Basic Cardiac Rhythm Interpretation Advanced Exam Review Update A+

Basic Cardiac Rhythm Interpretation Advanced Exam Review Update A+ 1 / 22 P Wave Atrial Depolarization stim￾ulated by the firing of the SA node. Evaluate: consistent ap￾pearance and 1:1 relation￾ship with QRS complex. If not identical some, or all, may be atrial, but not SA node, in origin. IF 1 P-wave precedes QRS a heart block may be present. Basic Cardiac Rhythm Interpretation Advanced Exam Review Update A+ 2 / 22 PR Interval Impulse traveling time from the atrium to the ven￾tricles. Measure from the begin￾ning of the P-wave to the beginning of the QRS com￾plex. Evaluate: Duration & regu￾larity of interval. If 0.20 seconds a con￾duction delay called an AV heart block is present. Basic Cardiac Rhythm Interpretation Advanced Exam Review Update A+ 3 / 22 QRS complex Ventricular Depolarization Measure from beginning of Q-wave to end of S-wave where it returns to base￾line. Evaluate: all complexes should look alike in the same lead. Normal Dura￾tion 0.12 seconds. Widening QRS complex suggests bundle branch block or other conduction delay. Basic Cardiac Rhythm Interpretation Advanced Exam Review Update A+ 4 / 22 ST segment T-wave Represents the completion of ventricular depolarization and the beginning of ventricular repolarization. Along isoelectric line between the end of the QRS complex and the beginning of the T-wave. Depressed with myocardial ischemia. Elevated with myocardial infarction. Ventricular Repolarization Upstroke = absolute refractory period Downstroke = relative refractory period