Mark A. Greenberg

Systemic and coronary effects of intravenous milrinone and dobutamine in congestive heart failure

The effects of dobutamine and intravenous milrinone on systemic hemodynamics, coronary blood flow and myocardial metabolism were studied in 11 patients with severe congestive heart failure. Although milrinone and dobutamine similarly increased cardiac index from 1.9 ± 0.4 to 2.5 ± 0.4 liters/min per m2(p Thus, dobutamine and milrinone produce similar improvement in cardiac index. However, dobutamine increases myocardial oxygen consumption, whereas milrinone does not. This difference can probably be explained by the substantial vasodilating properties of milrinone.

Cardiogenic shock due to cardiac free-wall rupture or tamponade after acute myocardial infarction: A report from the SHOCK Trial Registry

OBJECTIVES We sought to compare the characteristics and outcomes of patients with acute myocardial infarction (MI) and cardiogenic shock (CS) caused by rupture of the ventricular free wall or tamponade versus shock from other causes. BACKGROUND Free-wall rupture is a recognized cause of mortality in patients with acute MI. Some of these patients present subacutely, which provides an opportunity for intervention. Recognition of factors that distinguish them from the overall shock cohort would be beneficial. METHODS The international SHOCK Trial Registry enrolled patients concurrently with the randomized SHOCK Trial. Thirty-six centers consecutively enrolled all patients with suspected CS after MI, regardless of trial eligibility. RESULTS Of the 1,048 patients studied, 28 (2.7%) had free-wall rupture or tamponade. These patients had less pulmonary edema, less diabetes, less prior MI, and less prior congestive heart failure (all p < 0.05). They more often had new Q waves in two or more leads (51.9% vs. 31.5%, p < 0.04), but MI location and time to shock onset after MI did not differ. Of patients with rupture or tamponade, 75% had pericardial effusions. No hemodynamic characteristics identified patients with rupture/tamponade. Most patients with rupture/tamponade had surgery and/or pericardiocentesis (27/28); their in-hospital survival rate was identical to that of the group overall (39.3%). Women and older patients with rupture/tamponade tended to survive intervention less often. CONCLUSIONS Free-wall rupture and tamponade may present as CS after MI, and survival after intervention is similar to that of the overall shock cohort. All patients with CS after MI should have echocardiography in order to detect subacute rupture or tamponade and initiate appropriate interventions.

Impaired coronary vasodilator responsiveness as a cause of lactate production during pacing-induced ischemia in patients with angina pectoris and normal coronary arteries

Subgroups of patients with angina pectoris and normal coronary arteries are known to have pacing-induced lactate production and, therefore, myocardial ischemia. To examine the mechanism of this pacing-induced ischemia, the effect of incremental atrial pacing on coronary blood flow and metabolism was studied in 27 patients with angina and normal coronary arteries. Seventeen patients continued to exhibit normal lactate extraction even at heart rates up to 160 beats/min (Group 1), whereas in 10 patients (Group 2) lactate extraction changed to production at the highest pacing rate. Coronary blood flow increased in Group 1 patients by 18, 41 and 75%, respectively, as heart rate was increased by 20 beat/min increments from 100 to 160 beats/min. In contrast, coronary blood flow increased by only 8, 7 and 14%, at the three respective pacing rates in Group 2. Between the heart rates of 100 and 160 beats/min, coronary vascular resistance decreased 32% in Group 1 patients but was unchanged in Group 2 patients. There was no significant change in the ratio of myocardial O2 consumption/rate-pressure product in Group 1 patients, but this ratio decreased from 0.91 +/- 0.26 ml O2 X min-1 X (mm Hg X beats/min)-1 to 0.53 +/- 0.11 (p less than 0.05) in Group 2 patients as heart rate increased from baseline to 160 beats/min. Thus, patients with angina and normal coronary arteries who develop ischemia with pacing have a decreased coronary vasodilator response that interferes with their ability to increase myocardial oxygen supply to match the higher demand.

Dobutamine echocardiography and resting-redistribution thallium-201 scintigraphy predicts recovery of hibernating myocardium after coronary revascularization

The value of dobutamine echocardiography and resting thallium-201 scintigraphy to predict reversal of regional left ventricular wall motion dysfunction after revascularization in patients with chronic coronary artery disease was assessed. Improvement in wall motion during dobutamine echocardiography and normal or mildly decreased uptake on thallium-201 scanning are strong predictors of reversible left ventricular dysfunction. Dobutamine echocardiography and resting thallium-201 scanning are simple and safe methods of assessing hibernating myocardium.

Early postoperative angiographic assessment of radial artery grafts used for coronary artery bypass grafting

Abstract Despite a revival of interest in using the radial artery as an alternative conduit for myocardial revascularization, little angiographic documentation of early postoperative results has been presented, particularly in North America. Accordingly, 60 of 150 patients who underwent coronary artery bypass with radial arteries from November 1993 to July 1995 have had postoperative cardiac catheterization at our institution. The patency rate of the radial artery grafts was 95.7% (90 of 94 grafts patent) with an average internal diameter of 2.51 mm. Four radial artery grafts showed diffuse narrowing. The patency rate of the internal thoracic artery grafts was 100% with an average internal diameter of 2.25 mm. Three of 62 grafts demonstrated diffuse narrowing. Two of 24 (7.7%) saphenous vein grafts were occluded; the average internal diameter was 3.23 mm. The internal thoracic artery, the radial artery, and saphenous vein grafts were, respectively, 7.5%, 19.5%, and 53.3% larger than the anastomosed native coronary arteries. Graft-dependent flow was found in 81.1% of the radial artery grafts. Conclusion: The results of this study demonstrate that the short-term patency rate of radial artery grafts is excellent. (J THORAC CARDIOVASC SURG 1996;111:1208-12)

