Reference no: EM133595599

Determine ECG rhythm. For atrial rhythm, measure the P-P intervals (interval between consecutive P waves). Consistently similar P-P intervals indicates regular atrial rhythm. To determine ventricular rhythm, measure intervals between consecutive R waves in the QRS complexes; they should occur regularly. Variations of up to 0.04 second are normal. Trick: place the straight edge of a piece of paper along the strip's baseline. Copy two consecutive P waves with a pencil. Move the paper and compare to subsequent P-P intervals to determine if atrial rhythm is regular or irregular. Do the same for the R-R intervals.

Determine atrial and ventricular rate. The easiest way to calculate heart rate is the 10-times method. ECG paper is marked in increments of 3 seconds (15 large boxes). To determine atrial rate, obtain a 6-second strip, count the number of P waves, and multiply by 10. Ten 6-second strips represent 1 minute. Calculate ventricular rate the same way, using R waves.

Evaluate the P wave. Are P waves present? Do they all have normal configurations? Do they all have a similar size and shape? Is there one P wave for every QRS complex?

Determine the duration of the PR interval. Count the small squares between the start of the P wave and the start of the QRS complex (see diagram to the right); then multiply the number of squares by 0.04 sec. Is the duration normal (0.12 - 0.20 sec.)? Is the PR interval consistent?

Determine the duration of the QRS complex. Measure straight across from the end of the PR interval to the end of the S wave, not just the peak (see diagram to left). To calculate duration, count the number of small squares between the beginning and end of the QRS complex and multiply by 0.04 sec. Is the duration normal (0.06 - 0.10 sec.)? Are all QRS complexes the same size and shape (if not, measure each one and describe it individually)? Does a QRS complex appear after every P wave?

Evaluate the T waves. Are T waves present? Do they all have a normal shape? Do they all have normal amplitude? Do they all have the same amplitude? Do they have the same deflection as QRS complexes?

Determine the duration of the QT interval. Count the number of small squares between the beginning of the QRS complex and the end of the T wave, where the T wave returns to the baseline (see diagram to right). Multiply this number by 0.04 sec. Is the duration normal (0.36 - 0.44 sec.)?

Evaluate any other components. Check any other abnormalities. Also check the ST segment for abnormalities, and look for the presence of a U wave.