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ECK/EKG
Respiratory Ch. 6 Gary White
Question | Answer |
---|---|
depolarization | when the muscle cells are stimulated and contract (exchanging potassium for sodium) cells become more negatively charged on their outside surface |
repolarization | the contraction after depolarization, (exchange sodium for potassium) cells become positive on their outside surface |
What does the conduction system of the heart? | SA node (sinoatrial node), AV node (atrioventricular node), bundle of HIS, right and left bundle branches and the Purkinje fibers |
Known as the heart's pacemaker? | SA node |
P wave | occurs when the atria depolarize |
QRS complex | composed of the Q, R, and S waves represents depolarization of the ventricles. During ventricular depolarization, the atria repolarize. |
Can you see the repolarization of the atria? | No, the repolarization of the atria is "lost" or not seen in the QRS complex. It is hidden within the QRS. |
T wave | repolarization of the ventricles |
Sinus bradycardia | is a normal sinus rhythm at a lower rate (less than 60 beats per minute). - sinus bradycardia may indicated sinus node disease or increased parasympathetic tone or may be caused by drugs (digitalis) |
Atrial fibrillation (A-fib) | not an organized stimulation of the atria from the SA node. atrial depolarization does not occur, there is no P wave the atria never fully contracts. May be caused by underlying heart disease, hyperthyroidism, mitral valve disease, or even pulmonary |
Premature Ventricular Complexes (PVCs) | - occurs when the ventricles are stimulated prematurely. - Wide QRS complex. widening occurs because one ventricle depolarizes before the other, out of sequence. - PVCs are usually followed by a long pause before the next beat occurs. - occur randoml |
Bigeminy | refers to the occurrence of PVCs every other beat (every second beat). |