Palpitation of the Heart (by Dr JB Lim)

Dear Mr. Sandy Lee (not his real name)

Thank you for seeking my opinion about your relative’s case with palpitation of his heart, and the attachment of his 2-D cardio-echogram which showed nothing of significance.

Sorry for the delay in replying as I have a lot of other things to do.

Causes:

It is quite common to have palpitations of the heart. In normal circumstances the heart maintains a heart rate at about 65 -70 beats per minute at resting stage, slower at resting or sleeping stage, and faster in strenuous exercise when extra oxygen is needed . However, this also depends on the status of the heart's electrical system to conduct electricity through the heart muscles for the heart to pump blood.

Nevertheless, if there are changes in the levels of salts (electrolytes) like potassium, magnesium, and calcium, these too can affect hear rhythm and cause palpitations. A lack of iron that normally cause iron deficiency in women causing anemia or if the thyroid gland is overactive, a condition called hyperthyroidism, these too can cause the heart to pump faster or abnormally, a condition a patient feels it as palpitations.

Exercise, anxiety, fear, excitement, and anticipation can cause the heart to beat abnormally fast. These are the most common causes. The doctor needs to look into all these common causes first instead of suddenly do a 2-D cardio-echogram on the patient. This is far more expensive and totally unnecessary, except if a leaky heart valve is suspected. In that case, there are many other symptoms and signs, such as breathlessness, easily get tired, clubbing of the fingers, central cyanosis (blueness of lips, fingers, toes, tongue, etc).

Other common causes of palpitations may be due to drinking coffee (caffeine), smoking (nicotine), and drinking (alcohol). These substances like the hormone adrenalin is also released during exercise, excitement, fear, fight, anger, threats, etc. These stimuli act on the heart to cause it to beat faster > 100 beats per minute (tachycardia).

Often certain medications taken by the patient, especially pseudoephedrine, or even an herbal heart stimulant (ma huang), or even medications like albuterol inhalers or theophylline for asthma and thyroid replacement medications can all cause heart palpitations.

Other causes:

Of course there are also illegal hard drugs like cocaine, amphetamine, PCP, and marijuana that can also all cause the same pharmacological effect on the heart.

Adrenalin level in the body is increased at times of stress, and this itself can cause rapid heart rates. These, as well as exercise, and emotional factors are physiological responses that all may cause palpitations. These are the most common causes, but the palpitations may not last long, just for half hour or slightly longer depending on how long the stimuli act and last.

Of course there are also specific causes of palpitations due to structural abnormalities in the heart. For instances, if the coronary arteries are narrowed due to cholesterol and plaque deposits or an inflammation, they can cause a decreased in blood supply to the heart muscle. These can irritate the heart muscles, and cause abnormal heart beats like premature ventricular contractions, ventricular tachycardia, or ventricular fibrillation.

Structural wiring abnormalities can cause paroxysmal supraventricular tachycardias or Wolfe-Parkinson-White syndrome. But these are much rarer, and can easily be detected by a simple and much cheaper ECG instead of doing a 2-D cardio-echogram which actually detects structural abnormalities of the heart rather than abnormalities on the electrical conduction within the heart muscles. They may not be the cause of palpitation.

Heart valves incompetence:

Heart valve incompetence can also cause irregular heart beat in about 40% of people especially those with mitral valve prolapse. But these are much rarer. Heart valve prolapses and incompetence can easily, easily be detected by simply listening to the heart with a stethoscope, so why use 2-D echogram for this?

The doctor needs to take history of all these causes first, and then use his clinical judgment to find out exactly why he has temporary palpitations of his heart. Sometimes it is due to an overactive thyroid gland, and there is excessive thyroid hormone.

However, sometimes palpitation may be due to a condition in which the thyroid gland is over active, a clinical condition we call hyperthyroidism.

Auscultation of heart for murmurs:

But the easiest of all signs is the murmurs of the heart which can easily be heard with a stethoscope without costing a single cent to the patient. All these should have been done first as they are the easiest to detect, most common causes of palpitation, and it does not cost a single cent to the patient to listen to the heart for murmurs using a simple stethoscope. So why must that doctor ask him to straight away do a 2-D echogram of his heart which is really a great waste of money and totally unnecessary?

