Thursday, September 23, 2010

6.16 Heart Palpitation/Atrial Fibrillation

Physician's Notebooks 6  - - See Homepage
16. Rate & Rhythm and Palpitations Update 16 December 2018 (Note "EKG" is the elektrokardiogram, from the German, to distinguish it from echocardiogram, "ECG")
The heartbeat normally seems to be regular, but, careful attention, to each minute of it, will reveal what is called sinus arrhythmia, a normal speeding and slowing of the heart rate that occurs with breathing in and out. It is usually quite pronounced in children and steadily gets less with age. A youth sometimes notices the slowing effect and feels faint and it can cause a neurotic fixation on the heartbeat that results in excessive testing. It is easily diagnosed by noting the difference in your pulse rate at the height of a deep breathing-in (relatively rapid pulse) and then at the low point of a deep breathing-out (slowest pulse). Actually it is a sign of a healthy heart. The heart that does not show the effect is a sign of aging and the dysfunction of poor blood supply. A 20-year-old woman I know described the effect as being worse when she lay down and least when she was in erect position. Now, at age 25, with an explanation that it was normal, she doesn't notice it anymore.
The most common palpitation heart symptom is what some call the missed beat. Here is one description: 
"After I get deeply involved in something and lose my sense of time, I forget to take a breath; then I feel a thump in my chest and get scared it's my heart." 
This sequence is caused by a missed heartbeat being sensed and causing one to catch a breath and then the next heartbeat is too strong because the heart has over-filled and gives the thump in chest. This may turn a person into a neurotic; but it is normal occasionally to miss a heartbeat. The problem is when one's attention gets called to it. Since this is such a common problem, a young person with no past history of heart disease who notes an occasional premature contraction should be reassured it is normal and harmless. If you do consult a doctor, request a 24-hour continuous EKG (Holter Monitor) and basic blood tests to rule out some chemical condition of the blood or anemia that might make your heart irritable. Premature contractions disturb a young person for a few weeks or months and fade into the normal background of life. I write this based on 60 years of my physician's experience and book learning plus having once had a premature heartbeat neurosis as a young man.
   Heartbeat rate is per minute; measuring a normal resting rate  should be done after at least 5 minutes quiet sitting, no recent food or drink, and in a contented, unstressed state. Count all beats in 60 seconds. The count may be by stethoscope over your heart or by fingertip feel of your carotid pulse in neck or wrist pulse.
  Normally the rate should be same at wrist, over carotid artery and over chest. Pulse rates at wrist slower than heartbeat from stethoscope (called, pulsus deficit) on chest are abnormal. (They should not be faster; if they are you have made an error recording pulse or heartbeat)
Rapid heart rate, or tachycardia, with rates of 100 to 130 per minute is almost always sinus tachycardia on EKG; at rest it is abnormal but usually not serious. It may be excitement, food or drink, medication, fever, exertion, early heart failure, anemia, or thyroid disease. Sudden onset tachycardia between 130 and 180 is paroxysmal tachycardia. Paroxysmal Atrial Tachycardia (PAT) is usually a short-lasting, frightening episode that can be stopped by an experienced fingertip pressure on a carotid artery or on both eyeballs or aValsalva maneuver (Trying to exhale with glottis closed like when you strain on the toilet seat). Paroxysmal supraventricular tachycardia (PSVT) originates from between the right atrium and ventricle; it is more long lasting. Paroxysmal ventricular tachycardia (PVT) is a preliminary to ventricular fibrillation (VF). It is up to 200 bpm, with faintness and collapse and is an extreme emergency requiring EKG and automatic external defibrillator (AED).
  Bradycardia is a heart rate less than 60 beats per minute. In young, well trained persons, a rate down to 50 may be healthy; but less than 50 per minute should have EKG. In older person or anyone with heart disease, a heart rate below 60 bpm suggests some degree of AV heart block or else what is called an idioventricular rhythm, and may require emergency pacemaker.  
Palpitation is consciousness of one’s heart action, whether fast or slow, regular or irregular. Not only in chest! Commonest cause is increase in rate or force of heartbeat by excitement or exercise or change in position or coffee or other stimulant. Frequently it is a premature beat, described at the start of this chapter.
