Laboratory tests: 1. Depending on the cause of the pulse leak, electrolytes and acid-base balance should be routinely checked; 2. Check thyroid function and kidney function; 3. Check blood sedimentation, anti-O, immune function and myocardial enzyme profile, etc. Other auxiliary examinations: 1. ECG is the main method to diagnose arrhythmia. Firstly, find out a P-wave in each lead of ECG, measure the P-P interval and determine the atrial rate. Observe the regularity of P waves, whether the morphology of P waves is normal and whether the P-P interval is consistent, and find out the abnormal morphology, premature occurrence, bradycardia, sinus block or arrest. Next, the pattern and morphology of the QRS waves should be understood; if the QRS time is not wide and the morphology is normal, it means that the excitation originates from above the branches of the AV bundle and comes from the sinus node, atrium or junctional area, which is collectively called supraventricular; if the QRS is widened and the morphology is strange, it comes from below the branches of the AV bundle and is ventricular. The R-R interval is measured for equality to identify premature beats or escape beats. Then analyze the relationship between P waves and QRS waves, whether each P wave is followed by a QRS wave, and whether the P-R interval is fixed. The above ECG analysis determines the main rhythm, which is sinus rhythm or ectopic rhythm. The ectopic rhythm should be identified as active or passive, from the atrium, junctional area, or ventricle. The presence of interference or conduction block is also noted. The presence or absence of baseline instability should be noted when analyzing the ECG to avoid mistaking arrhythmias for arrhythmias. For complex arrhythmias, the P-wave leads should be selected for a longer tracing. Generally, synchronous tracing of lead II or aVF is used to facilitate the analysis of P-wave patterns and morphology. If the P waves are not obvious in the conventional ECG leads, the S5 or CR1 leads can be added to show the P waves. In the former case, the negative pole (red) is placed on the sternal stalk and the positive pole (yellow) is placed on the 5th intercostal space on the right edge of the sternum, and the lead selection knob is toggled to the Ⅰ lead position for tracing; in the latter case, the negative pole (red) is placed on the right forearm and the positive pole (yellow) is placed on the 4th intercostal space on the right edge of the sternum, and the Ⅰ lead position is also taken for tracing (Figure 5). 2.24h ambulatory ECG is also called Holter monitoring. It is a method to record ECG continuously for 24-72h under active conditions, which can improve the detection rate of arrhythmias. It has been widely used in the diagnosis of arrhythmias and observation of the effect of drug therapy. It has been reported that 62 patients with normal conventional ECG were found to have various arrhythmias in 30 cases (48%) after 24h ambulatory ECG monitoring. In patients with arrhythmia-related symptoms such as palpitations, dizziness and syncope, arrhythmias not detected by conventional ECG may be detected by 24-h monitoring with ambulatory ECG, such as frequent pre-term contractions, paroxysmal tachycardia and intermittent conduction block. The ECG can also be used to quantify the number of abnormal rhythms, the total number of precontractions and the percentage of all beats in a 24-h period, the number of paroxysmal tachycardias, and the number of sustained beats per period. In addition, asymptomatic arrhythmias can be detected; the relationship between conscious symptoms and arrhythmias can be observed; and whether arrhythmias are induced by activity or occur in silence.