Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.
Dr. Kulick received his undergraduate and medical degrees from the University of Southern California, School of Medicine. He performed his residency in internal medicine at the Harbor-University of California Los Angeles Medical Center and a fellowship in the section of cardiology at the Los Angeles County-University of Southern California Medical Center. He is board certified in Internal Medicine and Cardiology.
Many patients with atrial fibrillation have no symptoms and are unaware of the
abnormal heart rhythm. The most common symptom of atrial fibrillation is
palpitations, an uncomfortable awareness of the rapid and irregular heartbeat.
Other symptoms of atrial fibrillation are caused by the diminished delivery of
blood to the body. These symptoms include
dizziness,
fainting,
weakness,
fatigue,
shortness of breath, and
angina (chest pain due to reduced blood flow
to the heart muscles).
Atrial fibrillation (AF) is the most common, abnormal rhythm of the
heart.
The heart contracts (beats) and pumps blood with a regular rhythm, for example,
at a rate of 60 beats per minute there is a beat every second. The heart may
beat faster or slower with a shorter or longer interval between beats, but at
any one rate the interval between beats is constant. This regular rhythm occurs
as a result of regular electrical discharges (currents) that travel through the
heart and cause the muscle of the heart to contract. In atrial fibrillation, the electrical
discharges are irregular and rapid and, as a result, the heart beats irregularly
and, usually, rapidly.
Atrial fibrillation is common; half a million new cases are diagnosed yearly
in the U.S., and billions of dollars are spent annually on its diagnosis and
treatment.
What causes atrial fibrillation?
Normal function of the heart
The
heart has four chambers. The upper two chambers are the atria, and the
lower two chambers are the ventricles. Blood returning to the heart from the body in the
superior and inferior vena cava contains low levels of oxygen and high levels
of carbon dioxide. This blood flows into the right atrium and then into the
adjacent right ventricle. After the ventricle fills, contraction of the right atrium
pumps additional blood into the right ventricle. The right ventricle then
contracts and pumps the blood to the lungs where the blood takes up oxygen and
gives off carbon dioxide. The blood then flows from the lungs to the left atrium
and into the adjacent left ventricle. Contraction of the left atrium pumps
additional blood into the left ventricle. The left ventricle then contracts and
pumps the blood to the rest of the body. The heartbeat (pulse) that we feel is
caused by the contraction of the ventricles.
The ventricles must deliver enough blood to the body for
the body to function normally. The amount of blood that is pumped depends on
several factors. The most important factor is the rate of contraction of the
heart (the heart rate). As the heart rate increases, more blood is pumped. In
addition, the heart pumps more blood with each beat when the atria contract and fill the
ventricles with additional blood just before the ventricles contract.
With each beat of the heart, an electrical discharge (current) passes through
the electrical system of the heart. The electrical discharge causes the muscle
of the atria and ventricles to contract and pump blood. The electrical system of
the heart consists of the SA node (sino-atrial node), the AV node
(atrio-ventricular node) and special tissues in the atria and the ventricles
that conduct the current.
The SA node is the heart's electrical pacemaker. It is a small patch of
cells located in the wall of the right atrium; the frequency with which the SA
node discharges determines the rate at which the heart beats. The electrical
current passes from the SA node, through the special tissues of the atria and
into the AV node. The AV node serves as an electrical relay station between the
atria and the ventricles. Electrical signals from the atria must pass through
the AV node to reach the ventricles.
The electrical discharges from the SA node cause the atria to contract and
pump blood into the ventricles. The same discharges then pass through the AV
node to reach the ventricles, traveling through the special tissues of the
ventricles and causing the ventricles to contract. In a normal heart, the rate
of atrial contraction is the same as the rate of ventricular contraction.
At rest, the frequency of the electrical discharges originating from the SA
node is low, and the heart beats at the lower range of normal (60-80
beats/minute). During exercise or excitement, the frequency of discharges from
the SA node increases, increasing the rate at which the heart beats.
Function of the heart during atrial fibrillation
During
atrial fibrillation, electrical
discharges are not generated solely by the SA node. Instead, electrical discharges
come from other parts of the atria. These abnormal discharges are
rapid and irregular and may exceed 350 discharges per minute. The rapid
and irregular discharges cause ineffective contractions of the atria. In fact,
the atria quiver rather than beat as a unit. This reduces the ability of
the atria to pump blood into the ventricles.
