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Ailmemts & Remedies

Arrhythmia

Definition:
The heart is a pump that functions by pushing the blood through its four chambers. The blood is “pushed” through in a controlled sequence of muscular contractions. The sequence is controlled by bundles of cells which control the electrical activity of the heart. When the sequence is disturbed, heart arrhythmias occur.

Arrhythmias are abnormal rhythms of the heart.  Arrhythmias cause the heart to pump blood less effectively.  Most cardiac arrhythmias are temporary and benign.  Most temporary and benign arrhythmias are those where your heart skips a beat or has an extra beat. The occasional skip or extra beat is often caused by strong emotions or exercise. Nonetheless, some arrhythmias may be life-threatening and require treatment.

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Types of Arrhythmias:
Arrhythmias can be divided into two main categories ventricular and supraventricular.  Supraventricular arrhythmias occur in the heart’s two upper chambers called the atrium.  Ventricular arrhythmias occur in the heart’s two lower chambers called the ventricles.


Electrical conduction in the heart originates in the SA node and travels through the AV node to the ventricles, resulting in a heart beat.
Supraventricular and Ventricular arrhythmias are further defined by the speed of the heartbeats: very slow, very fast and fast uncoordinated.  A very slow heart rate is called bradycardia.  In bradycardia, the heart rate is less than 60 beats per minute. A very fast heart rate is called Tachycardia meaning the heart beats faster than 100 beats per minute. A fast uncoordinated heart rate is called Fibrillation.  Fibrillation is the most serious form of arrhythmia are contractions of individual heart muscle fibers.  Arrhythmias cause nearly 250,000 deaths each year.

Supraventricular Arrhythmia

A very common long term arrhythmia is atrial fibrillation. Atrial fibrillation is very abnormal.  A normal heart beats between 60 and 100 times a minute. However, in atrial fibrillation, the atria (upper lobes of the heart) beat 400 to 600 times per minute. In response to this, the ventricles usually beat irregularly at a rate of 170 to 200 times per minute. So in Atrial Fibrillation, the upper part of the heart may beat up to 8 times as much as a normal heart.  Unfortunately, atrial fibrillation is seen in many types of heart disease; once established, it usually lasts a lifetime.

Ventricular Arrhythmia
One of the most serious arrhythmias is sustained ventricular tachycardia. In sustained ventricular tachycardia, there are consecutive impulses that arise from the ventricles at a heart rate of 100 beats or more per minute until stopped by drug treatment or electrical conversion. This condition is very dangerous.  It is dangerous because it may degenerate further into a totally disorganized electrical activity known as ventricular fibrillation. In ventricular fibrillation, heart’s action is so disorganized that it quivers and does not contract, thus failing to pump blood.

SADS:
SADS, or sudden arrhythmic death syndrome, is a term used to describe sudden death due to cardiac arrest brought on by an arrhythmia in the absence of any structural heart disease on autopsy. The most common cause of sudden death in the US is coronary artery disease.[citation needed] Approximately 300,000 people die suddenly of this cause every year in the US.[citation needed] SADS occurs from other causes. There are many inherited conditions and heart diseases that can affect young people and subsequently cause sudden death. Many of these victims have no symptoms before dying suddenly.

Causes of SADS in young people include viral myocarditis, long QT syndrome, Brugada syndrome, Catecholaminergic polymorphic ventricular tachycardia, hypertrophic cardiomyopathy and arrhythmogenic right ventricular dysplasia

Signs and symptoms:
The term cardiac arrhythmia covers a very large number of very different conditions.

The most common symptom of arrhythmia is an abnormal awareness of heartbeat, called palpitations. These may be infrequent, frequent, or continuous. Some of these arrhythmias are harmless (though distracting for patients) but many of them predispose to adverse outcomes.

