Question | Answer |
P wave | Atrial depolarization/contraction (see slides) |
QRS Complex | Ventricular depolarization/contraction (see slides) |
T wave | Ventricular repolarization (see slides) |
Jagged peaks of irregular height and spacing with a shifting baseline | Somatic (muscular) tremor - ask patient to lie still, if shivering get a blanket, etc (see slides) |
Series of uniform spikes | AC interference - make sure lead wires are not crossed, use three prong outlet; unplug electrical appliances; turn off fluorescent lights (see slides) |
Stylus of ECG machine moves violently up and down on the paper and into the margin | Interrupted Baseline - Check lead wire cables and connecting tips; check to see if an electrode has come loose or off. |
Stylus moves in wavelike pattern up or down from base line | Wandering baseline - patient may be moving; electrode may be loose; electrode may be on bone rather than soft tissue/intercostal spaces. (see slides) |
Extra P waves | atrial arrhythmias |
Bradycardia | < 60 bpm |
Tachycardia | > 100 bpm |
Atrial flutter | 200-350 bpm (see slides) |
PVC - premature ventricular contraction | Irratic large waveform (see PVC slide) |
Time expressed on a large square of the ECG paper | 0.2 seconds (See ECG paper slide) |
Time expressed on a small square of the ECG paper | 0.04 seconds (See ECG paper slide) |
Height measurement expressed on a large square of the ECG paper | 5 mm (See ECG paper slide) |
Height measurement expressed on a small square of the ECG paper | 1 mm (See ECG paper slide) |
PR interval | contraction traversing the AV node |
ST segment | time interval between ventricular contraction and the beginning of ventricular recovery |
U wave (not always present) | Associated with further ventricular relaxation |
Baseline | Heart at rest |
QT interval | Time interval between the beginning of ventricular contraction and the subsiding of ventricular contraction |
Precordial Leads | V1, V2,V3,V4,V5,V6 |
What skin prep may be necessary while hooking up the patient for ECG? | Cleanse skin with alcohol pad and/or gauze sponge. Clip or shave away hair. |
Color coding of ECG lead wires | Right leg: Green
Left leg: Red
Right arm: White
Left arm: Black
V1: Red
V2: Yellow
V3: Green
V4: Blue
V5: Orange
V6: Purple |
P wave normal duration | 0.06-0.11 seconds |
PR interval normal duration | 0.12-0.20 seconts |
QRS complex normal duration | 0.08-0.12 seconds |
ST segment normal location | on baseline (isoelectric line) |
T wave normal amplitude | less than or equal to 5 mm in Leads I, II, III; less than or equal to 10 mm in V1-V6 |
QT interval normal duration | Should not be more than half the RR interval if patient has a regular rhythm |
V-fib (ventricular fibrillation) | complete loss of synchronization of conduction system. Erratic deflections on the ECG (can be either coarse or fine) |
Asystole | < 5 beats/min; death imminent; flatline |
Biochemical arrhythmias | Digitalis Toxicity - swooping ST segment depression and/or extended PR intervals.
Hypokalemia - Low potassium shows prominent U waves, T wave and U wave look like two-hump camel.
Hyperkalemia - High K shows peaked T wave (can be as tall as R) wide forms |
SA Node (sinoatrial) | Found in right ventrical, known as pacemaker of the heart. Intrinsic rate of 60-80 bpm |