Do you think you know enough about cardiac rhythm disorders? Well, if you want to become a mother, you`ll start hearing lots of heartbeats really soon, so you may want to find out more about the heart and its disorders.
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About the Heart
The heart, the pump that ensures the blood circulation in the organism, is a muscle organ, empty on the inside, consisting of 4 different cavities, 2 superior ones (atria) and 2 inferior ones (ventricles). Each atrium communicate with the ventricle on its same side through a hole provided with valves that have the function of flaps, allowing the blood circulation in a unique direction, namely from the atria to the ventricles. The hole from the left side has 2 valves, and the one from the right side has 3 valves.
The right atrium receives blood through veins that is poor in oxygen, and which comes back from the organs to the heart and directs it towards the right ventricle. This sends the blood in the lungs where oxygenates before traversing the left atrium to be directed in the left ventricle. The left ventricle, being more voluminous, pumps the blood in the arteries and, from here in the entire body.
For the heart to pump blood as efficiently as possible, the billions of cells from the superior chambers and ventricles need to contract simultaneously. This particular coordination is triggered by an electrical impulse. These actions are directed by the sinus node, located in the right atrium. From there, the electrical current passes from one cell to another until the atrioventricular node, located at the junction between atria and ventricles. Passing this node, the electrical impulse, rapidly excites the entire cells of the ventricles through a network known as the His-Purkinje system.
The heart`s electrical activity can be recorded using the electrocardiogram (ECG) to see if it`s synchronized. The electrocardiogram carries out a 3-way trajectory: P wave track corresponds to the contractions of atria, QRS wave path corresponds to the ventricular contractions, and the T wave path which reflects the regeneration of the heart cells. Between the beats, the electrical system is recharged just as the heart muscle, which between 2 contractions, relaxes and fill with blood again.
Therefore, each contraction of the heart is triggered electrically. The process of this phenomenon being repeated leads to a single result: heart rate. The sinus node is the one that gives a measure to this rhythm. It has the propriety of adapting the cadence to the body`s needs through its sensitivity to the stimulation of the nervous system and hormones (e.g. adrenaline). So, it accelerates the heart beats during an effort or during an emotion and slows it down during rest.
So, the pump function of the heart is maintained by its electrical system which ensures the contraction of the heart muscle in a certain order.
The electrical impulse that initiates the contraction starts in the sinoatrial node, the heart`s natural peacemaker. The electrical signal from the sinoatrial node passes the 2 atria, then reaches the atrioventricular node to finally spread into the 2 ventricles.
There`s a network of nervous threads around the heart that signals its necessity of beating slower or faster.
Cardiac rhythm disorders are caused by issues of this electrical system. Sometimes, the electrical system are driven too slowly or aren`t able to cross this electrical system at all.
Some the causes are:
- Valvular lesions.
- Respiratory failure.
- Drinking alcohol or tobacco.
- Ischemic heart illness.
- Hydroelectrolytic imbalances.
Some disorders are more serious than other ones. Sometimes, there`s a vicious circle between the heart`s function and the abnormal rhythm. Therefore, a weak heart can be the cause of the disorder, but the disorder itself can lead to the heart`s weakening. – Read more!
It`s not really mandatory for cardiac rhythm disorders to show any signs. Still, you shouldn`t let unnoticed any possible rapid heartbeats (tachycardia), slow heartbeats (bradicardia), tiredness, chest pains, general sensation of weakness, sweating, breathing difficulties, dizziness or fainting,. These signs of weakness or tiredness can occur due to the acceleration of heart rate, reason for which the blood pressure is diminished.
Types of Cardiac Rhythm Disorders
Extrasystoles can occur in any healthy person. Only if they are frequent, we can talk about arrhythmia. Arrhythmias are categorized depending on the place of formation and depending on the effects of the heart rate. As mentioned above, when the heart rhythm is accelerated, it`s know as tachycardia, and bradicardia when it`s slow.
