What are the EKG signs of bilateral enlargement?

EKG Signs of Bilateral Enlargement

Bilateral enlargement on EKG is recognized by identifying features of both right and left chamber abnormalities simultaneously, though sensitivity is notably low due to cancellation of opposing QRS vectors. 1

Biventricular Hypertrophy Recognition

The key to identifying biventricular hypertrophy is looking for combined features that suggest both ventricles are enlarged despite the inherent cancellation effect where increased QRS vectors from each ventricle oppose each other. 1

Primary Diagnostic Features:

• Right axis deviation in the presence of LVH criteria is a strong indicator of coexisting RVH 1
• Prominent S waves in V5 or V6 when LVH criteria are already met suggest additional RVH 1
• Unusually tall biphasic R/S complexes in several leads indicate biventricular involvement 1
• Signs of right atrial abnormality accompanying LVH criteria support biventricular hypertrophy 1

Specific Voltage Criteria:

• In patients with congenital heart defects and RVH, combined tall R waves and deep S waves in leads V2 to V4 with total amplitude >60 mm (6.04 mV) suggests coexisting LVH 1

Biatrial Abnormality Recognition

Combined atrial abnormality requires identifying features of both right and left atrial abnormalities on the same EKG. 1

Left Atrial Abnormality Features:

• P-wave duration ≥120 ms is the most consistent finding 1, 2
• Widely notched (bifid) P wave with ≥40 ms separation between peaks creating an M-like appearance 1, 2
• Increased P terminal force in lead V1 (product of amplitude and duration of terminal negative component) 1, 2
• Left axis of terminal P wave (−30° to −90°) 1

Right Atrial Abnormality Features:

• Tall upright P wave in lead II >2.5 mm with peaked or pointed appearance 1
• Prominent initial positivity of P wave in V1 or V2 ≥1.5 mm (0.15 mV) 1, 3
• Rightward P-wave axis with peaked morphology 1
• P-wave duration usually remains normal unless surgically repaired congenital heart disease is present 1

Combined Atrial Abnormality Pattern:

• Look for simultaneous presence of increased P-wave amplitude (right atrial component) AND increased P-wave duration with terminal negativity in V1 (left atrial component) 1
• The combination creates a tall, wide, notched P wave that reflects both atrial abnormalities 1

Critical Clinical Pitfalls

• Low sensitivity is inherent to bilateral ventricular hypertrophy detection because opposing vectors cancel each other out—absence of criteria does not exclude the diagnosis 1
• Do not rely on single criteria—use multiple electrocardiographic features to increase diagnostic confidence 1
• Adjust interpretation for age, gender, race, and body habitus as these significantly affect voltage criteria 1
• Clinical context is essential—probability estimates should incorporate diagnoses suggesting congenital heart disease, valvular disease, or chronic pulmonary disease 1
• Use preferred terminology: "atrial abnormality" rather than outdated terms like "enlargement," "hypertrophy," or "P-mitrale/P-pulmonale" 1, 2

Algorithmic Approach to Bilateral Enlargement

1. First, identify if LVH criteria are present (voltage criteria, strain pattern)
2. Then look for superimposed RVH features: right axis deviation, prominent S waves in V5-V6, tall biphasic complexes, or right atrial abnormality 1
3. For atrial assessment, measure P-wave duration first (≥120 ms suggests left atrial involvement) 1, 2
4. Next, assess P-wave amplitude in lead II and V1/V2 (>2.5 mm in II or ≥1.5 mm initial positivity in V1/V2 suggests right atrial involvement) 1, 3
5. Evaluate P-wave morphology: notching suggests left atrial abnormality, peaking suggests right atrial abnormality 1
6. Correlate with clinical findings and echocardiography to confirm the diagnosis given the low ECG sensitivity 1, 4