Party A and Party B were racing on the road, and an old woman on the roadside was frightened and died of a heart attack. Is there a causal relationship between the death of the old woman and the behavior of Party A? Legally speaking, to judge whether there is a causal relationship between Party A and Party B's racing on the highway and the death of an old woman who was frightened by a heart attack on the roadside, the following factors usually need to be considered:

1.** illegal behavior * *: whether the speeding behavior of Party A and Party B violates traffic laws and regulations or not.

2.** Behavior fault * *: Should Party A and Party B foresee that their racing behavior may cause harm to people around them?

3.** directness of causality * *: Is the old woman's heart attack directly related to Party A's speeding behavior?

4.** Predictability of the result * *: Can Party A and Party B foresee that their racing behavior may cause the old woman to have a heart attack due to fright?

If Party A and Party B's racing behavior is considered illegal, which directly leads to the old woman's fright and heart attack, and this situation is foreseeable, then there may be a causal relationship in law. This may cause Party A and Party B to bear corresponding legal responsibilities.

However, the specific legal judgment needs to be decided according to the specific circumstances of the case, local laws and regulations and judicial practice. In the actual situation, the court will make a judgment based on all relevant evidence and legal provisions.