OPINION OF THE COURT
Román, J.This action alleges medical malpractice, lack of informed consent and wrongful death. Defendants allegedly misdiagnosed decedent’s condition and performed an unnecessary and contraindicated medical procedure, thereby injuring decedent and ultimately causing his death.
Defendants* moved for summary judgment solely on the cause of action for wrongful death, and the trial court granted defendants’ motions finding that plaintiff failed to raise an issue of fact with respect to whether the malpractice alleged caused decedent’s death. We now reverse.
In support of their motion, defendants Kamran Tabaddor, M.D. and New York Neuroscience Institute, EC. submitted, among other things, an affirmation from Dr. Richard Stein, a board-certified physician in internal medicine and cardiovascular disease. Based on a review of decedent’s medical records, evincing atherosclerosis, hypertension and diabetes, and decedent’s autopsy report, listing the cause of death as atherosclerotic and hypertensive cardiovascular disease, Dr. Stein concludes that decedent’s death was not caused by any of the procedures performed upon him by the defendants. Rather, Dr. Stein concludes that decedent died of unrelated and preexisting cardiovascular disease.
In opposition to defendants’ motions, plaintiff submitted, among other things, an affirmation from a physician board cer*206tified in internal medicine and cardiovascular disease. Based on a review of decedent’s medical records and citing medical literature, plaintiffs medical expert concludes that decedent’s death was in fact caused by the medical treatment rendered by the defendants. Specifically, plaintiffs expert alleges that insofar as stress can trigger a heart attack, decedent’s death was hastened and precipitated by stress, directly resulting from defendants’ malpractice.
In an action premised upon medical malpractice, a defendant doctor establishes prima facie entitlement to summary judgment when he/she establishes that in treating the plaintiff there was no departure from good and accepted medical practice or that any departure was not the proximate cause of the injuries alleged (Thurston v Interfaith Med. Ctr., 66 AD3d 999, 1001 [2009]; Myers v Ferrara, 56 AD3d 78, 83 [2008]; Germaine v Yu, 49 AD3d 685 [2008]; Rebozo v Wilen, 41 AD3d 457, 458 [2007]; Williams v Sahay, 12 AD3d 366, 368 [2004]). When medical malpractice forms the basis of a wrongful death action, in establishing that he/she did not proximately cause the injuries alleged to have caused plaintiffs death, a defendant establishes prima facie entitlement to summary judgment as to the wrongful death action as well (see Koeppel v Park, 228 AD2d 288 [1996]; Thurston v Interfaith Med. Ctr., 66 AD3d 999 [2009], supra; Myers v Ferrara, 56 AD3d 78 [2008], supra).
With respect to opinion evidence, it is well settled that expert testimony must be based on facts in the record or personally known to the witness, and that an expert cannot reach a conclusion by assuming material facts not supported by record evidence (Cassano v Hagstrom, 5 NY2d 643, 646 [1959]; Gomez v New York City Hous. Auth., 217 AD2d 110, 117 [1995]; Matter of Aetna Cas. & Sur. Co. v Barile, 86 AD2d 362, 364-365 [1982]). Thus, a defendant in a medical malpractice action who, in support of a motion for summary judgment, submits conclusory medical affidavits or affirmations fails to establish prima facie entitlement to summary judgment (Winegrad v New York Univ. Med. Ctr., 64 NY2d 851, 853 [1985]; Cregan v Sachs, 65 AD3d 101, 108 [2009]; Wasserman v Carella, 307 AD2d 225, 226 [2003]). Further, medical expert affidavits or affirmations, submitted by a defendant, which fail to address the essential factual allegations in the plaintiff’s complaint or bill of particulars fail to establish prima facie entitlement to summary judgment as a matter of law (Cregan at 108; Wasserman at 226).
*207Once the defendant meets his burden of establishing prima facie entitlement to summary judgment, it is incumbent on the plaintiff, if summary judgment is to be averted, to rebut the defendant’s prima facie showing (Alvarez v Prospect Hosp., 68 NY2d 320, 324 [1986]). The plaintiff must rebut defendant’s prima facie showing without “[g]eneral allegations of medical malpractice, merely conclusory and unsupported by competent evidence” (id. at 325). Specifically, to avert summary judgment, plaintiff must demonstrate that the defendant did in fact commit malpractice and that the malpractice was the proximate cause of the plaintiffs injuries (Coronel v New York City Health & Hosps. Corp., 47 AD3d 456 [2008]; Koeppel at 289). In order to meet the required burden, the plaintiff must submit an affidavit from a medical doctor attesting that the defendant departed from accepted medical practice and that the departure was the proximate cause of the injuries alleged (Thurston at 1001; Myers at 84; Rebozo at 458).
Here, defendants established prima facie entitlement to summary judgment with regard to the cause of action for wrongful death. As previously noted, Dr. Stein’s affirmation established that the malpractice, if any, was not the proximate cause of decedent’s death. Instead, Dr. Stein concluded that decedent’s death was caused by preexisting cardiovascular disease. Dr. Stein’s affirmation constituted competent evidence inasmuch as it is based on the record and addressed the pertinent allegations in the complaint.
In opposition, however, plaintiffs expert’s opinion, based upon his review of the decedent’s medical records, as well as pertinent medical literature, clinical studies and his own experience, raised factual issues as to whether defendants’ treatment of the decedent caused or substantially contributed to his death. Specifically, plaintiffs expert concluded that defendants’ malpractice stressed decedent and that the stress contributed to the hastening of his cardiovascular disease and thus to his death. Accordingly, questions of fact preclude summary judgment in defendants’ favor.
Accordingly, the order of the Supreme Court, Bronx County (Sallie Manzanet-Daniels, J.), entered July 1, 2008, which granted defendants’ motions to dismiss the wrongful death cause of action, should be reversed, on the law, without costs, the motions denied and the cause of action reinstated.
With the exception of defendant Our Lady of Mercy Medical Center, against whom this action was discontinued, all defendants moved for summary judgment on the ground discussed.