CARDIAC RHYTHM RECOGNITION WITH 100% CORRECT ANSWERS.

Electrocardiograph ECG a device that detects, amplifies and records the electrical activity generated by the heart, followed by the mechanical contractions sinoatrial (SA) node pacemaker of the heart; intrinsic rate 60-100; initiate & transmits impulses through the atria Brainpower Read More atrioventricular (AV) Node Collection area for impulses from atria intrinsic 40-60 impulses per minute bundle branches, bundle of his, purkinji fibbers Transmit impulses through ventricle, intrinsic rate 20-40 impulses per minute Automaticity The ability of the heart to generate and conduct electrical impulses on its own. Excitability Cardiac cells respond to a stimulus by initiating cardiac impulses Contractility Cardiac cells to contact in response to an impulse Conductivity Allows cardiac cells to respond to an impulse by transmitting it along cell membrane Depolarization Electrical impulses travel through the cardiac muscle sodium moves into the cells while potassium moves out, proceeds from endocardium to epicardium Repolarization Cardiac sells return to the resting state sodium moves out of the cell and potassium moves into cells, ventricles repolarize from epicardium to endocardium Diastole "Resting" phase; cardiac muscle is relaxed allowing blood to fill chamber Systole Myocardial pressure and tension increased causing blood to fill chamber Absolute Some cardiac cells have not completed repolarization and cannot be stimulated to conduct an impulse may be seen/felt as a skipped beat Relative Some cardiac cells have completed repolarization and can be stimulated to conduct an impulse; may be seen/felt as a premature (early) beat P-waves atrial depolarization, deflection can be positive, negative or biphasic, should be regular and same shape throughout strip! The first wave in the cardiac cycle is the P wave PR interval Due to impulse collection at the AV node PR interval time 0.12-0.20 seconds (3-5 small boxes) too long PR interval 1st degree AV block ( think to much digoxin) Too short PR interval Impulses not initiating in SA nodes QRS complex ventricles depolarization QRS complex time interval < 0.12 (2-3 small boxes) Q wave First NEGATIVE deflection after the P wave R wave First POSITIVE deflection after the P wave S wave first negative deflection after the R wave ST segment Normal isoelectric (follows baseline) What occur from the end of QRS complex to start of the T wave St segment What can elevate or depress St segment Myocardial injury T wave ventricular repolarization