ECG: Left and Right Atrial Enlargement
Left atrial hypertrophy An increase in the thickness of the left atrial wall is known as left atrial hypertrophy . This occurs frequently in left ventricular enlargement, although it can also occur alone. The P wave is often widened because of the increased time that it takes the impulse to travel over the thickened atrial wall. The P wave is notched, like an M shape . This is known as P-mitrale. In some leads (typically V1) the P wave becomes negative. Right atrial hypertrophy An increase in the thickness of the right atrium is known as right atrial hypertrophy. If the right atrium is hypertrophied there will be an increase in the height of the P wave (2.5 mm or more). This is seen most clearly in Lead II, and is due to the increase in the number of impulse directions travelling directly towards Lead II. The P wave also looks peaked. This is known as P-pulmonale . The width of the P...