From the Guidelines
Left atrial abnormality on ECG is characterized by a P wave duration of 120 ms or more, and a widely notched P wave, which are indicative of prolonged atrial activation time and increased left atrial pressure or volume. These changes are primarily seen in the P wave, which represents atrial depolarization, and can be caused by conditions such as mitral valve disease, hypertension, heart failure, and coronary artery disease 1. The classic ECG finding for left atrial abnormality is a P wave that is wider than normal and often notched or bifid in lead II, with a prominent negative terminal component in lead V1, known as the P terminal force 1.
Key ECG Findings
- P wave duration of 120 ms or more
- Widely notched P wave (40 ms or more)
- Prominent negative terminal component in lead V1 (P terminal force)
- Left axis of the terminal P wave (30 to 90)
- Possibly, the P-wave area
Clinical Significance
Left atrial abnormality is clinically significant as it may indicate increased risk for atrial fibrillation, stroke, and other cardiovascular complications 1. When identified on ECG, left atrial abnormality should prompt further cardiac evaluation, typically with echocardiography, to assess left atrial size and function and to identify the underlying cause 1.
Treatment
Treatment focuses on addressing the underlying condition causing the left atrial pressure or volume overload rather than treating the ECG finding itself. This may involve management of conditions such as hypertension, heart failure, and coronary artery disease, as well as consideration of anticoagulation therapy to reduce the risk of stroke in patients with atrial fibrillation 1.
From the Research
Left Atrial Abnormality Changes in ECG
- Left atrial abnormalities can be detected through electrocardiographic (ECG) changes, which may indicate an increased risk of atrial arrhythmias and stroke 2, 3, 4.
- Studies have shown that impaired left atrial strain is associated with subclinical atrial arrhythmias, including atrial fibrillation, premature atrial contractions, and supraventricular tachycardia 2.
- ECG-defined left atrial abnormality has been linked to an increased risk of ischemic stroke, particularly cryptogenic or cardioembolic stroke, independently of atrial fibrillation 4.
- The P-wave terminal force in lead V1 has been used as a marker of left atrial abnormality, with higher values indicating increased risk of stroke 3, 4.
Association with Stroke
- Left atrial abnormalities have been associated with an increased risk of stroke, including ischemic and hemorrhagic stroke 3, 4.
- The risk of stroke is higher in patients with left atrial abnormality, particularly those with a history of hypertension, advanced age, coronary artery disease, diabetes mellitus, and valvular heart disease 3.
- Echocardiographic parameters, such as left atrial volume and left atrial reservoir strain, have been shown to be independent predictors of stroke risk in patients with atrial fibrillation 5.
Predictive Factors for Arrhythmia Recurrence
- Left atrial size and function, as assessed by three-dimensional echocardiography, have been shown to be predictive of arrhythmia recurrence after radiofrequency catheter ablation for atrial fibrillation 6.
- A combination of clinical data and echocardiographic parameters, including left atrial expansion index and maximal volume, can predict the success of ablation procedures 6.
- Age and left atrial maximum volume have been identified as predictors of arrhythmia recurrence in patients undergoing repeated ablation procedures 6.