ECG Changes in COPD

1. P-Wave Changes

P Pulmonale

• Peaked, tall P waves (>2.5 mm) in leads II, III, and aVF
• Reflects right atrial enlargement/overload from chronically elevated pulmonary pressures
• One of the most commonly reported findings in COPD studies (present in ~33% of patients)

Vertical P-wave Axis

• The frontal plane P-wave axis shifts toward vertical (>+60°), highly sensitive and specific for emphysema
• Correlates with spirometric severity (FEV₁) and CT-based emphysema scoring
• Considered among the most diagnostically useful solitary ECG criteria for COPD

Other P-wave changes

• Increased P-wave amplitude in inferior leads ("Gothic P waves")
• Increased P-terminal force in V1
• PR segment depression (due to atrial repolarization abnormalities from atrial enlargement)

2. QRS Changes

Low Voltage Complexes

• QRS amplitude <5 mm in limb leads and/or <10 mm in precordial leads
• Caused by hyperaeration acting as an insulator between the heart and recording electrodes
• Very characteristic of emphysema

Poor R-Wave Progression (PRWP)

• Diminished or absent R waves in V1–V4 (slow R-wave progression)
• Results from downward displacement of the diaphragm and heart due to lung hyperinflation
• Important: Chronic cor pulmonale from COPD does not typically produce tall right precordial R waves (as seen in other causes of RVH) — instead it shows PRWP. This is a key distinction emphasized in Harrison's:

"Chronic cor pulmonale due to obstructive lung disease usually does not produce the classic ECG patterns of right ventricular hypertrophy noted above. Instead of tall right precordial R waves, emphysema is more typically associated with diminished r waves in right to mid-precordial leads (slow R-wave progression) due in part to downward displacement of the diaphragm and the heart." — Harrison's Principles of Internal Medicine, 22nd Ed.

Right Axis Deviation (RAD)

• The most common ECG abnormality in some series (present in ~41% of patients)
• QRS axis >+90° in the frontal plane
• Worsens with disease severity — present in 82% of very severe (GOLD Stage 4) COPD

S1S2S3 Pattern

• Persistent S waves in leads I, II, and III
• Reflects clockwise cardiac rotation from right heart enlargement and diaphragmatic depression

Lead I Sign

• Small or absent R wave + prominent S wave in lead I (vertical heart/axis)

Right Bundle Branch Block (RBBB)

• Complete or incomplete RBBB may develop with right ventricular pressure overload

3. Repolarization Changes

ST-T Wave Abnormalities

• ST-segment and T-wave changes (often called "sagging PR and ST segments")
• PR segment depression particularly characteristic
• T-wave inversions in right precordial leads (V1–V3) with RVH

Right Ventricular Hypertrophy (RVH) Pattern

• When cor pulmonale develops: dominant R wave in V1, deep S in V5/V6, right axis deviation
• Present in ~36% of COPD patients overall; much more common in severe/very severe disease

4. Arrhythmias

Multifocal Atrial Tachycardia (MAT)

• Pathognomonic association with COPD and hypoxia
• Irregular, narrow-complex tachycardia with ≥3 distinct P-wave morphologies
• Driven by hypoxia, hypercapnia, catecholamines, and theophylline toxicity
• Rate typically 100–180 bpm

Sinus Tachycardia

• Common — due to hypoxia, dyspnea, or bronchodilator therapy (β₂-agonists)

Atrial Fibrillation / Atrial Flutter

• Increased prevalence compared to general population
• Related to right atrial dilatation and hypoxemia

Other Atrial Arrhythmias

• Atrial tachycardia, PACs common with severe disease

5. Correlation with COPD Severity (GOLD Stages)

ECG Example — COPD with Cor Pulmonale

Summary Table