Emergency tachyarrhythmias can be divided into two categories based on the width of the QRS wave group, namely narrow QRS wave group (QRS wave group time frame ≤120ms) tachycardia and wide QRS wave group (QRS wave group time frame >120ms) tachycardia. If the tachycardia is narrow QRS tachycardia, it is usually a supraventricular tachycardia and is usually benign. If the tachycardia is wide QRS wave group tachycardia, it is usually ventricular tachycardia, supraventricular tachycardia with atrioventricular block or preexcitation syndrome. The diagnosis of paroxysmal supraventricular tachycardia by electrocardiogram: ①mostly seen in the elderly; ②often associated with organic heart disease, such as pulmonary heart disease, coronary heart disease; ③the ectopic point of origin is located in the atria, which can be divided into autonomic atrial tachycardia and refractory atrial tachycardia, or monomorphic atrial tachycardia and polymorphic atrial tachycardia; ④frequency 150-250 beats/min; ⑤stimulation of the vagus nerve cannot be (6) Hemodynamic disorders suggest critical condition, such as blood pressure drop, dyspnea, angina pectoris and syncope; ventricular rate >200 beats/min during the attack; elderly or patients with organic cardiovascular disease. Paroxysmal atrioventricular folding tachycardia: ①mostly seen in middle-aged and young people without organic heart disease; ② electrocardiogram characterized by sudden onset and stop, normal QRS wave group morphology (occult preexcitation) or wide deformity (dominant preexcitation or combined with bundle branch block), heart rate of 150-250 beats/min; ③ stimulation of the vagus nerve can often be terminated; ④ hemodynamic disorders, ventricular rate >200 beats/min during the attack are indicative of critical condition. (3) stimulation of the vagus nerve is often terminated; (4) hemodynamic disturbances and ventricular rate >200 beats/min during the attack are indicative of critical condition. Paroxysmal atrioventricular nodal tachycardia: (1) is usually seen in young and middle-aged people without organic heart disease; (2) is characterized by abrupt onset and abrupt cessation of the electrocardiogram, normal QRS wave pattern unless accompanied by bundle branch block, heart rate 150-250 beats/min, average 180 beats/min; (3) can often be terminated by vagal nerve stimulation; (4) hemodynamic disturbances suggest critical condition. If the clinical treatment is hemodynamically stable, vagus nerve stimulation is usually the first step to terminate the attack, but vagus nerve stimulation methods cannot terminate atrial tachycardia. If supraventricular tachycardia cannot be terminated by these methods, pharmacological treatment is required. First-line drugs such as adenosine triphosphate, calcium antagonists or β-blockers are available, while cardioplegia and amiodarone are second-line drugs. Patients with hemodynamic instability or persistent supraventricular tachycardia should be promptly electrically resuscitated if antiarrhythmic drugs and vagus nerve stimulation fail to revert. Polygenic atrial tachycardia is often confused with atrial fibrillation and thus may lead to inappropriate DC electrical resuscitation. In patients with digoxin toxicity, electrical resuscitation may cause refractory ventricular fibrillation and should therefore be contraindicated. Atrial fibrillation Electrocardiographic diagnostic points of atrial fibrillation: ① paroxysmal atrial fibrillation may be without obvious organic heart disease, while persistent atrial fibrillation mostly has organic heart disease or hyperthyroidism. Ectopic pacing points are located in the pulmonary veins, left and right atria; ③ ECG is characterized by the disappearance of P waves and the appearance of f waves with a frequency of 350-600 beats/min; QRS wave groups are supraventricular and RR intervals are absolutely irregular. ④Atrial fibrillation combined with pre-excitation, combined with high or complete atrioventricular block is at high risk and requires urgent treatment. Atrial flutter: (1) Most often seen in organic heart disease; (2) Ectopic pacing points are located in the atria. The ECG is characterized by the disappearance of P waves and the appearance of F waves with a frequency of 250-350 beats/min; the QRS wave group has normal morphology and time frame, and may show fixed or irregular atrioventricular conduction. ④Atrial flutter with 1:1 atrioventricular conduction and combined with third-degree atrioventricular block has a high risk and requires urgent treatment. Treatment strategies for the choice of ventricular rate or rhythm control and the trade-off between the effectiveness and safety of anticoagulation remain two key clinical challenges for clinicians and patients with AF. In hemodynamically unstable patients with acute atrial fibrillation, sinus rhythm should be rapidly reverted to restore hemodynamic homeostasis, so direct current electrical resuscitation is preferred, followed by pharmacological resuscitation or electrical resuscitation combined with pharmacological resuscitation. In hemodynamically stable patients with acute onset atrial fibrillation, the therapeutic goal is to relieve symptoms and prevent complications, and pharmacological interventions are mostly chosen to achieve heart rate control, sinus rhythm conversion, and anticoagulation therapy. Ventricular rate control: atenolol, metoprolol, diltiazem and verapamil are available, with digoxin as a second-line agent. Drug diversion: Class I antiarrhythmics flecainide and propafenone, Class III antiarrhythmics amiodarone and ibrit have a high success rate in diversion of atrial fibrillation; flecainide and propafenone are not used in patients with organic heart disease. Anticoagulation: anticoagulation is not required