Left anterior hemiblock in otherwise healthy pilots.

We studied 15 male pilots with left anterior hemiblock (LAH) and compared them to 15 age-matched controls. Exercise testing was normal in all 15 pilots with LAH. There was no significant difference in the measurements of cardiac geometry in the 15 pilots compared to the controls, with valve thickness, mitral valve posterior motion and septal thickness also being similar in the two groups. The pilots remained asymptomatic and on active flying duty during the mean follow-up period of 52 +/- 8 months. We conclude that LAH is a benign condition in young asymtomatic men.