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ecg and ekg
electrocardiography
Question | Answer |
---|---|
ECG or EKG | electrocardiograhm measures the amount of the electrical activity produced by the heart and the time necessary for impulses to travel through the heart during each heartbeat. |
5 reasons for ecg | 1. damage to the mycardium caused by MI 2. detect and evalualate cardio arrythythemia 3. detect mycardio ischemia 4. asses effects of cardiac meds on the heart. 5. determine if electrolyte imbalance is present. |
4 chambers of the heart | 2 upper chambers: the atria 2 lower chambers: ventricles |
right atrium | deoxygenated blood enters the heart here |
aorta | oxygenated blod leaves the heart here and is delivered cells, tissues and organs of the body |
Sinoatrial node | sa: the bodys natural pacemaker located in the upper part of the right atrium sends out an electrical impulse that begins and regulates the heartbeat |
depolarazation | contraction of cardiac cells |
repolarazation | when the heart recovers electrically. |
polarazation | heart relaxes breifly |
baseline | a flatline is present when there is no current flowing in the heart |
waves | deflection upward-postive deflection, delection downward negative deflection |
P, QRS, T | waves represent depolarization (contraction) and repolarazation (recovry) of the myocardial cells. |
P wave | represents atrial depolarazation and is recorded as a positive deflection |
QRS complex | represents ventricular depolarazation |
T wave | respresents ventricular repolarization and is a positive deflection |
cardiac cycle time | 0.8 seconds |
single channel electrocardiograph | 12 lead single channel ecg- record each lead either manually or automatically on a single strip of paper that requires the paper to be cut and mounted |
multichannel electrocardiograph | an electrocardiograph that can simultaneously record several different leads advantage is speed requires paper that is 8 1/2 inches and it fits into the patient record with no cutting or mounting |
3 channel | records three channels at one time. it records 1, 2, 3, aVR, aVL, and aVF and V1, V2, V3, V4, V5 and V6 |
ECG paper | is heat and pressure sensitive |
Electrolyte | skin is a pore conductor of electroclyte, there are various types of conductive current substances applied with each electrode to pick up the electrical current. Gels, Paste, Lotions or presaturated pads |
Sensors or electrodes | detect electrical impulses on the body surface and relay them through cables or lead wires to the ECG machine, disposable electrodes should be kept in an airtight bag because they dry out and will not stick well |
Standard ECG | consists of 10 sensors that record 12 leads of the hearts electrical activity from different angles allowing for a through three dimensional interpretation of its activity |
Electrical Impulse | given off by the heart are picked up by the electrodes and conduct into the machine through lead wire. |
Placement of leads | 4 limbs and chest |
Standard limb or bipolar leads | first three leads that are recorded on standard ecg are called leads 1, 2, 3 |
Bipolar leads | placed on 2 limb electrodes that record simultaneously |
LEAD 1 | records the electrical activity between the RA and LA |
LEAD 2 | records the electrical activity between the RA and LL |
LEAD 3 | records the electrical activity between the la and ll |
Rhythm strip | is on lead 2 because it protrays the hearts rhythm better than other leads the rhythm strip is usally a seperate, longer recording approximately 6-12 inches long |
Augmented Leads | the next 3 leads are augmented (added to) or combined leads and are designated aVR, aVL and aVF these are Unipolar leads |
aVR | records the electrical activity from the midpoint between the LA added to the LL directed to the RA |
aVL | records the electrical activity from midpoint between the right arm added to the LL directed to the LA |
aVF | records the electrical activity from the midpoint between the ra addded to the la directed to the ll |
Chest Leads or precoridal leads | these are unipolar leads v1-v6. record the hearts electrical impulse from central point within the heart to one of six predesignated positions on the chest wall where an electrode is attached |
v1 | 4th intercostals space to the right of the sternum |
v2 | 4the intercostals space to the left of the sternum |
v4 | 5th intercostals space at the left midclavicular line |
v3 | midway between v2 and v4 |
v6 | horizontal to v4 at the left midaxillary line |
v5 | horizontal to v4 at the left anterior axillary line between v4 and v6 |
Standaraztion of the machine | is a quality set assurance check to determine if the machine is working properly |
Somantic Tremor Artifacts | aka muscle tremor, characterized by jagges peaks or irregularity of spacing and height occurs when a paitent is apprenhesive or uncomfortable |
AC interference | caused by electrical interference appears as a serier of small regular peaks electricity present in medical wquipment or wires in the area can leak a small amt of energy into the room in which the ecg is being recorded, causes, improper grounding. |
wandering baseline | occurs when the stylus moves from the center of the ecg paper resulting in the complexes wandering across the paper, electrodes too loose or too tight |
interrupeted baseline | break between waves possible causes a lead wire becomes detached |
Normal sinus rhythm | refers to an ecg that is within normal limits |
60 to 100 beats per minute | normal limits for adult |
bradycardia | less than 60 beats per minute |
tacycardia | 100 beats per minute or more |
Premature atrial contraction | cardiac cycle that occurs before the next cycle is due pwave is shaped differently than a p wave of normal cycle |
paroxysmal atrial tachycardia | seen in healthy and cardiac patients characterized by its unprovoked sudden onset and abrupt termination heart rate is regular and ranges between 160-250 beats per min |
atrial fibrillation | seen in healthy or cardiac patiens |
hypertension | characterized by extremely rapid incomplete contractions 400-500 beats per minute resulting in small irregular and uncoordinated complexes that are difficult to measure because P wave cannot be distinguished |
Premature ventricular contractions | seen in healthy patients with HTN, CAD and lung disease in healthy patients it can be caused by tobacco anxiety alchol and medications that contain epinephrine |
Ventricuar tachycardia | seen in patients with acute and chronic heart isease common in patients with CAD and as a result of an MI its manifested by 3 or more PVC with a rate ranging from 150-250 beats per minute |
v tach | is lefe threatening and can rapidly deteriorate infibrillation and cardiac standstill |
Defibrillation | an electrical device that applies counter shocks to heart through electrodes or pads placed on the chest wall, purpose is to convert cardiac arrhythmia into normal sinus rhythm used in emergency situation |
Holter Monitor | portable continuos recording of cardiac activity for a 24 hour period, helps to diagnose cardiac arrhythmias by correlatin them with a patients symptoms |
mV1(holter monitor) | 4th intercostal right of sternum A (black) |
mV5 (holter monitor) | right clavicle, lateral to sternum b (white) |
mV1 (holter monitor) | left clavicle, lateral to sternum c (brown) |
mV5 (holter monitor) | 5th intercostals, left axillary line d (red) |
ground (holter monitor) | lower right chest wall e (green) |
diary of holter monitor | eating meals, ascending and descending stairs, sexual activity, medication taken, times of sleep, smoking, bowel movements and physical exercise. |
treadmill stress test or exercse tolerance ecg | aids in the determination of the patients diagnosis and prognosis it's taken under controlled conditions while the patient is closely monitored by the ma and provider |
thallium stress test | simlilar to the treamill stress test in that the patient has an ecg tracing while exercising on the treadmill after having an injection of a radioactive substance such as thallium |
PTCA | percutaneous transluminal coronary angioplasty a procedure that widens a narrowed or blocked coronary artery |
CAB | coronary artery bypass graft or cabbagge |