Showing posts with label amiodarone. Show all posts
Showing posts with label amiodarone. Show all posts

Saturday, September 29, 2012

Fibrillation of the heart

Fibrillation of the heart

In the next part of the article we will discuss about fibrillation of the heart, one type of irregular heart rate and what are the consequences for our body. Our heart is an organ that has a so called „automatism”, an intrinsic property of the cardiac tissue to create its own electric impulse, a signal that allows changes in cell metabolism in order to generate cardiac muscle contraction and therefore pumping blood into the arteries. This electric signal is generated in the sinus node (a structure capable of generating electric signal, located in right atrium) and then conducted through special structures until it reaches the ventricles (heart chambers that pump blood into the arteries). If these structures called pacemakers, can’t function normally, irregular heart rate occurs and one of them is fibrillation of the heart.

 What is fibrillation of the heart ?

What is fibrillation of the heart? And how many types of fibrillation of the heart exist? There are two types of fibrillation of the heart: one is called atrial fibrillation and another ventricular fibrillation. The difference between these types of fibrillation of the heart is not just in name, but also in origin and prognostic. The first type of fibrillation of the heart-the atrial fibrillation-is an irregular heart rate generated in multiple atrial cells (but not in the sinus node which is the „natural” heart pacemaker).
Patients with atrial fibrillation may experience palpitations, shortness of breath, chest pain, dizziness, drowsiness, fainting, but there are some patients that don’t complain of any symptom and they are diagnosed with the occasion of a routine medical check or when the complications occur. Usually, atrial fibrillation allows blood clots to form and they can flow in the arteries and block them, causing a condition known as ischemia: the tissues won’t receive enough blood and oxygen and cells start to die. In this situation, strokes, pulmonary embolism (clots in the pulmonary arteries that can lead to death), limbs ischemia (if untreated it can lead to amputation) can occur and can lead to patient’s death, if immediate  measures aren’t taken. On the electrocardiogram, in atrial fibrillation there is an irregular heart rate, without „P” waves (which are a mark of  heart rate generated by the sinus node) and the frequency of the heart beats can vary: low, average or rapid.
If this arrhythmia was discovered at its beginning, a conversion to the normal heart rate called sinus rhythm can be tried (either using medication or with electric shocks). After this procedure succeeded, other medication is needed in order to maintain the normal heart rate, to control the normal frequency of the heart beats and prevent blood clotting. In some patients, when the beginning of this arrhythmia is unknown, doctors will use only drugs to control the heart rate (beta blockers like metoprolole, atenolol; digoxin-a drug that increases heart contractility and also has antuarrthymic properties, very often used in the treatment of atrial fibrillation, calcium channel blockers like amlodipine, verapamil, diltiazem) and prevent blood clotting. Atrial fibrillation associated with rapid heart rate can be a severe medical condition affecting the level of consciousness and the only way to save patient life is the electrical conversion to the sinus rhythm using electric shocks.
The other type of fibrillation of the heart-ventricular fibrillation is an irregular heart rate generated in the ventricular cells and is not compatible with life, meaning that is one of the heart rate that generates cardiac arrest. Heart stops from beating and emergency measures of resuscitation are needed-cardiac massage alternating with artificial oxygenation of lungs, using facial masks with balloons or orotracheal intubation (which is preferred if it is possible to perform), electric shocks, specific medication like adrenaline, vasopressin, amiodarone. If in 30-45 minutes all these maneuvers are unsuccessfully, then the patient is declared dead.

As we saw above, fibrillation of the heart is a major heart disorder, that requires  special attention, knowledge, maneuvers and skills, since ventricular fibrillation is the most frequent cause of cardiac arrest in adults.


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