Try to hear the heartbeat by placing your ear against the left side of the chest just behind the elbow. (thesprucepets.com)
Simple work is done on one side of the chest while the shirt is designed in collar style. (latestasianfashions.com)
Most heart attacks involve discomfort in the center or left side of the chest that often lasts for more than a few minutes or goes away and comes back. (nhlbi.nih.gov)