy of myocardial contrast echocardiography (MCE), quantitative rest-redistribution thallium-201 (Tl-201) tomography and low and high dose (up to 40 microg/kg body weight per min) dobutamine echocardiography (DE) in identifying myocardial hibernation. BACKGROUND: Myocardial contrast echocardiography can assess myocardial perfusion and may therefore be useful in predicting myocardial hibernation. However, its accuracy in comparison to myocardial perfusion scintigraphy and to that of high dose DE remains to be investigated. METHODS: Eighteen patients (aged [+/- SD] 57 +/- 10 years) with stable coronary artery disease and ventricular dysfunction underwent the above three modalities before coronary revascularization. Myocardial contrast echocardiography was achieved with intracoronary Albunex. Rest echocardiographic and Tl-201 studies were repeated > or = 6 weeks after revascularization. RESULTS: Of 109 revascularized segments with severe dysfunction, 46 (42%) improved. Left ventricular ejection fraction increased from 38 +/- 14% to 45 +/- 13% at follow-up (p = 0.003). Rest Tl-201 uptake and the ratio of peak contrast intensity of dysfunctional to normal segments with MCE were higher (p < 0.01) in segments that recovered function compared with those that did not. Myocardial contrast echocardiography, thallium scintigraphy and any contractile reserve during DE had a similar sensitivity (89% to 91%) with a lower specificity (43% to 66%) for recovery of function. A biphasic response during DE was the most specific (83%) and the least sensitive (68%) (p < 0.01). The best concordance with MCE was Tl-201 (80%, kappa 0.57). Changes in ejection fraction after revascularization related significantly to the number of viable dysfunctional segments by all modalities (r = 0.54 to 0.65). CONCLUSIONS: In myocardial hibernation, methods evaluating rest perfusion (MCE, Tl-201) or any contractile reserve have a similar high sensitivity but a low specificity for predicting recovery of function. A limited contractile reserve (biphasic response) increases the specificity of DE. Importantly, the three techniques identified all patients who had significant improvement in global ventricular function.

Comparison of two-dimensional echocardiography with gated radionuclide ventriculography in the evaluation of global and regional left ventricular function in acute myocardial infarction.

Two-dimensional echocardiography and gated radionuclide ventriculography were performed in 93 patients (66 men, 27 women; mean age 61 years) with 95 episodes of acute myocardial infarction within 48 hours and at 10 days after infarction. Electrocardiographic sites of infarction were: 35 anterior, 49 inferoposterior and 11 nonlocalized. Abnormal motion of the anterior wall, septum or apex was seen in 97 and 100% of anterior infarctions by radionuclide ventriculography and echocardiography, respectively. Abnormal motion of an inferior or posterior wall segment was seen in 91% of inferoposterior infarctions by echocardiography versus 61% seen by radionuclide ventriculography. Ejection fractions determined by echocardiography and radionuclide ventriculography correlated well (r = 0.82) and did not change from the first 48 hours to 10 days after infarction (0.48 +/- 0.14). Similarly, wall motion score showed minimal change from the first 48 hours to 10 days. In-hospital mortality was 37 and 42% in patients with an ejection fraction of 0.35 or less by echocardiography and radionuclide ventriculography, respectively. No mortality was seen in patients with an ejection fraction above 0.40 by either test. The echocardiographic wall motion score was also predictive of mortality (40 versus 2%; score less than or equal to 0.50 versus greater than 0.50). The 1 year mortality rate in the 81 short-term survivors was 17%. Mortality was lowest in patients with an ejection fraction above 0.49 or wall motion score above (0.79 (2 to 5%) and worse in those with an ejection fraction below 0.36 or wall motion score below 0.51 (36 to 63%) by either technique. Thus in acute myocardial infarction, echocardiography and radionuclide ventriculography provide a comparable assessment of left ventricular function and wall motion in anterior infarction. Echocardiography appears more sensitive in detecting inferoposterior wall motion abnormalities. Both techniques are capable of identifying subgroups of patients with a high risk of death during the acute event and with an equally high mortality rate over a 1 year follow-up period.

