Cardiology and Internal Medicine Comprehensive Review Notes –
Medical Board Exam Preparation (Clinical Summaries and Diagnostic
Criteria)
Premature Ventricular Contractions (PVC) - correct answer QRS w/o P-wave
Types:
Early After Depolarization
Delayed After Depolarization
Ectopic Foci Location
Positive V1: From Left
Negative V1: From Right
Can present as:
1. Compensatory pause (2x normal sinus rhythm b/c ventricles are refractory to atrial
stimulation)
2. Noncompensatory (<2x normal sinus rhythm b/c atrium depolarized by ectopic foci)
*Note: Contraction after Compensatory pause presents as palpitation!
Timing:
1) During P-wave
2) During PR segment (Ventricular fusion)
3) During T wave (R-on-T Phenomenon)
Frequency:
1) Ventricular Bigeminy: PVC after each cardiac cycle
,2) Ventricular Trigeminy: PVC after every 2 cycles
3) Multiple Foci: Different morphological PVCs
Complications:
Vtach or Vfib
Premature Atrial Contractions (PAC) - correct answer Early abnormal P-waves +/- QRS
Ectopic Atrial Focus causes SA depolarization
Noncompensatory Pause is common: P-P*-P is shorter than P-P-P length.
Ectopic Foci Location:
Inverted P-wave: Bottom of Atrium
Short PR Interval: Close to AV Node
Timing of Ectopic Depolarization:
1) Conducted to Ventricles (Normal QRS)
2) One Ventricle is in refractory (abnormal wide QRS b/c conducts abhorrently to refractory
ventricle)
3) AV is in refractory (no QRS but SA is still reset causing overfilling of ventricle)
Frequency:
1) Atrial Bigeminy: PAC after each cycle
2) Atrial Trigeminy: PAC after every 2 cycles
Complications:
Afib
,AVRT - correct answer Accessory pathway from ventricles to atria causing SVT
Most common type is Wolff Parkinson White Syndrome: Uses bundle of Kent accessory
pathway
P-wave visibility is determined by accessory path location
Tx w/ Radioablation of accessory pathway
AVNRT - correct answer Accessory Pathway is close to AV Node
Pathways:
Alpha is slow conduction w/ short refractory period
Beta is Fast w/ long refractory period
Types:
Typical (Slow-Fast) AVNRT: Down Alpha (Slow) up Beta (Fast)
Atypical (Fast-Slow) AVNRT: Down Beta (Fast) up Alpha (Slow)
Symp: SOB, Palpitations, Dizziness
P-waves may not be visible b/c buried under QRS
Tx w/ Vagal Maneuvers to block AVN or radioablate Alpha Pathway
Long QT Syndome - correct answer Defined as:
>440ms @ Males
>460ms @ Females
, Must be @ 60bpm otherwise must be corrected to QTc via Bazetts Formula
QT Interval: Time between Ventricular Depolarization & Repolarization
Causes:
1) Dysfunctional L-Type CaC
2) Na or K Channel Dysfunction
Both can result in Early After Depolarization (EAD) causing PVC
3) Class 1a & III Antiarrhythmics (1: Na & K Channel Blockers; 3: K Channel)
EAD can lead to:
Reentriant Tachycardia such as Torsade de Pointes (Palpation's, Dizziness, Syncope) otherwise
known as Polymorphic VT
Atrial Flutter - correct answer Definition: Atrial Contraction >300bpm secondary to reentrant
rhythm
Presents as sawtooth p-waves
Type 1: Counterclockwise Rhythm around Tricuspid Valve
Type 2: R or L atrium exact location is left defined
Risk Factors: Condition causing ischemia results in altered cardiomyocytes predisposing pt to
reentrant rhythm
AVN 330s refractory period limits ventricular rate. If ventricular rate >100 its considered SVT
SVT along w/ other condition predisposes pt to symptomatic Aflut (SOB, CP, Dizziness, Nausea)
Medical Board Exam Preparation (Clinical Summaries and Diagnostic
Criteria)
Premature Ventricular Contractions (PVC) - correct answer QRS w/o P-wave
Types:
Early After Depolarization
Delayed After Depolarization
Ectopic Foci Location
Positive V1: From Left
Negative V1: From Right
Can present as:
1. Compensatory pause (2x normal sinus rhythm b/c ventricles are refractory to atrial
stimulation)
2. Noncompensatory (<2x normal sinus rhythm b/c atrium depolarized by ectopic foci)
*Note: Contraction after Compensatory pause presents as palpitation!
