Tongue twister diagnosis describes wayward electrical signal



November 6, 2019 - 9:27 AM

Dear Dr Roach: My 35-year-old son recently complained of some chest pain. He went to his doctor, and it was determined that he strained himself exercising. However, the doctor recommended he go for a stress test. By the time he got to a cardiologist, his chest pain was gone, but he underwent a stress test anyhow. His cardiologist wrote: “Your stress test looks OK. No major changes in EKG while on the treadmill for 10 minutes. However, the test is not 100% accurate because you have right bundle branch block.” Can you explain that to us? Is it serious? What is the treatment and outlook? — C.D.S.

Answer: The heart has an electrical conduction system, similar to wires, connecting the pacemaker of the heart (in the top right chamber, the right atrium) to all the other chambers. It does this by way of the atrioventricular node, which continues into the ventricles as the Bundle of His. That structure then breaks into two main bundles of specialized cells that transmit the signal to the ventricles, called the left and right bundle branches.

If the bundle branch is unable to send a signal, it is called a bundle branch block. The electrical impulse will still find its way to the muscle, but it will get there a little slower. This is not enough to cause mechanical problems to the heart, but it can be seen on the electrocardiogram. The presence of a right bundle branch block does make the EKG part of a stress test a little harder to interpret; however, the ability to diagnose heart attack and damage to the heart is largely unimpaired, since the crucial first part of the EKG wave is not affected by a right bundle branch block (unfortunately, a left bundle branch block makes the EKG much less interpretable for diagnosing angina and heart attack).

Most studies on people with RBBB have suggested little or no increased risk of heart attack. There may be a slight increase in the risk of heart failure, and a significant risk in developing further conduction problems, which may ultimately require your son to get a pacemaker in the distant future.

Dear Dr Roach: I am 87 and was diagnosed with an 80% blockage in one of my coronary arteries. I do not want invasive surgery. Can this blockage be stented or at least opened a bit? — E.F.S.

Answer: Blockages in the arteries providing blood to the heart muscle is the hallmark of coronary artery disease. While surgery is still sometimes used, the need for surgery has dropped by 90% due to better medical care and the advent of local treatments on the blood vessels, such as stenting.

A blood vessel first needs to be opened up. This can be done by balloon angioplasty. The plaque blocking the blood vessel is broken up by a cardiologist using a balloon. After that, a metal stent is placed to keep the vessel from closing up again. The patient will need to take medication for a time to help keep the vessel open. Stents have been shown to improve symptoms, but not make people live longer.

No cardiac surgeon rushes to take an 87-year-old to surgery except under very special circumstances, so I suspect medication treatment, possibly with a stent, rather than surgery is in your future.

Most people with a new diagnosis of coronary artery disease could benefit from some lifestyle changes, including diet, exercise and stress management. These are as important as the medicines and procedures, and need to be emphasized.