Your Medical Device Patient Identification Card: Don’t Leave Home Without It

Back in the 80s, American Express ran a popular series of commercials featuring the logo: “American Express: Don’t Leave home without it.” These commercials featured unnamed stars with their names imprinted on an AMEX card who touted the benefits of the card, especially for those who were frequent travelers.

For select patients, the same phrase can be applied to not leaving home without a record of your implanted medical devices including coronary artery stents, pacemakers and defibrillators.

Patients who have had stents for coronary artery blockages will be provided with a patient identification card listing the type of stent, the date of of implant, and the vessel in which the stent was placed. This information is useful for the physician who has never seen you because it can give clues to how long you should be on anti-platelet medications such as Plavix (clopidogrel). Additionally, the location of the stent will also give your doctor an idea of areas of the heart to pay extra attention to during tests such as echocardiograms or stress tests.

A sample stent card from Boston Scientific:

stent cardFor patients with a pacemaker or implantable cardioverter-defibrillator (ICD), the patient identification card will include your name, type of device, manufacture, lead information, as well as the date of implant.

A sample ICD Card from St. Jude Medical:

st jude icdEach manufacture has a machine called a programmer that is only able to check on its own brand of devices. Your patient identification card will help your doctor select the correct programmer to use. The programmer will provide valuable information such as the presence of life-threatening arrhythmias, battery life, settings, and other diagnostic information.  If many years have passed since your pacemaker or ICD was implanted and the correct programmer can’t link up with your device, it may suggest that the battery has run out and you are due for a replacement, called a generator change.

A sample programmer from St. Jude Medical:

merlin_systemThese are just some of the items that you can carry around to keep you and your doctors better informed about your cardiac history. A medical device patient identification card is just like your drivers license–don’t leave home without it.

How Your Ejection Fraction (EF) is like the Number of Cylinders in a Car

There are many ways to assess the function of your heart, and one of the easiest and most convenient methods is with an ultrasound of your heart called a echocardiogram. During a transthoracic echocardiogram, you will be asked to lay on your left side and an ultrasound technician will obtain images of your heart using sound waves.

Echocardiogram

 

From these images, your cardiologist can determine the size of your heart chambers, the structure and function of your valves, how well your heart squeezes, and the pressures within the heart.

How well your heart squeezes with every beat is called the ejection fraction, which represents the volume of blood pumped by your left ventricle divided by the total volume of blood in that ventricle. The ejection fraction, or EF, is represented as a percent. Roughly speaking, normal EF’s range between 55-70% and low normal EF is 50-55%. Ejection fractions less than 50% are reduced.

To explain and simplify the concept of ejection fraction to my patients, I sometimes use the analogy that your EF is like the number of cylinders in a sports car. Many sports cars have 6 cylinders. Think of a car having 6 cylinders as being proportional to a person with an EF of 60%.  As the number of cylinders that are functional decrease, the power to the car also decreases and its harder to get the car to zip along like normal. Similarly, as the EF decrease, patients generally begin to experience symptoms consistent with a failing heart. These symptoms can include shortness of breath, swelling in the legs, waking up at night gasping for air, or having to sleep on many pillows.

If you have heart failure, make sure you are aware of what your ejection fraction is to gauge your treatment progress. Read more about ejection fraction and ways to measure it from the American Heart Association.

Image: NHLBI