The term 'carditis' sounds like a disease. Whatever that may be, it's not a gunshot or other wound received in action. The Shenandoah Valley Campaign lasted several months by was over by mid-Novermber of 1864. Early's troops appeared outside Washington DC on July 11/12, 1864.

The service card should state where the soldier was treated for this disease. Frankly, I have a hard time imagining how and why a Confederate soldier living on Nov. 17, 1864, would have been buried at Spotsylvania. That is, unless he died after the war and happened to be buried there.