Diagnostic utility of ECG for diagnosing pulmonary embolism

Date First Published:
April 18, 2001
Last Updated:
July 20, 2005
Report by:
Ged Brown, Specialist Registrar (Manchester Royal Infirmary)
Search checked by:
Kerstin Hogg, Manchester Royal Infirmary
Three-Part Question:
In [a patient presenting with features suggestive of pulmonary embolus] what is [the diagnostic utility of ECG] in [stratifying risk of pulmonary embolus]?
Clinical Scenario:
A thirty year old man presents to the emergency department with a spontaneous onset of atraumatic pleuritic chest pain. He is in a low risk group clinically. The medical registrar suggests that the fact that the ECG is normal makes the diagnosis of pulmonary embolus much less likely. You wonder whether his assertion that a normal ECG will help to exclude a pulmonary embolus is safe.
Search Strategy:
Medline OVID 1966-week 4 June 2005
The Cochrane Library Issue 1 2005
Search Details:
[exp Pulmonary Embolism OR exp THROMBOEMBOLISM OR PE.mp OR pulmonary infarct$.mp OR Pulmonary Embol$.mp] AND [exp Electrocardiography OR Electrocardio$.mp OR ECG.mp OR EKG.mp] LIMIT to human AND English.

[{Pulmonary embolism MeSH OR thromboembolism MeSH}] AND [{electrocardiography MeSH}]
Outcome:
952 papers were found of which 947 were not directly relevant to the question, were of insufficient quality or did not report enough data to assess the diagnostic utility of ECG or a scoring system in which it was included. The remaining papers are summarised in the table below.
Relevant Paper(s):
Study Title Patient Group Study type (level of evidence) Outcomes Key results Study Weaknesses
Multivariate Analysis-Based Prediction Rule for Pulmonary Embolism. Stollberger C, Finsterer J, Lutz W, et al. 2000, Austria 168 (derivation) and 139 (validation) inpatients suspected of pulmonary embolus Prospective Derivation/Validation study Risk factors, objective clinical signs, LDH, ECG ('signs of Right heart strain'), Arterial blood gases, Venography/Plethysmography results and Chest X-Ray recorded<br><br>Multivariate logistic regression established those associated with the diagnosis of PE Individual signs 16-48% sensitive for PE, 83-94% specific Small sample size
Inpatient population only
'PE Score' (including ECG signs of Right heart strain) developed and validated in second group PE score's performance is reported for 17 different scores in paper. Examples are given below:<br><br>PE score >0.3 Sn100%, Sp 79%<br><br>PE Score >0.5 Sn 70%, Sp 99%
Diagnostic value of the Electrocardiogram in Suspected Pulmonary Embolism. Rodger M, Makropolous D, Turek M, et al. 2000, Canada 212 consecutive patients referred for V/Q or Pulmonary angiogram for suspected PE Prospective validation of previously derived scoring system Prevalence of 28 ECG abnormalities in those subsequently diagnosed as PE positive (49) or negative (163) Only 2 abnormalities (tachycardia and incomplete RBBB) significantly more prevalent in PE positive than PE negative patients Small numbers (possibility of false negative results)
Diagnostic utility of ECG scoring system (previously derived in patients diagnosed as PE positive) assessed for validation Positive and negative predictive values of scoring system 57.1 and 81.7 respectively
A structured clinical model for predicting the probability of pulmonary embolism. Miniati M, Monti S, Bottai M. 2003, Italy 1100 consecutive patients referred for investigation for PE Derivation/Cross Validation study Objective signs, risk factors, ECG and CXR recorded. Multivariate logistic regression established those associated with the diagnosis of PE Scoring system (included ECG signs of right heart strain) developed which divides patients into low, intermediate, moderately high and high groups<br>Pre-test probability by group<br>Low- 4%<br>Intermediate- 22%<br>Moderately high- 74%<br>High- 98% Subjective inclusion criteria
No prospective validation study (cross validation only)
Electrocardiographic findings in Emergency Department patients with pulmonary embolism. Richman PB, Louti H, Lester SJ et al. 2004, USA Patients assessed for pulmonary embolus over 1 year. 49 with PE compared to 49 without Observational ECG changes classically associated with PE Sinus tachycardia (18.8%vs 11.8%), Incomplete RBBB (4.2% vs 0%), S1Q3T3 (2.1% vs 0%) S1Q3 (0 vs 0) Incomplete cohort used in that 252 patients investigated for PE were not used in analysis
Role of the 12-lead electrocardiogram in diagnosing pulmonary embolism. Sinha N, Yalamanchili K, Sukhija R et al. 2005, USA Patients undergoing CT pulmonary angiography at a tertiary hospital over 30 months Retrospective cohort ECG changes significantly associated with PE Sinus tachycardia (39% vs 24%) Atrial tachyarhythmias (15% vs 4%) Q3 (40% vs 26%) Q3T3 (8% vs 1%)
Author Commentary:
While it is clear that there are some ECG changes that occur more frequently in patients with PE, these occur infrequently. There is no evidence that an ECG alone has adequate sensitivity or specificity to rule out or in a pulmonary embolus. It may have utility as part of risk stratification strategies.
Bottom Line:
An ECG alone is of little value in the diagnosis of pulmonary embolus. Its main value is in ruling out other causes of the presenting symptoms, or as part of a risk stratification strategy to inform a further investigative protocol.
References:
  1. Stollberger C, Finsterer J, Lutz W, et al.. Multivariate Analysis-Based Prediction Rule for Pulmonary Embolism.
  2. Rodger M, Makropolous D, Turek M, et al.. Diagnostic value of the Electrocardiogram in Suspected Pulmonary Embolism.
  3. Miniati M, Monti S, Bottai M.. A structured clinical model for predicting the probability of pulmonary embolism.
  4. Richman PB, Louti H, Lester SJ et al.. Electrocardiographic findings in Emergency Department patients with pulmonary embolism.
  5. Sinha N, Yalamanchili K, Sukhija R et al.. Role of the 12-lead electrocardiogram in diagnosing pulmonary embolism.