The Watchman device and diving

I had a Watchman device implanted after developing atrial fibrillation (AFib). My cardiac ejection
fraction is normal, and I no longer take blood thinners but am still in AFib. I take medications for
elevated blood pressure but am otherwise in excellent physical condition. Can I return to diving?

Fulfilling the metabolic needs of a diver depends on the heart’s ability to deliver an adequate
cardiac output to the rest of the body. AFib, a common heart-rhythm abnormality affecting millions of people, impairs this crucial delivery. The heart’s natural pacemaker, called the sinoatrial (SA) node, usually fires impulses at 60–100 beats per minute that cause the left and right atria to simultaneously contract and fill the ventricles. The impulse then slows when going through the atrioventricular (AV) node, allowing time for the ventricles to fill with blood. The impulse continues into the left and right ventricles, causing them to simultaneously contract.

In AFib, however, the atria fire  off impulses at a higher rate (up to 300 beats per minute), which
causes the upper chambers of the heart to quiver, creating an irregular and chaotic atrial rhythm. The AV node cannot transmit at such a high rate; the speed at which it can transmit these impulses varies by patient depending on factors such as age, medications and other medical conditions. The AV node transmits what impulses it can to the ventricles, resulting in an irregular pulse. The atrial contractions lose their effectiveness in maximizing blood to the ventricles, decreasing the cardiac output and reducing the maximal exercise capacity if it persists.

The quivering action of the atria can cause blood to pool in the left atrium appendage. This pooled blood may begin to clot, and the clots can be pumped to the brain, resulting in
a stroke. Interventional cardiologist Dr. Douglas Ebersole, who is also an avid diver and dive instructor, reports that people who develop AFib increase their risk of a stroke fivefold.

To mitigate this risk, physicians often prescribe blood thinners or anticoagulants, which can decrease the risk of a stroke by 60–70 percent but increase the risk of hemorrhage. Some patients, however, are unable to tolerate long-term anticoagulation therapy due to prior bleeding or a high risk of bleeding due to health or occupational conditions.

The Watchman device is indicated for those patients who have a CHA2DS2-VASc score of 3 or more. The CHA2DS2-VASc score uses age, gender and other medical conditions to estimate an individual’s stroke risk. Scuba diving alone is not a reason to get a Watchman device and be
exposed to the inherent risks of the procedure, Dr. Ebersole advises. Approximately 45 days after surgeons implant the Watchman device in the left atrial appendage of the heart, tissue that has grown over the device closes off the appendage, stopping any clots from escaping and
entering circulation. Most patients are able to return to full activity about a week after the procedure and will need to take anticoagulants and aspirin for 45 days and then transition to an aspirin and clopidogrel for several months before transitioning to just aspirin.

Divers who have AFib should be well rate controlled, both at rest and when performing moderate exercise, and understand the possible complications of their condition before considering diving. We recommend not diving while taking anticoagulants.

Discuss your condition and current medications with a physician trained in dive medicine to
understand the risks associated with diving. If the physician approves your return to diving, be cautious and dive near a facility that can provide adequate medical care should a bleeding problem occur. Contact DAN for a referral to a dive medicine physician near you.
— Robert Soncini, NR-P, DM