Know Your Heart

We all know that Heart is a crucial organ in our body that constantly and tirelessly pumps blood to all parts of our body. It starts functioning at about 6 weeks of Intrauterine Life. From then it functions continuously till the very end of life. Normal functioning of every other organ is dependent on the normal functioning of heart.

Chambers of Heart

Heart has 4 chambers- two Atria (atrium-singular) and two Ventricles. The atria have thinner walls compared to those of ventricles which are thick and muscular. The atria receive blood and ventricles pump blood. The wall that separates left and right atria is known as Inter Atrial Septum(IAS) and the one that separate ventricles is called Inter Ventricular Septum(IVS)

Blood vessels Attached to Heart

Right Atrium has two large veins bringing blood to it. Superior Vena Cava(SVC)

Major vessels of Heart

Right Atrium receives blood from all over the body through two large veins. Superior Vena Cava(SVC) brings blood from upper body while Inferior Vena Cava(IVC) drains the lower body. IVC contributes 60% of the blood return. Apart from this, one major route of blood return is the Coronary Sinus(CS), which returns blood from the veins of heart itself

Left Atrium receives pure blood from the lungs via 4 pulmonary veins. Two on Right(Right Superior and Inferior pulmonary veins)and two on the left(Left Superior and Inferior pulmonary veins)

The right ventricle pumps its blood into large pulmonary Artery while left ventricle ejects into Aorta- the biggest artery in the body.

Coronary Arteries

Heart muscles too require oxygenated blood, which is supplied through Coronary arteries which are the first two branches of aorta. These are Left(LCA) and Right (RCA) coronary arteries. The left Coronary Artery after a short broad stem(Left main artery)divides into two major branches-Left Anterior Descending Artery(LAD) which supplies the front of heart and interventricular Septum(IVS)and Left Circumflex Artery(LCA) which supplies the lateral and posterior part of the left ventricle. Right Coronary Artery mainly supplies the Right Ventricle, Inferior(lower)part of the Left ventricle and part of IVS

How Heart beats regularly?

Have you ever wondered what makes our heart beat so efficiently and regularly?
What decides rhythm of heart?

The secret is the internal pacemaker(timer)and the conducting system of the heart(Electrical circuit). The natural pacemaker is situated at the junction of Right Atrium and SVC. It is called SA note. There is a network of special fibres starting from the pacemaker and going all over the heart muscles. This is called the conduction system. The pacemaker is capable of producing regular stimuli of electrical activity which travels along the conduction system to the entire heart making the muscles contract.

Testing the Heart(Modes of investigating heart)

  • ECG( Electrocardiography) and TMT
  • Chest X ray
  • Echocardiography
  • Coronary Angiography
  • CT Scan
  • MRI
  • Nuclear scanning

ECG and TMT

Electrocardiography is a recording of the electrical activity of the heart from the body surface. It is done by using sensitive electrodes placed on standard positions on the chest and limbs and recording the activity on a special graphical paper Normal ECG has certain features. But every normal ECG is not identical. There are wide ranges of normalcy. So two ECGs appearing to be different to a layman’s eyes, could be normal. Likewise, all abnormal ECGs do not necessarily indicate serious problems In spite of limitations, ECG remains an easily accessible, simple and useful initial investigation. In expert’s hands, it is a very valuable tool and can detect variety of conditions.
One of the commonest uses of ECG is to detect ischaemia(reduced blood supply)to heart muscles. During Angina(chest pain)or Myocardial infarction (heart attack), ECG will show typical charges which are diagnostic
Stress ECG or Treadmill Test(TMT) is a method of recording ECG while the subject is exercising (alternatively, heart can be stressed by some drugs like dobutamine). Stress or exercise will uncover some ischaemia that is not obvious while at rest. A strongly positive TMT mostly indicate blocks in the coronary arteries. But a negative TMT does not completely rule out blocks(Negative predictive value is about 75%)
Holter ECG is a continuous recording of ECG for 24 hours or more using a portable device. This may be helpful in picking up transient rhythm disturbances or ischaemia which would otherwise escape detection during standard ECG.

