Ben D. McCallister

ACC/AHA 2002 Guideline Update for Exercise Testing: Summary Article: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1997 Exercise Testing Guidelines)

The American College of Cardiology (ACC)/American Heart Association (AHA) Task Force on Practice Guidelines regularly reviews existing guidelines to determine when an update or full revision is needed. This process gives priority to areas where major changes in text, and particularly recommendations, are mentioned on the basis of new understanding or evidence. Minor changes in verbiage and references are discouraged. The ACC/AHA guidelines for exercise testing that were published in 1997 have now been updated. The full-text guidelines incorporating the updated material are available on the Internet (www.acc.org or www.americanheart.org) in both a version that shows the changes in the 1997 guidelines in strike-over (deleted text) and highlighting (new text) and a “clean” version that fully incorporates the changes. This article describes the 10 major areas of change reflected in the update in a format that we hope can be read and understood as a stand-alone document. The table of contents from the full-length guideline (see next page) indicates the location of these changes. Interested readers are referred to the full-length Internet version to completely understand the context of these changes. All new references appear in boldface type; all original references appear in normal type.⇓ View this table: Table of Contents The ACC/AHA classifications, I, II, and III are used to summarize indications as follows: Class I: Conditions for which there is evidence and/or general agreement that a given procedure or treatment is useful and effective. Class II: Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of a procedure or treatment. IIa: Weight of evidence/opinion is in favor of usefulness/efficacy. IIb: Usefulness/efficacy is less well established by evidence/opinion. Class III: Conditions for which there is evidence and/or general agreement that the procedure/treatment is not useful/effective and in some cases may be harmful. In the original …

ACC/AHA Guidelines for Exercise Testing: Executive Summary A Report of the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines (Committee on Exercise Testing)

The American College of Cardiology/American Heart Association Task Force on Practice Guidelines was formed to make recommendations regarding the appropriate use of testing in the diagnosis and treatment of patients with known or suspected cardiovascular disease. Exercise testing is widely available and relatively low in cost. For the purposes of these guidelines, exercise testing is a cardiovascular stress test using treadmill or bicycle exercise and electrocardiographic and blood pressure monitoring. Pharmacological stress testing and imaging modalities (radionuclide imaging, echocardiography) are beyond the scope of these guidelines. These guidelines have been endorsed by the American College of Sports Medicine, the American Society of Echocardiography, and the American Society of Nuclear Cardiology. This executive summary appears in the July 1, 1997, issue of Circulation. The guidelines in their entirety are published in the July 1997 issue of the Journal of the American College of Cardiology. Reprints of both the executive summary and the full text are available from both organizations. Exercise testing is a well-established procedure that has been in widespread clinical use for many decades. It is described in detail in previous publications of the AHA, to which interested readers are referred. Although exercise testing is generally a safe procedure, both myocardial infarction and death have been reported and can be expected to occur at a rate of up to 1 per 2500 tests. Good clinical judgment should therefore be used in deciding which patients should undergo exercise testing. Absolute and relative contraindications to exercise testing are summarized in Table 1⇓. View this table: Table 1. Contraindications to Exercise Testing The vast majority of treadmill exercise testing is performed in adults with symptoms of known or suspected ischemic heart disease. Special groups who are exceptions to this norm are discussed in detail in sections VI and VII. Sections II through IV illustrate the variety …

Percutaneous transluminal coronary angioplasty with and without thrombolytic therapy for treatment of acute myocardial infarction

Successful percutaneous transluminal coronary angioplasty (PTCA) was performed during evolving acute myocardial infarction (AMI) in 41 patients. Catheterization was performed within 1 hour of presentation, from 1 to 12 hours (mean 3.3) following symptom onset. In 17 of 29 patients with a totally occluded coronary artery, successful thrombolytic therapy was followed by PTCA of a residual high-grade atheromatous stenosis. Successful PTCA without prior thrombolytic therapy was employed in 11 of 12 subtotal coronary stenoses producing acute infarction syndromes and in two patients having critical coronary stenoses not immediately responsible for AMI. Three patients experienced early in-hospital reocclusion with reinfarction. One death occurred in a patient presenting with cardiogenic shock. All remaining patients had prompt pain relief, subsequent stable clinical courses, and no clinical or late angiographic evidence of coronary reocclusion. Dramatic improvement of regional and global left ventricular function was evident in 22 of 27 patients undergoing late left ventricular angiography. At follow-up, 94% of patients remained free of angina although three required repeat dilatation of recurrent stenoses. We concluded that PTCA may be performed with or without thrombolytic therapy in selected patients with AMI and may reduce the likelihood of late reocclusion following successful thrombolytic therapy.

