ECG Flashcards
(54 cards)
Things you can detect on an ECG
cardiac rhythm, detection of myocardial ischemia and infarction, conduction system abnormalities, preexcitation, long QT syndromes, atrial abnormalities, ventricular hypertrophy, pericarditis
ECG is used in the evaluation of syncope. T/F
True
contraindications to performing an ECG?
No absolute contraindications to performing an ECG exist, other than patient refusal. Some patients may have allergies or, more commonly, sensitivities to the adhesive used to affix the leads; in these cases, hypoallergenic alternatives are available from various manufacturers.
Prep/positioning for ECG?
patient lying quietly in the supine position
skin is clean and trimmed of excess hair in the areas in which the leads are to be placed.
Which lead is placed at the fourth intercostal space at the right sternal border?
V1
Placement for lead V2?
Lead V2 is placed at the left sternal border directly across from lead V1, also in the fourth intercostal space.
Which lead is placed in the fifth intercostal space at the mid clavicular line
Lead V4
due to obfuscation of bony landmarks in women with large breasts, it is recommended that the electrodes be placed overlying, rather than beneath, the breast. T/F
False
it is recommended that the electrodes be placed beneath, rather than overlying, the breast.
Steps in reviewing an ECG
Rate: Normal versus tachycardia versus bradycardia
Rhythm: Abnormal versus normal sinus
Intervals: PR, QRS, QT
Axis: Normal versus left deviation versus right deviation
Chamber abnormality: Atrial enlargement, ventricular hypertrophy
QRST duration: Q waves, poor R-wave progression, ST-segment depressions/elevations, or T-wave changes
How much time does each ECG box represent
On the horizontal axis, each large box represents 0.2 seconds at a typical paper speed of 25 mm per second, which is then divided into five smaller boxes that each represent 0.04 seconds
Placement of lead V5?
lead V5 is placed in the same horizontal plane as that of lead V4 in the anterior axillary line or midway between leads V4 and V6 when the anterior axillary line is not readily discernible.
Placement of lead V6?
Lead V6 is placed in the horizontal plane of V4 at the mid-axillary line
What can be determined by the interval between 2 successive QRS complexes
Heart rate, when cardiac rhythm is regular
How to calculate heart rate on ECG?
300 / (no. of large boxes between 2 successive QRS complexes) bpm
The ECG displays a period of 8 seconds. T/F
F
the ECG displays a period of 10 seconds
How to obtain average heart rate when heart rate is irregular
If the heart rate is irregular, count the number of QRS complexes on the ECG and multiply by 6 to obtain the average heart rate in bpm (the ECG displays a period of 10 seconds; thus, 6 × 10 seconds = 60 seconds [1 minute]).
P wave represents?
atrial depolarization
The normal P wave morphology is upright in what leads?
I, II, and aVF, but it is inverted in lead aVR.
Abnormal p wave?
The P wave is typically biphasic in lead V1 (positive-negative), but when the negative terminal component of the P wave exceeds 0.04 seconds in duration (equivalent to one small box), it is abnormal.
What do you suspect with increased p wave duration
Left atrial enlargement
What does right atrial enlargement look like on ECG?
Right atrial enlargement is associated with a peaked P wave taller than 2.5 mm in the inferior leads and more than 1.5 mm tall in leads V1 and V2.
What represents the time from the depolarization of the sinus node to the onset of ventricular depolarization
PR interval
Normal duration of PR interval?
between 0.12 to 0.20 seconds.
The measurement starts from the beginning of the P wave to the first part of the QRS complex
Ventricular depolarization ECG?
QRS complex
