Cardiac Dysrhythmias

Terms	Definitions
-Right coronary artery -cicumflex artery	-Provides 90% of blood to AV node, 50% to SA node -- so insult is significant to conduction system. -45% to SA node and 10% to AV node
Conduction system	SA node-->intra-arterial pathway-->AV node-->Bundle of His-->Left Bundle Branch, Right Bundle Branch, Purkinje fibers
How to Read EKG	What is rate? Reg or ireg? P for every QRS? QRS for every P? What is PR interval? What is QRS time? What is QT interval? Is the ST isoelectric?
How to measure rate	(1) 6 second strip: # complexes x10; (2) *For reg rhythms: 1500 method - 1500 / # small boxes between 2 QRS; (3) 300 method: # large boxes between 2 QRS / 300 (have to memorize #s)
Boxes on EKG	.04 seconds is small box (5 small boxes in 1 big box); 0.2 seconds is big box (5 big boxes = 1 second --> tick marks on EKG)
Normal Sinus Rhythm	Regular, rate 60-100, P for every QRS, QRS for every P, PR = .12-.20 sec (3-5 small boxes), QRS < .12 (3 small boxes)
Sinus Bradycardia	Sinus rhythm, <60, P for every QRS, QRS for every P, PR=.12-.2 sec; QRS <.12
Sinus Tachycardia	Still sinus, but rate is > 100 bpm
Sinus Bradycardia cause and treatment	Could be from hypothyroidism, increased ICP, inferior wall MI Treat with atropine, pacemaker
Sinus Tachycardia cause and treatment	Associated with stressors: exercise, pain, hypovolemia, MI, HF, fever; Treatment: Based on underlying cause Fluid, beta-blockers, antipyretics, analgesics, etc.
Atrial Fibrillation 1	Total disorganization of atrial electrical activity due to multiple ectopic foci resulting in loss of effective atrial contraction. No discernible P waves, irregular rhythm. Increases w/ age
Atrial Fibrillation 2	Disorganized activity, should have P waves coordinated. Thrombi may form in atria, embolus when P wave -->stroke. Also decreases CO.
Atrial Fibrillation causes	Underlying CAD, cardiomyopathy, HF, pericarditis, thyrotoxicosis, ETOH intox, caffeine use, e- disturbances, cardiac surgery
Atrial Fibrillation Treatment	02, Decrease ventricular response, prevent embolic stroke, drugs for rate control (digoxin, beta blocker, CC blockers, anticoagulants, Convert to sinus: amiodarone, cardioversion
Tachycardia causes (H and Ts)	Hypoxia (Acidodic), Hypovolemia, Hydrogen ion (acidosis), Hypo/Hyper-kalemia, Hypoglycemia, Hypothermia, Toxins, Tamponade (cardiac), Tension (pneumothorax), Thrombosis, Trauma
Premature Ventricular Contractions	Contraction originating in ectopic focus of the ventricles. Premature occurrence of a wide and disorted QRS complex. Ventricle wants to be in charge and causes electrical current to travel in both directions
Premature Ventricular Contractions types	Multifocal (all look different), unifocal (look same), ventricular bigeminy (every other beat), ventricular trigeminy (q 3rd beat), couples (2 PVs travel together), triplets (3 travel together), R on T phenomena (can send person to v tach-bad!)
PVC causes	Associated with: Stimulants (Caffeine, alcohol, nicotine, epi) Digoxin, e- imbalances, Hypoxia, Fever, MI, mitral valve prolapse, HF, CAD
PVC clinical significance	In normal heart usually ok. In heart disease, it may decrease CO --> angina and HF. Monitor. Usually can't feel in peripheral pulse (do apical-radial assessment). May occur w/ thrombolytic therapy or after percutaneous coronary intervention
Ventricular Tachycardia	Run of three or more PVCs; Regular rate, >180 bpm, widened QRS, no P; Considered life-threatening because of decreased CO and possibility of V Fib
V Tach treatment	Must be rapid. Determine cause and treat. Could do cardioversion if unstable, amiodarone if stable, code if no pulse
Ventricular Fibrillation	Severe derangement of the heart rhythm characterized by irregular undulations of varying contour and amplitude. No effective contraction or CO. Unresponsive, pulseless, apneic - death if not treated
V Fib treatment	Defibrillate, CPR - don't worry about synchronization here
Asystole	Total absence of ventricular electrical activity; CPR, ACLS (no shockable)
Myocardial Infarction	Looking at ECG you'll see rhythm regular; QRS duration normal; P wave normal; ST element does not go to isolelectric line*
V Fib
V Tach
PVC
A Fib