Postexercise electrocardiography: Correlations with coronary arteriography and left ventricular hemodynamics

Abstract Postexercise electrocardiograms were related to coronary arteriograms in 100 cases and were correlated with left ventricular hemodynamics at rest and during mild exercise in 78 of these cases. The incidence and degree of exercise-induced “ischemie” S-T segment depression increased significantly with increasing extent of coronary artery disease. A criterion for abnormality of 0.5 mm or greater S-T depression offered a specificity of true negative responses of 83 percent and a sensitivity of true positive responses of 63 percent. A criterion of 1.0 mm or greater S-T depression produced a specificity of 100 percent but at the expense of a reduced sensitivity of 35 percent true positive responses. Left ventricular end-diastolic pressure was the only hemodynamic index that correlated with either the extent of coronary artery disease or the degree of exercise-induced S-T segment depression. Patients with S-T segment depression of 1.0 mm or greater had significantly greater values for left ventricular end-diastolic pressure, both at rest and during exercise, than did patients with lesser degrees of S-T depression. The “2-step” exercise test provides an imperfect though independent means for predicting the presence and extent of significant coronary artery disease in the individual patient, and abnormal results on this test may suggest an associated abnormal rise in left ventricular filling pressure during exercise.

Coronary angioplasty versus repeat coronary artery bypass grafting for patients with previous bypass surgery.

OBJECTIVES We attempted to determine the relative risks and benefits of percutaneous transluminal coronary angioplasty (PTCA) and repeat coronary artery bypass grafting (re-CABG) in patients with previous coronary bypass surgery (CABG). BACKGROUND Due to an expanding population of patients with surgically treated coronary artery disease and the natural progression of atherosclerosis, an increasing number of patients with previous CABG require repeat revascularization procedures. Although there are randomized comparative data for CABG versus medical therapy and, more recently, versus PTCA, these studies have excluded patients with previous CABG. METHODS We retrospectively analyzed data from 632 patients with previous CABG who required either elective re-CABG (n = 164) or PTCA (n = 468) at a single center during 1987 through 1988. The PTCA and re-CABG groups were similar with respect to gender (83% vs. 85% male), age > 70 years (21% vs. 23%), mean left ventricular ejection fraction (46% vs. 48%), presence of class III or IV angina (70% vs. 63%) and three-vessel coronary artery disease (77% vs. 74%). RESULTS Complete revascularization was achieved in 38% of patients with PTCA and 92% of those with re-CABG (p < 0.0001). The in-hospital complication rates were significantly lower in the PTCA group: death (0.3% vs. 7.3%, p < 0.0001) and Q wave myocardial infarction (MI) (0.9% vs. 6.1%, p < 0.0001). Actuarial survival was equivalent at 1 year (PTCA 95% vs. re-CABG 91%) and 6 years (PTCA 74% vs. re-CABG 73%) of follow-up (p = 0.32). Both procedures resulted in equivalent event-free survival (freedom from dealth or Q wave MI) and relief of angina; however, the need for repeat percutaneous or surgical revascularization, or both, by 6 years was significantly higher in the PTCA group (PTCA 64% vs. re-CABG 8%, p < 0.0001). Multivariate analysis identified age > 70 years, left ventricular ejection fraction < 40%, unstable angina, number of diseased vessels and diabetes mellitus as independent correlates of mortality for the entire group. CONCLUSIONS In this nonrandomized series of patients with previous CABG requiring revascularization, an initial stategy of either PTCA or re-CABG resulted in equivalent overall survival, event-free survival and relief of angina. PTCA offers lower procedural morbidity and mortality risks, although it is associated with less complete revascularization and a greater need for subsequent revascularization procedures.

