[Exercise test parameters after acute myocardial infarction. Relationship with coronary angiography].

OBJECTIVE

To analyze the relation between characteristics of symptom-limited treadmill exercise stress test, after acute myocardial infarction (MI) and coronariographic results (number of diseased vessels). Both tests were performed before hospital discharge.

DESIGN

Retrospective study with comparative analysis between variable defined groups.

POPULATION AND SETTING

From 232 patients interned in the department of Cardiology of Hospital de Santa Marta with a first acute MI, a population of 112 patients submitted to exercise stress test and coronary angiography before discharge were selected (aged 29 to 69 years).

METHODS

Symptom-limited treadmill exercise stress tests were performed according to Bruce protocol, with no heart-rate limitation. The following parameters were analyzed: Stress test duration (DUR); Double product variation (varDP); Metabolic equivalent units (METS); Maximal heart rate (FCmax); Percentage of the maximal reached heart rate (% FCmax); Incidence of ST segment depression (InfST); Maximal ST segment depression (Max-InfST); Onset minute of ST segment depression (MinInfST); Heart rate at the onset of ST segment depression (FCInfST); Double product at the onset of ST segment depression (DPInfST); Recovery minute of ST segment depression (MinRInfST); Onset minute of angina (MinAng); Heart rate at the onset of angina (FCAng); Double product at the onset of angina (DPAng).

RESULTS

Statistical significant differences were obtained between coronariographic groups concerning the following parameters: DUR: 1-vessel/3-vessel P = 0.02; VarDP: 1-vessel/3-vessel p = 0.008, 2-vessel/3-vessel p = 0.004; METS: 1-vessel/3-vessel p = 0.01. No differences were seen between anterior and inferior myocardial infarctions regarding all the stress test parameters. However in patients with anterior MI significant differences were obtained concerning the following variables: VarDP: 1-vessel/2-vessel p = 0.02; InfraST: 1-vessel/2-vessel p = 0.006, 1-vessel/3-vessel p = 0.03; MaxInfST: 1-vessel/2-vessel p = 0.01, 1-vessel/3-vessel p = 0.0006; Angina: 1-vessel/2-vessel p = 0.0005, 1-vessel/3-vessel p = .001. In inferior myocardial infarctions only the stress duration differed between 1-vessel and 3-vessel groups (p = 0.003).

CONCLUSIONS

Symptom-limited treadmill exercise stress tests, safely performed in our institution, were an important method for post MI evaluation and allowed the diagnosis of a great number of patients with residual ischemia. Statistical significant differences were found in ergometric parameters, between coronariographic groups (defined by the number of diseased vessels), emphasising the importance of stress tolerance analysis.