Sinus Rhythms
What is the normal pacemaker of the heart that produces a sinus rhythm?
The Sinoatrial (SA) node
What is a premature atrial complex (PAC)?
Early atrial beat
Where does a junctional rhythm originate?
AV junction / area near bundle of His.
What is a premature ventricular complex (PVC)?
PVC = early beat from ventricles with wide, bizarre QRS.
What is a first‑degree heart block? Give the PR interval criterion.
PR interval > 0.20 s0.20 s.
Define sinus tachycardia and give the typical heart rate range for it
Sinus tachycardia = fast sinus rhythm; rate roughly 100−150 BPM
What EKG feature distinguishes atrial flutter from atrial fibrillation?
Flutter has regular sawtooth F waves; fibrillation has no discrete P waves and irregular rhythm
Define a premature junctional complex (PJC) and how its timing differs from a junctional escape beat.
PJC is an early beat from the junction (premature); junctional escape beat is late (occurs when SA fails).
Define unifocal versus multifocal PVCs
Unifocal = identical PVC morphology; multifocal = varying morphologies.
Describe the characteristic PR interval pattern in Mobitz type I (Wenckebach).
Progressive PR lengthening until a dropped beat.
Describe sinus arrhythmia and explain one common physiological reason it occurs.
Sinus arrhythmia = sinus rhythm with irregular R‑R intervals, often varying with respiration (normal in many people)
Define multifocal atrial tachycardia (MAT) and explain how P waves appear on the tracing
MAT = multiple different P wave morphologies, rate > 100 BPM100 BPM for MAT (wandering atrial pacemaker if rate < 100 BPM100 BPM).
Give the rate range for a junctional escape rhythm and for an accelerated junctional rhythm.
Junctional escape: 40−60 BPM40−60 BPM; accelerated junctional: 60−100 BPM60−100 BPM.
What pattern name is used when a PVC occurs every other beat? Every third beat?
Every other beat = bigeminy; every third beat = trigeminy.
Explain the difference between Mobitz type II and third‑degree heart block in terms of atrial‑ventricular relationship.
Mobitz II = fixed ratio of dropped beats with consistent PR on conducted beats; third‑degree = no relationship between P waves and QRS complexes
Explain sinus arrest
Sinus arrest = SA node fails to initiate impulse causing pause
A patient’s EKG shows no visible P waves, an irregular R‑R interval, and ventricular rate 90 BPM. What is the likely atrial rhythm classification and how would you describe control?
Atrial fibrillation, controlled (ventricular rate under 100 BPM100 BPM).
Describe how a retrograde P wave might look on the EKG when junctional tissue produces a beat.
Retrograde P wave may be inverted, occur before, during, or after QRS depending on timing.
Define ventricular tachycardia (VT) and explain when VT becomes especially dangerous.
VT = 3+ PVCs in a row; dangerous if sustained > 30–60 seconds or hemodynamically unstable — can progress to VF.
List two signs on an EKG that suggest a patient has an artificial pacemaker.
Visible pacing spikes before paced complexes; paced morphology (e.g., wide paced QRS for ventricular pacing, atrial spike before P waves for atrial pacing).
Given: Heart rate 54 BPM, P waves upright & uniform, QRS 0.10 s, PR interval 0.24 s. Provide the most precise EKG interpretation:
Sinus bradycardia with prolonged PR (interpretation: Sinus bradycardia with prolonged PR interval / first‑degree features if PR > 0.20 s
Explain why atrial fibrillation increases the risk of stroke and name one usual medical intervention to reduce that risk.
AFib → blood pools in the atria → risk of blood clots → stroke; anticoagulants (blood thinners) often used.
A tracing shows heart rate 55 BPM, P wave not visible, QRS 0.06 s, regular rhythm. Interpret and explain one clinical concern for a patient with this rhythm
Junctional rhythm; concern: loss of atrial kick (force of and atria contracting) → reduced cardiac output, may need monitoring/treatment.
Describe torsades de pointes and identify one distinguishing EKG feature compared with monomorphic VT.
Torsades = polymorphic VT with QRS twisting around isoelectric line; rate very fast and morphology varies beat to beat.
Define "failure to sense" and "failure to capture" for pacemaker complications, and explain why an EKG technician should report suspected pacemaker malfunction.
Failure to sense = pacemaker does not detect intrinsic activity and may fire inappropriately; failure to capture = pacing spike present but no resulting depolarization or paced complex. Report to provide