(1) Flutter. Flutter is a very rapid heart rate with rhythm present. Usually
the heart rate is much faster than in simple tachycardia (between 200 to 400 beats per
minute).
(2) Fibrillation. Fibrillation is a term which refers to an extremely rapid
heart rate with no rhythm. This condition is treated with an electric defibrillator that
reverses fibrillation with the use of an electric shock.
d. Angina Pectoris. Angina pectoris is an acute condition in which one or
more of the coronary arteries becomes blocked. A sharp burning pain in the chest that
may be felt also in the neck and left arm characterizes angina. The coronary arteries
may become partially occluded (closed) by an embolism or thrombus, or a simple
increase in oxygen demand when exercising, but is usually attributed to be a result of
atherosclerotic obstruction of the coronary arteries. The heart muscle cells are thus
deprived of oxygen because of the decreased flow of blood and death of the myocardial
cells may result if the condition is not remedied. Acute management of angina pectoris
is usually achieved with the use of a rapid acting vasodilator such as nitroglycerin or
amyl nitrite.
e. Myocardial Infarction. A myocardial infarction is similar to angina pectoris,
but it is usually more serious. During angina pectoris the coronary arteries are usually
only partially blocked; however, during a myocardial infarction complete blockage of one
of the coronary arteries results. The symptoms are essentially the same as angina
pectoris, but are not usually relieved by vasodilators. Complete bed rest is essential for
the patient. Death of cardiac muscle cells often results unless another vessel is able to
carry blood to the affected area.
f. Congestive Heart Failure. Congestive heart failure is defined as a
decrease in the efficiency of the pumping of the heart. This condition usually leads to
pulmonary edema, a complication attributed to the fluid back up. Because of decreased
blood flow, there is a decrease in renal circulation that can further aggravate the
associated edema because of both decreased glomerular filtration rate and increased
sodium retention. Vasodilators that belong to a class of drugs called Angiotensin
Converting Enzyme Inhibitors (ACE inhibitors) are the first line drug of choice for
treatment of congestive heart failure. If a patient cannot tolerate ACE inhibitors, they
may be placed on a nitrate (Isordil) and hydralazine instead. As heart failure worsens
and edema increases, diuretics are used to decrease edema. Digitalis glycosides
(digoxin) used to be the drug of choice for heart failure, however due to many drug-drug
interactions and narrow therapeutic index, it is reserved for acute symptomatic heart
failure or in patients with heart failure and atrial fibrillation. Digoxin works by increasing
the efficiency of the heart as a pump by decreasing both the size of the heart and the
rate of the heart while at the same time increasing the force of contraction. As heart
failure worsens, treatment may involve the addition of beta-adrenergic blockers
(carvedilol, metoprolol) and spironolactone (potassium-sparing diuretic).
MD0806
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