Supine bicycle versus post-treadmill exercise echocardiography in the detection of myocardial ischemia: a randomized single-blind crossover trial.

OBJECTIVES: We sought to determine the comparative accuracy of supine bicycle exercise echocardiography (SBE) and posttreadmill exercise echocardiography (TME) in detecting myocardial ischemia in patients with known or suspected coronary artery disease (CAD). BACKGROUND: Supine bicycle echocardiography and TME have been used for evaluation of CAD. However, the comparative accuracy of these modalities in the detection of ischemia in the same patients is not known. METHODS: Seventy-four patients (age 59 +/- 9 years [mean +/- SD]) referred for evaluation of coronary disease underwent SBE (starting at 25 to 50 W with 25-W increment every 3 min) and post-TME (Bruce protocol) in a random sequence. Digitized images at baseline and maximal exercise were interpreted in a random and blinded fashion. RESULTS: Maximal heart rate was higher during TME, whereas systolic blood pressure was higher during SBE, resulting in a similar double product. At quantitative angiography (n = 67), 57 patients had coronary stenosis (>50%). During SBE, ischemia was detected in 47 patients compared with 38 patients by TME (p < 0.001). Wall motion score index at maximal exercise was higher with SBE than with TME (1.48 +/- 0.51 vs. 1.38 +/- 0.43; p < 0.001). The extent of myocardial ischemia (number of ischemic segments) was higher during SBE compared with TME (3.3 +/- 3.4 vs. 2.3 +/- 2.9 segments; p = 0.004), whereas severity of abnormal wall motion was similar. The sensitivity of SBE and TME for CAD was 82% and 75% with a specificity of 80% and 90%, respectively. Image quality was similar with both techniques. Patients and sonographers favored SBE over TME. CONCLUSIONS: During SBE and TME exercise, patients achieve a similar double product. During SBE, however, the detection of ischemia is more frequent and more extensive which, along with patient and sonographer preference, makes supine bicycle exercise a valuable stress echocardiographic modality.

Assessment of myocardial perfusion in humans by contrast echocardiography. I. Evaluation of regional coronary reserve by peak contrast intensity.

Myocardial contrast echocardiography was performed during coronary angiography with 2 ml of sonicated meglumine diatrizoate sodium 76% (meglumine) in 40 patients (ranging in age from 25 to 79 years) before and 10 to 15 s after intracoronary injection of papaverine, 8 mg into the right coronary artery (n = 43) and 10 mg into the left (n = 46). The same protocol was repeated in 17 patients 5 to 10 min after completion of coronary angioplasty. In 13 patients with normal coronary angiograms, peak contrast intensity corrected for background myocardial intensity was measured in 36 regions and was found to increase after papaverine from 36 +/- 16 to 55 +/- 22 U (p less than 0.001). In contrast, in the 27 patients with angiographic evidence of coronary artery disease, peak intensity in 64 regions remained unchanged after papaverine (35 +/- 22 versus 36 +/- 23 U). An increase in peak intensity greater than or equal to 10 U was 80% sensitive and 92% specific for coronary artery disease. After successful coronary angioplasty, peak intensity in the involved regions improved significantly (p less than 0.001) during baseline contrast injections (from 32 +/- 16 to 50 +/- 25 U) as well as in the postpapaverine contrast injections (from 30 +/- 12 to 60 +/- 26 U). In conclusion, measurement of peak contrast intensity after intracoronary injections of sonicated meglumine provides a relative index of myocardial perfusion that allows assessment of regional coronary reserve in patients with coronary artery disease. This may be of particular value in evaluating the immediate effects of coronary angioplasty on myocardial perfusion.

End-diastolic wall thickness as a predictor of recovery of function in myocardial hibernation: relation to rest-redistribution T1-201 tomography and dobutamine stress echocardiography.

