Independent blinded reference standard, applied in all patients from a non-consecutive appropriate spectrum.
Reference standard: Diagnostic test: 1. initial ECG (mean time to reading 17 minutes): positive if: 2. serial ECGs (mean time to reading starting 48 minutes; monitored for 128 minutes). ST segment magnitude read every 20 seconds, automated readings at least every 20 minutes. positive if:

The evidence

pre-test probability of MI: 20%, (95% CI: 18% to 23%)
pre-test probability of acute coronary syndrome: 52%, (95% CI: 49% to 55%)

Chest pain: serial ECGs may be useful in low risk patients.

Clinical bottom line (level 2b)

  1. Around half of patients attending the emergency department with chest pain had unstable angina or MI.
  2. Serial ECG monitoring could not safely exclude unstable angina or MI.
  3. It added little to the care of high-risk patients with chest pain, but may be useful in diagnosing acute ischaemic heart disease in patients at low risk of cardiac complications.
Fesmire et al: Annals of Emergency Medicine 1998; 31 (1): 3-11
Expires March 2003

The study

Setting: emergency department, university hospital, USA

1000 patients (aged range 23 to 94 years; mean 56, 61% male) chest pain suspicious for coronary ischaemia

Excluded if
  • <1 hour of serial ECG monitoring
  • recent cocaine use
  • presence of VT, SVT or fast atrial fibrillation
  • pulmonary oedema
  • demand pacemaker
  • not admitted



    • Independent blinded reference standard, applied in all patients from a non-consecutive appropriate spectrum.
    Reference standard:
    • WHO criteria for MI:
      • serial rise and fall in CK and CK-MB (>12 mg/dl, and 4% total CK) within 24 hours
      • new Q waves within 24 hours
      • patient dead within 24 hours
    Diagnostic test: 1. initial ECG (mean time to reading 17 minutes): positive if:
    • acute injury- ST elevation of 1 mm or more in two contiguous limb leads, or 2 mm or more in two contiguous precordial leads, not suggestive of early repolarisation, pericarditis or repolarisation abnormality from left ventricular hypertrophy or bundle branch block. If previous ECG available then 1 mm or more in any two contiguous leads
    • acute ischaemia- ST depression 1 mm or more in two contiguous leads or symmetrical T wave inversion of 3 mm or more in two contiguous leads, not consistent with LVH or BBB
    • in patients with BBB- significant if ST depression or elevation 1 mm or more towards deflection of main QRS deflection in two contiguous leads, or 7 mm ore more away from QRS deflection and >50% amplitude of T wave in two contiguous leads
    2. serial ECGs (mean time to reading starting 48 minutes; monitored for 128 minutes). ST segment magnitude read every 20 seconds, automated readings at least every 20 minutes. positive if:
    • evolving injury or ischaemia
    • new injury or ischaemia

    The evidence

    pre-test probability of MI: 20%, (95% CI: 18% to 23%)
    pre-test probability of acute coronary syndrome: 52%, (95% CI: 49% to 55%)

    diagnostic test MI no MI LR+
    (95% CI)    		 post-test probability LR-
    (95% CI)    		 post-test probability
    initial ECG 113 43 10
    (7.5 to 14)     		72% 0.47
    (0.40 to 0.55)     		11%
    serial ECG 139 41 13
    (9.7 to 18)     		77% 0.34
    (0.27 to 0.41)     		8%
    total 200 800


    diagnostic test acute coronary syndrome no acute coronary syndrome LR+
    (95% CI)    		 post-test probability LR-
    (95% CI)    		 post-test probability
    initial ECG 142 14 9.5
    (5.6 to 16)     		91% 0.75
    (0.70 to 0.79)     		44%
    serial ECG 177 3 55
    (18 to 170)     		98% 0.66
    (0.62 to 0.70)     		41%
    total 520 480

    Comments

    1. Since risk of MI and unstable angina is so high in patients with chest pain, serial ECG adds little to the diagnostic process. Tests that exclude MI would be more useful.
    2. This study does not take into account enzyme markers which are also crucial in risk stratifying patients presenting with chest pain but not AMI.

    Citation

    1. Fesmire FM, Percy RF, Bardoner JB, et al: Usefulness of automated serial 12-lead ECG monitoring during initial emergency department evaluation of patients with chest pain. Annals of Emergency Medicine 1998; 31 (1): 3-11
    Search Terms: handsearch
    Contributor: Chris Ball and Clare Wotton, July 2000
    Reviewer: Michael Christian

    Clinical Question.
    Patient chest pain
    Intervention or Exposure serial ECGS
    Outcome diagnosis of unstable angina or MI
diagnostic test MI no MI LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
initial ECG 113 43 10
(7.5 to 14) 		72% 0.47
(0.40 to 0.55) 		11%
serial ECG 139 41 13
(9.7 to 18) 		77% 0.34
(0.27 to 0.41) 		8%
total 200 800


diagnostic test acute coronary syndrome no acute coronary syndrome LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
initial ECG 142 14 9.5
(5.6 to 16) 		91% 0.75
(0.70 to 0.79) 		44%
serial ECG 177 3 55
(18 to 170) 		98% 0.66
(0.62 to 0.70) 		41%
total 520 480

Comments

  1. Since risk of MI and unstable angina is so high in patients with chest pain, serial ECG adds little to the diagnostic process. Tests that exclude MI would be more useful.
  2. This study does not take into account enzyme markers which are also crucial in risk stratifying patients presenting with chest pain but not AMI.

Citation

  1. Fesmire FM, Percy RF, Bardoner JB, et al: Usefulness of automated serial 12-lead ECG monitoring during initial emergency department evaluation of patients with chest pain. Annals of Emergency Medicine 1998; 31 (1): 3-11
Search Terms: handsearch
Contributor: Chris Ball and Clare Wotton, July 2000
Reviewer: Michael Christian

Clinical Question.
Patient chest pain
Intervention or Exposure serial ECGS
Outcome diagnosis of unstable angina or MI