Background: Various statements are made concerning peaks of heart rate (HR), blood pressure (BP) and double product (product of HR and systolic BP) as triggers for ST-segment depression. The aim of the present study was to identify determinants of ST-segment depression with a new ambulatory device for simultaneous 24-h electrocardiogram (ECG) and BP monitoring.
Methods: A total of 63 treated patients (63 +/- 9 years, 33 women and 30 men) with arterial hypertension and ischemic heart disease were studied with a new ambulatory 24-h BP measurement (ABPM) device evaluated according to the BHS protocol (Cardiotens, Meditech, Hungary). This device allows simultaneous ST-segment analysis with extra BP recordings triggered by episodes of ST-segment depression.
Results: ST-segment (Holter ECG) depression (> 1 mm and > 60 s) was demonstrated in 26 patients with a mean duration of 4.95 +/- 2.6 min and a peak in the early morning hours. All ST-segment depressions were silent and occurred during a significant increase of BP (15 +/- 11 mmHg systolic and 10 +/- 5 mmHg diastolic, compared with the mean ABPM values) and a significant increase of the double product from 10 921 +/- 2 395 (24-h mean) to 14 515 +/- 2329 (during ST-depression). The recorded systolic and diastolic BP (SBP, DBP) values from the pre ST-event were significant higher compared with 24-h values (153 +/- 19 versus 145 +/- 22 mmHg systolic, 83 +/- 12 versus 78 +/- 14 diastolic). The mean pulse pressure (PP) value in the group with ST-depression was significantly higher than in the group without ST changes (69 +/- 16 versus 58 +/- 10 mmHg; P < 0.005). A total of 73% of patients with ST-events compared with 35% without ST-events showed a PP >or= 60 mmHg (P = 0.025).
Conclusion: Simultaneous ABPM and ST-segment analysis identifies episodes of silent myocardial ischemia during increases of BP and HR. Hypertensive patients with ischemic heart disease and ST events show higher mean pulse pressure values than are observed in patients without events. A PP of >or= 60 mmHg is linked to an increased risk of silent myocardial ischemias.