Table 1.

Cardiologic disorders along with their conventional marker and limitations.

cardiologic disorder	conventional marker	remarks
acute and remote myocardial infarction with coronary artery disease	acute ST-elevation, Q-wave	after an acute MI resolves repolarization, abnormalities stabilize and only Q-wave then remains as a marker of MI. Q-waves regress or even disappears with time and there is no specific sign of a non-Q-wave MI non-ST elevation MI [2,4].
BBB, premature ventricular complexes and paced rhythm	QRS ≥ 120 ms	no ECG diagnosis prior MI scar without the presence of Q-wave has been defined. Patients have to undergo expensive diagnosis test e.g. SPECT test, echocardiography, etc [5].
left ventricular aneurysm with QRS ≤ 120 ms	ST elevation with the presence of prominent R wave in aVR	low specificity as ST-segment elevation is present in many cardiac diseases and Goldberger's sign of prominent R also has low sensitivity [3].
cardiac sarcoidosis	no current marker	diagnosed by myocardial biopsy, cardiac magnetic resonance imaging with gadolinium-delayed enhancement images, echocardiography. Myocardial biopsy is invasive and has low sensitivity. There is no single diagnostic test but a combination of clinical data and investigation of CMR with GDE are used for diagnosis [9].
non-ST-elevation myocardial infarction	ischaemic T-waves, ST-segment depression, microvolt T-wave alternans, late potentials on the signal-averaged ECG, pathologic Q-waves	sensitivity and specificity of f-QRS have been found to be higher than ischaemic T-waves. For other biomarkers, their correlation with the exact anatomic location of the culprit lesion is not very high [8].