Timing:
1) During P-wave
2) During PR segment (Ventricular fusion)
3) During T wave (R-on-T Phenomenon)
Frequency:
1) Ventricular Bigeminy: PVC after each cardiac cycle
,2) Ventricular Trigeminy: PVC after every 2 cycles
3) Multiple Foci: Different morphological PVCs
Complications:
Vtach or Vfib
Premature Atrial Contractions (PAC) - correct answer Early abnormal P-waves +/- QRS
Ectopic Atrial Focus causes SA depolarization
Noncompensatory Pause is common: P-P*-P is shorter than P-P-P length.
Ectopic Foci Location:
Inverted P-wave: Bottom of Atrium
Short PR Interval: Close to AV Node
Timing of Ectopic Depolarization:
1) Conducted to Ventricles (Normal QRS)
2) One Ventricle is in refractory (abnormal wide QRS b/c conducts abhorrently to refractory
ventricle)
3) AV is in refractory (no QRS but SA is still reset causing overfilling of ventricle)
Frequency:
1) Atrial Bigeminy: PAC after each cycle
2) Atrial Trigeminy: PAC after every 2 cycles
Complications:
Afib
,AVRT - correct answer Accessory pathway from ventricles to atria causing SVT
Most common type is Wolff Parkinson White Syndrome: Uses bundle of Kent accessory
pathway
P-wave visibility is determined by accessory path location
Tx w/ Radioablation of accessory pathway
AVNRT - correct answer Accessory Pathway is close to AV Node
Pathways:
Alpha is slow conduction w/ short refractory period
Beta is Fast w/ long refractory period
Types:
Typical (Slow-Fast) AVNRT: Down Alpha (Slow) up Beta (Fast)
Atypical (Fast-Slow) AVNRT: Down Beta (Fast) up Alpha (Slow)
Symp: SOB, Palpitations, Dizziness
P-waves may not be visible b/c buried under QRS
Tx w/ Vagal Maneuvers to block AVN or radioablate Alpha Pathway
Long QT Syndome - correct answer Defined as:
>440ms @ Males
>460ms @ Females
, Must be @ 60bpm otherwise must be corrected to QTc via Bazetts Formula
QT Interval: Time between Ventricular Depolarization & Repolarization
Causes:
1) Dysfunctional L-Type CaC
2) Na or K Channel Dysfunction
Both can result in Early After Depolarization (EAD) causing PVC
3) Class 1a & III Antiarrhythmics (1: Na & K Channel Blockers; 3: K Channel)
EAD can lead to:
Reentriant Tachycardia such as Torsade de Pointes (Palpation's, Dizziness, Syncope) otherwise
known as Polymorphic VT
Atrial Flutter - correct answer Definition: Atrial Contraction >300bpm secondary to reentrant
rhythm
Presents as sawtooth p-waves
Type 1: Counterclockwise Rhythm around Tricuspid Valve
Type 2: R or L atrium exact location is left defined
Risk Factors: Condition causing ischemia results in altered cardiomyocytes predisposing pt to
reentrant rhythm
AVN 330s refractory period limits ventricular rate. If ventricular rate >100 its considered SVT
SVT along w/ other condition predisposes pt to symptomatic Aflut (SOB, CP, Dizziness, Nausea)
