Immediate Cause

The conduct of wife A aroused the ire of her husband B. Incensed with anger almost beyond his control, B could not help but inflict physical injuries on A. Moments after B started hitting A with his fists, A suddenly complained of severe chest pains. B realizing that A was indeed in serious trouble, immediately brought her to the hospital. Despite efforts to alleviate A's pains, she died of a heart attack. It turned out that she had been suffering from a lingering heart ailment.

What crime, if any, could B be held guilty of?

B could be held liable for parricide because his act of hitting his wife with his fist blows and therewith inflicting physical injuries on her, is felonious. A person committing a felonious act incurs criminal liability although the wrongful consequence is different from what he intended.(Art.4, par.1, Revised Penal Code)

Although A died of a heart attack, the said attack was generated by B's felonious act of hitting her with his fists. Such a felonious act was the immediate cause of the heart attack, having materially contributed to and hastened A's death. Even though B may have acted without intent to kill his wife, lack of such intent is of no moment when the victim dies. However, B may be given the mitigating circumstance of having acted without intent to commit so grave a wrong as that committed. (Art.13, par.3, Revised Penal Code)