Q4_Fall_2016_AlertDiver

and especially the health and

function of the right ventricle.

Factors such as age and

chronic hypertension can result

in thickening of the ventricle walls

(hypertrophy) and loss of cardiac elasticity

that reduce the heart’s ability to adapt to

physiologic stress. Various factors — including

immersion, exercise and cold water — shift fluid from the body’s

periphery to the core and increase cardiac workload. If the muscle of the

right ventricle is compromised in some way, the heart may not be able to

handle these diving-associated fluid shifts.

If the leak is mild enough that symptoms are not apparent and the right

ventricle is of normal size and function, it is likely that diving can be done

safely. Valvular incompetence can result in increased right ventricular stress

and result in hypertrophy (independent from systemic elevations in blood

pressure). How the heart muscle responds to this overload depends on the

severity of the condition and how long it has been present. Chronic overload

can result in hypertrophy, which reduces cardiac efficiency and requires

increased blood flow to the heart muscle itself. During physiologically

stressful states such as immersion, exercise and extreme temperatures, the

heart may not be able to meet the demands of cardiac muscle. Hypertrophic

disease also increases the risk of irregular heartbeats (arrhythmia), which

may lead to heart failure or unstable heart rhythms. Hypertrophic ventricles

are also less able to accommodate significant fluid shifts.

Valve repair can require lifelong anticoagulant therapy, although this

is more common with the aortic and mitral valves. Although the use

of anticoagulants alone is not necessarily an absolute disqualifier from

recreational diving, it should factor into an overall decision about one’s

medical fitness to dive.

It is important to seek medical evaluation prior to diving, and it would be

prudent to consult a cardiologist, who may order a cardiovascular stress test

or other testing to determine cardiac function and your ability to perform

at the higher levels of activity needed for diving. If you have additional

questions, call the DAN Medical Information Line at

+1-919-684-2948

— Payal Razdan, MPH, EMT, and Nicholas Bird, M.D., MMM

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