1 The way the heart works in a healthy person
The excitation of the heart of a healthy person starts from the sinus node, which sends out a rhythmic excitation (60~100 times/minute), and then the excitation is transmitted to the ventricles through the atria and atrioventricular node in turn, so that the whole heart contracts and diastole in a regular and coordinated manner, thus ensuring the pumping function of the heart to meet the needs of the body.
2. Atrial fibrillation
Atrial fibrillation, referred to as atrial fibrillation, is one of the most common clinical arrhythmias. The total prevalence of AF in the general population is 0.4%, and the prevalence of adults is between 0.5% and 0.95%, and the prevalence of those under 60 years old is 1%, with the increase of age, AF has a tendency to gradually increase, and it can reach 10% in people over 75 years old. Ni Weibing, Department of Cardiovascular Medicine, Nantong Hospital of Traditional Chinese Medicine
In atrial fibrillation, the direction of excitation conduction in the atria is inconsistent, and the frequency is fast and irregular, which makes the atria lose their effective contraction function. In atrial fibrillation, the frequency of atrial excitation is as high as 300-600 beats/min. Although the protective effect of the atrioventricular node prevents all these excitations from reaching the ventricles, the ventricular rate (heart rate) can still reach 100-160 beats/min, which is not only much faster than the normal sinus rhythm, but also the rhythm is absolutely irregular.
3. Causes or concomitant factors of atrial fibrillation
n Hypertension
n Coronary artery disease
n Cardiac surgery
n Valvular disease
n Chronic lung disease
n Heart failure
n Cardiomyopathy
n Congenital heart disease
n Pulmonary artery embolism
n Hyperthyroidism
n Pericarditis
n Combination of other types of arrhythmias
n Other: may be related to alcohol consumption, stress, electrolyte or metabolic imbalance, severe infection.
4. Clinical manifestations of atrial fibrillation
n Palpitations DD feeling of heartbeat, disturbed heartbeat or rapid heartbeat
n Physical fatigue or exertion
n Dizziness DD dizziness or fainting
n Chest discomfort DD pain, pressure or discomfort
n Shortness of breath DD Feeling breathless during light physical activity or at rest
n Although some patients may not have any symptoms, the danger is still there! (complications of thromboembolism)
5. Major risks of AF
n Thrombosis and embolism: Atrial fibrillation causes loss of contraction of the atria, and blood is easily stagnated in the atria and forms thrombi, which can be dislodged with the blood to all parts of the body, leading to cerebral embolism (stroke, hemiplegia), arterial embolism of the limbs (even amputation in severe cases), etc. The annual incidence of stroke is about 1% in patients with atrial fibrillation who are younger than 60 years old without other diseases, and 2% in patients who are 60 to 75 years old or older. In the presence of other embolic risk factors, the annual incidence of stroke can be as high as 4%. Risk factors for stroke in patients with atrial fibrillation include a history of previous embolism, hypertension, diabetes, coronary artery disease, heart failure, left atrial enlargement, and age over 65 years.
n Rapid heart rate and irregular rhythm can cause palpitations in patients.
n Loss of atrial systolic function and prolonged increase in heart rate can lead to heart failure.
n Increased mortality (twice as high as normal).
6. Diagnosis of atrial fibrillation
The initial diagnosis of atrial fibrillation can be made based on clinical symptoms and signs, but confirming the diagnosis requires an electrocardiogram, which is simple and easy to perform. For transient episodes of atrial fibrillation, tests such as ambulatory electrocardiography are required.
7. Treatment of atrial fibrillation
n Drug therapy
1. anticoagulation therapy (to prevent thromboembolic complications)
2. antiarrhythmic therapy (to revert sinus rhythm or control ventricular rate)
n Major non-pharmacological treatments
1. electrical cardioversion (conversion of sinus rhythm)
2. radiofrequency ablation therapy (complete cure of atrial fibrillation)
3. occlusion of the left ear (to prevent thromboembolic complications)
8. Objectives of atrial fibrillation treatment
n Restoration of sinus rhythm: the best outcome of AF treatment. Complete treatment of AF can only be achieved if sinus rhythm (i.e., normal heart rhythm) is restored; therefore, treatment to restore sinus rhythm should be attempted in any patient with AF.
n Control of rapid ventricular rate: For patients with atrial fibrillation who cannot regain sinus rhythm, medications can be used to slow down the faster ventricular rate.
n Prevention of thrombosis and stroke: In atrial fibrillation, anticoagulants can be applied to prevent thrombosis and stroke if sinus rhythm cannot be restored.
