The effect of minocin on the pericardium

The purpose of this study was to evaluate in a dog model whether intrapericardial instillation of tetracycline is superior to the effect of drainage alone in causing pericardial adhesions and cavity obliteration. Twelve mongrel dogs were randomly divided into two experimental groups. All dogs received a pericardial drain through a sterile thoracotomy. Group A dogs (n = 6) received minocycline hydrochloride, 20 mg/kg, group B received normal saline. All dogs were sacrificed 1 month later. Echocardiograms performed 1 week postsurgery were normal in all dogs. Macroscopic evaluation disclosed that all group A dogs had over 25% cavity obliteration whereas group B dogs had no adhesions or had obliteration of less than 25% of the cavity area. Microscopic evaluation showed that group A dogs had severe pericardial fibrosis and thickening with slight focal lymphoplasmocytic infiltration. Myocardial damage was not seen. Our results support the clinical use of injecting tetracycline into the pericardium (in addition to drainage) to cause cavity obliteration in patients with persistent pericardial effusion.