Spontaneous delayed recovery of perfusion after thrombolyzed acute myocardial infarction: is it predictable before discharge?

In patients with thrombolyzed acute myocardial infarction, early assessment of the final infarct size is difficult because spontaneous recovery of perfusion and function of the left ventricle may be delayed. This study was undertaken to evaluate the ability of predischarge low-dose dobutamine echocardiography to predict late spontaneous recovery of perfusion assessed by single-photon emission computed tomography after acute myocardial infarction. We prospectively studied 53 consecutive patients with myocardial infarction treated with thrombolysis. Low-dose dobutamine echocardiography and resting (99m)Tc-sestamibi single-photon emission computed tomography (MIBI SPECT) were performed 4 +/- 2 days after infarction. A follow-up SPECT study was carried out in 45 patients after 6 months. Myocardial recovery was defined as a reduction of SPECT defect size by more than 10% at follow-up compared with the early study. In 25 of the 45 patients, the size of the left ventricular perfusion defect decreased significantly from 42% +/- 16% to 27% +/- 10% (group 1), whereas in the remaining 20 patients it showed no significant change (group 2). Predischarge low-dose dobutamine echocardiography showed a significant improvement in wall motion score index compared with baseline in group 1, from 1.62 +/- 0.28 to 1.41 +/- 0.24, P <.001, whereas in group 2 this index remained without significant change. Predischarge low-dose dobutamine echocardiography is an accurate tool for prediction of late recovery of myocardial perfusion after acute myocardial infarction treated with thrombolysis.

Risk assessment in patients with acute myocardial infarction treated with thrombolytic therapy.

OBJECTIVE: Several noninvasive methods have prognostic information regarding mortality and new coronary events after an acute myocardial infarction (AMI). The practical for clinical decision-making in the immediate postmyocardial infarction (MI) period is, however, less evident. We investigated consecutive patients with AMI treated with thrombolysis to further clarify this issue. DESIGN: A total of 100 patients (27% women) aged 64 +/- 9 years (mean +/- SD) were studied. Risk assessment based on a clinical score system, myocardial perfusion scintigraphy single photon emission computed tomography (SPECT) at rest and during adenosine stress, echocardiography, radionuclide angiography, symptom-limited exercise stress test, and 24-h Holter ECG recording with ST-analysis and analysis of heart rate variability (HRV) were performed 5-8 days after hospital admission. Mortality, nonfatal reinfarction, and the need for revascularization were followed during 12 months. SETTING: A university hospital. RESULTS: A total of 6 patients died, seven had a nonfatal reinfarction, and 23 were revascularized. Inability to perform an exercise test (P = 0.004) and an ejection fraction (EF) < 40% (P = 0.002) were the only parameters separating those who died from the survivors. No method could predict a nonfatal reinfarction. Patients suffering either death or nonfatal reinfarction had a clinical risk assessment score 2 points higher (8.8 vs. 6.7, P = 0.05) than the group without such events. A positive symptom-limited exercise stress test (P = 0.027), ST-depressions on Holter ECG (P = 0.04), and reversibility on myocardial perfusion scintigraphy (P = 0.029) predicted the need for revascularization. CONCLUSION: Risk assessment based on clinical information, exercise stress testing, and an estimate of left ventricular function (e.g. via echocardiography) contribute with prognostic information in thrombolysed MI-patients. Additional noninvasive investigations such as adenosine-SPECT, analysis of HRV, and Holter-monitoring do not add to these commonly available tools in risk stratification of subjects at low to medium risk.

Myocardial viability in patients with thrombolyzed myocardial infarction: is it assessable by predischarge exercise electrocardiography test?

BACKGROUND: Most studies concerning exercise electrocardiography (ECG) testing after acute myocardial infarction (AMI) were carried out in the prethrombolytic era. ST-segment elevation in the infarction area during exercise has usually been interpreted as indicating the presence of dyskinesia as a result of extensive left ventricle damage. HYPOTHESIS: This study was undertaken to evaluate the contributions of exercise-induced ST-segment elevation and T-wave pseudonormalization to the assessment of myocardial viability in patients with thrombolyzed myocardial infarction (MI), compared with low-dose dobutamine echocardiography. METHODS: The study comprised 52 consecutive patients with AMI treated with thrombolysis. All patients underwent low-dose dobutamine echocardiography and symptom-limited exercise testing before discharge. RESULTS: Nineteen patients showed ST-segment elevation (Group 1), 9 showed isolated T-wave pseudonormalization (Group 2), and 24 patients did not exhibit either of these ST-T segment changes (Group 3). Low-dose dobutamine echocardiography revealed evidence of viability in 16 patients (84%) in Group I (p = 0.01), 5 (56%) in Group 2 (p = NS), and 11 patients (46%) in Group 3 (p = NS). CONCLUSION: Exercise-induced ST-segment elevation may contribute to the evaluation of myocardial viability in patients with AMI treated with thrombolysis. However, in the absence of exercise-induced ST-segment elevation, further noninvasive studies might be indicated to assess myocardial viability.