Chest Xray

A well taken radiograph of the chest gives valuable information about heart and lungs. The size, shape and position of heart can change in disease process. the chambers may dilate. The vascularity (Blood circulation) to the lungs may increase or decrease in different situations. These changes can be detected by a chest X Ray

Different views of chest X Ray

PA (Posteroanterior)View:- most common. The machine at the back and film in front of person’s chest. AP (Anteroposterior) View: Used in patients confined to bed(eg: after surgery)
Lateral View: From the sides

Echocardiography

Echocardiography is another form of ultrasound imaging. It allows the structures of the heart to be visualised. The imaging is done by a probe placed on the chest well. The two dimensional echocardiography (TransThoracic Echo or TTE) provides sections of the structures and chambers of the heart. Serial images may be combined to give a real time view. Doppler Echocardiography is based on Doppler principle sound waves reflected from moving objects sustain a change in frequency. By detecting the speed and direction of red blood cells, we can accurately calculate the properties of blood flow. The information obtained may be converted to colour patterns to indicate velocity and direction of blood flow. This gives accurate measurement of valve leaks. Two dimensional echo combined with doppler is a simple noninvasive and reliable method of assessing structure and function of heart.

Transesophageal Echocardiography: In this mode, the interrogating probe is placed in the esophagus(ford pipe)like an endoscope and closer and more accurate views of the heart chambers and valves can be obtained. This is especially useful in the assessment of left atrium and mitral valve. Some of the ASDs(Atrial septal Defects) not detectable on Transthoracic echo may be picked up on TEE

CT scan and CT coronary angiogram:

CT scan is a computerized serial X-ray imaging which revolutionized the field of medical imaging in the 70s. This method can be applied to Cardiac and vascular imaging in many ways. CT gives images of the internal structures with good clarity and accuracy within short time. With the help of Contrasts (dyes that used to make blood visible to X-ray), CT can give detailed and precise pictures of the blood vessels and their abnormalities. However, presence of calcification in the wall and constant motion of the coronary arteries make CT Coronary angiogram less accurate compared of conventional coronary angiogram.
Uses of CT in Cardiology: Plain CT can be used to evaluate the calcium load in the coronaries and major vessels like aorta. Tumors and thrombus (clots) can be detected. Pericardial diseases can be accurately assessed.
CT coronary angiogram is of benefit as a non-invasive imaging in the assessment of atypical chest pain. It is very useful in assessing post-operative bypass grafts.

For primary assessment of blocks in the coronary arteries, Conventional Coronary Angiogram is still the ‘Gold Standard’


Contrast CT scan with 3D reconstruction gives amazingly accurate imaging of other blood vessels like Aorta, Carotid arteries and Renal arteries.

Coronary Angiography (CAG):

This is a real time invasive contrast imaging of the coronary arteries. Special catheters are introduced via femoral or radial artery and contrast is injected directly into the coronary arteries. Continuous simultaneous fluoroscopy is done. The imaging is 2D and assessment of the blocks is by assessing the diameter reduction of the artery.

Method of CAG: As mentioned earlier, the special catheter needs to be guided into the coronary artery to perform CAG. The access can be from femoral artery (in the groin) or Radial artery (at the wrist). Traditionally CAG was done through femoral route. It is often uncomfortable for the patient and needs overnight stay at hospital. However, femoral artery being a larger vessel , this approach is easier and versatile.
Radial Angiography: When the approach is radial, it does not affect patient’s mobility and he can be home the same evening. Most often the angioplasty if required, can also be done via this route. The only disadvantage is that radial artery is more likely to go into spasm (temporary shrinking while handling). This can make manipulation of the catheter difficult and cause discomfort to patient. In such situations the approach may have to be changed to femoral.

Risks of CAG: Remember, coronary angiography is an invasive procedure. It is not with-out its share of complications. So it is important to be sure of the need for CAG before going ahead.

Watch how coronary arteries look on normal Coronary Angiogram:

  • Left coronary artery
  • Right coronary artery
Some complications of diagnostic CAG
Death - 0.1%
Myocardial Infarction - 0.1 – 0.2%
Neurological events - 0.1 – 0.2%
Vessel injuries - 1.0 – 2.0%

Dye or contrast used in Coronary Angiogram or CT Angiogram is nephrotoxic (toxic to kidney). It is a must to assess kidney function before these tests. It is also advisable to consult a Nephrologist in case the Blood Urea and Serum Creatinine are elevated

Some radioactive isotopes (eg. Technetium 99) up by the myocardium. The uptake at rest and during exercise can be detected by gamma cameras which pick up the gamma rays emitted by these isotopes. By simple logic viable muscles will have more uptake and ischemic muscles will show decrease in uptake during exercise. Dead or scarred muscles will have no uptake. This information could be extremely valuable in the decision making while considering revascularization, especially in patients with left ventricular dysfunction.), when injected intravenously are preferentially taken

MRI (Magnetic Resonance Imaging):

MRI scanners use strong Magnetic fields and Radiowaves to form images of body.This modality can provide structural and physiological information. It does not require ionising radiations. It does not use nephrotoxic contrasts. This has become the imaging choice in Neurological practice.
Physiological data may be obtained from the signal returned from moving blood. High resolution MRI can provide vivid pictures of cardiac chambers and spatial relationships of structures. The images can be comparable to CT. With the use of MR contrast agents like Gadolinium, MR angiograms can be obtained and viability study of the myocardium can be done.