Some arrhythmias do not cause symptoms, and are not associated with increased mortality. However, some asymptomatic arrhythmias are associated with adverse events. Examples include a higher risk of blood clotting within the heart and a higher risk of insufficient blood being transported to the heart because of weak heartbeat. Other increased risks are of embolisation and stroke, heart failure and sudden cardiac death.

If an arrhythmia results in a heartbeat that is too fast, too slow or too weak to supply the body’s needs, this manifests as a lower blood pressure and may cause lightheadedness or dizziness, or fainting.

Some types of arrhythmia result in cardiac arrest, or sudden death.

Medical assessment of the abnormality using an electrocardiogram is one way to diagnose and assess the risk of any given arrhythmia.

Causes:
Many types of heart disease cause arrhythmia.  Coronary disease is often a trigger.  It triggers arrhythmia because coronary heart disease produces scar tissue in the heart.  This scar tissue disrupts the transmission of signals which control the heart rhythm.  Some people are born with arrhythmias, meaning the condition is congenital. Atherosclerosis is also a factor in causing arrhythmia. Other medical conditions such as diabetes and high blood pressure also are factors. Furthermore,  stress, caffeine, smoking, alcohol, and some over-the-counter cough and cold medicines can affect your heart’s natural beating pattern.

Diagnosis:
Many different techniques are used to diagnose arrhythmia.  The techniques include:

•A standard electrocardiogram (ECG or EKG).
An EKG is the best test for diagnosing arrhythmia. This test helps doctors analyze the electrical currents of your heart and determines the type of arrhythmia you have.

•Holter monitoring.
Holter monitoring gets a continuous reading of your heart rate and rhythm over a 24-hour period (or more). You wear a recording device (the Holter monitor), which is connected to small metal disks on your chest. With certain types of monitors, you can push a “record” button to capture a rhythm when you feel symptoms. Doctors can then look at a printout of the recording to find out what causes your arrhythmia.

•Trans telephonic monitoring. Transtelephonic monitoring documents problems that may not be detected within a 24-hour period. The devices used for this type of test are smaller than a Holter monitor. One of the devises is about the size of a beeper, the other device is worn like a wristwatch. Like with Holter monitoring, you wear the recording device. When you feel the symptoms of an arrhythmia, you can telephone a monitoring station, where a record can be made. If you cannot get to a telephone during your symptoms, you can turn on the device’s memory function. Later, you can send the recorded information to a monitoring station by using a telephone. These devices also work during episodes of fainting.

•Electrophysiology studies (EPS). Electrophysiology studies are usually performed in a cardiac catheterization laboratory. In this procedure, a long, thin tube (called a catheter) is inserted through an artery in your leg and guided to your heart. A map of electrical impulses from your heart is sent through the wire to find out what kind of arrhythmia you have and where it starts. During the study, doctors can give you controlled electrical impulses to show how your heart reacts. Medicines may also be tested at this time to see which medicines will stop the arrhythmia. Once the electrical pathways causing the arrhythmia are found, radio waves can be sent through the catheter to destroy them.

•A tilt-table exam. A tilt-table exam is a way to evaluate your heart’s rhythm in cases of fainting. The test is noninvasive, which means that doctors will not use needles or catheters. Your heart rate and blood pressure are monitored as you lie flat on a table. The table is then tilted to 65 degrees. The changing angle puts stress on the area of the nervous system that maintains your heart rate and blood pressure. Doctors can see how your heart responds under carefully supervised conditions of stress.

Treatment:

Treatment of arrhythmia depend on the type of arrhythmia, the patients age, physical condition and age.  Methods are available for prevention of arrhythmia.  These methods include relaxation techniques to reduce stress, limit intake of caffeine, nicotine, alcohol and stimulant drugs. Many arrhythmias require no treatment, they are naturally controlled by the body’s immune system. However if it is  necessary that arrhythmias must be controlled, they can be controlled by drugs, Cardioversion, Automatic implantable defibrillators or an Artificial pacemaker. Arrhythmias are very serious.

Arrhythmias that start in the lower chambers of the heart (the ventricles) are more serious than those that start in the upper chambers (the atria).

