Ventricular remodeling in active myocarditis

Background Remodeling of the left ventricle with the development of a spher ical cavity occurs in dilated cardiomyopathy and is associated with a poor long-term prognosis. The early effects of myocarditis on left ventricular g eometry have not been previously described or correlated with clinical outc ome. Methods The baseline echocardiograms of 35 patients with biopsy-confirmed m yocarditis were compared with 20 normal controls, left ventricular end-dias tolic volume, long axis length, and mid-cavity diameter were measured. The degree of sphericity was expressed as the ratio of the mid-cavity diameter to the long axis length. left ventricular ejection fraction was assessed by radionuclide angiography. Results In patients with myocarditis, mean left ventricular volume of 81 +/ - 29 mL/m(2) was significantly greater than 50 +/- 8 mL/m(2) in controls (P =.001). Chamber dilatation occurred primarily along the mid-cavity diamete r, which measured 5.3 +/- 0.8 cm in patients with myocarditis versus 4.2 +/ - 0.4 cm in controls (P =.001). The degree of left ventricular sphericity i n patients with myocarditis, 0.64 +/- 0.08, was significantly greater than that of controls, 0.54 +/- 0.04 (P =.001). When patients were stratified ac cording to left ventricular volume, patients with increased left ventricula r volume (>75 mL/m(2)) were associated with a more spherical chamber and lo wer left ventricular ejection fraction than patients with a more normal lef t ventricular volume (less than or equal to 75 mL/m(2)). Conclusions Active myocarditis is associated with early left ventricular re modeling and the development of a spherical chamber. These changes correlat e with ventricular dilatation and reduced left ventricular ejection fractio n.