for atrial fibrillation of less than 48 h duration, warfarin anticoagulation is required for more than 48 h. Oral anticoagulants should be given for indeterminate duration of atrial fibrillation. Ventricular tachyarrhythmia ECG diagnostic points ventricular tachycardia: ① common organic heart disease, coronary artery disease most often; ② ECG features originated below the bifurcation of the bundle of Hitchcock, left and right ventricles, QRS wave wide deformity, QRS wave time limit ≥ 0.12s; persistent monomorphic ventricular tachycardia RR interval is almost regular, persistent polymorphic ventricular tachycardia RR interval varies widely, frequency 100-250 times/min. P-wave and QRS wave relationships have atrial separation, ventricular capture, and ventricular fusion waves. Ventricular flutter and ventricular fibrillation: (1) ventricular flutter quickly turns into ventricular fibrillation, which is the main cause of sudden cardiac death; (2) the ECG of ventricular flutter is characterized by continuous, uniform fluctuations, with waveforms similar to atrial flutter F waves, and QRS waves, ST segments and T waves cannot be distinguished, with frequencies >200 beats/min; (3) the ECG of ventricular fibrillation is characterized by continuous, irregular and small amplitude fluctuations, with QRS wave groups and T waves completely disappearing, with frequencies of 250 ～(3) Ventricular fibrillation is characterized by continuous, regular and small amplitude fluctuations, complete disappearance of QRS and T waves, frequency of 250 to 500 beats/min. Cardiac arrest includes ventricular fibrillation, pulseless electrical activity and ventricular arrest. Pulseless electrical activity includes cardiac mechanical separation, ventricular escape, ventricular autonomic rhythm after defibrillation, and ventricular arrest and cardiac mechanical separation are signs of death. Cardiac electrical storm (sympathetic electrical storm) refers to 3 or more episodes of ventricular fibrillation or hemodynamically unstable ventricular tachycardia within 24h, requiring electrical cardioversion or electrical defibrillation therapy. Treatment strategies Pharmacological treatment: amiodarone, cardioplegia, procainamide, sotalol are available for patients with stable monomorphic ventricular tachycardia. In the absence of electrical cardioversion equipment or when electrical cardioversion is ineffective, amiodarone therapy may be effective in hemodynamically stable polymorphic ventricular tachycardia (except tip-twist type) and lidocaine is ineffective. Electrical resuscitation: (1) ventricular tachycardia: emergency electrical resuscitation should be performed for hemodynamic instability, and intravenous antiarrhythmic drugs can be used to restore sinus rhythm for hemodynamically stable patients. (2) Ventricular fibrillation: asynchronous electrical defibrillation with energy selection of 360 J. (3) Electrical resuscitation in special populations: pediatric patients with non-pulseless ventricular tachycardia or ventricular fibrillation with energy selection of 1~2 J/kg; some studies have reported that electrical resuscitation is safe during pregnancy. Long QT syndrome Whether congenital or acquired, sudden death can be triggered by ventricular fibrillation or tip-twist ventricular tachycardia. Risk factors for cardiac arrest in patients with long QT syndrome include a QT interval >500 ms, a history of syncope, and a family history of sudden death. If acute onset of torsional ventricular tachycardia causes hemodynamic disturbances, asynchronous electrical resuscitation is preferred, followed by pharmacological treatment: (1) if caused by drugs, discontinue the corresponding drugs; (2) correct electrolyte disturbances, such as potassium and magnesium supplementation; (3) lidocaine can shorten the QT interval, especially for drug-induced torsional ventricular tachycardia; (4) temporary pacing and isoproterenol can increase the heart rate (>120 beats/min) and thus shorten the QT interval; ⑤ patients with congenital long QT syndrome require long-term therapy such as β-blockers, implantation of a permanent pacemaker/ICD or combination therapy; ⑥ avoid prolonging the QT interval with drugs and avoid strenuous exercise in patients with exercise related symptoms of long QT syndrome (often LQT1 or LQT2). Slow arrhythmias ECG diagnostic points Pathological sinus node syndrome: ① Most commonly seen in the elderly, combined with coronary artery disease and degenerative fibrosis of the cardiac conduction system; ② Young people are more likely to consider inflammatory diseases, such as myocarditis and pericarditis; ③ ECG characteristics are persistent sinus bradycardia, sinus block, sinus arrest, atrioventricular block, regular or irregular tachyarrhythmia alternating with slow ventricular rate. Atrioventricular block: ①Common in myocarditis, conduction system fibrosis, such as Lev’s disease, coronary artery disease, cardiomyopathy, electrolyte disorders, etc. ②High atrioventricular block, with 2 or more consecutive atrial excitations not transmitting down at an atrial rate ≤ 135 beats/min, and junctional or ventricular escape rhythm < 45 beats/min. (3) Complete atrioventricular block, junctional escape rhythm with QRS wave not wide, frequency 40-60 beats/min; ventricular escape rhythm with QRS wave wide and distorted, frequency 25-40 beats/min. Treatment strategies ① Discontinue or reduce heart rate slowing drugs, such as digoxin, β-blockers, calcium antagonists; ② Atropine: caution should be taken in patients with acute coronary syndrome, because accelerated heart rate can aggravate myocardial ischemia or expand infarct area; ③ Cardiac pacing: cardiac pacing is recommended for patients with ineffective atropine and severe symptoms. Repost