EKG Fundamentals
What is the standard paper speed and gain for ECG monitoring?
25 mm/s and 10 mm/mV
Define atrial fibrillation on a single-lead monitor.
Irregularly irregular R–R with no distinct P waves; fibrillatory baseline.
Define 1st-degree AV block.
PR interval >200 ms with 1:1 AV conduction.
What is lead loss and how does it appear?
Electrode/lead off causing flatline or wandering baseline in that channel; check connections.
Name two rhythms that typically require urgent escalation.
VF and 3rd-degree.
Define PR interval and its normal range.
Start of P to start of QRS; 120–200 ms (0.12–0.20 s).
Differentiate atrial flutter from SVT on single-lead.
Flutter: sawtooth F-waves with a 2:1/3:1/4:1 conduction ratio; SVT: narrow regular tachycardia with hidden P waves.
Describe Mobitz I (Wenckebach).
Progressive PR prolongation until a non-conducted P; repeating cycle.
Name two features suggesting artifact vs VT.
QRS present in one channel but not another, baseline noise with preserved pulses; check electrode/lead stability.
Define the 'pause' event threshold commonly used.
Asystolic pause ≥3 seconds.
What does the QRS complex represent and normal duration?
Ventricular depolarization; ≤120 ms
Define ventricular tachycardia criteria on a strip.
≥3 consecutive wide QRS beats at >100 bpm, typically, AV dissociation may be present.
Describe Mobitz II.
Intermittent non-conducted P waves with constant PR intervals in conducted beats.
How can patient movement mimic AF?
Fine tremor/respiratory artifact produces irregular baseline; look for consistent QRS timing and true P absence.
What is the recommended action if an event is borderline to the protocol threshold?
Escalate/send as critical to ensure patient safety when near threshold.
Name two ways to estimate ventricular rate from a rhythm strip.
300 method using large boxes; or count QRS in 6 seconds ×10.
What is an idioventricular rhythm (IVR)?
Wide QRS rhythm from a ventricular focus, usually 20–40 bpm (AIVR 40–100).
Define 3rd-degree (complete) AV block.
No AV association; independent atrial and ventricular rhythms with AV dissociation.
When should you invert the displayed lead?
When the vector is reversed (e.g., negative P/QRS expected), to better visualize morphology consistently for interpretation.
Name three distinguishing features between Mobitz I and complete heart block on a single-lead monitor.
Mobitz I: progressive PR prolongation, grouped beats, predictable dropped P following lengthening PR. Complete heart block: constant P–P and R–R with no relation (AV dissociation), escape rhythm regularity, variable PR with no pattern.
What is the clinical meaning of a biphasic P wave?
Atrial conduction with vector change—can suggest atrial enlargement or axis variation; recognize morphology change.
Describe torsades de pointes.
Polymorphic VT with twisting QRS amplitude around the baseline; often with prolonged QT.
One clue to differentiate Wenckebach with escape beats vs 3rd-degree on single-lead?
Grouped beating & progressively lengthening PR favors Wenckebach; consistent AV dissociation favors 3rd-degree.
What does a biphasic P wave indicate on single-lead and how to confirm?
Change in atrial vector; confirm by consistent morphology across beats and correlation with rate/rhythm context.
When confirming patient identity, which two identifiers are recommended?
Name and DOB