Patients with Pacemakers and implants with moving ferromagnetic parts should not undergo MRI, as the magnetic field can affect or damage the implants.Patients with Mechanical heart valves should contact their doctor before undergoing MRI

DISEASES OF HEART CORONARY ARTERY DISEASE:

What is it?

The heart’s muscles get its blood supply through coronary arteries. When blocks develop in these arteries heart is deprived of essential blood circulation. The block or stenosis is caused by a disease process called Atherosclerosis, which is deposition of lipid rich material in the vessel walls. Depending on the severity of the blocks the symptoms vary from absence of symptoms to severe myocardial infarction (Heart attack)

Symptoms

Angina or chest pain is the commonest presenting symptom. This is generally felt as a heaviness or uneasiness in the centre of chest. It is usually brought out by effort and relieved by rest. Angina lasts for short periods and seldom lasts for more than 20 minutes. Nitrates (medicines taken to relax coronary arteries) have the ability to relieve angina very quickly (Almost instantaneously if kept under the tongue ie., sublingual)

Angina is felt usually in the centre of chest (Left sided chest pains re usually not angina)

Typically angina appears as chest discomfort. It may radiate to neck, jaws, left shoulder or left arm. Rarely it can present as back pain, headache or even abdominal pain.
If you suffer from repeated burning sensation in your upper abdomen and not relieved by usual medicines, a detailed check up is required. Angina presenting as stomach burn has misled even doctors to make wrong judgements.

Beware of “gas trouble” which is recurrent and not relieved by usual medicati ons! ANGINA can present as ‘stoma

Heart attack or Myocardial Infarction (MI) is another form of presentation. While angina is almost completely reversible, MI threatens permanent myocardial damage. This happens when there is sudden complete occlusion in the coronary arteries. Usually this occlusion occurs at pre-existing stenotic lesions. The common cause is a plaque rupture (separation of the atheromatous plaque and clot formation underneath). The myocardium supplied by the particular coronary artery is under threat of permanent damage.
The pain of MI is more severe and lasts longer. Patient may vomit and sweat. It is often described as a feeling of ‘Impending death”. This condition is severe and can be fatal at times. It calls for urgent attention. Patient needs urgent hospitalisation and treatment.

How to Diagnose?

When the physician sees a patient with symptoms of CAD, a thorough assessment is made. A detailed history of risk factors, previous events, procedures, medications and family history is obtained. A careful physical examination is the next step.
Generally, ECG and few blood tests may be done along with the first visit. If symptoms are suggestive of CAD, further investigations are required. This may include ECHO, TMT and Coronary Angiogram depending on the type and severity of symptoms.

Treatment:

Of all the patients with CAD, nearly three fourth requires only medicines. Rest of the symptomatic patients may require some form of invasive treatment depending on the findings of the CAG.
Common treatments are of two types – PTCA (Percutaneous Transluminal Coronary Angioplasty) or ANGIOPLASTY and CABG or Bypass Operation. The requirement and suitability of each modality of treatment is decided by the treating specialist. (for details read the section on PTCA Vs CABG)


RHEUMATIC HEART DISEASE

What is it?

Rheumatic Heart Disease is the sequelae of Rheumatic fever which is an infection by a bacterium (beta hemolytic streptococcus). The fever affects children or young adults. It typically presents with fever and joint inflammations. The common joints affected are knee, hip and elbow. The swelling and pain in joints has a characteristic ‘fleeting’ nature. They affect one joint at a time and seem to migrate from one joint to another. The joint lesions heal without any scar.

Rheumatic Valvular Disease is caused by the immunological reaction of the body which is misdirected at the valvular tissue. It causes inflammation and scarring of the heart valves and result in valve dysfunction – stenosis or regurgitation or a combination. Mitral valve is affected most. But other valves are also affected singly or along with mitral valve.

Symptoms:

The symptoms of valvular diseases will vary depending on the type valve, nature of lesion (block or leak), severity of lesion and rapidity of progress.

