Does heavy alcohol consumption slow wound healing?

Yes. It depends a little on what you define as "heavy" consumption. It is known that alcoholics have certain nutritional deficiencies that could impair wound healing potential.
Yes it can. The direct affects of heavy alcohol intake on wound healing are less than the indirect affects such as poor nutrition and neglect of a wound due to inebriation. The immune system is know to be diminished in those who are heavy drinkers.