Palpitation

tall-bushes-profiling-the-blue-skyWhat is palpitation?

Normally our heart is beating regularly at a rate between 60-100 per minute. But we are not aware of it. In certain circumstances, we become aware of our own heart beat. This is known as palpitation. Very often palpitation is just a manifestation of anxiety. When you are stressed or with exercise, the heart races and we become of our heart beating fast. Though most often palpitation is harmless, in some situations it could be a manifestation of a dangerous disease. For example, abnormal heart rhythms can cause palpitation. Very fast rhythms can be regular or irregular. Sometimes it may not be continuous palpitation, but feeling of an occasional flutter in the chest. This is due to transient irregularity in the heart rhythm, which is often of not much significance.

Serious forms of palpitation occurs in those with severe heart disease – either electrical or structural. Structural abnormalities of the heart which damage the heart muscle or heart valves can cause paliptation due to extra load which it gives the heart. Electrical disorders of the heart often produce either very fast rhythms or very slow rhythms, both of which can be life threatening if severe.

One of the simple tests to analyse the heart rhythm in case of palpitation is an ECG. Structural damage to the heart can be assessed by ultrasound imaging of the heart known as echocardiography. Both these tests are commonly done for evaluation of heart disease. Other more advanced tests are needed only in selected cases. If the palpitation is only occasional, it can be recorded by long term ECG monitoring known as Holter monitoring (typically 24-48 hours) or event monitoring (one week to three months). If still longer recording is needed, we have implantable loop recorders – small devices which can be implanted under the skin under local anaesthesia, which can record electrical abnormalities of the heart for up to 3 years. These devices have wireless options which can relay the signals to a device at home which in turn can transmit it to a central server by mobile networks. The central server could be even located in another continent!

Lungs and heart disease

wild-red-flowersCan lung disease cause heart disease?

Heart disease as a consequence of lung disease is known as cor pulmonale. ‘Cor’ means related to heart and ‘pulmonale’ means related to the lungs. When there is severe lung disease, the blood vessels in the lung get destroyed or contract, increasing the blood pressure in the main blood vessels taking deoxygenated blood to the lung for oxygenation (pulmonary arteries). When the pressure in the pulmonary arteries rise (pulmonary hypertension), the strain on the right ventricle which pumps blood to the lungs increases. The right ventricular muscle gets thickened (right ventricular hypertrophy). When the load is more, the right ventricle becomes enlarged in addition to being thickened. If the lung disease is progressive, a stage may come when the right ventricle is unable to bear the extra load and may fail. When the right ventricle fails, the pressure in the right atrium increases. Walls of the right atrium gets thickened. Back pressure into the great veins which bring blood to the right atrium causes prominent distended neck veins (jugular veins). Increased pressure in the venous system of the abdomen and lower limbs cause excess fluid (edema) to collect in the lower limbs and abdomen (ascites). Increased pressure in the veins of the face give the face a congested appearance.

Excercise and prevention of heart disease

hedge-bushHow can exercise prevent heart disease?

Dr. Paul Dudley White, the famous physician who has taught many a luminary in the field of cardiology once wrote that heart disese before eighty is our fault and not God’s will or nature’s will. This means that he recognized long back, the role of life style modification in preventing heart disease. Exercise in a regular pattern is one of the important life style modifications which everyone can adopt to prevent or delay heart disease. Exercise helps in various ways. Regular exercise conditions the body so that the effort tolerance, lung and muscle function improves. So does our feeling of well being. Of course exercise burns out extra calories and reduces body weight, which in turn is due to a decrease in the fat deposits. A decrease in fat deposits can reverse the process of block formation in our blood vessels.

Regular exercise can bring down the blood pressure in the long run. Though blood pressure rises progressively with increasing exercise, it reduces the resting blood pressure in the long run. Lower blood pressures means lower workload for the heart and the chance of thickening of heart muscle and heart failure are reduced.

High density lipoprotein (HDL) cholesterol in the blood increases with regular exercise. HDL is the good cholesterol which gives us protection from heart disease. Low density lipoprotein (LDL) cholesterol which is otherwise known as bad cholesterol, decreases with exercise, again providing protection from heart disease.

Heart disease in women

yellow-flower-bedWhat are the problems in diagnosis of heart disease in women?

In general, heart disease is less common in women of childbearing age group. Hence both the patient and physician has low index of suspicion when women do have heart disease. Moreover symptoms may be atypical in some women. These may lead to delay in diagnosis.

Which types of heart disease are likely to occur more in women?

Though diseases of blood vessels of the heart (coronary artery disease) is less common in women of childbearing age, rheumatic heart disease secondary to rheumatic fever is often more common in women in regions where it is prevalent. Hence valvular heart disease due to rheumatic fever may cause problems during pregnancy. In postmenopausal women coronary artery disease is probably as common as in men, especially in the elderly. Response to treatment is also sometimes suboptimal in women when they do have heart disease and it is the top cause of mortality in elderly women.

A specific form of heart disease in women is peripartum cardiomyopathy which occurs in late stages of pregnancy or soon after delivery. In this disease, heart muscle becomes quite weak and they become breathless and may go into heart failure. Usually this disease recovers spontaneously after delivery, though there is high chance of recurrence in subsequent pregnancies, especially if the heart function has not fully recovered after delivery. Clots in veins are also sometimes more often seen in women than in men. Certain birth defects of the heart like atrial septal defect (defect in the wall between the upper chambers of the heart) are also more common in women.

Tests for heart disease

tree-in-shadeWhat are the important tests for heart disease?

