Posted by: keherenf | November 1, 2007

Tachycardia

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I will never forget the day I was walking back to my dorm room and collapsed. For someone who had worked out consistently for years, it seemed really odd that my heart was fluttering so quickly, and I had never felt tightness in my chest like that before. By the time I made it to the emergency room, the doctors said that everything looked fine, in fact, they thought I was probably just stressed out. But, after six months of various testing, I was finally diagnosed with PSVT (Paroxymal Supraventricular Tachycardia). The diagnosis is tricky, because when the actual episode is not occurring, the heart looks completely and acts completely normal. It also mimics symptoms of being stressed out or drinking too much caffeine.

A normal heart beat typically remains constant at a rate of 60-100 beats per minute (bpm). Once the rate exceeds 100 bpm, the heart is considered to be experiencing tachycardia. In fact, the term “tachycardia” solely means “fast heart”. This can be induced by exercise, tobacco, alcohol, excitement, heart disease, or other non-related factors. However, for someone who has a true electric problem not related to these external factors, a tachycardia can range from a slight annoyance to a severe hindrance.

Pathology: Tachycardia is related to the electricity pathways of the heart. When the electrical pathways do not conduct electricity in the exact right way, an arrhythmia may follow. This video gives a great overview of how this happens.

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 Symptoms:

  •  Palpitations (the feeling that the heart is beating too fast, fluttering, etc)
  •  Dizziness, light-headedness, near fainting, or actual fainting
  •  A feeling of tightening or fullness in the chest
  • Shortness of breath
  • Anxiety

Risk Factors: The greatest risk factors for developing tachycardia derive from having other heart conditions, including but not limited to: coronary heart disease, cardiomyopathy (damaged heart muscle), damaged heart valves, and high blood pressure. Older age, overactive thyroid, and genetic factors may also play a role.

Testing: Although I do not normally write about tests, my own personal experiences have left me compelled to share the different options as I experienced most of them over the course of my treatment.

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The first thing I received was an event monitor. Unlike a holter monitor which records the heart continuously for 24 straight hours, the event monitor is worn for a longer period of time and only records when the carrier activates it. After reporting these episodes, I also recorded exactly what I was doing before the event, how long it lasted, what symptoms I experienced, and any other reflections. This allowed my cardiologist to try and find patterns between my lifestyle and my episodes. This was my favorite testing device, as I got to use it for a month and pretend that I was pretty official (after all, it looks like an important paging device).


Next, I received an echocardiogram. This is essentially a sonogram of the heart- the technician rubbed cool gel on my chest

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and looked at my heart, taking pictures along the way. As the doctor expected, I had no structural damage. But, it was awesome to look at my heart beat…the very thing that keeps me alive every second of the day was now a black, white, and gray pulsing blurb on a small screen.


 

 

 

To better try and capture one of my episodes, the cardiologist ordered a stress test. Electrodes were placed literally all overstress_test.jpg my body, and the wires all fed into one central tube which I was instructed to hold. These wires were attached to a treadmill. Under the nurses supervision, you start out on the treadmill at a very low speed with no incline, and your heart’s activity is continually recorded. Over the course of the next 15-20 minutes, the nurse increases the speed and incline to 10 different levels until you feel as though you just cannot take it anymore. Despite the fact that I had been training for a half marathon and was at my physical peak, I only made it to level 8. They still did not capture one of my episodes.

 

The final test was a dual effort to solve my problem once and for all. 8 months after my first severe episode, I was checked into an amazing hospital to undergo an EP (electrophysiological) study/ radiofrequency cardiac ablation (to be discussed later). In my EP study, I was put under general anesthesia. Catheters were then placed down my neck and up my groin into the heart. After this insertion, the anesthesiologist repeatedly injected adrenaline into my heart to trigger an increased heart rate. With my entire chest covered in electrode sheets, the many physicians in the room could look at all the parts in my heart to target the electrical circuit in my body that kept misfiring. Although I was not too excited about the procedure at the time, I still think it is one of the most fascinating studies I have ever heard of…after all, they studied my heart by putting tubes through my legs!

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Treatment:

Depending on what causes the tachycardia, treatment options vary. One of the best treatment options is actually prevention. Those predisposed to tachycardia should limit tobacco and alcohol use, as well as caffeine intake. Although exercise may induce tachycardia, in the long term it actually helps it by lowering the resting heart rate. It also helps prevent obesity, which may further induce tachycardia.

Another way to try and stop the tachycardia instantly is through “bearing down” or the valsalva maneuver. In “bearing down”, the patient is instructed to push the muscles as if having a bowel movement. During the valsalva maneuver, a nurse or physician can use his/her fingers to rub an artery that reduces the heart rate (note: this should ONLY be attempted by a licensed health care professional).

If the prevention treatments do not help, some people take medications either through pill form or under the supervision of a physician which resets the circuit in the heart. Often times, those experiencing a tachycardiac episode actually get stuck in a loop which the heart may have difficulty breaking out of, which sustains the experience. By going to a hospital or doctor, drugs can be given intravenously to stop this circuit.

Should the tachycardia become too unbearable, a patient may opt for surgical procedures. This could include acquiring a pacemaker, an implantable cardiac defibrillator (ICD, used for those with severely high heart rates), or the minimally invasive radiofrequency ablation procedure. In this procedure, the cardiac electrophysiologist finds the “trouble spot” in the heart, threads it with electrode-tipped catheters, and uses radiofrequency to ablate (“burn”) the spot so electricity does not hit it again.

Morbidity: This is hard to quantify as there are so many causes to tachycardia. However, many Americans are affected by arrhythmias in general, and they are considered to be quite common.

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For More Information:

The Mayo Clinic

The American Heart Association

eMedicineHealth

National Institute of Health

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Responses

  1. Greetings!

    Ever since I had my cardiac event on June 25, 2008, I have also been interested in the different tests they can do on the hear now-a-days. Come to my blog and read up on what was done to me. In 4 weeks I get to see my Cardiologist for an update and review of the Echocardiogram, the Angiogram and all the other tests done to see what went wrong with me. You are so right – The best medicine is prevention. I believe in it 100%.

  2. Can I use your picture of SVT in a school pressentation


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