Acute right bundle branch block due to pneumothorax

Changes in electrocardiogram (ECG) due to pneumothorax have been studied and are well described mainly in case of left-sided pneumothorax. Classic ECG finding in left-sided pneumothorax includes right-axis deviation, diminution of QRS complex, T-wave inversion, phasic R wave variation, and reduced R wave in precordial leads. There has been reported case of incomplete right bundle branch block (RBBB) in left-sided pneumothorax. We hereby report the first case of acute-onset complete RBBB due to left-sided pneumothorax in a young patient after blunt chest trauma from a motor vehicle accident. ECG findings revert back to normal after 1.5 h of decompression of pneumothorax. We summarize the possible mechanisms that could lead to this unusual finding on ECG. Pneumothorax can cause unusual ECG changes like in our case and should be kept in the list of differential diagnosis in appropriate clinical conditions.