High blood pressure leads to premature contraction and retardation of atria. Supraventricular extrasystole might also be caused by weakness in the heart muscle. – Click this link!
- Sinus tachycardia (heart rhythm – 90-120/min);
- Sinus bradycardia (heart rhythm below 60/min).
- In both, the normal focus of heart impulses is kept: the sinus node.
They have their origins at the atria level:
- Atrial extrasistles – ectopic pulses;
- Atrial paroxysmal tachycardia (regular frequency 140-220/min);
- Atrial fibrillation & atrial flutter (irregular rhythm disorders).
- Ventricular extrasystole – it occurs due to an irritating ventricular region which is no longer synchronized with the heart block. The causes may involve: emotion, an infection, an imbalance in retaining mineral salts (excessive consumption of laxatives) or fever. In these cases, arrhythmia is considered benign, but its occurrence along with a heart illness may reveal an issue that requires treatment.
- Ventricular paroxysmal tachycardia – generally, it`s the manifestation of a major heart muscle dysfunction. It may appear at any age, but it`s usually the result of a myocardial infarction. There`s a desynchronization between the atrial contraction and the beats of the ventricles, the consequence being a decreased cardiac output. Hospitalization is necessary due to the heart`s weakening.
- Fibrillation & ventricular flutter.
Atrial Paroxysmal Tachycardia
During tachycardia, the heart contracts suddenly and starts beating fast, up to 140 – 220 beats per minute. These episodes can last a few seconds or a few hours. They stop just as suddenly as they occurred. Paroxysmal tachycardias can occur from youth and can last the entire life. After the crisis, the patient feels tired, but this type of arrhythmia is quite rarely dangerous. Still, it requires the consultation of a doctor, because it may diminish the quality of life.
Atrial Fibrilation & Atrial Flutter
It`s a serious issue which needs medical consultations and treatment, the cause being an “electrical storm” at the atrium level. The coordinated contraction of atria no longer occurs. The heart loses around 20% of its capacity. The ventricle can compensate for the moment this loss, but on the long term, its exhaustion may lead to heart failure. The states felt come from the pulse`s irregularity due to the fact that the ventricles are no longer trained by the sinus node, the pulse having sometimes high values of 140 beats per minute and even more, and sometimes very low of 50 beats per minute, causing dizziness. – Learn more!
A complication of atrial fibrillation consists in the dilation of the atria. The blood which stagnates in them may clot. The passage of such a mass of coagulated blood into the circulation may lead to embolus.
Atrial fibrillation might appear after fever as well. When this arrhythmia is the consequence of a heart disease, the treatment will address to this illness. Fibrilation might occur in a over-consumption of alcohol or thyroid illness as well.
The doctor will listen to your heart and take your pulse. Your tension may be high or low. He may identify the heart`s arrhythmias and their substrate by performing the following tests: holter outpatient monitoring, coronarography, EKG, echocardiography, electrophysiological studies.
When the cardiac rhythm disorder is serious and life-threatening, you may need emergency treatment to restore the normal rhythm of your heart. This treatment may consist of the intravenous administration of antiarrhythmic medications, the application of an external electrical shock or the implantation of a pacemaker for a temporary period of time.
The preventing of recurrence of arrhythmias is performed by treating the illness that generated the arrhythmia or by administering antiarrhythmic medications. They may also have side effects, like pro-arrhythmic effects.
Ablation represents an invasive technique which destroys regions in the heart which cause some of these disorders.
When arrhythmia is considered life-threatening, there`s an intracardiac defibrillator implanted that discharges an electrical impulse in order to initiate arrhythmia.
The peacemaker is implanted when the heartbeats are too rare. Sometimes, the peacemaker is used to stop a fast or irregular rhythm disorder.
The prognosis of arrhythmias usually depends on a few factors: the existence of concomitant cardiac illness, the type of the disorder, the pump function of the heart appreciated by the ejection fraction.