APEX EKG Test - Questions and Answers (Complete Solutions)

APEX EKG Test - Questions and Answers (Complete Solutions) Phase 0 of the cardiac action potential correlates to what event, EKG piece, and ion movement? Depolarization QRS Na+ influx Phase 1 of the cardiac action potential correlates to what event, EKG piece, and ion movement? Initial repolarization QRS Cl- influx K+ efflux Phase 2 of the cardiac action potential correlates to what event, EKG piece, and ion movement? Plateau ST segment Ca+2 influx K+ efflux Phase 3 of the cardiac action potential correlates to what event, EKG piece, and ion movement? Final repolarization T wave K+ efflux Phase 4 of the cardiac action potential correlates to what event, EKG piece, and ion movement? Resting phase End of T wave --> next QRS Na+ efflux (Na/K pump restores RMP) What are the Bipolar leads? I, II, III What are the limb leads? aVR, aVL, aVF What are the precordial leads? V1, V2, V3, V4, V5, V6 What are the 3 internodal tracts that connect the SA to the AV node? Anterior = Bachmann bundle Middle = Wenckebach Posterior = Thorel P wave Duration 0.08 - 0.12 sec PR interval Duration 0.12 - 0.20 seconds What condition can prolong the PR interval? Pericarditis Q wave Duration < 0.04 seconds What 3 variations of the Q wave could be indicative of an MI? amplitude > 1/3 of R wave duration > 0.04 seconds depth > 1mm QRS complex Duration < 0.10 seconds What 5 conditions could cause wide QRS? LVH BBB ectopic beat WPW Hyperkalemia QT interval Duration < 0.45 men < 0.47 women What electrolyte disturbances can cause a short QT? Hyperkalemia Hypercalcemia What electrolyte distrubances can cause a long QT? Hypokalemia Hypocalcemia The T wave usually points in the same direction as the QRS. If the T wave points opposite of QRS under what 2 circumstances? Myocardial ischemia BBB Consider an MI if the ST segment shows elevation or depression > ______mm 1mm Peaked T waves can be caused by what 3 conditions? myocardial ischemia hyperkalemia intracranial bleed A U wave, which is usually absent, may be a sign of what electrolyte disturbance? hypokalemia (if > 1.5mm) Where do you measure ST changes?