The Heart & Diving

The Heart & Diving

Issues Involving Implanted Pacemakers

A pacemaker is a small battery-operated device that helps an individual's heart beat in a regular rhythm. It does this by generating a slight electrical current that stimulates the heart to beat. The device is implanted under the skin of the chest, just below the collarbone, and is hooked up to heart with tiny wires that are threaded into the organ through its major vessels. In some individuals, the heart may need only intermittent help from the pacemaker, if the pause between two beats becomes too long. In others, however, the heart may depend completely on the pacemaker for regular stimulation of its beating action.

Effect on Diving

Every case involving a pacemaker must be evaluated individually. The two most important factors to take into account are the following:
  1. Why is the individual dependent on a pacemaker?

  2. Is the individual's pacemaker rated to perform at depths (in other words, pressures) compatible with recreational diving — plus an added margin of safety?

The reason for the second factor is that a pacemaker is implanted in tissues just under the skin and thus is exposed during a dive to the same ambient pressures as the diver. For safe diving, a pacemaker must be rated to perform at a depth of at least 130 feet (40 meters) and must also operate satisfactorily during conditions of relatively rapid pressure changes, such as would be experienced during ascent and descent.

As with any medication or medical device, the underlying problem that led to the implantation of the pacemaker is the most significant factor in determining someone's fitness to dive. The need to have a pacemaker implanted usually indicates a serious disturbance in the heart's own conduction system.

If the disturbance arose from structural damage to the heart muscle itself, as is often the case when someone suffers a major heart attack, the individual may lack the cardiovascular fitness to dive safely.

Some individuals, however, depend on a pacemaker not because the heart muscle has been damaged but simply because the area that generates the impulses which make the heart muscle contract does not function consistently or adequately. Or the circuitry that conducts the impulses to the heart muscle may be faulty, resulting in improper or irregular signals. Without the assistance of a pacemaker, such individuals might suffer episodes of syncope (fainting). Others may have suffered a heart attack mild enough that they sustained minimal residual damage to their heart muscle, but their conduction system remains unreliable and thus needs a boost from a pacemaker.

If a cardiologist determines that an individual's level of cardiovascular fitness is sufficient for safe diving, and the individual's pacemaker is rated to function at a pressure of at least 130 feet (40 meters), that individual may be considered fit for recreational diving. But once again, it cannot be emphasized strongly enough that any divers with cardiac issues check with their doctor before diving.