ECG Results

The ECG must be considered in the context of the history and physical examination. The discussion above refers to the pivotal role of an ECG in the patient with a history of ischaemic cardiac chest pain. However, the ECG will also be useful in patients who have non-ischaemic pain (see Figure 1 and Table 10).

Normal ECG

A normal ECG significantly reduces the probability of AMI [4,5]. It does not, however, reduce this probability enough to allow confident safe discharge based upon the history and ECG alone [2].

Therefore, patients who present with chest pain in whom cardiac ischaemia is suspected and who have a normal ECG should undergo further diagnostic testing (i.e. delayed cardiac markers, exercise testing, etc.) before they can be confidently ascribed to a low risk group.

Table 10: ECG findings associated with non-ischaemic chest pain conditions(4,6)

ECG finding Context Diagnosis
Diffuse concave-upward ST segment elevation Positional pain
Pericardial rub
Right ventricular strain Pattern Pleuritic pain
Pleural rub
Pulmonary embolus
Diffuse ST/T wave changes Atypical pain
Heart failure
Inferior ST elevation
Normal (30%) LVH (26%)
Tearing chest pain
Radiation to back
Differential pulses
Differential blood pressures
New diastolic murmur
Aortic dissection

Learning Bite

A normal ECG in a patient with chest pain does not allow safe discharge without further investigation.