Effects of first myocardial infarction on left ventricular systolic and diastolic function with the use of mitral annular velocity determined by pulsed wave doppler tissue imaging.

This study was undertaken to assess the effect of a first myocardial infarction (MI) on the systolic and diastolic velocity profiles of the mitral annulus determined by pulsed wave Doppler tissue imaging and thereby evaluate left ventricular (LV) function after MI. Seventy-eight patients with a first MI were examined before discharge. Peak systolic, peak early diastolic, and peak late diastolic velocities were recorded at 4 different sites on the mitral annulus corresponding to the septum, anterior, lateral, and inferior sites of the left ventricle. In addition, the amplitude of mitral annular motion at the 4 above LV sites, the ejection fraction, and conventional Doppler diastolic parameters were recorded. Nineteen age-matched healthy subjects served as controls. Compared with healthy subjects, the MI patients had a significantly reduced peak systolic velocity at the mitral annulus, especially at the infarction sites. A relatively good linear correlation was found between the ejection fraction and the mean systolic velocity from the 4 LV sites (r = 0.74, P <.001). The correlation was also good when the mean peak systolic mitral annular velocity was tested against the magnitude of the mean mitral annular motion (r = 0.77, P <.001). When the patients were divided into 2 different groups with respect to an ejection fraction > or =0.50 or <0.50, a cutoff point of mean systolic mitral annular velocity of > or =7.5 cm/s had a sensitivity of 79% and a specificity of 88% in predicting a preserved global LV systolic function. Similar to systolic velocities, the early diastolic velocity was also reduced, especially at the infarction sites. The peak mitral annular early diastolic velocity correlated well with both LV ejection fraction (r =.66, P <.001) and mean systolic mitral annular motion (r = 0.68, P <.001). However, no correlation existed between the early diastolic velocity and conventional diastolic Doppler parameters. The reduced peak systolic mitral annular velocity seems to be an expression of regionally reduced systolic function. The peak early diastolic velocity is also reduced, especially at the infarction sites, and reflects regional diastolic dysfunction. Thus, quantification of myocardial velocity by Doppler tissue imaging opens up a new possibility of assessing LV function along its long axis.

Right ventricular function in patients with first inferior myocardial infarction: assessment by tricuspid annular motion and tricuspid annular velocity.

BACKGROUND: Unlike left ventricular function, right ventricular (RV) function has not been widely studied after a myocardial infarction (MI). The current study describes RV function determined by tricuspid annular motion and tricuspid annular velocity after MI. METHODS AND RESULTS: Thirty-eight patients with a first acute inferior MI were prospectively compared with 33 patients with a first anterior MI and 24 age-matched healthy individuals. Association of RV infarction in inferior MI was defined as the presence of >/=1-mm ST-segment elevation at the right precordial lead, V(4)R, of the electrocardiograms. From the echocardiographic apical 4-chamber views, the systolic motion of the tricuspid annulus was recorded at the RV free wall with the use of 2-dimensional guided M-mode recordings. Peak systolic and peak early and late diastolic velocities of the tricuspid annulus at the RV free wall also were recorded with the use of pulsed-wave Doppler tissue imaging. The tricuspid annular motion was reduced in inferior MI compared with that in healthy individuals (20.5 and 25 mm, P <.001). The peak systolic velocity of the tricuspid annulus was significantly reduced in inferior MI compared with that in healthy individuals (12 vs 14.5 cm/s, P <.001) and patients with anterior MI (12 and 14.5 cm/s, P <.001). Patients with inferior MI were divided into 2 subgroups: those with and those without electrocardiographic signs of RV infarction. The tricuspid annular motion was significantly lower in patients with RV infarction than in patients without RV infarction (17 and 22.7 mm, P <.001). In addition, compared with patients without electrocardiographic signs of RV infarction, patients with RV infarction also had a significantly decreased peak systolic tricuspid annular velocity (13.3 and 10.3 cm/s, P <.001) and peak early diastolic velocity (13 and 8.2 cm/s, P <.001). CONCLUSIONS: These results suggest that tricuspid annular motion and tricuspid annular velocity can be used to assess RV function in association with inferior MI.

Cardioversion of atrial fibrillation and its effect on right ventricular function as assessed by tricuspid annular motion.