Management:
The method of cardiac rhythm management depends firstly on whether or not the affected person is stable or unstable. Treatments may include physical maneuvers, medications, electricity conversion, or electro or cryo cautery.

Physical maneuvers
A number of physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node. This can slow down or stop a number of arrhythmias that originate above or at the AV node (you may click to see: supraventricular tachycardias). Parasympathetic nervous supply to the heart is via the vagus nerve, and these maneuvers are collectively known as vagal maneuvers.

Antiarrhy
thmic drugsMain article: Antiarrhythmic agents
There are many classes of antiarrhythmic medications, with different mechanisms of action and many different individual drugs within these classes. Although the goal of drug therapy is to prevent arrhythmia, nearly every antiarrhythmic drug has the potential to act as a pro-arrhythmic, and so must be carefully selected and used under medical supervision.

Other drugs

A number of other drugs can be useful in cardiac arrhythmias.

Several groups of drugs slow conduction through the heart, without actually preventing an arrhythmia. These drugs can be used to “rate control” a fast rhythm and make it physically tolerable for the patient.

Some arrhythmias promote blood clotting within the heart, and increase risk of embolus and stroke. Anticoagulant medications such as warfarin and heparins, and anti-platelet drugs such as aspirin can reduce the risk of clotting.

Electricity
Dysrhythmias may also be treated electrically, by applying a shock across the heart — either externally to the chest wall, or internally to the heart via implanted electrodes.

Cardioversion is either achieved pharmacologically or via the application of a shock synchronised to the underlying heartbeat. It is used for treatment of supraventricular tachycardias. In elective cardioversion, the recipient is usually sedated or lightly anesthetized for the procedure.

Defibrillation differs in that the shock is not synchronised. It is needed for the chaotic rhythm of ventricular fibrillation and is also used for pulseless ventricular tachycardia. Often, more electricity is required for defibrillation than for cardioversion. In most defibrillation, the recipient has lost consciousness so there is no need for sedation.

Defibrillation or cardioversion may be accomplished by an implantable cardioverter-defibrillator (ICD).

Electrical treatment of dysrhythmia also includes cardiac pacing. Temporary pacing may be necessary for reversible causes of very slow heartbeats, or bradycardia, (for example, from drug overdose or myocardial infarction). A permanent pacemaker may be placed in situations where the bradycardia is not expected to recover.

Electrical cautery
Some cardiologists further sub-specialise into electrophysiology. In specialised catheter laboratories, they use fine probes inserted through the blood vessels to map electrical activity from within the heart. This allows abnormal areas of conduction to be located very accurately, and subsequently destroyed with heat, cold, electrical or laser probes.

This may be completely curative for some forms of arrhythmia, but for others, the success rate remains disappointing. AV nodal reentrant tachycardia is often curable. Atrial fibrillation can also be treated with this technique (e.g. pulmonary vein isolation), but the results are less reliable.

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Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://www.mamashealth.com/ardiag.asp
http://www.mamashealth.com/arrhythmia.asp
http://hrssc.com/hrssc-patient-resource-how-to-diagnose-arrhythmias.html
http://www.nsmc.partners.org/web/service/heart_arrhythmia
http://www1.ecardio.com/PS/Cardiac.aspx
http://www.medicompinc.com/holter_service.html

http://www.nhlbi.nih.gov/health/dci/Diseases/ekg/ekg_during.html

http://commons.wikimedia.org/wiki/File:Heart_conduct_atrialfib.gif

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Categories
Ailmemts & Remedies

Heart Block

A diagram of a heart with an ECG indicator; di...Image via Wikipedia

Definition:
A heart block is a disease in the electrical system of the heart. This is opposed to coronary artery disease, which is disease of the blood vessels of the heart. While coronary artery disease can cause angina (chest pain) or myocardial infarction (heart attack), heart block can cause lightheadedness, syncope (fainting), and palpitations.