9. Methods of radical treatment of atrial fibrillation and their advantages and disadvantages
n Atrial fibrillation can be cured.
The current methods for the radical treatment of atrial fibrillation are catheter ablation therapy and surgical maze surgery.
Catheter ablation is suitable for most patients with atrial fibrillation. It is minimally invasive and easily accepted by the patient.
Surgical maze surgery is currently used for patients with atrial fibrillation who require cardiac surgery for other heart conditions.
Atrial fibrillation may disappear on its own or may persist after the cause is removed in certain diseases such as hyperthyroidism, acute moderate alcohol, or medications.
10. Anticoagulation in atrial fibrillation
Stroke is one of the greatest risks of atrial fibrillation. The incidence of stroke is 5.6 times higher in patients with non-valvular AF and 17.6 times higher in patients with valvular AF; moreover, the consequences of stroke caused by AF are more serious, with a disability rate of about 25% and a mortality rate of 25%. Anticoagulation or antiplatelet therapy (commonly known as hemodilution) drugs such as warfarin can reduce the risk of blood clotting and prevent strokes. Warfarin reduces the risk of stroke in patients with atrial fibrillation (by 2/3). When warfarin is administered, regular blood tests should be performed to ensure that the blood is diluted to a safe and effective level. Some patients who cannot tolerate warfarin may be treated with aspirin or may undergo occlusion of the left ear.
11. Advantages and disadvantages of anticoagulation therapy
Anticoagulation is necessary to prevent thrombosis and embolism in patients with atrial fibrillation, and the risk of stroke is reduced by 68% with warfarin anticoagulation.
Anticoagulation is only a preventive treatment for the risk of thromboembolism in atrial fibrillation. It does not eliminate atrial fibrillation and therefore does not improve clinical symptoms such as palpitations, weakness, or heart failure.
n Anticoagulant therapy has an increased risk of bleeding.
Long-term use of warfarin requires INR testing, and many patients do not adhere to it for long periods of time.
n The effect of warfarin is easily influenced by other drugs or diet, making dose adjustment difficult to control.
12. Patients requiring anticoagulation therapy
Patients with atrial fibrillation should be treated with anticoagulation if they have one of the following conditions and are also at high risk of being considered for radical catheter ablation.
n Age ≥ 65 years
n A history of previous stroke or transient ischemic attack
n Congestive heart failure
n Hypertension
n Diabetes mellitus
n Coronary artery disease
n Enlarged left atrium
n Echocardiographic findings of left atrial thrombus
n ……
13. Anticoagulation therapy needs to be performed under testing
Anticoagulation strength testing must be supervised by a specialist:
n Over-anticoagulation may lead to bleeding
n Inadequate anticoagulation has no preventive effect
n Warfarin efficacy is influenced by many factors (especially the drug) and varies greatly among individuals
14. methods, effects and general indications of resuscitation therapy
Resuscitation is a method of restoring the patient to sinus rhythm from atrial fibrillation. It includes both pharmacological and electrical resuscitation methods. Pharmacological resuscitation is the application of oral drug therapy to restore sinus rhythm. Electrical resuscitation is a method of restoring sinus rhythm by using two electrode pads placed in the appropriate part of the patient’s chest and distributing current through a defibrillator. Electrical resuscitation is indicated for
n Atrial fibrillation in combination with other emergencies; such as myocardial infarction, extremely rapid heart rate, hypotension, angina pectoris, heart failure, etc.
n Atrial fibrillation with severe symptoms that are difficult for the patient to tolerate.
Atrial fibrillation that has been successfully resuscitated without drug maintenance and has recurred.
Atrial fibrillation is not a cure for atrial fibrillation. Patients often have recurrences of atrial fibrillation, and some patients need to continue taking antiarrhythmic drugs to maintain sinus rhythm.
