acute atrial fibrillation attack refers to the first attack of atrial fibrillation. During paroxysmal atrial fibrillation and persistent or permanent atrial fibrillation with rapid ventricular rate and/or symptom exacerbation, patients often experience sudden and significant aggravation of symptoms due to rapid and irregular ventricular rate, requiring urgent intervention< span>.
Strategies and procedures for emergency management of atrial fibrillation
Acute atrial fibrillation is firstly divided into two categories, hemodynamically unstable and hemodynamically stable, according to whether the vital signs are stable or not. . Hemodynamically unstable atrial fibrillation should be terminated as soon as possible and converted to sinus rhythm; hemodynamically stable atrial fibrillation should be based on the duration of atrial fibrillation onset, the severity of symptoms, the risk of stroke, and the underlying heart disease. Different treatment strategies are adopted to relieve symptoms, improve prognosis, and reduce the occurrence of cardiovascular events.
Figure 1 Flow chart of emergency atrial fibrillation cardioversion
Hemodynamically unstable acute atrial fibrillation
hemodynamically unstable The definition of stable atrial fibrillation: ①systolic blood pressure <90 mmHg, and the performance of hypoperfusion, such as restlessness, restlessness, dullness, clammy skin, decreased urine output (<20 ml/h), etc.;< /span>②pulmonary edema;③myocardial ischemia (chest pain and/or electrocardiographic manifestations of acute ischemia).
For hemodynamically unstable atrial fibrillation, the primary task is to convert sinus rhythm. If there are no contraindications, synchronous direct current cardioversion should be given immediately (I, B). For atrial fibrillation complicated with pre-excitation syndrome, if the ventricular rate is >200 beats/min, emergency synchronized cardioversion is recommended; if the ventricular rate reaches 250 beats/min, immediate synchronized cardioversion is recommended. Therapeutic amount of unfractionated heparin or low molecular weight heparin should be administered immediately before electrical cardioversion for anticoagulation; Molecular weight heparin (I, C). Except for low-risk stroke patients with atrial fibrillation duration < 24 hours, oral anticoagulant therapy should be continued for 4 weeks after electrical cardioversion, preferably NOAC; and then whether long-term oral anticoagulation therapy is required based on CHA₂DS₂-VASc risk assessment ( I, A). Persistent atrial fibrillation or unsuccessful electrical cardioversion can be given a drug to convert atrial fibrillation and then cardioverted again.
Hemodynamically stable acute atrial fibrillation
For hemodynamically stable acute atrial fibrillation, the risk of thromboembolism should be evaluated first, and the time to start anticoagulation and whether long-term anticoagulation should be determined; For qualitative heart disease, decide whether to control the ventricular rate; finally decide whether to cardioversion, the time and method of cardioversion, and the prevention of recurrence of atrial fibrillation after cardioversion. 1. Anticoagulation therapyfor patients with paroxysmal atrial fibrillation/attack duration ≥48 h, or for patients with unclear duration of atrial fibrillation/atrial flutter Cardioversion was performed after 3 weeks of effective anticoagulation therapy (I, B); or cardioversion was performed after atrial thrombus was excluded by TEE examination at the same time as anticoagulation therapy (I, B). Routine anticoagulation was given for 4 weeks after cardioversion, and long-term anticoagulation was determined according to the CHA₂DS₂-VASc score. For patients with acute atrial fibrillation at high risk of stroke, if the duration of atrial fibrillation is ≥12 h, anticoagulation therapy is required for 3 weeks before conversion to atrial fibrillation, and long-term anticoagulation therapy is required after conversion. For patients with acute atrial fibrillation at low and intermediate risk of stroke, anticoagulation therapy should be initiated for the duration of atrial fibrillation episodes ≥ 24 hours to prepare for subsequent cardioversion of atrial fibrillation. Continue anticoagulation for 4 weeks. For patients at intermediate risk of stroke, continuation of long-term anticoagulation therapy will be considered. For patients with low risk of stroke, if the duration of atrial fibrillation is less than 24 hours, anticoagulation can be avoided after cardioversion of atrial fibrillation. OAC is preferably NOAC (I, A). Low molecular weight heparin combined with oral warfarin can also be used. After warfarin anticoagulation takes effect, it is gradually transitioned to oral warfarin alone. 2. Ventricular rate controlIf there is atrial fibrillation with rapid ventricular rate and obvious symptoms, the ventricular rate should be controlled first to relieve symptoms, and then other treatment strategies should be considered in a timely manner Machine (I, B). At present, it is recommended to choose loose ventricular rate control, that is, the target value of the resting ventricular rate is ≤100 beats/min or the ventricular rate when walking is ≤110 beats/min. If the symptoms are not relieved, strict ventricular rate control, that is, resting Ventricular rate <80 beats/min. In terms of drug selection, patients without cardiac insufficiency can choose intravenous beta-blockers (metoprolol, esmolol, etc.), non-dihydropyridine calcium channel blockers (vitamin) Lapamil, diltiazem, etc.); patients with chronic heart failure can choose a combination of low-dose beta-blockers or digitalis preparations (euroside C, etc.).
