While playing golf, a 74-year-old man felt tingling down the medial side of his left arm. He continued to play, but 10 minutes later began to have difficulty breathing and became dizzy. He sat down on a nearby bench but soon complained of severe chest pain and then lapsed into unconsciousness. He was rushed to the hospital where an electrocardiogram showed irregularities in the heart's electrical activity. Some minutes later, he deteriorated markedly, and his blood pressure dropped dramatically. He lapsed into a deep coma and died several minutes later. A post-mortem showed total obstruction of the left coronary artery and near-complete obstruction of the right coronary artery.
Questions:
1. What is the cause of the tingling sensation in the left arm?
2. How does coronary artery disease cause irregularities in the cardiac cycle?
3. Which coronary artery is more likely to cause irregularities in rhythm if obstructed?
4. Where do anastomoses occur between the coronary arteries?