What is the significance of P mitrale (P mitrale, a sign of left atrial enlargement) on an electrocardiogram (EKG)?

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Last updated: May 29, 2025View editorial policy

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From the Guidelines

P mitrale on an EKG is a specific pattern indicating left atrial enlargement, characterized by a notched, broad P wave with two peaks, and requires further cardiac evaluation to identify the underlying cause. This pattern is commonly associated with conditions such as mitral valve disease, hypertension, aortic valve disease, and left ventricular dysfunction, as noted in the guidelines by the American Heart Association 1. The appearance of P mitrale is due to the prolonged depolarization of the enlarged left atrium, resulting in a widened, notched P wave on the electrocardiogram. Some key points to consider when identifying P mitrale on an EKG include:

  • The P wave duration is greater than 0.12 seconds, with two distinct peaks, particularly visible in leads I, II, and V4-V6.
  • The condition is often associated with left atrial enlargement, which can be caused by various factors, including mitral stenosis, mitral regurgitation, and hypertension, as discussed in the American College of Cardiology guidelines 1.
  • Further evaluation, such as echocardiography, is necessary to confirm left atrial enlargement and determine the underlying cause of P mitrale.
  • Treatment should be directed at the underlying condition, rather than the P wave abnormality itself, to improve patient outcomes and reduce morbidity and mortality.

From the Research

P Mitrale on EKG

  • P mitrale is a term used to describe a specific pattern on an electrocardiogram (EKG) that indicates left atrial enlargement.
  • According to a study published in 2003 2, the P-wave area measured from lead II of a standard 12-lead ECG can be used to diagnose left atrial enlargement in patients with mitral stenosis.
  • The study found that a P-wave area of ≥ 4 ms x mv had an 85.8% sensitivity and 93.7% specificity for left atrial enlargement.
  • The P-wave area was also found to have a better overall sensitivity than the P-wave duration or amplitude in diagnosing left atrial enlargement.

Diagnosis and Treatment

  • Left atrial enlargement can be estimated by P-wave area measured from ECG lead II in patients with mitral stenosis 2.
  • The use of beta-blockers and ACE inhibitors has been studied in various cardiovascular diseases, including heart failure and hypertension 3, 4, 5.
  • However, the use of beta-blockers has been associated with impaired left atrial function in hypertension 6.
  • The combination of beta-blockers and ACE inhibitors may be beneficial in certain patients, but the decision to initiate treatment should be tailored on an individual basis 4, 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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