Impact of the New York State Cardiac Surgery and Percutaneous Coronary Intervention Reporting System on the management of patients with acute myocardial infarction complicated by cardiogenic shock

BACKGROUND Studies suggest that the New York State Cardiac Surgery and Percutaneous Coronary Intervention Reporting System, which makes public the operator-specific mortality for patients undergoing coronary artery bypass graft surgery (CABG) or percutaneous coronary intervention (PCI), may deter operators from providing revascularization to high-risk cardiac patients in New York compared to other states. METHODS We performed a retrospective analysis of 545 US patients with acute myocardial infarction and cardiogenic shock due to predominant left ventricular failure enrolled in the SHOCK Registry. Adjusting for case mix using a propensity score method, we compared the use of coronary angiography, PCI, CABG, and outcomes between 220 patients in New York and 325 in other states. RESULTS New York patients were older with similar or less severe baseline characteristics. After propensity score adjustment, New York patients were less likely than non-New York patients to undergo coronary angiography (odds ratio 0.46, 95% CI 0.31-0.68, P < .001) and PCI (odds ratio 0.51, 95% CI 0.33-0.77, P = .002). Coronary artery bypass graft rates were similarly low (14.1% vs 15.1%, P = not significant), but New York patients waited significantly longer after shock onset for surgery (101.2 vs 10.3 hours, P < .001) with only 32.3% of New York patients vs 75.5% of non-New York patients (P < .001) taken for CABG within 3 days of shock onset. CONCLUSIONS In our propensity-adjusted retrospective analysis, New York patients with acute myocardial infarction and cardiogenic shock were less likely to undergo coronary angiography and PCI and waited significantly longer to receive CABG than their non-New York counterparts. These findings suggest that state-required reporting to the New York State Cardiac Surgery and Percutaneous Coronary Intervention Reporting System may result in the reluctance to revascularize the highest-risk cardiac patients.

Present use of bedside right heart catheterization in patients with cardiac disease

On September 18, 1996, a report describing a potential increase in morbidity and mortality associated with the use of the pulmonary artery balloon catheter in critically ill patients was published in the Journal of the American Medical Association [(1)][1]. The publication of this report was

Left ventricular volume and function during relief of cardiac tamponade in man.

To determine the causes of cardiac failure during cardiac tamponade in man, we studied left ventricular volume and function in eight patients during pericardiocentesis using gated equilibrium radionuclide ventriculography. In the seven patients with clinical and hemodynamic evidence of cardiac tamponade, end-diastolic and end-systolic volumes increased progressively as the initial 500 ml offluid were removed; the most marked increase occurred during the removal of the first 200 ml of pericardial fluid. After removal of 500 ml of pericardial fluid, end-diastolic volume increased from 52 ± 8 ml to 111 ± 13 ml (p < 0.05) and end-systolic volume from 17 ± 5 ml to 34 ± 7 ml (p < 0.05). Additional aspiration of fluid resulted in no further changes in left ventricular volume. The ejection fraction averaged 70% before removal offluid and was unchanged by pericardiocentesis. In the one patient who did not have hemodynamic evidence of tamponade, there were only minor changes in left ventricular volumes and ejection fraction. These data suggest that pump function of the left ventricle is well preserved in cardiac tamponade, and that the diminution in stroke volume and consequent cardiovascular collapse seen in tamponade are due to marked underfilling of the ventricle.

Constrictive pericarditis: early and late complication of cardiac surgery.

Constrictive pericarditis is not considered a complication of cardiac surgery. However, three cases are presented in which equalization of diastolic pressures and the ventricular pressure pattern of early diastolic dip-late diastolic plateau, characteristic of restrictive disease, appeared after cardiac surgery. In one patients cardiac constriction developed less than 2 weeks after surgery, and loculated clotted and unclotted viscous blood was removed from the pericardial space. In the other two patients the pericardial space was obliterated by dense adhesions. Thus constrictive pericarditis should be considered in postoperative patients who either do not recuperate satisfactorily after surgery or whose condition deteriorates after initial recovery.

Magnetic resonance imaging of suspected atrial tumors.

Two-dimensional echocardiography has become the standard technique for evaluation of cardiac and paracardiac mass lesions. We have used magnetic resonance imaging (MRI) as an independent assessment of cardiac-associated masses in patients with echocardiograms demonstrating sessile atrial tumors. MRI was performed in seven patients, ages 33 to 84, whose echocardiographic diagnoses included left atrial mass (five), right atrial mass (one), and interatrial mass (one). In four of the patients with a diagnosis of left atrial mass, MRI showed extracardiac compression of the atrium, simulating a tumor (hiatal hernia, tortuous descending aorta, bronchogenic cyst). MRI was entirely normal in one patient with an apparent left atrial mass. MRI elucidated extension of an extracavitary mass into the interatrial septum in two patients. One of these patients with an echocardiographic right atrial mass had extension of a lipoma into the interatrial septum without atrial tumor. MRI confirmed the echocardiographic diagnosis of an interatrial mass in the other patient. We conclude that MRI, because of its ability to define anatomic relationships and tissue characteristics, is a powerful noninvasive tool for evaluating suspected cardiac mass lesions. Although echocardiography remains the primary screening test for the detection of cardiac masses, MRI is a more specific modality for precise diagnosis. Correct MRI interpretation may obviate the need for invasive studies or surgery.