OBJECTIVES: The study assessed whether end-diastolic wall thickness (EDWT), measured with echocardiography, is an important marker of myocardial viability in patients with suspected myocardial hibernation, and it compared this index to currently established diagnostic modalities of dobutamine stress echocardiography (DSE) and rest-redistribution thallium-201 (T1-201) scintigraphy. BACKGROUND: Because myocardial necrosis is associated with myocardial thinning, preserved EDWT may provide a simple index of myocardial viability that is readily available from the resting echocardiogram. METHODS: Accordingly, 45 patients with stable coronary artery disease and ventricular dysfunction underwent rest 2D echocardiograms, DSE and rest-redistribution T1-201 tomography before revascularization and a repeat resting echocardiogram > or =2 months later. RESULTS: Global wall motion score index decreased from 2.38 +/- 0.73 to 1.94 +/- 0.82 after revascularization (p < 0.001). Thirty-eight percent of severely dysfunctional segments recovered resting function. Compared to segments without recovery of resting function, those with recovery had greater EDWT (0.94 +/- 0.18 cm vs. 0.67 +/- 0.22 cm, p < or = 0.0001) and a higher T1-201 uptake (78 +/- 13% vs. 59 +/- 21%; p < 0.0001). An EDWT >0.6 cm had a sensitivity of 94% and specificity of 48% for recovery of function. Similarly, a T1-201 maximal uptake of > or =60% had a sensitivity of 91% and specificity of 50%. Receiver operating characteristic curves for prediction of recovery of regional and global function were similar for EDWT and maximum T1-201 uptake. Combination of EDWT and any contractile reserve during DSE for recovery of regional function improved the specificity to 77% without a significant loss in sensitivity (88%). CONCLUSIONS: End-diastolic wall thickness is an important marker of myocardial viability in patients with suspected hibernation, and it can predict recovery of function similar to T1-201 scintigraphy. Importantly, a simple measurement of EDWT < or =0.6 cm virtually excludes the potential for recovery of function and is a valuable adjunct to DSE in the assessment of myocardial viability.

From Catheters To Ventricular Assist Devices: 60 Years of Cardiovascular Experiences With William L. Winters, JR., M.D.

Automatic typewriters, transistor radios, microfiche, black and white television…while considered high-tech in the 1950s, these technologies seem limited when viewed from the 21st century. The same is true for cardiovascular medicine, which back then relied on electrocardiograms and X-rays for most diagnoses. In the 60 years since, advances in medical capabilities have progressed at a staggering pace. Patient research that once required months poring over paper charts is now reduced to hours using electronic medical record databases. Diagnostic images that once took days to process can now be accessed instantly through ultrasound and magnetic resonance imaging. While a half-century ago no one would have imagined accessing any and all information with a 5-second Google search, so too would noninvasive heart surgery been considered unimaginable. Since the 1950s when he graduated from medical school, William L. Winters, Jr., has been a first-hand witness to breathtaking innovations in cardiovascular medicine-both globally and in Houston. Author of Houston Hearts: A History of Cardiovascular Surgery and Medicine at Houston Methodist DeBakey Heart & Vascular Center and long-time medical editor of the Methodist DeBakey Cardiovascular Journal, Dr. Winters sat down with the journal editors this past April to share his insights from the last half-century of medical practice.

Transluminal coronary angioplasty in the elderly.

The safety and clinical efficacy of percutaneous transluminal coronary angioplasty (PTCA) in elderly patients has not been established. Of 639 PTCAs performed between March 1980 and May 1984, 119 patients were 65 years or older (mean 70 years). On angiography, elderly patients differed only in the more frequent occurrence of visible calcific deposits (26% vs 8% in younger patients, p less than 0.01). Primary success was achieved in 81%, vs 80% in patients younger than 65 years. Major complication rates were comparable to those of younger patients: emergency coronary artery bypass surgery, 4.1% vs 4.7%; acute myocardial infarction, 2.5% vs 2.9%; and death, 0.8% vs 0. Late clinical follow-up ranging from 5 to 50 months (mean 18) showed that symptomatic improvement was achieved in 91% of patients in whom PTCA was successful, with 55% being asymptomatic. Seventy percent of patients were as active or more active (30%) than before PTCA and 47% were taking fewer medications. Four late deaths occurred, none from cardiac causes. These data support the safety and clinical effectiveness of PTCA in elderly patients and justify the extension of indications for PTCA to selected patients with multivessel disease in this age group.

