REPOST: Underwater Scan Finds Significant Heart Changes in Divers

The Wall Street Journal’s Anne Lukits reports about a test that can be used to identify divers with undetected cardiac abnormalities which can put them at risk during a dive.

Image source: After the dive: The volume of the left ventricle, a lower heart chamber that pumps newly oxygenated blood to the body, increased significantly, while the flow of blood into the ventricles decreased.

An underwater ultrasound scan of scuba divers’ hearts found significant changes in cardiac function during and after a dive, according to a small study in the journal Acta Physiologica. The test could be used to identify novice scuba divers with undetected heart disease or cardiac abnormalities that might prove fatal during a dive, researchers said.

Scuba diving is growing in popularity among older Americans and heart attacks and unknown heart rhythms are the most common cause of diving-related deaths after age 40, according to the Divers Alert Network, a nonprofit research group.

The study, conducted in Italy, involved 18 scuba divers, including 16 men and two women. The participants were about 42 years old and each had made at least 100 dives. None smoked or had hypertension, heart or lung disease.

Cardiac-ultrasound tests were conducted on land before and after diving, and underwater at two depths. The divers wore suits with access for an ultrasound probe and maintained a kneeling position for 10 minutes at a depth of about 33 feet, then five minutes at 16.4 feet.

Among the heart changes recorded during and after the dive: The volume of the left ventricle, a lower heart chamber that pumps newly oxygenated blood to the body, increased significantly, while the flow of blood into the ventricles decreased. These changes may be due to a diving-related shift of blood from the lower extremities to the upper body, exerting a constrictive effect on the chest, the researchers said.

Bradycardia, the term for a slow resting heart rate, a condition that can cause dizziness and weakness if the rate falls below 50 beats per minute, was documented after but not during the scuba diving. The cardiovascular changes that occur during immersion may increase the risk of cardiac problems in divers who are unfit, overweight or have underlying heart disease, researchers said.

Caveat: Heart rate may have been higher underwater because divers were disturbed or stressed by the ultrasound tests, researchers said.

Regular health check is one of the safety protocols in diving that professionals like Phil Newsum advocate. For regular updates on commercial and leisure diving, subscribe to this Facebook page.