Pulmonary Hypertension and ECG: A Detailed Explanation

Introduction

Pulmonary hypertension (PH) is a condition characterized by increased pressure in the pulmonary arteries, which can lead to right heart strain and failure if left untreated. An electrocardiogram (ECG) is a useful tool in the diagnosis and evaluation of PH, as it can reveal signs of right ventricular overload and related abnormalities.

How Pulmonary Hypertension Affects the Heart

PH increases resistance in the pulmonary circulation, forcing the right ventricle to work harder to pump blood into the lungs. Over time, this leads to right ventricular hypertrophy (RVH) and right atrial enlargement, both of which can be detected on an ECG.

ECG Findings in Pulmonary Hypertension

While an ECG alone cannot diagnose PH, specific patterns may suggest its presence. These include:

1. Signs of Right Ventricular Hypertrophy (RVH)

• Right axis deviation (> 90 degrees in adults)
• R wave dominance in lead V1 (R/S ratio > 1)
• Deep S waves in leads V5 and V6

2. Signs of Right Atrial Enlargement (RAE)

• Peaked P waves (P pulmonale) in leads II, III, and aVF (amplitude > 2.5 mm)

3. Signs of Right Ventricular Strain

• ST-segment depression and T-wave inversion in leads V1-V3
• Low voltage QRS complexes in limb leads (due to pericardial effusion in advanced cases)

4. Signs of Right Bundle Branch Block (RBBB)

• Incomplete or complete RBBB pattern with wide QRS (>120 ms)

5. Altered QRS Axis

• Extensive right axis deviation (> 110 degrees) due to RV hypertrophy

Clinical Relevance and Next Steps

If an ECG suggests the presence of PH, further evaluation is needed: - Echocardiography to estimate pulmonary artery pressures - Right heart catheterization for definitive pressure measurement - CT scan or MRI to evaluate lung and heart structure - Blood tests and lung function tests to rule out other causes

Early detection and management of pulmonary hypertension are crucial to improving outcomes and preventing right heart failure. Treatment options include medications such as phosphodiesterase inhibitors, endothelin receptor antagonists, and prostacyclin analogs, depending on the underlying cause.

Source recommendations

1. 2022 ESC/ERS Guidelines for the Diagnosis and Treatment of Pulmonary Hypertension

1. https://pubmed.ncbi.nlm.nih.gov/36017548/
2. https://academic.oup.com/eurheartj/article/43/38/3618/6673929
3. https://publications.ersnet.org/content/erj/early/2022/08/25/1399300300879-2022.abstract
4. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Pulmonary-Hypertension-Guidelines-on-Diagnosis-and-Treatment-of
5. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2022/08/30/19/11/2022-ESC-Guidelines-for-Pulmonary-Hypertension-ESC-2022

2. AHA/ACC Guidelines on Pulmonary Hypertension

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001136
2. https://www.sciencedirect.com/science/article/pii/S073510972106215X
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000603
4. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2022/08/30/19/11/2022-ESC-Guidelines-for-Pulmonary-Hypertension-ESC-2022
5. https://www.jacc.org/doi/10.1016/j.jacc.2018.08.1028