ABSTRACT
BACKGROUND: A recent pilot study suggested that exercise-induced myocardial ischaemia may lead to a delayed release of cardiac biomarkers, so that later sampling, for example, at 4 h after exercise could be used for diagnostic purpose. MATERIALS AND METHODS: In an observational study, we enrolled 129 consecutive patients referred for evaluation of a suspected coronary artery disease by rest/stress myocardial perfusion single-photon emission computed tomography. The treating cardiologist used all available clinical information to quantify clinical judgment regarding the presence of myocardial ischaemia using a visual analogue scale twice: prior and after stress testing. BNP levels were determined in a blinded fashion at rest, at peak stress and 4 h after peak stress. The presence of myocardial ischaemia was adjudicated based on perfusion single-photon emission computed tomography and coronary angiography findings by an independent cardiologist. RESULTS: Myocardial ischaemia was detected in 58 patients (45%). Patients with myocardial ischaemia had significantly higher BNP levels at all times, compared to patients without ischaemia: BNP rest (99 vs. 61 pg/mL P = 0·007), BNP stress (125 vs. 77 pg/mL P = 0·02) and BNP 4 h (114 vs. 71 pg/mL P = 0·018). Diagnostic accuracy as quantified by the area under the receiver operating characteristics curve (AUC) was moderate for all time points (AUC 0·64-0·66). The change in BNP between rest and 4 h did not provide added value, neither to the baseline BNP level nor to clinical judgment. CONCLUSION: In contrast to our hypothesis, myocardial ischaemia did not lead to a differential delayed release of BNP. Late sampling did not seem clinically useful.
Subject(s)
Coronary Artery Disease/blood , Myocardial Ischemia/blood , Natriuretic Peptide, Brain/blood , Aged , Area Under Curve , Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography , Coronary Angiography , Coronary Artery Disease/diagnosis , Coronary Artery Disease/diagnostic imaging , Exercise Test , Female , Humans , Male , Middle Aged , Myocardial Ischemia/diagnosis , Myocardial Ischemia/diagnostic imaging , Myocardial Perfusion Imaging , ROC Curve , Time FactorsABSTRACT
BACKGROUND: In contrast to ST-elevation myocardial infarction (STEMI), in non-STEMI (NSTEMI) patients the need for continuous rhythm monitoring in a coronary care unit, respective incidence and timing of serious arrhythmias are poorly defined. METHODS: We used a derivation-validation design and data from two independent prospective cohorts of consecutive haemodynamically stable NSTEMI patients to evaluate the incidence and timing of serious arrhythmias after successful early percutaneous revascularization. Serious arrhythmia was prospectively defined as any arrhythmia that requires immediate medical attention including persistent ventricular tachycardia (>30 s), ventricular fibrillation, asystole, and high degree atrioventricular (AV)-block requiring pacemaker insertion during hospitalization. RESULTS: In the derivation cohort, among 228 NSTEMI patients who underwent successful early percutaneous revascularization, one patient (0.4%, 95% confidence interval 0.02-2.8%) had a serious arrhythmia which occurred 21 h after revascularization. In the validation cohort, among 293 NSTEMI patients who underwent successful early percutaneous revascularization, no patient (0%, 95% confidence interval 0-1.6%) had a serious arrhythmia after revascularization. CONCLUSION: The incidence of serious arrhythmias in NSTEMI patients after successful early revascularization seems to be very low.
