Ailment Causes Heart To Race
Q. Several years ago, I was diagnosed with paroxysmal atrial tachycardia. What does that really mean? I’m able to keep it under control by taking Tenormin, Lanoxin and Verelan. Is there anything newer I could take to eliminate so much medication? - A.D., Reno, Nev.
A. What it means is that every now and then, at unpredictable times (hence the term “paroxysmal”), your heart rate can suddenly speed up to a heart rate of 150-200 beats per minute. A normal resting heart rate averages between 60 and 80 beats per minute.
Just to review, the heart has four pumping chambers: two upper chambers known as the right and left atria; and two lower chambers known as the right and left ventricles. The left ventricle is your main pumping chamber, sending blood out the aorta to all your arteries, capillaries and organs. Each pump is felt as a pulse. The right ventricle is the chamber that sends blood back to your lungs to get re-oxygenated. The right atrium collects blood from all your veins so it can be pumped into the right ventricle. The left atrium receives all the freshly oxygenated blood from the lungs so that it can be pumped into the left ventricle.
All this sounds so smooth and coordinated, doesn’t it? That’s because there’s “electrical wiring” within the heart muscle to control the rhythm. Each heartbeat begins with an electrical impulse fired by the pacemaker of the heart - the sino-atrial node.
This pacemaker sends an electrical impulse through the heart. First, the right atrium contracts (pumps); the left atrium contracts immediately after that. Then the signal travels through the heart by way of electrical bundles. Before the impulse can reach the ventricles, it must first pass through a small group of cells called the atrio-ventricular node, located between the atria and the ventricles. Its role is to create a time delay which allows ventricles time to fill up with blood pumped in from the two atria.
Paroxysmal atrial tachycardia, or PAT, is a sudden racing of the heart whose origin is in the left or right atria. There’s a focus of excessive electrical activity that is being passed on through to the ventricles. The net result is a sudden racing of one’s pulse.
What causes this to happen? Sometimes we can figure out a cause, such as excessive stress, an overactive thyroid, excessive intake of caffeine, use of amphetaminelike stimulants for weight loss, excessive alcohol intake, or underlying heart disease that may or may not be known about. Sometimes, it occurs in an otherwise healthy person, and we can’t identify an obvious cause.
The racing heart of PAT may bring about sensations of palpitations, anxiety, shortness of breath and chest tightness. Some people may feel like they’re about to pass out. As awful as a person feels during this event, it’s generally not considered to be life threatening - unless there’s underlying heart disease.
The treatment for PAT includes drugs to slow down the heart rate or to “break” the rhythm and convert the person back into a normal “sinus” rhythm with a normal resting pulse. Emergency departments have drugs that can sometimes correct this heart arrhythmia. It may return however, and for that reason many doctors will keep their patients on drugs such as the ones you describe.
I don’t know enough about your medical situation to say whether you still need to remain on all three drugs. The drugs you mention exert their effects by blocking or slowing down electrical impulses at the sino-atrial and atrio-ventricular nodes. I’d suggest that you continue taking all three drugs until you can discuss your situation with a cardiologist.