The rapid and irregular electrical discharges
from the atria then pass through the AV node and into the ventricles,
causing the ventricles to contract irregularly and (usually) rapidly. The
contractions of the ventricles may average 150/minute, much slower than the rate in
the atria. (The ventricles are unable to contract at 350/minute.) Even at an average
rate of 150/minute, the ventricles may not have enough time to fill maximally
with blood before the next contraction, particularly without the normal
contraction of the atria. Thus, atrial fibrillation decreases the amount of blood pumped by the
ventricles because of their rapid rate of contraction and the absence of normal
atrial contractions.
Heart rate during atrial fibrillation
In a heart that is beating normally, the rate of ventricular contraction is
the same as the rate of atrial contraction. In atrial fibrillation, however, the rate of
ventricular contraction is less than the rate of atrial contraction. The rate of
ventricular contraction in atrial fibrillation is determined by the speed of transmission of the
atrial electrical discharges through the AV node. In people with a normal AV
node, the rate of ventricular contraction in untreated atrial fibrillation usually ranges from
80 to 180 beats/minute; the higher the transmission, the higher the heart rate.
Some older people have slow transmission through the AV node due to disease
within the AV node. When these people develop atrial fibrillation, their heart rates remain
normal or slower than normal. As disease in the AV node advances, these people
can even develop an excessively slow heart rate and require a permanent
pacemaker to increase the rate of ventricular contractions.
Low blood pressure, also referred to as hypotension, is blood pressure that is so low that it causes symptoms or signs due to the low flow of blood through the arteries and veins. Some of the symptoms of low blood pressure include light-headedness, dizziness, or even fainting if not enough blood is getting to the brain. Diseases and medications can also cause low blood pressure. When the flow of blood is too low to deliver enough oxygen and nutrients to vital organs such as the brain, heart, and kidneys; the organs do not function normally and may be permanently damaged.
Congestive heart failure (CHF) is a condition in which the heart's function as a pump is inadequate to meet the body's needs. A poor blood supply resulting from congestive heart failure may cause the body's organ systems to fail, leading to a weakened heart muscle and fluid accumulation in the lungs and body tissue. There are many diseases that can impair pumping efficiency and symptoms of congestive heart failure including fatigue, diminished exercise capacity, shortness of breath, and swelling. Treatments include lifestyle modifications, medications, heart transplant, and therapy.
High blood pressure, also known as hypertension, is a repeatedly
elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above
140 with a diastolic pressure above 90. There are two causes of high blood pressure, primary and secondary. Primary high blood pressure is much more common that secondary and its basic causes or underlying defects are not always known. It is known that a diet high in salt increases the risk for high blood pressure, as well as high cholesterol. Genetic factors are also a primary cause. Secondary high blood pressure is generally caused by another condition such as renal hypertension, tumors, and other conditions. Treatment for high blood pressure is generally lifestyle changes and if necessary, diet.
Blood clots can occur in the venous and arterial vascular system. Blood clots can form in the heart, legs, arteries, veins, bladder, urinary tract and uterus. Risk factors for blood clots include high blood pressure and cholesterol, diabetes, smoking, and family history. Symptoms of a blood clot depend on the location of the clot. Some blood clots are a medical emergency. Blood clots are treated depending upon the cause of the clot. Blood clots can be prevented by lowering the risk factors for developing blood clots.
An arrhythmia is an abnormal heart rhythm. With an arrhythmia, the heartbeats may be irregular or too slow (bradycardia), to rapid (tachycardia), or too early. When a single heartbeat occurs earlier than normal, it is called a prmature contraction.
Hyperthyroidism is an excess of thyroid hormone resulting from an overactive thyroid gland. Symptoms can include increased heart rate, weight
loss, depression, and cognitive slowing. Treatment is by medication, the use of
radioactive iodine, thyroid surgery, or reducing the dose of thyroid hormone.
Heart attack happens when a blood clot completely obstructs a coronary
artery supplying blood to the heart muscle. A heart attack can cause chest pain, heart failure, and electrical
instability of the heart.
