ECG Tracing: Between Waves and Intervals (Part 4)
A Nihon Kohden ECG Machine Brand Review


We are now on the second to the last part of ECG Tracing: Between Waves and Intervals article series; as for this article, we will now be discussing the other 2 components of ECG tracing which are the ST segment and T wave.

ST segment

The ST segment connects the QRS complex and the T wave and has duration of 0.08 to 0.12 sec (80 to 120 ms). It starts at the J point (junction between the QRS complex and ST segment) and ends at the beginning of the T wave. However, since it is usually difficult to determine exactly where the ST segment ends and the T wave begins, the relationship between the RT segment and T wave should be examined together. The typical ST segment duration is usually around 0.08 sec (80 ms). It should be essentially level with the PR and TP segment.

• The normal ST segment has a slight upward concavity.
• Flat, downsloping, or depressed ST segments may indicate coronary ischemia.
• ST segment elevation may indicate myocardial infarction. An elevation of >1mm and longer than 80 milliseconds following the J-point. This measure has a false positive rate of 15-20% (which is slightly higher in women than men) and a false negative rate of 20-30%.

T wave

The T wave represents the repolarization (or recovery) of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period. The last half of the T wave is referred to as the relative refractory period (or vulnerable period).

• In most leads, the T wave is positive. However, a negative T wave is normal in lead aVR. Lead V1 may have a positive, negative, or biphasic T wave. In addition, it is not uncommon to have an isolated negative T wave in lead III, aVL, or aVF.
• Inverted (or negative) T waves can be a sign of coronary ischemia, Wellens' syndrome, left ventricular hypertrophy, or CNS disorder.
• Tall or "tented" symmetrical T waves may indicate hyperkalemia. Flat T waves may indicate coronary ischemia or hypokalemia.
• The earliest electrocardiographic finding of acute myocardial infarction is sometimes the hyperacute T wave, which can be distinguished from hyperkalemia by the broad base and slight asymmetry.
• When a conduction abnormality (e.g., bundle branch block, paced rhythm) is present, the T wave should be deflected opposite the terminal deflection of the QRS complex. This is known as appropriate T wave discordance.

And now, it’s time again for another round of introduction with yet another groundbreaking brand of ECU equipment with its featured products listed on the EKGShop.Com website: Nihon Kohden.


Nihon Kohden Cardiofax ECG 1250A - The ECG-1250A Full-Size Interpretive ECG features high-level processing single view verification and diagnostic quality recordings. Interpretive Analysis. Defibrillator protected. AC and battery operational. Large backlit Color LCD display 5.7inches. Alphanumeric keyboard. ECG patient age: 3 years to adult.     

Nihon Kohden CardioFax ECG 1350A - The ECG-1350A Full-Size Interpretive ECG features high-level processing single view verification and diagnostic quality recordings. Interpretive Analysis. 8.5 x 11 inches printouts. Defibrillator protected. AC and battery operational. Large backlit Color LCD display 5.7inches. Alphanumeric keyboard. ECG waveform of all 12 leads.

Founded in 1951, the Nihon Kohden company is Japan's leading manufacturer, developer and distributor of electronic medical equipment and their machines are used in nearly every country in the world. Not only is the technology top of the line and continually advancing, Nihon Kohden equipment is well known for its quality and ease of use. Nihon Kohden offers patient monitors, electroencephalographs, evoked potential and electromyograph systems, electrocardiographs, defibrillators, and hematology analyzers.