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Determine the following:

Figure. No caption a... - Click to enlarge in new windowFigure. No caption available.

Rhythm: _______________________________________


Rate: ___________________________________________


P waves: _______________________________________


PR interval: ____________________________________


QRS complex: __________________________________


What's your interpretation?


(Answers on next page)


Name that strip: Answers

Rhythm: Regular


Rate: 79 beats/minute


P waves: Sinus


PR interval: 0.16 to 0.18 second


QRS complex: 0.06 to 0.08 second


Interpretation: Normal sinus rhythm


Normal sinus rhythm (NSR) reflects the heart's normal electrical activity. The sinoatrial (SA) node normally initiates impulses at a rate of 60 to 100 beats/minute. Because this rate is faster than other pacemaker sites in the conduction system, the SA node retains control as the primary pacemaker of the heart. NSR originates in the SA node, and the impulse follows the normal conduction pathway through the atria, the atrioventricular node, the bundle branches, and the ventricles, resulting in normal atrial and ventricular depolarization.


NSR is regular with a heart rate between 60 and 100 beats/minute. The P waves are normal in size, shape, and direction and positive in lead II (a positive lead), with one P wave preceding each QRS complex. The duration of the PR interval and the QRS complex is within normal limits. Because NSR is the normal rhythm of the heart, no treatment is indicated.


Normal Sinus Rhythm: Identifying ECG Features


Rhythm: Regular


Rate: 60 to 100 beats/minute


P waves: Normal in size, shape, and direction; positive in lead II; one P wave precedes each QRS complex


PR interval: Normal (0.12 to 0.20 second)


QRS complex: Normal (0.10 second or less)