State law requirements which impose different or additional requirements on pleadings filed in federal court are not enforceable if they conflict with the Federal Rules of Civil Procedure, even if the state law would qualify as “substantive law.” Thus a Delaware law which required the filing of an affidavit of merit with a medical malpractice complaint is not enforceable if a medical malpractice complaint is filed in federal court.

A board-certified cardiologist satisfied the medical-malpractice expert witness requirements, even though the doctor’s specialty was not interventional cardiology.