European Heart Journal (1992) 13, 1468-1472
Prognostic importance of predischarge exercise capacity for long-term mortality and non-fatal myocardial infarction in patients admitted for suspected acute myocardial infarction and treated with metoprolol P. K. R0NNEVIK AND G. VON DER LlPPE
University School of Medicine, Haukeland Hospital, Bergen, and Central Hospital in Rogaland, Stavanger, Norway KEY WORDS: Acute myocardial infarction, prognosis, risk stratification, exercise testing, metoprolol. To evaluate the influence ofacute fi-blockade on the ability of predischarge exercise test data to predict long-term prognosis in patients admittedfor suspected acute myocardial infarction, patients randomized at hospital admission to intravenous metoprolol or placebo were studied. Among 190 patients discharged alive, total 4-year mortality was 20-5% (n = 39); (33 cardiac deaths, 6 non-cardiac deaths). Non-fatal infarction rate was 6-8% (n = 13). Multiple logistic regression analysis revealed that total mortality and non-fatal infarctions were independently predicted by (a) inability to perform predischarge stress testing (event-free survival for patients exercise tested 79-5% vs 56-9% for patients not eligible for testing; relative risk (RR) 1-40, 95% confidence interval (Cl) 110-178; P = 001), and (b) low predischarge exercise capacity ( RR 1-44, Cl 108-1-93; P = 0-034). ST segment shift ^ / mm did not predict mortality or reinfarction. Administration of metoprolol in the acute phase did not influence the predictive value of these parametres. It is concluded that assessment of exercise capacity at early exercise testing yields independent information for later death and myocardial infarctions, and that ^-blockade with metoprolol does not influence the predictive value of early exercise testing. Introduction Survivors of acute myocardial infarction have different risks for subsequent mortality and cardiac events. Identifying patients in various risk categories is clinically important, since high-risk patients could be offered special care which could improve their poor prognosis, and patients at low risk may be spared needless invasive studies and unwarranted physical restrictions. Early exercise test-induced chest pain, ST segment shift, inadequate blood pressure response, ventricular arrhythmias and exercise capacity in survivors of acute myocardial infarction have been reported to yield prognostic information for subsequent cardiac events'1"4'. However, the prognostic value of early exercise test data in patients admitted with chest pain with a suspicion of acute myocardial infarction has not been adequately assessed. Also, the importance of the influence of beta-blockers on exercise test variables of prognostic value, such as ST segment shift'5'6' is uncertain. In this paper we report the long-term prognostic importance of predischarge exercise test variables in patients admitted for suspected acute myocardial infarction and treated with the ^-blocking drug metoprolol or placebo during the hospital stay. Methods
Acute Myocardial Infarction)'71. Patients below 75 years of age admitted to the coronary care unit for suspected acute myocardial infarction within 24 h after onset of symptoms were eligible for inclusion. All patients gave informed consent before inclusion in the study, which was approved by the hospital's Ethics Committee. Patients currently on treatment with beta-blockers or calcium channel blockers, with a heart rate ^65 beats, min"1, systolic blood pressure ^105mmHg, left ventricular failure (basal rales > 10 cm), poor peripheral circulation, atrioventricular conduction disturbance (PQ >O24s or high degree atrioventricular block), severe chronic obstructive pulmonary disease, implanted pacemaker and patients unwilling or unable to give informed consent were excluded from entry. None received thrombolytic therapy. After randomization to double-blind treatment with metoprolol or matching placebo, the test drug was administered immediately intravenously (15 mg) and continued with an oral dose of 100 mgb.i.d. for 14 days. A detailed description of criteria for inclusion, exclusion, withdrawal, test drug administration and diagnostic criteria has been published previously'6-7'. After completion of the study period patients were considered for long-term prophylactic beta-blocker treatment according to the hospital's policy181.
