Cardiac Electrophysiology
This structure normally initiates every heartbeat.
What is the SA node?
A standard 12-lead ECG requires this many electrodes to acquire all 12 leads.
What is 10 electrodes?
This is the first step in a systematic ECG interpretation.
What is determining the heart rate?
This electrical event produces the QRS complex.
What is ventricular depolarization?
These two machine settings should always be verified before acquiring and interpreting an ECG.
What are 25 mm/sec paper speed and 10 mm/mV calibration?
Leads II,III & aVF look at this region of the heart.
What is the inferior portion of the heart?
This portion of the conduction system creates the physiologic delay that allows ventricular filling before ventricular contraction.
What is the AV node?
These patient preparation steps improve electrode contact and help reduce ECG artifact before acquisition.
What are cleaning/lightly abrading the skin, clipping excess hair, and ensuring good electrode adhesion?
These two leads are used to determine the heart's electrical axis.
What are Lead I and aVF?
An electrical impulse is traveling toward Lead II. How should the QRS deflection appear?
What is a positive or an upward deflection?
This technical problem should be corrected first when an ECG tracing demonstrates baseline wander or excessive artifact.
What is poor electrode contact (or improper patient/electrode preparation)?
This is the normal duration of the QRS complex on a standard EKG.
What is less than 0.12 seconds (less than 3 small boxes)?
This condition alters the heart's normal electrical vector because electrical impulses must travel around tissue that no longer conducts normally.
What is myocardial scar tissue (prior myocardial infarction)?
This technical error should be ruled out before interpreting poor R-wave progression on a 12-lead ECG.
"What is incorrect precordial lead placement?"
A 10-second rhythm strip contains 13 QRS complexes, the rhythm is regular, Lead I and aVF are positive, the PR interval is 0.16 seconds, and the QRS duration is 0.08 seconds. Based on a systematic interpretation, what is your overall assessment?
What is a normal sinus rhythm with a heart rate of approximately 78 beats per minute, a normal axis, and normal intervals?