COPD (chronic obstructive pulmonary disease) is a disorder that persistently obstructs bronchial airflow. COPD mainly involves three related conditions, chronic bronchitis, chronic asthma, and emphysema. Symptoms of COPD include chronic cough, shortness of breath, frequent respiratory infections, wheezing, morning headaches, and pulmonary hypertension. Treatment of COPD is focused on the related condition(s).
Mitral valve prolapse (MVP) is also also known as "click murmur syndrome" and "Barlow's syndrome." Mitral valve prolapse is the most common heart valve abnormality. Signs and symptoms of mitral valve prolapse include: fatigue, palpitations, chest pain, anxiety, and migraine headaches. Echocardiography is the most useful test for mitral valve prolapse. Most patients do not need any treatment, however, patients with severe prolapse may need treatment.
Heart rhythm disorders vary from minor palpitations, premature atrial contractions (PACs), premature ventricular contractions (PVCs), sinus tachycardia, and sinus brachycardia, to abnormal heart rhythms such as tachycardia, ventricular fibrillation, ventricular flutter, atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT), Wolf-White-Parkinson syndrome, brachycardia, or heart blocks. Treatment is dependant upon the type of heart rhythm disorder.
Pulmonary edema (swelling or fluid in the lungs) can either be caused by cardiogenic causes (congestive heart failure, heart attacks, abnormal heart valves) or noncardiogenic causes such as ARDS, kidney failure, high altitude, pneumothorax, pleural effusion, aspirin overdose, pulmonary embolism, and infections. The treatment of pulmonary edema depends on the cause of the condition.
Pericarditis is the inflammation of the pericardial sac that surrounds the heart. The causes of pericarditis include injury from heart attack, heart surgery, trauma; viral or fungal infection, HIV, tumors, mixed connective tissue disease, metabolic disease, medication reactions, or idiopathic. Treatment for pericarditis is generally medication, however, sometimes surgery is necessary.
When a portion of the brain loses blood supply, through a blood clot or embolus, a transient ischemic attack (TIA, mini-stroke) may occur. If the symptoms do not resolve, a stroke most likely has occurred. Symptoms of TIA include: confusion, weakness, lethargy, and loss of function to one side of the body. Risk factors for TIA include vascular disease, smoking, high blood pressure, high cholesterol, and diabetes. Treatment depends upon the severity of the TIA, and whether it resolves.
Rheumatic fever is a disease that sometimes occurs after a group A streptococcal infection of the throat. Symptoms and signs include carditis, polyarthritis, Aschoff bodies, rash, Sydenham's chorea, and fever. Treatment for rheumatic fever involves eliminating the bacteria with penicillin, erythromycin, or azithromycin. Further treatment focuses on alleviating the symptoms brought on by the body's immunologic response to the bacteria.
Heart attacks are the major causes of unexpected, sudden death among men and women. A heart attack is also a significant cause of heart failure. Learn the risk factors for heart attack such as high blood pressure, diabetes, and other heart conditions. Lowering your risk factor, lifestyle changes, and in some cases medication are the most effective way of preventing a heart attack.
Stroke is the third leading killer in the United States. Some of the warning signs of stroke include sudden confusion, trouble seeing with one or both eyes, dizziness, loss of balance, and more. Stroke prevention and reatable risk factors for stroke include lowering high blood pressure, quit smoking, heart disease, diabetes control and prevention.
A chest X-ray is a radiology test that involves exposing the chest briefly to
radiation to produce an image of the chest and the internal organs of the chest.
An X-ray film is positioned against the body opposite the camera, which sends
out a very small dose of a radiation beam. As the radiation penetrates the body,
it is absorbed in varying amounts by different body tissues depending on the tissue's composition of air, water, blood, bone, or muscle. Bones, for
example, absorb much of the X-ray radiation while lung tissue (which is filled with
mostly air) absorbs very little, allowing most of the X-ray beam to pass through
the lung.
What is a shadow on a chest X-ray?
Due to the differences in their composition (and, therefore, varying degrees
of penetration of the X-ray beam), the lungs, heart, aorta, and bones of the
chest each can be distinctly visualized on the chest X-ray. The X-ray film
reco...
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