October 21, 1964 REYNOLDS, J. Appeal by the employer and its carrier from a decision and award of death benefits on the ground that there is no substantial evidence of causal relation between decedent's death and a prior work-connected myocardial infarction. On December 12, 1956 decedent, a tugboat captain and part-time stevedore, suffered a myocardial infarction precipitated by carbon monoxide poisoning. This incident was concededly work-connected and decedent received compensation benefits until