What is a cardiac arrhythmia?
The cardiac conduction system consists of the special myocardium responsible for the formation and conduction of normal cardiac impulses. It includes the sinus node, inter-nodal bundle, atrioventricular node, Hitchcock’s bundle, left and right bundle branches, and Purkinje fibrous network. Arrhythmias are abnormalities in the frequency, rhythm, site of origin, conduction velocity or sequence of excitation of cardiac impulses. Arrhythmias can be classified into two categories: tachyarrhythmias and slow arrhythmias, depending on how fast or slow the heart rate is at the time the arrhythmia occurs.
What are the symptoms of arrhythmias?
Arrhythmias are common in people with heart disease of various causes, and a few types can be seen in normal people without organic heart disease. The clinical manifestation is a sudden onset of regular or irregular palpitations, chest pain, dizziness, anterior heart discomfort, stuffiness, shortness of breath, chills in the hands and feet, and even syncope. If you have the above symptoms, you must go to the hospital cardiovascular specialist in time to avoid delaying the disease.
What tests should be done for cardiac arrhythmia?
Electrocardiogram is the most important non-invasive technique to diagnose arrhythmias.
2, dynamic electrocardiography, also known as Holter ECG, uses a small portable recorder to continuously record the patient’s ECG for 24 hours, through 24 hours of continuous ECG recording may record the onset of arrhythmia, the patient’s daily work and activities are not restricted.
3.Exercise test can be performed to assist in the diagnosis of palpitations and other symptoms during exercise.
4.Esophageal ECG can record clear atrial potentials, and can perform rapid atrial pacing or programmed electrical stimulation. It is useful in establishing the diagnosis of supraventricular tachycardia, ventricular tachycardia, and pre-excitation syndrome, inducing and terminating tachycardia, and can assist in evaluating the efficacy of antiarrhythmic drugs. It is also used to evaluate the function of the sinus node.
Clinical cardiac electrophysiological examination is a method of arrhythmia research that uses a cardiac catheter to record the electrocardiogram of various parts of the heart and stimulates different parts of the myocardial tissue with pulsed electricity. This method can reflect the origin of the heart’s electrical activity and the sequence of excitation conduction very accurately, and is of great diagnostic and differential value for arrhythmias that are difficult to diagnose clinically or cannot be detected by other methods. The main indications for patients to undergo cardiac electrophysiological examination include: determination of sinus node function, atrioventricular and intraventricular conduction block, tachycardia and unexplained syncope.
6. Other tests: ventricular late potentials, ECG spectrum analysis, ventricular rate variability analysis, exercise ECG and tilt test are helpful in the diagnosis of complex or some specific arrhythmias. In addition, echocardiography, cardiac X-rays, ECT, CT and MRI are of great value in the diagnosis of organic and non-organic arrhythmias.
How are arrhythmias treated?
In addition to medication, arrhythmias can be treated with cardiac interventional procedures. Slow arrhythmias such as pathological sinus node syndrome and severe heart block can be treated with pacemaker implantation. Rapid arrhythmias such as paroxysmal supraventricular tachycardia, ventricular tachycardia, premature ventricular beats, and atrial fibrillation are treated with radiofrequency ablation. A cardioverter-defibrillator can be implanted in patients with recurrent ventricular tachycardia and ventricular fibrillation for which drug therapy has failed.
What is a pacemaker?
A pacemaker is a medical electronic device that stimulates the heart by distributing certain forms of electrical impulses to cause excitation and contraction, i.e., to mimic the formation and conduction of normal heart impulses, to cause heart contraction and to maintain pumping function. To treat cardiac dysfunction due to certain cardiac arrhythmias.
Clinical work is often divided according to the site of electrode lead implantation into.
① Single-chamber pacemakers;
② Double-chamber pacemakers;
(3) triple-chamber pacemakers. The former is used in patients with atrial block combined with paroxysmal atrial fibrillation to prevent and treat atrial fibrillation, while the latter is mainly used in certain cases of dilated cardiomyopathy, intractable heart failure to coordinate atrial and/or interventricular activity to improve cardiac function.
With the continuous research and development of new pacing technologies, the indications for pacemaker therapy have expanded from the treatment of slow arrhythmias to the treatment of various diseases, such as the prevention and treatment of atrial fibrillation and the prevention and treatment of malignant ventricular arrhythmias with long QT interval syndrome. In addition, pacemakers can also be used as an adjunct in the treatment of hypertrophic obstructive cardiomyopathy, dilated cardiomyopathy, intractable heart failure, and neurally mediated syncope.
What is an implantable cardioverter-defibrillator?
An implantable cardioverter-defibrillator (ICD) is a small automatic defibrillator implanted in the chest that is always on standby to deliver treatment when a fatal ventricular arrhythmia is detected, restoring the heart rhythm to normal.
What is radiofrequency ablation?
Radiofrequency electrical energy is a low voltage high frequency (30kHz ~ 1.5MHz ) electrical energy. Radiofrequency ablation instrument releases radiofrequency electrical energy through the electrode at the head of the catheter, and the electrical energy is converted into heat energy between the head of the catheter and the local myocardial endothelium, and after reaching a certain temperature (46 ℃ ~ 90 ℃), the specific local myocardial cells are dehydrated, degenerated and necrosed, and the autoregulation and conduction properties are changed, thus enabling the arrhythmia to be cured.
What arrhythmias can be treated by radiofrequency ablation?
① Pre-excitation syndrome with paroxysmal atrial fibrillation and rapid ventricular rate;
(2) Recurrent atrioventricular tachycardia, atrioventricular nodal tachycardia, atrial tachycardia and ventricular tachycardia without evidence of organic heart disease (idiopathic ventricular tachycardia);
③ Typical atrial flutter with frequent episodes and uncontrollable ventricular rate;
(iv) Atypical atrial flutter with frequent episodes and uncontrollable ventricular rate;
⑤ Ventricular tachycardia after myocardial infarction with frequent episodes and/or severe symptoms and poor prevention of episodes by drugs.
How is radiofrequency ablation performed?
A cardiac catheter electrode is first fed through the internal jugular or subclavian vein and bilateral femoral veins for electrophysiological examination to clarify the diagnosis and the location of the lesion to be ablated. Then, a special large-ended ablation catheter is used to reach the site of the lesion, and radiofrequency current is emitted for a short period of time. The radiofrequency current contacts the myocardial tissue and generates a local relative high temperature, which causes the local myocardial tissue to dry and necrotic, and the necrotic myocardial tissue no longer plays the role of conducting electrical signals, thus the arrhythmia is cured. The local damage caused by the radiofrequency current to the myocardium is very limited and does not affect the function of the heart. The procedure is completed after successful ablation is confirmed by intracardiac electrophysiological examination. The procedure is performed under local anesthesia and the patient is awake throughout the procedure and can tell the surgeon how he or she feels at any time. After the procedure is completed, most patients are able to move around the next day and are usually discharged in two to three days.