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ECG
Letters p,q,r
Term | Definition |
---|---|
Pacemaker | Hearts normal pacemaker: as node, the specialized group of cells that initiates the cardiac complex. |
Paroxysmal | Refers to the rapid onset and cessation of cardiac arrhythmias |
Polarization | Period between depolarization waves of myocardial cells in which there is a sense of electrical activity |
P-p interval | Time interval between contraction of the atria |
Precocial thump | Firm blow to midstream with the soft side of the clenched fist, a technique used to mechanically terminate witnessed, monitored ventricular tachycardia of fibrillation within the first minute of its occurrence |
Pre-excitation syndrome | Also called Wolff-Parkinson's-white syndrome. A disturbance in av conduction usually not diagnosed until young adulthood, in which accessory pathways exit around the normal pathway |
Premature atrial,nodal, or ventricular contraction (PAC,PNC,PVC) | The occurrence of an early contraction prior to the subsequent normal beat, premature contractions may originate from ectopic foci within the atrial av node, or ventricular tissue because of common characteristic automaticity |
P-R interval | Time interval involved in the depolarization of the SA node atria in the AV node measured from the first positive deflection of the P-wave to the first negative deflection of the Q wave |
Purkinje fibers | Fine network of conductive system branching from bundle branches throughout the peripheral myocardium depolarization of the Purkinje fibers produces ventricular depolarization and subsequent contraction |
P wave | Electrocardiograph representation of atrial activity the first component of the cardio complex |
Q wave | First negative deflection immediately following the p-r interval, not always present |
Refractory period | The period of time following contraction of cardiac muscle during which there is reduced ability to respond to stimuli |
Repolarization | The active process of restoring the cardiac fibers to the resting(polarized)state.Na+ ions leave the cell and K+ ions return to the song restoring the polarity of the cell membrane to the resting state(outside-,inside +) |
Retrograde | Electrical impulses conducted in a reverse or backward direction from the normal conduction(antegrade) usually refer to the backword conduction or impulses originating in the AV node of the ventricles |
R-R interval | Time interval between contractions of the ventricles representing one complete cardiac cycle |
R wave | Positive deflection following a PR interval or a Q waves representing initial wave of ventricular depolarization |