DysrhythmiasAutomaticityAbility to initiate an impulse spontaneously and continuouslyExcitabilityAbility to be electrically stimulatedConductivityAbility to transmit an impulse along a membrane in an orderly mannerContractilityAbility to respond mechanically to an impulseHow to read ECG Strip5mm = 0.2secand 0.5mV3 second markers at the top.Fifteen 5mm segments in 3 seconds (15 x 0.2sec = 3sec)Look at how many QRS intervals in 6 seconds then x 10 to get per minute.1 P Wave (atrial)oimpulse through the atrium oatrial contraction (a to v)oShould be uprighto0.06-0.12oDisturbance - conduction within atria2 PR Interval (atrial)oP to Qoimpulse through:atria AV node & bundle of His bundle branches Purkinje fibers right before ventricular contractiono0.12-0.20oDisturbance - usually in AV node, bundle of His, or bundle branches but can be in atria
3 QRS Complex (ventricular)oQ waveFirst negative (downward)after the P waveshort and narrownot present in several leads.<0.03Pathologic Q wave that is wide (≥0.03sec) and deep (≥25% of the height of the R wave) = InfarctionoR wave (not measured)First positive (upward) deflection in the QRS complex.oS wave (not measured)First negative (downward) deflection after the R wave.3 QRS Interval (ventricular)oMeasured from beginning to end of QRS complex. odepolarization (contraction) of both ventricles (systole).o<0.12oDisturbance in conduction in bundle branches or in ventricles4 ST Segment (ventricular)oS to Toventricular depolarization and repolarization (diastole).oShould be isoelectric (flat).o0.12oDisturbances (e.g., elevation, depression) usually caused by ischemia, injury, or infarction5 T Wave (ventricular)oventricular repolarization (relax and fill with blood). oShould be upright.o0.16oDisturbances (e.g., tall, peaked; inverted) usually caused byelectrolyte imbalances, ischemia, or infarction6 QT Interval (ventricular)oQRS complex to end of T wave. oentire electrical depolarization and repolarization of the ventricles.o0.34-0.43oDisturbances usually affecting repolarization more than depolarization and caused by drugs, electrolyte imbalances, and changes in heart rate1-P, 2-PR, 3-QRS, 4-ST, 5-T, 6-QTAssessing ECG
1.Atrial: Look for the P wave. Is it upright or inverted? 2.Atrial: Is there one P wave for every QRS complex or more than one?3.Are atrial fibrillatory or flutter waves present?4.Evaluate the atrial rhythm. Is it regular or irregular?5.Calculate the atrial rate. Count P waves in 6 seconds (2 ticks) 6.Atrial: Measure the duration of the PR interval. Is it normal duration or prolonged? 7.Evaluate the ventricular rhythm. Is it regular or irregular? 8.Calculate the ventricular rate. Count QT in 6 seconds (2 ticks) 9.Measure the duration of the QRS complex. Is it normal duration or prolonged?10.Assess the ST segment. Is it isoelectric (flat), elevated, ordepressed?