Intravenous preparations are mainly used in acute attacks of atrial fibrillation, with fast onset and positive effects. Once the ventricular rate is controlled, oral preparations should be used promptly to prevent rapid ventricular rate repeatsattack. Ventricular rate control does not improve long-term cardiac remodeling. After ventricular rate control in acute atrial fibrillation, cardioversion and maintenance of sinus rhythm can be considered according to the condition and the patient’s wishes, or continuous oral medication can be used to control the ventricular rate. When atrial fibrillation is combined with pre-excitation syndrome, β-blockers, calcium channel blockers and digitalis cannot be used to control the ventricular rate, and amiodarone has not been recommended in recent years. In such patients, electrical cardioversion should be considered as soon as possible. 3. Rhythm controlrhythm control can improve symptoms, and early rhythm control may improve prognosis (I, B). (1) Indications for cardioversionSevere symptoms of atrial fibrillation, significant heart failure, angina pectoris, long-term anticoagulation contraindications Cardioversion and sinus rhythm maintenance should be selected for patients who are unsatisfactory with ventricular rate control or for patients with unsatisfactory ventricular rate control effects; cardioversion therapy may be considered for patients with new onset atrial fibrillation, young patients, and patients whose symptoms are still obvious after ventricular rate control; pre-excitation syndrome Or pregnancy complicated with atrial fibrillation should give priority to cardioversion therapy; for atrial fibrillation with paroxysmal atrial fibrillation onset time <48 h and atrial fibrillation diagnosis <1 year with cardiovascular risk, cardioversion therapy can be considered according to the condition and the patient's wishes. (2) The best time for cardioversionConsidering the risk of thrombosis, it is often clinically characterized by persistent atrial fibrillation Time < 48 h was regarded as the time node for immediate cardioversion. Because atrial fibrillation lasts ≥48 hours, there is a possibility of thrombosis in the atrium, and cardioversion must be performed after 3 weeks of effective anticoagulation therapy or after exclusion of atrial thrombosis by TEE examination. The onset time of atrial fibrillation is less than 12 hours, and the ventricular rate should be controlled first to relieve symptoms; the onset time of atrial fibrillation in high-risk stroke risk patients is ≥12 hours, and the onset time of atrial fibrillation in patients with medium and low risk of stroke risk is ≥24 hours , anticoagulation therapy should be started to prepare for the subsequent cardioversion of atrial fibrillation or an extension of the cardioversion time window (≥48 h), and a “wait and see” strategy can be adopted (atrial fibrillation may be self-converted within 24 hours); If the duration of atrial fibrillation is ≥ 24 hours, cardioversion of atrial fibrillation can be initiated because it takes a certain amount of time for atrial fibrillation drug cardioversion to take effect. In summary, for acute atrial fibrillation or newly developed atrial fibrillation, the optimal timing of cardioversion may be 24-48 hours. (3) Cardioversion methodElectrical cardioversion terminates atrial fibrillation quickly and has a high success rate. In the emergency room, the success rate of electrical cardioversion is about 90%, and the success rate of drug cardioversion is 50% to 60%. ①Electrical cardioversionElectrical cardioversion can be used for paroxysmal atrial with poor ventricular rate control or obvious symptoms tremor patients. In patients with severe angina pectoris, myocardial infarction, and heart failure, electrical cardioversion should be synchronized immediately. Contraindications to electrical cardioversion are digitalis intoxication and severe hypokalemia. Addition of AAD before electrical cardioversion can improve the success rate of cardioversion, such as amiodarone, propafenone, ibutilide, sotalol, flecainide, etc. In addition, ventricular rate-controlling drugs such as beta-blockers, diltiazem, or verapamil may also be administered before electrical cardioversion. ②Drug cardioversionFor atrial fibrillation within 7 days of onset, drug cardioversion is effective. Commonly used drugs are class Ic drug propafenone, class III drugs dofetilide and ibutilide. After cardioversion of acute atrial fibrillation, timely transition to oral drugs to maintain sinus rhythm according to the situation can prevent or reduce the recurrence of atrial fibrillation.
Bibliography: Chinese Medical Association Electrophysiology and Pacing Branch, Professional Committee of Cardiology of Chinese Medical Doctor Association, Expert Working Committee of Atrial Fibrillation Prevention and Treatment of China Atrial Fibrillation Center Alliance. Atrial Fibrillation: Current Understanding and Treatment Recommendations (2021). Chinese Journal of Arrhythmia, 2022, 26(1): 15- 88.