Respondent's expert testified that it was "highly unlikely" that decedent's fall while on duty precipitated his myocardial infarction. This testimony, coupled with the other medical evidence in the record showing that decedent's condition was long standing and severe, provided competent evidence to rebut the "heart presumption" created by Retirement and Social Security Law § 363-a (see, Matter of Nerney v. New York State Policemen's Firemen's Retirement Sys., 156 A.D.2d 775, lv denied 75 N.Y.2d 710). Petitioner has failed to prove otherwise and we therefore agree with respondent that the death of petitioner's husband was not the natural and proximate result of an accident sustained in the performance of his duties as a firefighter. Any evidence to the contrary merely presented a conflict of medical opinion which was for respondent to resolve (see, Matter of Legault v. Regan, 105 A.D.2d 505, 506).
Weiss, P.J., Mikoll, Yesawich Jr. and Crew III, JJ., concur. Adjudged that the determination is confirmed, without costs, and petition dismissed.