In patients with atrial fibrillation, the reduced right ventricular function determined by tricuspid annular motion before cardioversion returns to normal 1 month after successful cardioversion to sinus rhythm. The simplicity of recording the tricuspid annular motion provides an easy opportunity to assess right ventricular function following electroconversion of atrial fibrillation to sinus rhythm.

Characteristics of mitral and tricuspid annular velocities determined by pulsed wave Doppler tissue imaging in healthy subjects.

Assessment of myocardial velocities by Doppler tissue imaging is gaining in importance. However, generally accepted reference values are still missing. In this study we examined 62 consecutive healthy subjects (mean age 46, range 22-82 years) by pulsed wave Doppler tissue imaging to characterize the systolic and diastolic velocity profiles of the left and right ventricles. The subjects were divided into 3 different age-groups: group I, younger than 40 years; group II, 40 to 59 years; and group III, 60 years and older. Recordings were made along the long axis in the apical 4- and 2-chamber views by using 4 sites (septal, anterior, lateral, and inferior) at the mitral annulus and 1 site at the tricuspid annulus. Systolic mitral annular velocity (10.3 +/- 1.4 cm/s) correlated strongly with global left ventricular function determined by M-mode echocardiographic mitral annular displacement (r = 0.70, P <.001). The systolic velocity was significantly lower in group III than in group I (9.6 vs 10.8 cm/s, P <.01). A relatively weak, but significant, correlation was found between systolic velocity and the age of the subjects (r = -0.43, P <.001). Mitral annular early diastolic velocity was also lower in group III compared with group I (11.3 vs 17.7 cm/s, P <.001), with a strong correlation with age (r = -0.81, P <.001) and other conventional Doppler diastolic parameters. Both the systolic and early diastolic mitral annular velocities at the septum were lower than at other left ventricular sites. Tricuspid annular systolic velocity (15.2 +/- 1.9 cm/s) was higher than mitral annular systolic velocity (P <.001). Unlike mitral annular velocity, systolic tricuspid annular velocity was not correlated with age. However, the diastolic tricuspid annular velocities correlated well with transtricuspid Doppler diastolic parameters. The method of recording the annular velocities was feasible in all subjects, simple and highly reproducible.

Prognostic value of symptom limited versus low level exercise stress test before discharge in patients with myocardial infarction treated with thrombolytics.

OBJECTIVE: To evaluate the benefits and risks of symptom limited exercise testing versus low level exercise testing soon after a thrombolytic treated acute myocardial infarction. DESIGN AND PATIENTS: 98 patients (71 men, 27 women), mean (SD) age 64 (9) years (range 45-75 years), were investigated 5-8 days after admittance to hospital. An ergometer cycle test was used, starting at 30 W with 10 W increments per minute. Each exercise test was interpreted at the symptom limited end point and a low level end point, which was defined as the point at which the patient rated exhaustion as 13 on the 6-20 point Borg scale for rating perceived exertion. SETTING: A university hospital. RESULTS: 75 of the 98 patients were able to perform a predischarge exercise test. Of the remaining 23 patients who could not perform an early exercise test (because of unstable angina, heart failure, or thrombus detected at echocardiography), five died or had a myocardial infarction and six underwent bypass surgery or percutaneous transluminal coronary angioplasty (PTCA) during a follow up period of one year. There were no complications related to the symptom limited exercise tests. The test results were positive in 15 patients at the low level end point and in 39 patients (p < 0.001) at the symptom limited end point. During a follow up period of one year, six of the 75 patients died or had a myocardial infarction. Two of these six patients had a positive low level exercise test and four had a positive symptom limited exercise test. Twenty three of the 75 patients who performed an exercise test had a cardiac event within one year (death, myocardial infarction, bypass surgery or PTCA); of these, 19 had a positive symptom limited exercise test and nine had a positive low level exercise test (p = 0.025). Four of the 36 patients with a negative symptom limited test suffered cardiac events within a year (two patients had a myocardial infarction and two had bypass surgery). CONCLUSION: Symptom limited exercise testing soon after thrombolytically treated myocardial infarction will identify more patients with exercise induced ST depression or chest pain than a low level test, and seems safe. A negative symptom limited test has a better negative predictive value (11% risk of an event within a year) than a negative low level (25% risk of an event within a year).

Detection of exercise-induced reversible right ventricular wall motion abnormalities using echocardiographic determined tricuspid annular motion.

Effects of exercise on tricuspid annular motion at the right ventricular free wall was studied by echocardiography. The results suggest that exercise-related reversible changes in tricuspid annular motion may be used to identify patients with proximal right coronary artery stenosis.

Early low-dose dobutamine echocardiography predicts late functional recovery after thrombolyzed acute myocardial infarction.

