A 57-year-old smoker with a history of chronic obstructive lung disease and sleep apnea is in the emergency department complaining of increasing dyspnea and cough during the past 3 days:

• Sinus tachycardia, 140/min
• Biatrial enlargement
• Right axis deviation
• Findings are suggestive of chronic pulmonary disease

Comment: The investigation demonstrated severe airway obstruction and hypoxemia, The patient was admitted to the respirology ward and vigorously treated. Prominent negative P waves in V1 to V3 may occasionally be seen in patients with chronic lung disease and pulmonary emphysema in the absence of Left Atrial Enlargement. Because of the low diaphragm, the right chest leads are abnormally high in relation to the atria, and the mean P vector projects on the negative side of V1-V3 (T-C Chou, Electrocardiography in Clinical Practice, 4th ed., Saunders 1996, page 32)