It should be noted that before any tests, a good medical evaluation is needed to decide which tests will be most useful for that particular person. Otherwise it may be a wastage of resources and the needed result may not be obtained. In general, tests are most useful when there is an intermediate probability of disease. When there is a low probability, a positive result could be false positive. Similarly, when the probability is high, a negative result may be a false negative. So we have to know the pretest probability of the disease before proceeding with a test, which is what we plan to achieve by a good medical evaluation.

One of the first tests to be done when heart disease is suspected, is an ECG (electrocardiogram), which records the electrical activity of the heart. Though it was started over a century back, it is still one of the best tests to diagnose a heart attack at the bedside. It does have its limitations – a normal ECG does not rule out heart disease. X-ray of the chest is useful to document the size of the heart and to look for enlargement of various chambers and blood vessels. It is also a simple and old test, with certain advantages and disadvantages.

Blood tests used in the emergency department to detect heart disease are Troponin estimation to detect heart attack and BNP (B-type natriuretic peptide) estimation to look for evidence of heart failure.

Next come the imaging tests. Ultrasound study of the heart is known as echocardiography, which can detected the function of the heart and structural abnormalities of the heart, major blood vessels and heart valves. It is now available in portable mode at the bedside. Cardiac CT (computerized tomography) is the next imaging test, which can be done at the radiology suite. An advanced form of cardiac CT is CT coronary angiography. Magnetic resonance imaging (MRI or CMR – cardiac magnetic resonance imaging) is yet another advanced mode of cardiac imaging. Nuclear scans of the heart include imaging the blood pool imaging with radioactive tracers, imaging the blood flow to the heart with tracers and assessing the metabolic function of the heart with PET scan (positron emission tomography).

Holter monitoring and treadmill tests are different forms of ECG evaluations in different settings. Holter is continuous ambulatory monitoring done for 24-48 hours. Treadmill test is exercise ECG, done with a computerised treadmill which monitors and records the ECG during gradual, stage wise increasing speeds of the treadmill. Electrophysiological study is an invasive form of ECG in which leads are introduced into the heart through blood vessels and recording of the electrical activity from various sites of the heart done from inside.

Gold standard for diagnosing coronary artery disease is coronary angiography. Allied tests to coronary angiography are coronary intravascular ultrasound (IVUS), fractional flow reserve (FFR) and optical coherence tomography (OCT). All these are invasive tests, requiring the introduction of small tubes known as catheters into the blood vessels and the procedure of introducing catheters into the heart is known as cardiac catheterization. Cardiac catheterization is done in a cardiac catheterization laboratory equipped with cine X-ray equipment.

Risk factors for heart disease

bloom-in-the-wildernessWhat are the important risk factors for heart disease?

In general, when we talk about risk factors for heart disease, we tend to think about the most common variety of heart disease in adults – coronary artery disease. Risk factors for heart disease can be divided into modifiable and non modifiable ones. The non modifiable ones are age, gender, ethnicity and family history. The risk of coronary artery disease increases as age advances. So also, the risk is more in males compared to pre-menopausal females. A strong family history of premature heart disease is an important risk factor. Some races are more prone to coronary artery disease than others. Obviously, all these risk factors cannot be modified.

We are more concerned about the modifiable risk factors because that is where the individual and the community can act to reduce the risk. Important modifiable risk factors are smoking, high blood pressure (hypertension), high blood sugar (diabetes mellitus), high body weight (obesity), high levels of lipids in the blood (dyslipidemia) and chronic kidney disease. There are other risk factors as well, though not always checked for – increased levels of homocysteine, fibrinogen, C-reactive protein (CRP) and lipoprotein (a) [Lp(a)] in the blood. Though Lp (a) levels carry significant risk, there are no well established ways of reducing the risk due to it.

Heart disease in pregnancy

forest-treeWhat are the risks of heart disease in pregnancy?

Important risk of heart disease in pregnancy is that the mother may go into heart failure with severe breathlessness. A potential risk of miscarriage is also there. In a rare form of heart disease with obstruction in the great vessel (aorta), a portion of the enlarged vessel may rupture during the strain of delivery, with catastrophic results. Another rare form of heart disease specific for pregnancy is peripartum cardiomyopathy which produces weakness of the heart muscle during pregnancy, usually improving after delivery. Severe forms of peripartum cardiomyopathy is also a high risk condition, leading to heart failure near the time of delivery or soon after.

Which types of heart diseases are poorly tolerated in pregnancy?

In general, any severe heart disease can worsen significantly during pregnancy as the work load of the heart increases markedly in later pregnancy. Heart diseases with some obstruction in the flow of blood is more likely to be worsened in pregnancy than leaks in the valves. Important obstructions which worsen in pregnancy are mitral stenosis (narrowing of the valve between the left atrium and left ventricle), aortic stenosis (narrowing of the valve between the left ventricle and aorta) and coarctation of aorta (narrowing of a region of the aorta). Birth defects of the heart which increase the blood pressure in the lungs markedly (Eisenmenger syndrome) also carries high risk in pregnancy. In Eisenmenger syndrome pregnancy is better avoided. In the other three obstructive conditions mentioned above, pregnancy can be considered after relieving the obstruction by treatment (surgery or dilatation using a balloon catheter).

At what term of pregnancy does women with heart disease start worsening?

Blood volume in the body progressively increases as the pregnancy advances. By about five months of pregnancy there is a significant increase in blood volume so that women with most severe forms of heart disease become more symptomatic. This will continue as the pregnancy advances unless the disease is relieved by treatment.