Dyspnea or Breathlessness:

This is one of the commonest symptom of any type of valvular disease. From mild to most severe form this symptom can vary in intensity. Milder forms present only on exertion while more severe forms can be present even at rest. In very severe types the patient may not be able to lay down comfortably (Orthopnea). He may also experience sudden bouts of severe breathlessness in the night which forces him to wake up with extreme difficulty in breathing associated with cough (Paroxysmal Nocturnal Dyspnea or PND). These extreme forms are most commonly seen in Mitral valve disease.

Palpitation:

Awareness of one’s own heartbeats is known as Palpitation. Valve disorders can present with various types of rhythm disturbances. Extra beats (Premature atrial / Ventricular Contractions) are quite common. Atrial Fibrillation is common in Mitral Stenosis and Mitral Regurgitation.

Awareness of one’s own heartbeats is known as Palpitation. Valve disorders can present with various types of rhythm disturbances. Extra beats (Premature atrial / Ventricular Contractions) are quite common. Atrial Fibrillation is common in Mitral Stenosis and Mitral Regurgitation.

Atrial fibrillation (AF) is an abnormal rhythm where atrial contractions are ineffective and rapid and ventricular contractions are irregular. Often presented as palpitation. In valvular diseases this condition is caused by atrial dilatation and commonly found in Mitral disease. Atrial fibrillation causes blood to stagnate in atria and can cause clots in the atria. This can lead to Thrombo-Embolism (Migration of small clots into the circulation causing occlusion of arteries) It can embolize to legs or abdomen. When it happens in the brain circulation, the result is a stroke! So AF is a serious condition which needs to be treated. Patient has to be on Anticoagulant medications (Blood thinning agents to prevent clots) until AF is reverted

Angina: Presentation of angina is just like that in Coronary Artery Disease. This symptom is common in Aortic Stenosis and can often be confusing
Giddiness: Often the presenting symptom in Aortic lesions. In Aortic stenosis it is seen early while in Aortic regurgitation it is late symptom.
Non-specific symptoms: Patients may experience extreme tiredness, nausea, loss of appetite and even weight loss.

Diagnosing Valvular Heart disease:

Thorough clinical evaluation and routine investigations are mandatory. However the mainstay of diagnosing valvular heart diseases is an Echocardiography.
Echo provides accurate information regarding structure of valve and dimensions of the chambers. Doppler information is valuable in calculating the degree of stenosis or regurgitation. Trans-Esophageal Echocardiography or TEE can be helpful in planning valve repairs.

Treatment:

Medical Treatment: Once the valve disorder is diagnosed, initial line of treatment will be medical. Depending on the type of lesion and severity of the lesion the treatment also differs. The medicines may include anti-hypertensive drugs, heart rate controlling medications, diuretics, anti-platelets and anti-coagulants. In rheumatic valvular diseases, Penicillin prophylaxis may be given. Patients with Atrial Fibrillation (AF) should receive anticoagulants.
If the symptoms are relieved by medications, the treatment can be continued until the disease progresses to the next stage. Sometimes in the course of treatment a decision may have to be taken regarding other treatment methods like surgery.
Balloon Valvotomy:In stenotic lesions of Mitral or Pulmonary valves, Dilatation of the stenosed valve by using a special balloon is a favored treatment. The valve must be soft with out calcification and pliable. Very hard valves can not be safely opened with balloon. It may cause balloon to rupture or valve may tear at an undesirable location causing severe valve leak. So the valve anatomy has to be carefully assessed by Echocardiography.
Valve Replacement:Severe valve disorders that cannot be treated by other methods may need valve replacement. Every patient has to be assessed individually and a careful decision made regarding replacement. Mitral and Aortic valves are the commonly affected valves and so the replacements are also common in these positions.
Variety of valves are available for replacement. However they can be broadly divided into two categories. Mechanical Valves and Bio-prosthetic (Tissue) valves. ‘Mechanical Vs Bio-prosthetic valves’ is dealt in another section.
Valve Repair: In spite of the tremendous progress made in the design and structure of mechanical and tissue valves, the ideal valve prosthesis is still far from reality. No man made valve can match the simplicity and efficiency of natural human valves. Even in partially defective condition natural valves function better than the prosthetic ones.
In spite of the tremendous progress made in the design and structure of mechanical and tissue valves, the ideal valve prosthesis is still far from reality. No man made valve can match the simplicity and efficiency of natural human valves. Even in partially defective condition natural valves function better than the prosthetic ones.

Repair has certain advantages

  • No need for anticoagulation
  • Natural valves are more resistant to infection (Prosthetic valve infection is a dreaded condition)

In short, ”RETAIN and REPAIR” is preferred over “RESECT and REPLACE”