The immediate success rate of electrical resuscitation of atrial fibrillation ranges from 86% to 94%, while the success rate of pharmacological resuscitation is lower than that of electrical resuscitation, ranging from 70% to 80% for newly developed atrial fibrillation to less than 50% for other patients. Many patients require medications to maintain sinus rhythm after resuscitation. The rate of sinus rhythm maintenance is about 23% after 1 year and 16% after 2 years in patients who are not maintained with medication after resuscitation; the rate of sinus rhythm maintenance is 40% and 33% after 1 and 2 years, respectively, when medication is added to maintain sinus rhythm.
The side effects of antiarrhythmic drugs used to maintain sinus rhythm are significant. Amiodarone, for example, is associated with 12% of discontinuations due to intolerable side effects, 2% of new arrhythmias, 8.4% of thyroid function abnormalities, and pulmonary fibrosis.
15. What is catheter-based radical therapy for atrial fibrillation?
The vast majority of patients have atrial fibrillation associated with the pulmonary veins, so catheter ablation for the radical treatment of atrial fibrillation is performed mainly in the left atrium around the pulmonary veins. This method uses special catheters inserted through the veins into the heart, and these catheters are then delivered to the pulmonary veins to deliver radiofrequency or other energy sources to eradicate atrial fibrillation.
16. Anatomical location of the pulmonary veins DDD posterior wall of the left atrium
17. Effectiveness and safety of radical treatment with atrial fibrillation catheters
n At present, in large treatment centers in Europe and the United States, catheter-based radical treatment of atrial fibrillation has become a routine method of atrial fibrillation treatment, with a success rate of 80-90%.
n Catheter ablation of atrial fibrillation in China began in 1998, and the success rate at recent follow-up is 70% for single ablation and 80-90% for two or more ablations
n Catheterization for atrial fibrillation is a complex procedure and should be performed at an experienced treatment center whenever possible
Similar to any other human procedure, catheterization for atrial fibrillation is not completely safe, but safety is assured at experienced centers
The main indications for radical catheterization of atrial fibrillation are
n Paroxysmal atrial fibrillation with frequent episodes and severe symptoms
persistent or chronic atrial fibrillation with severe symptoms
n Patients with asymptomatic atrial fibrillation with thromboembolic risk factors
Catheter ablation is currently used in most patients with atrial fibrillation in advanced medical centers abroad
20. Indications for left-ear occlusion
The left ear is the main site of thrombus formation in patients with atrial fibrillation, and left ear occlusion can prevent thrombus formation and embolic complications in atrial fibrillation. This technique is mainly used in patients who are unable to maintain sinus rhythm. In patients for whom warfarin anticoagulation is contraindicated, who cannot tolerate warfarin anticoagulation, or who cannot adhere to warfarin anticoagulation for long periods of time, left-ear occlusion can be used to prevent thrombosis and embolism.
21. Precautions in the life of patients with atrial fibrillation
n Quit smoking
n Limit alcohol consumption
n Limit or eliminate caffeine; some patients may need to avoid caffeine-containing substances such as tea, coffee, cola, and some over-the-counter medications
n Use caution with certain cough or cold medications, which may contain stimulants that may promote irregular heart rhythms; ask your doctor or read the instructions before taking them to see if they are right for you
The main methods currently used for the ablation of atrial fibrillation are
n Usually guided by a 3-D scaler system
n Ablation is performed around the pulmonary veins (dark red dots in the upper image and brown dots in the lower image are ablation lines)
n Some patients may require ablation of other areas (e.g., the left and right atrial isthmus and the top of the left atrium)
The procedure usually takes about 3 hours.
n Post-operative skin puncture sites are usually bandaged with pressure for 4 hours and bed rest for 6 hours
23. Preoperative preparation
Informed consent from you and your relatives
Esophageal ultrasound to rule out atrial thrombosis
Transthoracic ultrasound to determine the anatomy and function of the heart
n Pre-operative discontinuation and replacement with low molecular heparin for those taking warfarin
n General blood biochemical examination
24. Postoperative follow-up
n In addition to your usual basic medications, you will need to take an antiarrhythmic medication (probably one of the following, depending on your condition) for the first 3 months after catheter ablation.
