Skip to main content

Table 1 Patient characteristics, ECG findings, and clinical events

From: Angina at Low heart rate And Risk of imminent Myocardial infarction (the ALARM study): a prospective, observational proof-of-concept study

Patient characteristics  
 Number of patients recruited 111 (13 withdrew)
 Number of patients not recruited due to poor quality of ECG recordings or diary documentation 4
 Male 87 (78.4 %)
 Mean age (SD) 68.1 years (8.0)
 Recruited with prognostically significant coronary disease found at cardiac catheterisation 38 (34.2 %)
 Recruited after acute coronary syndrome 73 (65.8 %)
 Mean follow-up period between first and last heart rate recording (SD) 445.6 days (204.6)
 Prescribed a negative chronotropic drug at start of study 92 (82.9 %)
 Mean resting supine heart rate at start of study (SD) 58.4 bpm (9.4)
Number of patients with ECG recordings  
 Unsupervised 300-m walk 111 (100 %)
 Unsupervised flight of stairs 82 (73.9 %)
 Angina 43 (38.7 %)
Number of diary-documented events  
 Unsupervised 300-m walk (percentage of expected) 6705 (85.4 %)
 Unsupervised flight of stairs (percentage of expected) 4082 (74.2 %)
 Angina 591
Interpretable ECGs for diary-documented events  
 Unsupervised 300-m walka 5144 (76.7 %)
 Unsupervised flight of stairsa 3423 (83.9 %)
 Angina 383 (64.8 %)
 Supervised 300-m walka 688
 Supervised flight of stairsa 685
ECG quality (interpretable ECGs)  
 ECGs with two heart rate measurements 96.5 %
 Heart rate calculations based on five consecutive R waves 93.4 %
 Mean start of first heart rate calculation (SD) 2.0 s (3.8)
 Mean start of second heart rate calculation (SD) 25.2 s (4.2)
Mean difference in heart rate between the beginning and end of 30-s ECGs  
 Rest ECG for unsupervised 300-m walk (SD) −0.8 bpm (4.0)
 Postexertional unsupervised stairs (SD) −2.0 bpm (5.7)
 Postexertional unsupervised 300-m walk (SD) −4.1 bpm (5.0)
 Angina (SD) −2.0 bpm (5.4)
Clinical events during follow-up  
 ST elevation myocardial infarction 0
 Non-ST elevation myocardial infarction (number of patients) 2 (2)
 Unstable angina (number of patients) 6 (5)
 Coronary death diagnosed postmortem 1
  1. aECGs were recorded at rest and post-exercise, but the numbers refer to interpretable post-exercise ECGs