title: Heart rate response during exercise testing and ambulatory ECG monitoring in patients with syndrome X.
abstract: The response of the heart rate during exercise testing and 24-hour ambulatory electrocardiographic (ECG) monitoring performed with patients not receiving antianginal treatment was assessed in 26 patients (9 men and 17 women; mean age 51 +/- 8 years) with syndrome X (angina pectoris with normal coronary arteries), in 27 patients with coronary artery disease (10 men and 17 women; mean age 55 +/- 9 years), and in 21 healthy subjects (8 men and 13 women; mean age 47 +/- 11 years). In patients with syndrome X the slope of the regression line of heart rate versus time (heart rate/time slope) during exercise testing was similar to that of patients with coronary artery disease (3.3 +/- 0.8 versus 3.1 +/- 1.2 beats/min), but significantly lower than that in healthy subjects (4.2 +/- 1.1 beats/min; p less than 0.003). In patients with syndrome X the intercept of the heart rate/time slope was significantly higher than that in coronary artery disease patients and healthy subjects (102 +/- 15, 86 +/- 18, and 90 +/- 16 beats/min, respectively; p less than 0.015). Resting preexercise heart rate was also significantly higher in syndrome X, compared with coronary artery disease patients and healthy subjects (91 +/- 16, 79 +/- 16, and 80 +/- 14 beats/min, respectively). During ambulatory ECG monitoring, mean diurnal heart rate (from 6 AM to 6 PM) was higher in patients with syndrome X (83 +/- 8 beats/min) than in patients with coronary artery disease (75 +/- 8 beats/min) and healthy subjects (74 +/- 11 beats/min) (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Cardiovascular Unit, Royal Postgraduate Medical School, Hammersmith Hospital, London, England.
authors.forename: A R
authors.initials: AR
authors.lastname: Galassi
authors.forename: J C
authors.initials: JC
authors.lastname: Kaski
authors.forename: F
authors.initials: F
authors.lastname: Crea
authors.forename: G
authors.initials: G
authors.lastname: Pupita
authors.forename: S
authors.initials: S
authors.lastname: Gavrielides
authors.forename: D
authors.initials: D
authors.lastname: Tousoulis
authors.forename: A
authors.initials: A
authors.lastname: Maseri
mesh_terms: D000787:Angina Pectoris / Q000503:physiopathology*; D002940:Circadian Rhythm / Q000502:physiology; D017023:Coronary Angiography; D003327:Coronary Disease / Q000503:physiopathology; D015716:Electrocardiography, Ambulatory; D004837:Epinephrine / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D013577:Syndrome; D013997:Time Factors
chemical_list: D009638:Norepinephrine; D004837:Epinephrine