*Original post released 3/6/2020
First look at the rate and rhythm. If there is a consistent R-R interval, then it’s considered to be regular in rhythm. Is it a normal rate (60-100bpm)? Less than 60 = bradycardia. Greater than 100 = tachycardia.
Next, check to see if there’s a P wave for every QRS complex. If so, this means the rhythm is sinus no matter the HR.
Then, look at timing of certain intervals. The PR interval should be 0.2 seconds or less. If it’s greater than 0.2, this is a first degree heart block. If you have a widened QRS complex (greater than 0.12 seconds) it’s considered to be a bundle branch block…also abbreviated as BBB.
Finally, look for any wave abnormalities. Is the T wave tall, peaked, inverted, or normal? Does the ST segment follow the isoelectric line, or is it depressed or elevated? Is the Q wave pathological, meaning it has a notable downward spike. All of these are indications of an underlying pathology that needs additional work up.
For instance, if your T wave is abnormal, consider checking the patient’s electrolytes. If there are ST segment changes, it is likely that there is current or a history of myocardial injury. If there are pathologic Q waves, consider that the patient may be experiencing an ACTIVE MI. Notify the MD ASAP!
Don’t forget your look at your patient! They are not the monitor. ECG changes don’t always indicate current and active distress. Before alarming the MD and patient if an abnormal ECG is noted, go assess your patient and talk with them if able. Use your best judgment from there and always err on the side of caution. Trust your gut!