BACKGROUND: This study was undertaken to evaluate the ability of predischarge low-dose dobutamine echocardiography to predict late left ventricular functional recovery after thrombolyzed acute myocardial infarction. METHODS AND RESULTS: Low-dose dobutamine echocardiography was performed in 54 patients 4 +/- 2 days after acute myocardial infarction treated with thrombolysis. Follow-up resting echocardiography was carried out in 49 of these patients at a mean of 18 +/- 6 months later. Viability was defined as recovery of myocardial function at follow-up, expressed as an improvement of wall motion of at least 1 grade or more in at least 2 contiguous infarct zone segments. In 24 of the 49 patients (group I), wall motion at follow-up improved in comparison with the early resting echocardiographic study (1.72 +/- 0.29 vs 1.37 +/- 0.34, P <.001). In the remaining 25 patients (group II), no wall motion enhancement was seen at follow-up (1.57 +/- 0.38 vs 1.58 +/- 0.36, NS). In 22 of the 24 patients in group I, early low-dose dobutamine echocardiography showed improvement in the wall motion score index compared with baseline resting measurements (1.72 +/- 0.29 vs 1.44 +/- 0.24, P <.001). The positive and negative predictive value of early low-dose dobutamine echocardiography to predict functional recovery was 76% and 92%, respectively. CONCLUSION: Predischarge low-dose dobutamine echocardiography is an accurate tool for detecting viable myocardium and predicting late left ventricular recovery after acute myocardial infarction treated with thrombolysis.

Delayed recovery of myocardial perfusion in acute myocardial infarction: a scintigraphic study after early thrombolytic treatment.

BACKGROUND: Assessments of compromised myocardium and infarct size early after thrombolytic treatment in acute myocardial infarction (AMI) are important for risk stratification and for treatment management. We have therefore evaluated the clinical usefulness of myocardial perfusion scintigraphy (MIBI-SPECT) for the assessment of myocardial viability early after AMI. METHODS: Seventy-one patients [53 men and 18 women, aged 64 +/- 9 years (range 45-75 years)] with AMI treated by thrombolysis took part in this prospective study at University Hospital, Stockholm, Sweden. Sixty of them underwent adenosine-stress and resting MIBI-SPECT 2-4 days after AMI, and 11 were examined only at rest. Six months after the AMI, a repeat MIBI-SPECT at rest was obtained for comparison. RESULTS: All patients had significant perfusion defects compared with an age- and sex-matched healthy reference population. Seventy-six percent of the patients able to undergo a complete adenosine-stress and rest SPECT showed signs of reversible perfusion defects. Defect size (extent) and severity at rest decreased between the tests at 2-5 days and 6 months after AMI (P < 0.001). Reversible perfusion defects early after AMI were not related to spontaneous improvement of myocardial perfusion 6 months later. Early, semiquantitative MIBI-SPECT was not able to predict final infarct size as measured by resting perfusion data 6 months after AMI, regardless of whether the threshold value was set at 30, 40, 50 or 60% of the maximal isotope uptake in the early resting scan. CONCLUSIONS: Myocardial perfusion scintigraphy with adenosine-stress and resting MIBI-SPECT early after AMI underestimates myocardial viability in the majority of patients treated with thrombolytic agents. Neither reversible perfusion defects nor regional semi-quantitative perfusion data appear to predict spontaneous improvement of perfusion 6 months after AMI.

Emotional distress before coronary bypass grafting limits the benefits of surgery.

BACKGROUND: The inclusion of large, heterogeneous groups of patients for coronary bypass grafting (CABG) surgery has resulted in a more mixed treatment outcome. Thus it becomes important to identify patients who are less likely to benefit from surgery or who may require additional support to improve treatment outcome. The aim of the present study was to examine whether psychological status measured before CABG can contribute to prediction of short- and long-term outcomes of the surgery. METHODS AND RESULTS: One hundred seventy-one consecutive patients from two large university hospitals in Stockholm completed a psychosocial questionnaire before being scheduled for surgery. One year after CABG, patients again completed the questionnaire. Follow-up of medical charts was conducted during the first 3 years after surgery. All major cardiac events (cardiac death, definite myocardial infarction, revascularization, and unstable angina verified by angiography or myocardial scintigraphy) were recorded. Although the overall effect of surgery was excellent in the majority of cases, the patients exhibiting a high degree of distress (anxiety, depression, and tiredness) before surgery assessed their status as being much worse both before the operation and at the 1-year follow-up. Equally important was the fact that patients considered distressed before surgery had significantly higher rates of cardiac events (16%) in the 3-year follow-up period compared with nondistressed patients (5%) (chi-square=5.11, degrees of freedom=1, p < 0.02). CONCLUSIONS: Systematic evaluation and treatment of emotional distress in the candidates for coronary revascularization may be expected to result in more optimal subjective results and a reduction in the number of serious cardiac events after surgery.