Infrequently, slow heart rates (<50) have as 1st sign, palpitation because of force of beat. The longer-than-normal-interval-between-beats heart chamber gets over-filled with blood and responds with a more powerful beat. 
Atrial fibrillation (AF) affects 1 in 4 persons in a lifetime. It is an irregular heartbeat pulse like no other; it has no pattern. It has rates upwards of 150 irregular beats per minute but can be a very slow pulse at the wrist, because of heart block or if a patient is on medication, or because many of the irregular heartbeats are too weak to be felt at the wrist.
   Some with AF do not even feel it at first and walk around for days in a daze with cough, nausea, loss of appetite and fatigue, and are finally discovered by a physician or emergency room. The diagnosis can be made by listening to the heart; but should be confirmed by EKG.
   Two types present. Both start suddenly but many cases start and stop after seconds, minutes, hours. These are paroxysmal  or intermittent AF but may just be a stage of persistent AF. Another naming is Lone atrial fibrillation (LAF), an AF without obvious heart disease. Finally, atrial flutter is, essentially, atrial fibrillation, the difference being that in atrial flutter, the atrial p waves are countable and the pulse rate at wrist and carotid, and the heartbeat over chest is relatively regular, while in atrial fibrillation individual p waves cannot be made out and heart rate is chaotically irregularBoth have the same risks and need the same treatments to slow the heart and prevent blood clots but atrial flutter is said to be a better candidate for electro-ablation treatment. In this chapter AF stands for both atrial flutter  and fibrillation.
  AF has two risks: First, the formation of blood clot in left side of heart and breaking off of the clot to form a traveling piece of clot, or embolus. From left side of heart, a brain stroke usually happens, but an embolus may go to other part of body and cause organ or tissue damage. Then heart failure may begin, especially in older person or with other heart disease due to the rapid un-coordinated heartbeats.
   The AF at start should be treated as emergency. First, if anticoagulation (slowing of blood clotting) is not high risk it should be started, usually Coumadin (Warfarin) oral med. At home, chew an aspirin at start of suspected AF and get to emergency. (Recently, oral anticoagulants that do not need blood test monitoring, as Coumadin does, are being given by mouth; check with your cardiologists)
Once heart function tests give diagnosis and reason for the AF, allow an electro-physiologist a try at an electrical conversion of AF back to normal rhythm; in select cases electro-ablation of abnormal heart-impulse pathway may cure the AF. Also, anti-arrhythmic medications may be tried to convert the AF to normal rhythm; in all cases they are continued after  AF electro-conversion or -ablation to prevent return of the AF.
Important: After reversion of AF to normal rhythm, alcohol drink should be a No-No because of frequent stories of reversion back to AF during alcohol drinking shortly after conversion of AF to normal rhythm. Other activities said to bring on or revert to AF are overfilled stomach, too much coffee, rigorous exercise or exertion and emotional upset. If the tries at conversions to normal rhythm do not work, a person should adjust to life with AF using a ventricular rate slowing beta-blocker.
Many patients with treated AF continue with it for a long active life, using anticoagulation and beta-blocker. In cases where AF is causing inefficient heart action or heart failure, a permanent pacemaker may be needed.
   The AF may be due to anatomic heart disease of the mitral valve with enlarged left atrium (LA) ; an echocardiogram should always include transesophageal scan to best view the LA and its valve, which are the frequent diseased areas causing AF and sources of the complicating strokes from clots. When heart disease is not found, AF may be due to high thyroid hormone. A thyroid test screen should be done at the start of AF.
Since risk of AF rises after age 60, it is one of several reasons why daily low-dose beta blocker and ACE inhibitor or blocker should be part of healthy longevity program. A statin pill taken to lower cholesterol also lowers risk of AF.
End Note: To read about A-V Block, an important cause of heart palpitation not dealt with in this chapter, click the below and also read next chapter on EKG.
End of Chapter. To read next now, click 6.17 Electrocardiography Explained

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