In addition, the presence of postoperative atrial muscle stenosis may not restore atrial function immediately, and there is still a risk of thrombus formation, so you will need to take the anticoagulant drug warfarin. The anticoagulant drug warfarin can only be discontinued one month after discontinuation of the antiarrhythmic drug after the absence of atrial fibrillation has been confirmed by ambulatory electrocardiogram and conscious symptoms, otherwise you need to contact us promptly to determine whether to continue it.
A follow-up echocardiogram is required three months after surgery to determine whether atrial function has fully recovered and whether the left atrial diameter has decreased.
n
An ambulatory electrocardiogram (Holter) will be performed once a month for the first three months after surgery to determine the status of AF treatment.
25. Postoperative antiarrhythmic drug use
n The electrical disturbances in the atria may not return to normal immediately after surgery, and antiarrhythmic drugs are taken to speed up the return of normal electrical activity. Because different patients can receive different medications, we often ask you to take one of the following medications
l Codarone (Amiodarone)
This drug is preferred if tolerated or if there are no contraindications.
Dosage: first week 200mg (1 tablet) 3 times a day
Week 2 200mg (1 tablet) twice daily
Week 3 200mg (1 tablet) once daily
Thereafter, take 1 tablet daily until we ask you to stop
l Heart Rhythm
Dosage: 150mg per dose (150mg per tablet for the imported formulation of Eflornithine, 1 tablet is sufficient.
(for domestic products, 50mg per tablet, 3 tablets are needed), 3 times daily
Sotarolol
80mg (1 tablet) each time, 2 times a day
n Side effects
l Common side effects
These arrhythmogenic effects may be slowed heart rate (less than 50 beats/minute), conduction block, premature beats, ventricular tachycardia, or even ventricular fibrillation. If you are also taking diuretics, these arrhythmias are likely to occur in the presence of electrolyte disturbances.
Hypotension
Side effects specific to cortarone
Common thyroid function abnormalities (hyperthyroidism or hypothyroidism)
Eye photosensitivity
Pulmonary fibrosis can be caused by long-term higher doses, which is rare in China
n Precautions
l Thyroid function needs to be checked after 2 months of use and every 2 to 3 months thereafter.
ECG should be checked if a slowed heart rate (less than 50 beats/minute) and lower blood pressure are observed, which may lead to increased dizziness and fatigue
Because of the effect of antiarrhythmic drugs on the ECG, the ECG should be checked at least once a month, even if there is no discomfort.
If you experience any side effects or if your symptoms worsen as a result of the medication, you should stop taking the medication and see your doctor promptly to determine the cause before deciding whether to continue or reduce the dosage
l
26. Post-operative anticoagulant use
The effect of warfarin therapy needs to be confirmed by blood tests. Since the response of the drug varies greatly from one individual to another, several blood draws may be required at the beginning of the dosing period to find the right dose for you. The appropriate anticoagulant strength of warfarin is a blood INR (International Normal Ratio in Chinese) of 1.8 to 2.5. Adjust the dose of warfarin as follows.
1. blood tests should be taken after the 3rd day, 1 week and 10 days of dosing, and if the INR reaches the standard, it should be checked again after the 20th day and 1 month, and if it still reaches the standard, it should be checked once a month thereafter.
2. If the INR does not reach the standard (INR below 1.8 or above 3.0), you need to adjust the dose (increase or decrease) as recommended by your doctor, and repeat the first monitoring protocol above after each dose adjustment until the INR reaches the standard.
3. The efficacy of warfarin is influenced by a variety of medications and foods, so when your diet composition changes significantly or other therapeutic medications are adjusted (often with the addition of antibiotics or sedative-hypnotic drugs), the INR may be affected, which in turn may affect the anticoagulant effect of warfarin. In this case you need to contact your doctor promptly and initiate a blood draw to check the INR value. However, the adjusted dose of warfarin in the context of the same diet and medication is reliable and the drug is safe within the therapeutic dose. Sometimes a high INR value (more than 3) may cause bleeding complications, commonly bleeding from the skin and mucous membranes. In case of bleeding complications you need to stop the drug immediately, take blood for INR and readjust the dosage of warfarin (reduce the dosage).
Remember to tell your treating physician that you are using warfarin if you are undergoing surgery for other reasons.
Multiple blood draws may be inconvenient for you, but the proper dose of warfarin treatment is necessary and safe!
Email: [email protected]
Tel: 0513-85126128