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The heart has four chambeacemaker is called the sinoatrial (SA) node or sinus node. It’s a small mass of specialized crs. The top two are called the atria. The bottom two are called the ventricles.
The heart’s “natural” pells in the heart’s right atrium. It produces electrical impulses that make your heart beat. For your heart to beat properly, the signal must travel from the SA node down a specific path to reach the ventricles. As the signal goes from the atria to the ventricles, it passes through specialized conducting tissue called the atrioventricular (A’tre-o-ven-TRIK’u-ler) (AV) node.

On an electrocardiogram (e-lek”tro-KAR’de-o-gram) (ECG), a portion of the graph called the P wave shows the impulse passing through the atria. Another portion of the graph, the QRS wave, shows the impulse passing through the ventricles. As long as the impulse is transmitted normally, the heart pumps and beats at a regular pace.

Sometimes the signal from the heart’s upper to lower chambers is impaired or doesn’t transmit. This is “heart block” or “AV block.” This does not mean that the blood flow or blood vessels are blocked.

Heart block is classified according to the level of impairment — first-degree heart block, second-degree heart block or third-degree (complete) heart block.

Types of heart block
A heart block can be a blockage at any level of the electrical conduction system of the heart.

1.Blocks that occur within the sinoatrial node (SA node) are described as SA nodal blocks.
2.Blocks that occur within the atrioventricular node (AV node) are described as AV nodal blocks.
3.Blocks that occur below the AV node are known as infra-Hisian blocks (named after the bundle of His).
4.Blocks that occur within the left or right bundle branches are known as bundle branch blocks.
5.Blocks that occur within the fascicles of the left bundle branch are known as hemiblocks.

Clinically speaking, most of the important heart blocks are AV nodal blocks and infra-Hisian blocks.

Types of SA nodal blocks
The SA nodal blocks rarely give symptoms. This is because if an individual had complete block at this level of the conduction system (which is uncommon), the secondary pacemaker of the heart would be at the AV node, which would fire at 40 to 60 beats a minute, which is enough to retain consciousness in the resting state.

Types of SA nodal blocks include:

SA node Wenckebach (Mobitz I)
SA node Mobitz II
SA node exit block
In addition to the above blocks, the SA node can be suppressed by any other arrhythmia that reaches it. This includes retrograde conduction from the ventricles, ectopic atrial beats, atrial fibrillation, and atrial flutter.

The difference between SA node block and SA node suppression is that in SA node block an electrical impulse is generated by the SA node that doesn’t make the atria contract. In SA node suppression, on the other hand, the SA node doesn’t generate an electrical impulse because it is reset by the electrical impulse that enters the SA node.

Types of AV nodal blocks
There are four basic types of AV nodal block:

First degree AV block
Second degree AV block
Type 1 second degree AV block (Mobitz I) (also known as Wenckebach phenomenon)
Third degree AV block (Complete heart block)

Types of infra-Hisian block
Infrahisian block describes block of the distal conduction system. Types of infrahisian block include:

Type 2 second degree heart block (Mobitz II)
Left bundle branch block
Left anterior fascicular block
Left posterior fascicular block
Right bundle branch block
Of these types of infrahisian block, Mobitz II heart block is considered most important because of the possible progression to complete heart block.

Symptoms:
The symptoms and severity of heart block depend on which type you have. First-degree heart block rarely causes severe symptoms.

Second-degree heart block may result in the heart skipping a beat or beats. This type of heart block also can make you feel dizzy or faint.

Third-degree heart block limits the heart’s ability to pump blood to the rest of the body. This type of heart block may cause fatigue (tiredness), dizziness, and fainting. Third-degree heart block requires prompt treatment, because it can be fatal.

A medical device called a pacemaker is used to treat third-degree heart block and some cases of second-degree heart block.

This device uses electrical pulses to make the heart beat at a normal rate.

Sometimes, however, there are no symptoms at all.

