TALKS 2025-2026 | Graded
to Pass | Rhythm
Interpretation & Cardiology
Exam Prep | Pass Guaranteed
- A+ Graded
## **PART A: RHYTHM STRIP IDENTIFICATION (Q1–25)**
* *Q1:** Lead II rhythm strip shows irregularly irregular narrow QRS rhythm with no discernible P
waves. Rate varies between 110 and 150 bpm. What is the rhythm?
- A. Atrial flutter with variable block
- B. Multifocal atrial tachycardia (MAT)
- C. Atrial fibrillation
- D. Sinus tachycardia with PACs
* *[CORRECT]** C
*Rationale: Atrial fibrillation is defined by irregularly irregular RR intervals, absence of P waves,
and narrow QRS complexes. Distractor B (MAT) requires at least three distinct P wave
morphologies with varying PR intervals, not absent P waves; A (flutter) demonstrates
characteristic sawtooth flutter waves.*
---
* *Q2:** Lead II rhythm strip shows regular narrow QRS at 180 bpm. No visible P waves. Rhythm
starts and stops abruptly. What is the rhythm?
- A. Sinus tachycardia
- B. Atrial flutter with 2:1 block
,- C. AV nodal re-entry tachycardia (AVNRT)
- D. Atrial tachycardia
* *[CORRECT]** C
*Rationale: AVNRT presents as a regular narrow-complex tachycardia at 150–250 bpm with
absent or retrograde P waves and sudden onset/termination (paroxysmal). Distractor A (sinus
tachycardia) has visible upright P waves and gradual rate changes; B (flutter) shows flutter
waves at ~300 bpm with 2:1 conduction giving ~150 bpm but has visible atrial activity.*
---
* *Q3:** Lead II rhythm strip shows regular narrow QRS at 150 bpm. Sawtooth flutter waves
visible at 300 bpm with 2:1 AV conduction. What is the rhythm?
- A. Sinus tachycardia
- B. Atrial flutter with 2:1 AV block
- C. AVNRT
- D. Atrial tachycardia
* *[CORRECT]** B
*Rationale: Atrial flutter with 2:1 block demonstrates characteristic sawtooth flutter waves at
~300 bpm with every other impulse conducted, producing a ventricular rate of ~150 bpm.
Distractor C (AVNRT) lacks flutter waves and typically has rates of 180–220 bpm; A (sinus
tachycardia) has normal P waves preceding each QRS.*
---
* *Q4:** Lead II rhythm strip shows irregular narrow QRS rhythm at ~120 bpm. At least three
distinct P wave morphologies with varying PR intervals are present. What is the rhythm?
- A. Atrial fibrillation
- B. Sinus tachycardia with frequent PACs
- C. Multifocal atrial tachycardia (MAT)
- D. Atrial flutter with variable block
* *[CORRECT]** C
*Rationale: MAT is diagnosed by an atrial rate >100 bpm with at least three distinct P wave
morphologies and varying PR intervals in the same lead. Distractor A (AFib) has no organized P
waves; B (PACs) would show a dominant sinus P wave morphology with occasional premature
beats, not three or more distinct P morphologies.*
---
* *Q5:** Lead II rhythm strip shows regular narrow QRS at 200 bpm. Retrograde P waves visible
in the terminal portion of the QRS (pseudo-S wave in inferior leads). What type of AVNRT is
this?
, - A. Atypical AVNRT (fast-slow)
- B. Typical AVNRT (slow-fast)
- C. Orthodromic AVRT
- D. Antidromic AVRT
* *[CORRECT]** B
*Rationale: Typical (slow-fast) AVNRT accounts for ~90% of cases and demonstrates retrograde
P waves buried within or immediately following the QRS, often appearing as pseudo-S waves in
inferior leads. Distractor A (atypical) shows late retrograde P waves with RP > PR interval; C
(orthodromic AVRT) uses an accessory pathway and may show distinct retrograde P waves
after the QRS.*
---
* *Q6:** Lead II rhythm strip shows regular narrow QRS at 190 bpm. Retrograde P waves
appear after the QRS with RP interval longer than PR interval. What is the rhythm?
- A. Typical AVNRT
- B. Atypical AVNRT (fast-slow)
- C. Orthodromic AVRT
- D. Sinus tachycardia
* *[CORRECT]** B
*Rationale: Atypical (fast-slow) AVNRT is characterized by anterograde conduction down the
fast pathway and retrograde up the slow pathway, producing RP > PR interval with late
retrograde P waves. Distractor A (typical) has RP < PR with P waves buried in the QRS; C
(orthodromic AVRT) typically has RP < PR and may show pre-excitation in sinus rhythm.*
---
* *Q7:** Lead II rhythm strip shows regular wide QRS tachycardia at 160 bpm. QRS duration 160
ms, RBBB morphology (rsR' in V1), extreme right axis deviation (northwest quadrant). No AV
dissociation is visible. What is the most likely diagnosis?
- A. SVT with aberrant conduction (RBBB)
- B. Antidromic AVRT
- C. Monomorphic ventricular tachycardia (VT)
- D. Pre-excited atrial fibrillation
* *[CORRECT]** C
*Rationale: Monomorphic VT is the most likely diagnosis when wide-complex tachycardia shows
extreme axis deviation (northwest quadrant), which is not consistent with bundle branch block
patterns. Per 2025 ACLS and Brugada criteria, extreme axis deviation strongly favors VT.
Distractor A (SVT with aberrancy) typically shows axis consistent with the underlying BBB; B
(antidromic AVRT) usually shows a maximally pre-excited QRS morphology.*