Left Ventricular Performance During Mild Supine Leg Exercise in Coronary Artery Disease

Left ventricular (LV) performance was studied during mild exercise (100 kg-m/min for 3 minutes) in 19 cases of coronary artery disease (CAD). Each patient suffered from a severe anginal syndrome. None had ventricular aneurysm, cardiomegaly, or clinical heart failure. Mean resting values follow: LV end-diastolic pressure (LVEDP), 19 ± 7 mm Hg; LV systolic pressure (LVSP), 150 ± 16 mm Hg; stroke volume index (SVI), 48 ± 10 ml/beat/m2; and LV stroke work index (LVSWI), 81 ± 19 g-m/m2. During exercise LVEDP rose to 30 ± 8 mm Hg (P≤0.001) and LVS to 160 ± 20 (not significant [NS]); SVI diminished to 46 ± 11 (NS) and LVSWI, to 76 ± 24 (NS). Patients with decreased or asynchronous areas of LV myocardium identified on cine left ventriculograms had higher mean LVEDPs during exercise than did those with normal ventriculograms (34 ± 10 versus 26 ± 4 mm Hg; P≤0.05). The difference between responses to exercise of patients who experienced angina during the study and of those who did not was NS. Administration of nitroglycerin reduced the increase in LVEDP during exercise. An abnormality in LV performance-a significant rise in LVEDP without a significant increase in SVI or LVSWI-was observed in 13 of 19 cases of CAD.

Lovastatin plus probucol for prevention of restenosis after percutaneous transluminal coronary angioplasty

Combination lovastatin and probucol reduced total cholesterol (27%) and low-density lipoprotein levels (30%), but did not prevent restenosis or clinical events during the first 6 months after percutaneous transluminal coronary angioplasty.

Paroxysmal ventricular tachycardia and fibrillation without complete heart block: Report of a case treated with a permanent internal cardiac pacemaker

Abstract Recurrent paroxysmal ventricular tachycardia and fibrillation in a patient without evidence of atrioventricular block were successfully controlled by a permanently implanted internal pacemaker with the pacing rate set at 100/min. The rationale for the choice of the pacemaker rate is discussed. It is suggested that, should other conventional forms of therapy such as cardiac depressant drugs be ineffective, implantation of a permanent cardiac pacemaker may be useful in the control of this serious tachyarrhythmia.

Accuracy of treadmill testing in assessment of direct myocardial revascularization.

Near-maximal treadmill exercise tests (TET) performed at the time of coronary arteriography and bypass graft visualization an average of 13 months after direct myocardial revascularization were analyzed in 217 consecutive patients to assess the accuracy of the TET in predicting completeness of revascularization. TET results were correlated with bypass patency and extent of revas- cularization. Although conversion of a TET from an abnormal to a normal test or relief of TET-induced angina following surgery is closely correlated with bypass graft patency, the high incidence of normal exercise tests in the presence of residual coronary disease limits their usefulness in the individual postoperative patient in estimating the completeness of revascularization.

Serum glutamic oxaloacetic transaminase and electrocardiographic changes after myocardial revascularization procedures in patients with coronary artery disease

Serial serum glutamic oxaloacetic transaminase (SGOT) determinations and electrocardiograms were obtained from 40 patients after myocardial revascularization procedures for treatment of severe coronary artery disease. SGOT was measured in units (U), with 1 U equalling 1 micromole of oxaloacetic acid formed per minute at 37C. Twenty-three patients had initial SGOT levels lower than 100 U/liter (mean, 50 U/liter) on the first postoperative day, followed by a gradual decrease by postoperative day 7 (mean, 25 U/liter). The electrocardiographic changes in this group were confined to repolarization abnormalities. Seventeen patients had initial SGOT levels higher than 100 U/liter or a secondary increase greater than 50 percent of the preceding value. Seven of these 17 patients had electrocardiographic evidence of a postoperative myocardial infarction, only 3 of which were clinically recognized. In 4 additional patients the diagnosis of myocardial infarction was suspected on the basis of an abnormal enzyme pattern and temporally related symptoms suggesting myocardial ischemia, although the electrocardiographic changes were nonspecific. Five patients had unexplained increases in the level of SGOT. The incidence of postoperative myocardial infarction was greater in the present series than is usually emphasized. This finding must be considered in selecting individual patients for operation and in evaluating the postoperative clinical result.