It is important to note that during a period of heart block, persons may not know how to describe what they are feeling. They may have trouble keeping up with other persons, realize they are having “spells” and want to sit down and rest.

Causes:
Heart block has a variety of causes. It can sometimes be a result of a congenital defect. It can also occur after a heart attack or as a result of myocarditis (inflammation of the heart muscle), cardiomyopathy (a disorder of the heart muscle) and other types of heart disease. Although these conditions are more common in older people, young people can also be affected.

Heart block may also occur after heart surgery and in this case may be either temporary or permanent. Wenckebach block may occur as a result of taking too much digoxin, or can occur after a heart attack. Heart block may be caused by coronary artery disease, inflammation of the heart muscle, rheumatic fever, or overdose of certain heart drugs. Treatment depends on the degree of heart block experienced. Some cases need no treatment while others require medication or an artificial pacemakers.

Diagnosis

Heart block may occur spontaneously with unpredictable timing. Therefore, in some cases, the condition may require specialized tests to acquire an accurate diagnosis. If your doctor suspects that a person has heart block, he or she will order one or more of the following diagnostic tests to determine the cause of person’s symptoms.

Electrocardiogram –– An electrocardiogram (ECG or EKG) records the heart’s electrical activity. Small patches called electrodes are placed on person’s chest, arms and legs, and are connected by wires to the ECG machine. The electrical impulses of your child’s heart are translated into a graph or chart, enabling doctors to determine the pattern of electrical current flow in the heart and to diagnose arrhythmias.

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Holter Monitor — A Holter monitor is a small, portable machine that the person wears for 24 hours. It is about the size of a portable tape player and provides a continuous 24-hour recording of your child’s heartbeat onto a tape. You will be asked to keep a diary of your activities and symptoms. This monitor may detect arrhythmias that might not show up on a resting electrocardiogram, which only records a heartbeat for a few seconds at rest.

Event Monitor — This is a small monitor about the size of a pager that the person can have for up to a month. Since the arrhythmia may occur at unpredictable times, this will help to record the abnormal rhythm when he or she is experiencing symptoms. He or she can just push a button on the pager and record the heartbeat. The recording can than be transmitted by phone to the doctor.

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Exercise Stress Test –– An exercise stress or treadmill test, records the electrical activity of the person’s heart during exercise, which differs from the heart’s electrical activity at rest.

Electrophysiology Study –– In an electrophysiology (EP) study, doctors insert special electrode catheters — long, flexible wires — into veins and guide them into the heart. These catheters sense electrical impulses and also may be used to stimulate different areas of the heart. Doctors can then locate the sites that are causing arrhythmias. The EP study allows doctors to examine an arrhythmia under controlled conditions and acquire more accurate, detailed information than with any other diagnostic test.

Treatment
Heart block is a rhythm disturbance that can be treated with the implantation of a permanent pacemaker. The pacemaker helps your heart beat consistently. A pacemaker is a medical device that regulates the heart beat. It consists of two parts — the generator and the lead. The generator is a small metal container with a battery and tiny computer. The lead is an insulated wire that carries electrical impulses to the heart to ensure a stable heartbeat.

The computer in the pacemaker is constantly monitoring your heartbeat. This is called sensing. When the pacemaker senses your heartbeat, it continues to “watch” or monitor your heart and does not send a signal to stimulate the heart to beat. If no electrical impulse is sensed by the pacemaker, it sends out a signal to stimulate your childs heart to beat.

Proper Yoga exercise specially Deep Breathing and Pranayama are very helpful for all types of heart block.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://www.americanheart.org/presenter.jhtml?identifier=4611
http://en.wikipedia.org/wiki/Heart_block
http://www.nhlbi.nih.gov/health/dci/Diseases/hb/hb_whatis.html
http://www.ucsfhealth.org/childrens/medical_services/heart_center/arrhythmia/conditions/block/diagnosis.html
http://heart-disease.health-cares.net/heart-block-causes.php

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