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P biatriale Combination of P mitrale and P pulmonale >Biatrial enlargement

P mitral .Duration: ≥ 0.12 sec Polarity .Bifid  in lead II: peak-to-peak interval of > 0.04 sec Biphasic in lead V1: negative deflection > 1 mm  Left atrial enlargement

P pulmonale Amplitude: ≥ 0.25 mV in leads II, III, and aVF ECG schematic (paper speed: 25 mm/s) Top: normal P-wave morphology Bottom (P pulmonale): increased P-wave amplitude (≥0.25 mV) Due to Right atrial enlargement

P Wave morphology in precordial leads The P wave represents atrial depolarization. The average of the right and left atrial electrical vectors is directed in a left-anterior direction in the transverse (axial) plane, roughly towards leads V2–V4 (which, therefore, have the highest P-wave amplitudes) Since excitation begins in the sinus node (in the right atrium), the first part of the P wave (green) is primarily determined by right atrial depolarization, while the second part (orange), is primarily determined by left atrial depolarization. The right atrial vector (green arrow) is directed anteriorly and positive in all precordial leads. In contrast, the left atrial vector (orange arrow) is usually directed slightly posteriorly, which may result in a terminal negative deflection in V1. The remaining precordial leads have monophasic positive P waves. Deviations from this normal physiological morphology may indicate atrial pathologies (e.g., atrial enlargement due to valvular heart disease).

P wave morphology in limb lead The P wave represents atrial depolarization. The average of the right and left atrial electrical vectors is directed in a left-inferior direction in the frontal (coronal) plane, roughly towards lead II (which, therefore, has the highest P-wave amplitude). Since excitation begins in the sinus node (in the right atrium), the first part of the P wave (green) is primarily determined by right atrial depolarization, while the second part (orange), is primarily determined by left atrial depolarization. Since the right atrial vector is directed slightly further to the right, an initial negative deflection may occur in lead aVL. Conversely, the more left-directed left atrial vector may result in a terminal negative deflection in lead III. Since both atrial vectors are directed away from aVR, the P wave is always monophasic negative in this lead. Conversely, the P wave is always monophasic positive in lead I and usually so also in leads II, III, and aVF. Deviations from this normal physiological morphology may indicate atrial pathologies (e.g., atrial enlargement due to valvular heart disease).

The P wave represents the sequential depolarization of the right (RA) and left atrium (LA). Since depolarization originates from the sinoatrial node in the RA, the first part of the P wave (green) primarily reflects right atrial depolarization, while the second part (orange) primarily reflects left atrial depolarization. - In lead II, this can result in a slightly notched/bifid P wave. - In lead V1, the P-wave may be biphasic, since the vector of left atrial depolarization is directed away from V1. Pathological changes to the right atrium primarily affect the first part of the P wave, while pathological changes to the left atrium tend to affect the second part. Right atrial enlargement slows depolarization of the RA, synchronizing it with left atrial depolarization and resulting in an overall larger P wave (P pulmonale). Left atrial enlargement slows depolarization of the LA, increasing P wave duration and exaggerating both the notching in lead II and the negative deflection in lead V1.

• Ectopic atrial premature beat or rhythm • AV junctional/ventricular premature complex or rhythm with retrograde atrial activation • Dextrocardia : Inverted P-QRS-T in leads I and aVL with reverse R wave progression in the precordial leads • Reversal of right and left arm leads : Inverted P QRS-T in leads I and aVL with normal R wave progression in the precordial leads

1️⃣. Inverted P wave in lead I DDx??

The P wave is the first deflection in the ECG and indicates that the sinus impulse has spread to the atria.

Abnormality of 🔤 Wave????