Introduction

Elevated pulmonary pressures in pulmonary hypertension (PH) can be associated with  right ventricular hypertrophy (RVH) and right atrial enlargement which may be observed on electrocardiogram.

PH is defined as an increase in mean pulmonary arterial pressure( PAPm) ≥25 mmHg at rest as assessed by right heart catheterization.

Picture 1 Haemodynamic definitions of pulmonary hypertension as per ESC guidelines

2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension.

Pathophysiology

Classification of PH as per ESC:

• Pulmonary artery hypertension
• Pulmonary hypertension due to left heart disease
• Pulmonary hypertension due to lung diseases and/or hypoxia
• Chronic thromboembolic pulmonary hypertension and other pulmonary artery obstructions
• Pulmonary hypertension with unclear and/or multifactorial mechanisms

Main causes of PH:

1. respiratory

• hypoxic vasoconstriction increases pulmonary hypertension

2. cardiac 

• LA or LV disease -> ↑ LA pressure -> ↑ pulmonary venous pressure -> ↑ PAP -> ↑PVR
• L to right shunt will also cause high PVP

Consequences 

• vasoconstriction 
• altered vascular endothelium and smooth muscle function
• cellular remodelling
• increased vascular contractility
• lack of relaxation in response to various endogenous vasodilators
• fibrosis of vascular tissue

Clinical presentation 

• shortness of breath
• weakness and fatigue
• chest pain 
• syncope or presyncope
• cough
• signs of heart failure

ECG manifestation 

ECG findings suggestive of RVH in pulmonary hypertension  - sensitivity (55%) and specificity (70%) :

• Right axis deviation
• R/S ratio > 1 in V1
• R wave > 7mm in V1
• rSR' complex in V1 with R' > 10mm
• qR complex in V1

Right ventricular strain pattern (more sensitive than signs of RVH on ECG):

• ST segment and T wave inversion in V1-V3 and occasionally in inferior leads (II, III, AVF)
• Right bundle branch block: QRS duration > 0.12 seconds, rSR' in leads V1 & V2, wide slurred S waves in lateral leads (V5, V6, I)

ECG findings suggestive of right atrial enlargement:

• P pulmonale: P wave amplitude >2.5mm in inferior leads (II, III, AVF) or >1.5mm in V1/V2
• P wave axis shifted rightward >70°
• Prolongation of the QRS complex and QTc suggest severe disease
• Supraventricular arrhythmias may occur in advanced disease, in particular atrial flutter, but also atrial fibrillation

ECG 1 Patient with pulmonary artery hypertension - RBBB, right axis deviation (dominant negative deflection in leads I and aVL), R wave > 7mm in V1, ST depressions in V1-V3, P pulmonale

ECG 2 Patient with cor pulmonale related to chronic severe COPD - P pulmonale in inferior leads.

Management

• treatment of underlying disease
• O2
• diuretics
• anticoagulation 
• advanced vasodilatory therapy
• lung transplantation 

References

1. Ryan JJ, Thenappan T, Luo N, et al. The WHO classification of pulmonary hypertension: A case-based imaging compendium. Pulm Circ. 2012;2(1):107-121. doi:10.4103/2045-8932.94843
2. Lan NSH, Massam BD, Kulkarni SS, Lang CC. Pulmonary Arterial Hypertension: Pathophysiology and Treatment. Diseases. 2018;6(2):38. Published 2018 May 16. doi:10.3390/diseases6020038
3. Henkens IR, Scherptong RW, van Kralingen KW, Said SA, Vliegen HW. Pulmonary hypertension: the role of the electrocardiogram. Neth Heart J. 2008;16(7-8):250-254. doi:10.1007/BF03086156
4. Barto, Donna MA, RN, CCRN Recognizing pulmonary hypertension on the ECG, Nursing Critical Care: March 2011 - Volume 6 - Issue 2 - p 11-13 doi: 10.1097/01.CCN.0000394497.97148.d7
5. Galiè N, Humbert M, Vachiery JL, Gibbs S, Lang I, Torbicki A, Simonneau G, Peacock A, Vonk Noordegraaf A, Beghetti M, Ghofrani A, Gomez Sanchez MA, Hansmann G, Klepetko W, Lancellotti P, Matucci M, McDonagh T, Pierard LA, Trindade PT, Zompatori M, Hoeper M; ESC Scientific Document Group. 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension: The Joint Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS): Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC), International Society for Heart and Lung Transplantation (ISHLT). Eur Heart J. 2016 Jan 1;37(1):67-119. doi: 10.1093/eurheartj/ehv317. Epub 2015 Aug 29. PMID: 26320113.

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