Chamber Enlargement Flashcards Preview

ECG interpretation > Chamber Enlargement > Flashcards

Flashcards in Chamber Enlargement Deck (20)
Loading flashcards...
1

What are the bounds of a normal P-wave axis?

+30° to +75°

2

Describe P-wave axis deviation in the presence of left or right atrial enlargement.

RAE may result in a P-wave axis >75° while LAE may result in a P-wave axis <30°

Note that P-wave axis deviation is neither sensitive nor specific for atrial enlargement, especially LAE, and should never be used in isolation to identify atrial enlargement.

3

The P-wave axis is generally most aligned with lead _______, making it the first choice of lead to look for atrial pathologies.

Lead II

4

Give indicators for right atrial enlargement

  • Peaked P-wave morphology with amplitude >2.5mm in lead II ("P-pulmonale")
    • Due to enlargement of p-wave component attributable to Right atrial depolarization. Since R. atrium depolarizes first, this phenomenon increases overlap and leads to peaked morphology
  • Prominent positive defleciton of P-wave in V1 (area under curve >1 small box)
  • Potential P-wave axis >75°

5

Give indicators for left atrial enlargement

  • Increased P-wave duration (>120ms)
  • Notched P-wave appearance in lead II
  • More prominent negative deflection of P in V1 (area under curve >1 small box)

6

Describe typical P-wave morphology in leads II and V1

  • II: typically uniphasic, upright, with the largest amplitude of any lead, duration <120ms.
  • V1: typically biphasic and isoelectric/equiphasic

7

Describe typical QRS morphology in V1 and V6

  • V1: small inital r followed by dominant S wave 
    • r due to septal depolarization followed by S due to dominant L. ventricular depolarization away from V1
  • V6: small initial q (septal/physiologic q) followed by dominant R
    • q due to septal depolarization followed by dominant L. ventricular depolarization in direction of V6

8

Describe qualitative changes to QRS morphology in V1 and V6 in right ventricular hypertrophy

  • V1: Shift to dominant R wave with small or absent s
    • potential appearance of initial q and T-wave inversion
  • V6: shift to equiphasic or S-dominant appearance

In summary, RVH leads to a reversal of normal QRS morphology in V1 and V6

9

Describe qualitative changes to QRS morphology in V1 and V6 in left ventricular hypertrophy

  • V1: Deep, broad S-wave with potential loss of initial r
  • V6: Tall, broad R-wave with potential loss of septal q.
    • Potential T-wave inversion with downsloping ST depression

LVH leads to exageration of normal QRS morphology

10

Describe ECG changes due to secondary repolarization abnormalities in ventricular hypertrophy.

T-wave inversion and downsloping ST-depression in leads over the affected ventricle

11

Assess the following ECG for signs of chamber enlargement:

  • Normal P-wave morphology in II and V1 (subtle pre-pathologic peaking in II suggestive of early RAE)
  • Dominant R in V1 with downsloping ST-depression and T-wave inversion
  • Equiphasic or dominant S in V6
  • Right axis deviation
  • Suggests RVH

12

The term "ventricular strain pattern" is no longer encouraged, and is instead referred to as __________

secondary repolarization abnormalities

13

Describe intrinsicoid deflection and how it can be used in assessing for ventricular hypertrophy

  • intrinsicoid deflection is the duration from the initial QRS deflection to peak of the first R-wave
  • Prolonged intrisicoid deflection is indicative of ventricular hypertrophy
    • >35ms in RVH
    • >45ms in LVH

14

Describe qualitative ECG findings in RVH

  • Unusually tall R waves in V1 and V2 ± secondary repolarization abnormalities (downward sloping STD with T wave inversions)
  • Unusually deep S in V5, V6, I, and aVL
  • Right axis deviation (>+90°)
  • Right atrial enlargement
  • RBBB may be present
  • Poor R-wave progression

15

Describe qualitative ECG findings in LVH

  • Unusually tall R waves in V5, V6, I, and aVL ± secondary repolarization abnormalities (downward sloping STD with T wave inversions)
  • Unusually deep S in V1 and V2
  • Left axis deviation (< -30°)
  • Left atrial enlargement
  • LBBB may be present
  • Delayed intrinsicoid deflection

16

What are ECG findings associated with RVH in COPD, beyond normal RVH findings. (so-called pulmonary disease pattern)

  • Low voltage
  • rS pattern in all precordial leads
  • Rarely, extreme axis deviation

17

ECG findings for ventricular hypertrophy tend to be highly ____________ (sensitive/specific), but not the other.

specific (not sensitive)

18

Summarize the Sokolow-Lyon criteria for LVH

  • S-wave amplitude in V1 + R wave amplitude in V5 or V6 > 35mm

19

Describe features of chamber enlargement seen in this ECG

  • Multiple signs of LVH
    • LAD (QRS axis ~ -60°)
    • Sokolow-Lyon voltage criteria (SV1 + RV5 >> 35mm)
    • Secondary repolarization abnormalities in V5, V6, I, and aVL
    • Intrinsicoid deflection in V5 and V6 >0.050ms

20

Describe features of chamber enlargement seen in this ECG

  • Multiple signs of RVH
    • RAD (QRS axis ~ +150°)
    • Prominent RV1 and SV6
    • Secondary repolarization abnormalities in V1-V4