STUDY POPULATION
The study was performed at one of the hospitals participating in the international MIAMI trial (Metoprolol In Submitted for publication on 4 July 1991 and in revised form 6 April 1992 Correspondence Dr Per K. Ronncvik, Section of Cardiology, Haukeland Hospital, N-5021 Bergen. Norway. OI95-668X
Prognostic importance of predischarge exercise capacity for long-term mortality and non-fatal myocardial infarction in patients admitted for suspected acute myocardial infarction and treated with metoprolol P. K. R0NNEVIK AND G. VON DER LlPPE
University School of Medicine, Haukeland Hospital, Bergen, and Central Hospital in Rogaland, Stavanger, Norway KEY WORDS: Acute myocardial infarction, prognosis, risk stratification, exercise testing, metoprolol. To evaluate the influence ofacute fi-blockade on the ability of predischarge exercise test data to predict long-term prognosis in patients admittedfor suspected acute myocardial infarction, patients randomized at hospital admission to intravenous metoprolol or placebo were studied. Among 190 patients discharged alive, total 4-year mortality was 20-5% (n = 39); (33 cardiac deaths, 6 non-cardiac deaths). Non-fatal infarction rate was 6-8% (n = 13). Multiple logistic regression analysis revealed that total mortality and non-fatal infarctions were independently predicted by (a) inability to perform predischarge stress testing (event-free survival for patients exercise tested 79-5% vs 56-9% for patients not eligible for testing; relative risk (RR) 1-40, 95% confidence interval (Cl) 110-178; P = 001), and (b) low predischarge exercise capacity ( RR 1-44, Cl 108-1-93; P = 0-034). ST segment shift ^ / mm did not predict mortality or reinfarction. Administration of metoprolol in the acute phase did not influence the predictive value of these parametres. It is concluded that assessment of exercise capacity at early exercise testing yields independent information for later death and myocardial infarctions, and that ^-blockade with metoprolol does not influence the predictive value of early exercise testing. Introduction Survivors of acute myocardial infarction have different risks for subsequent mortality and cardiac events. Identifying patients in various risk categories is clinically important, since high-risk patients could be offered special care which could improve their poor prognosis, and patients at low risk may be spared needless invasive studies and unwarranted physical restrictions. Early exercise test-induced chest pain, ST segment shift, inadequate blood pressure response, ventricular arrhythmias and exercise capacity in survivors of acute myocardial infarction have been reported to yield prognostic information for subsequent cardiac events'1"4'. However, the prognostic value of early exercise test data in patients admitted with chest pain with a suspicion of acute myocardial infarction has not been adequately assessed. Also, the importance of the influence of beta-blockers on exercise test variables of prognostic value, such as ST segment shift'5'6' is uncertain. In this paper we report the long-term prognostic importance of predischarge exercise test variables in patients admitted for suspected acute myocardial infarction and treated with the ^-blocking drug metoprolol or placebo during the hospital stay. Methods
Acute Myocardial Infarction)'71. Patients below 75 years of age admitted to the coronary care unit for suspected acute myocardial infarction within 24 h after onset of symptoms were eligible for inclusion. All patients gave informed consent before inclusion in the study, which was approved by the hospital's Ethics Committee. Patients currently on treatment with beta-blockers or calcium channel blockers, with a heart rate ^65 beats, min"1, systolic blood pressure ^105mmHg, left ventricular failure (basal rales > 10 cm), poor peripheral circulation, atrioventricular conduction disturbance (PQ >O24s or high degree atrioventricular block), severe chronic obstructive pulmonary disease, implanted pacemaker and patients unwilling or unable to give informed consent were excluded from entry. None received thrombolytic therapy. After randomization to double-blind treatment with metoprolol or matching placebo, the test drug was administered immediately intravenously (15 mg) and continued with an oral dose of 100 mgb.i.d. for 14 days. A detailed description of criteria for inclusion, exclusion, withdrawal, test drug administration and diagnostic criteria has been published previously'6-7'. After completion of the study period patients were considered for long-term prophylactic beta-blocker treatment according to the hospital's policy181.
STUDY POPULATION
The study was performed at one of the hospitals participating in the international MIAMI trial (Metoprolol In Submitted for publication on 4 July 1991 and in revised form 6 April 1992 Correspondence Dr Per K. Ronncvik, Section of Cardiology, Haukeland Hospital, N-5021 Bergen. Norway. OI95-668X