ECG is best for electrical conduction anomalies:

I just cannot understand the justifications of doing this at great cost to the patient who merely has palpitations for only a short period of time. To do an echogram instead of a much cheaper ECG is really beyond belief. An ECG to look if there was any abnormality in the electrical conduction (heart block) that will show up as irregularities in the PQRST waves in the ECG would have been far more useful. As far as I am concerned, he has been cheated of his money by his doctor who did the unnecessary echogram on the patient.

Electrical anomaly:

An ECG would have brought up blocks within the sinoatrial (SA nodes), antrioventrcular node (AV node), below the AV node (infra-Hisian block; named after the bundle of His), within the left or right bundle branch or within its fascicles (hemiblocks).

These would have identified either first, second degree AV block (Mobitz I, II or Wenckebach block), or a total heart block (third degree block).

Clinically speaking, most of the important heart blocks are AV nodal blocks and infra-Hisian block. Even these may not necessary be the causes of common palpitations as I have already explained.

Take medical history first:

The first step in the ethical practice of good medicine is to ask the patient what is his complaints, how long has been his condition, under what circumstance does he have the symptoms, etc. This is the first step if he is a good diagnostician with very good clinical acumen and clinical judgment, and not all those scans and blood tests. A well-trained and experienced clinician can make a minimum of 80 % accuracy by just taking the history and just by asking and listening to what the patient has to say. That is the first step in good medical practice.

Only if…:

It is only when the doctor comes to a date-end with the history-taking and the basic clinical examination, or the need to differential diagnose from other conditions that mimic the symptoms, would he request for laboratory examinations. No good and well-trained and experienced medical doctor will jump the gun from using basic examination first.

The doctor needs to take history of all these causes first, and then use his clinical judgment to find out exactly why he has temporary palpitations of his heart. Sometimes it is due to an overactive thyroid gland, and there is excessive thyroid hormone.

Sometimes palpitation may be due to a condition in which the thyroid gland is over active, a clinical condition we call hyperthyroidism.

Hormone evaluation later:

If we suspect his heart palpitation was due to an overproduction of thyroid hormones T4 (thyroxine) and T3 (triiodothyronine) or hyperthyroidism causing thyrotoxicosis, or certain conditions like Graves Disease (example), then there is justifications of doing a blood test, else, a big NO. A very competent clinician (medical doctor) uses his ears, ears, fingers and good judgment, not all those scans and blood tests first.

More clinical signs and symptoms:

If he suspects the patient’s palpitation is due to an overactive thyroid gland, the main clinical signs he should look for would be:

1. Weight loss (often accompanied by an increased appetite)

2. Anxiety
3. Intolerance to heat
4. Hair loss
5. Muscle aches, weakness and fatigue
6. Hyperactivity
7. Irritability
8. Hypoglycemia (low blood sugar levels)
9. Apathy
10. Polyuria (increased urine volume), and Polydipsia (excessive thirst)
11. Delirium
12. Tremor
13. Pretibial myxedema (PTM) or thyroid dermopathy
14. Sweating
15. Palpitations and arrhythmias especially atrial fibrillation
16. Dyspnea (shortness of breath)
17. Loss of libido
18. Amenorrhea (in women)
19. Nausea
20. Vomiting
21. Diarrhoea
22. Gynaecomastia (breast enlargement in males and feminization)
23. Osteoporosis (if untreated)
24. Ocular (eye) signs such as eyelid retraction ("stare")
25. Lid-lag (von Graefe's sign)
26. Extra-ocular muscle weakness

If these signs are present, all the doctor needs to do is to confirm them by a simple blood test on the levels of his thyroid hormones. A blood test for thyroid hormones is much simpler, and far cheaper. That’s all that is needed.

All I know is that the patient has been cheated by his doctor by asking him to do an unnecessary 2-D cardio-echogram for a simple palpitation of his heart that lasted just a few hours. I just cannot believe these types of doctors are roaming in our decent society?

I have explained here far more than what his doctor would have done for him, or told him, and I don’t wish to discuss any further as it is not profitable and unnecessary for me.

jb lim

BSc (Physiol), PG Dip Nutr, MSc, MD, PhD (Med), FRSPH, FRSM