Patterns of patency of 596 vein grafts up to seven years after aorta-coronary bypass.

The long-term behavior of vein grafts and their effect on the native circulation were studied by examining 596 vein grafts in 343 patients at a mean follow-up of 15.4 months, range zero to 84 months. Serial studies were performed on 27 patients with 38 grafts. The over-all graft patency rate was 84 per cent, and the rate after more than 5 years was 89 per cent. The patency rate in asymptomatic patients was 91 per cent compared with 81 per cent in the remainder. The patency of grafts attached distal to total occlusions was 82 per cent (78/82). The angle of origin of the grafts from the aorta did not appear to influence patency or the severity of intimal proliferative changes. In 76 patients with 126 grafts, pre- and postoperative cineangiograms were compared, and changes in the graft and underlying coronary artery classified as Groups 1 to to 6: Group 1, patent graft, bidirectional flow in the grafted vessel, proximal lesion unchanged; Group 2, patent graft, bidirectional flow, proximal lesion progressed to occlusion locally; Group 3; patent graft, distal flow only, occlusion of lesion and segment between graft and lesion; Group 4, graft occluded, native artery unaltered; Group 5, graft occluded, native artery now occluded at lesion and region of anastomosis; Group 6, new distal lesion. Results were as follows; Group 1, 58 per cent; Group 2, 21.2 per cent; Group 3, 5 per cent, Group 4, 12.5 per cent; Group 5, 2.5 per cent; and Group 6, 0.8 per cent. Native coronary arteries undergoing closure (Group 2) had lesions 95 per cent or greater in 93 per cent of patients. The rate of closure of ungrafted lesions was 2 per cent. We believe these results encourage the continued used of vein bypass grafts.

Echo-phonocardiographic evaluation of obstruction of prosthetic mitral valve.

Echo-phonocardiograms of 64 patients with multiple types of prosthetic mitral valves (PMV) were evaluated. Six patients demonstrated findings suggesting valve obstruction: four had surgical confirmation of prosthetic obstruction, one reduced cardiac output and pulmonary hypertension but no prosthetic dysfunction at surgery, and one is asymptomatic. Three of four patients with confirmed obstruction had variable second sound to opening click intervals (A2-MO) with interrupted disc opening; two had interrupted disc closure with split closing clicks and three of four had reduced diastolic closure rate. In 58 clinically well patients with PMV, cycle-to-cycle A2-MO varied little: 0-10 msec in sinus rhythm and 10-25 msec in atrial fibrillation. Diastolic closure rates of five different types of PMV were similar: 21.6 mm/sec, (range 14-49). No patient had interrupted opening, closing or multiple closing clicks. Thus, delayed PMV opening or closure, altered A2-MO interval and double closing clicks are highly useful in detecting patients with obstruction of a variety of mitral prostheses.

Aortocoronary saphenous vein autograft accidentally attached to a coronary vein: follow-up angiography and surgical correction of the resultant arteriovenous fistula.

The fate of aortocoronary saphenous vein bypass graft to the left anterior descending (LAD) coronary vein is reported. The vein graft communicated with the coronary sinus through the proximal LAD vein, producing a functional coronary arteriovenous fistula. The LAD vein was totally occluded distally at follow-up four months after operation. The natural history of congenital fistulas between coronary arteries and the coronary sinus suggested that bacterial endocarditis, pulmonary hypertension, and cardiac failure were all possible future complications in this patient. Operation was performed to revascularize the LAD artery to relieve persistent angina, and to close the fistula. Postoperative angiography showed a patent graft to the LAD artery with complete obliteration of the fistula. The patient is asymptomatic ten months after operation.