Ventricular arrhythmias are clinically common and include ventricular premature beats, ventricular tachycardia, ventricular flutter, and ventricular fibrillation. The clinical presentation of ventricular arrhythmias varies widely, and patients may be asymptomatic, but may also have palpitations, blackness, and even sudden cardiac death (SCD). Ventricular arrhythmias are prone to recurrence after correction and should be combined with the patient's condition to decide whether to use prophylaxis and to evaluate indications for drug, catheter ablation, and implantable arrhythmia defibrillator (ICD) therapy.
At the 32nd Great Wall Conference of Cardiology (GW-ICC 2021), Professor Li Xuebin from the Department of Cardiology, Peking University People's Hospital summarized the new progress of ventricular arrhythmias in combination with the cases.
introduction
The guidelines for ventricular arrhythmias and sudden death are constantly updated, and since 1980, a number of ICD guidelines have been issued in the field of electrocardiology. Early guidelines, in both Class I and Class II indications, emphasized that ventricular arrhythmias that are ineffective in drug and/or other treatments (surgical and/or catheter ablation), intolerance to drug therapy, or difficulty predicting drug efficacy are indications for ICD therapy. With the development of large clinical trials, the indications for ICD therapy have been expanded. For nearly 20 years, clinical trials of ICDs have shifted to implantable resynchronization therapy for cardioverter defibrillators (CRT-D). In 2019, the international consensus on HRS/EHRA/APHRS/LAHRS ventricular arrhythmia catheter ablation was released.
Ischemic heart disease with ventricular rate
Case 1
The patient is a male, 62 years old.
Main complaint: Episodic palpitations for 2 days.
Present medical history: the patient had no obvious cause of chest tightness and pressure 2 days ago, accompanied by panic and dizziness, and there was no relief after taking nitroglycerin, and the symptoms were relieved after electroborhel therapy, but the above symptoms recurred.
Past history: pre-May coronary artery bypass grafting and ventricular wall tumor plasty.
Figure 1 EcG: I. Lead T wave inverted, chest lead shows negative isotropy, R wave increment is poor.
Judging from the patient's multi-year history of ventricular wall tumors, the above figure is not an ELECTROG manifestation of an acute coronary event. Ventricular tachycardia is one of the complications of ventricular wall tumors due to the presence of scar tissue in the myocardium, forming a relapse. After admission, the patient was treated with drugs and electrical cardioversion, and the symptoms continued to recur, and ventricular septal folding and ablation were performed. The patient re-developed ventricular fibrillation after 1 year and was treated effectively with ICD.
2017 AHA/ACC/HRS Chamber Speed and Sudden Death Guidelines
2014 HRS/ESC/APHRS Expert Consensus – Sustained Monomorphic Chamber Rate
Organic ventricular arrhythmias
In the scarring ventricular rate of organic heart disease, the retracement ring may be located subendontial, intracardial, and extracardial. The retracement ring can be large or small, extending to a few centimeters outside the scar or to a small area around the scar.
Since ischemic ventricular velocity is caused by a regurgitation mechanism, a possible regressive ring location needs to be identified by mapping the scar area. The ablation target is the key isthmus (i.e., the path between scars and scars, scars and natural barriers), and the method of tug-of-the-go can also be used to find the best ablation target.
The success rate of organic non-sustained ventricular tachycardia with radiofrequency ablation is about 50%, which makes it possible to cure such ventricular tachycardia, and the use of mesh-like electrodes (shown in Figure 2) to collect electrical signals in the heart can determine the folding loop and treat the ventricular velocity by blocking the regressive loop.
Fig. 2 Mesh basket electrode
Arrhythmogenic right ventricular cardiomyopathy (ARVC)
Case 2
Male, 56 years old.
Main complaint: Chest tightness with decreased activity tolerance for 10 years, aggravated by 1 month.
Present medical history: chest tightness 10 years ago, electrocardiogram suggests ventricular tachycardia, electroversion returns to normal, ultrasound suggests a marked enlargement of the right heart, except coronary angiography. Before 1 month, the ventricular rate is recurrent, the drug efficacy is not good, and the recurrence after electroversion is repeated.
Past history: hypertension, OSAHS, right femoral head replacement after surgery.
Fig. 3 ECG: Lead V1 has left bundle branch block, lead I is positive, and lead II and III are negative.
Cardiac ultrasound suggests that the left ventricular ejection fraction is 46%, the right atrium diameter is 7.7 cm, the right ventricle diameter is 5.9 cm, and the tricuspid valve has severe regurgitation. In combination with the ε waves seen on the patient's sinus rhythm ECG, the diagnosis of arrhythmic right ventricular cardiomyopathy (ARVC) is considered.
The pathogenesis of the disease is mainly right ventricular myocardial scar fibrosis, adipose tissue replacement, which constitutes the structural basis of ventricular tachycardigenesis. After the patient underwent catheter ablation, the symptoms of heart failure and related indicators were significantly improved.
Figure 4 HD Grid calibration technology: Electrodes can be placed in the heart, which can record the electrical activity and local voltage of the heart, accurately identify necrotic myocardium, and prepare for targeted ablation.
ICD treatment of hereditary arrhythmias
Note: Syncope is the strongest predictor of sudden cardiac death.
2019 HRS/EHRA/APHRS/LAHRS Ventricular Arrhythmia Catheter Ablation International Consensus
Hypertrophic cardiomyopathy
Case 3
Male, 52 years old.
Main complaint: Hypertrophic cardiomyopathy was found for 20 years, and recurrent ventricular rate was 8 years.
Present medical history: 8 years ago, the patient suddenly had palpitations, electrocardiogram of ventricular tachycardia, followed by loss of consciousness, and recovered after electroversion and amiodarone therapy. EcG after recovery: high lateral wall myocardial infarction, ICD implantation. After surgery, Ibinodone, metoprolol, etc. are taken regularly. Coronary angiography was not abnormal 8 years ago and 3 years ago.
Figure 5 Electrocardiogram: Ventricular tachycardia.
After admission, the patient was confirmed by dry pericardial puncture that the ventricular tachycardi originated in the endocardium, followed by voltage calibration in the epicardium and successful ablation therapy.
Hypertrophic cardiomyopathy tends to progress to dilated cardiomyopathy over time, with a decrease in ejection fraction. Most ventricular tachycardia in hypertrophic cardiomyopathy originate at the proximal annulus of the outer membrane at the base of the left ventricle, and ECG features under sinus rhythms are found before ablation.
Case 4
The patient, 56 years old, hypertrophic non-obstructive cardiomyopathy for many years, chronic heart failure for 7 years, ICD implantation for 4 years, recurrent ventricular rate.
In these patients, a ventricular left ventricular color agonism (VT-LV Activation Map) can be used for standardization (as shown in Figure 6) to perform ablation of key points.
Figure 6 Left chamber color agonism
According to literature reports, the folding ring is not limited to a simple eight-character return, and all kinds of folding rings may exist. Ischemic cardiomyopathy, ARVC, and hypertrophic cardiomyopathy are all caused by myocardial scarring and ventricular arrhythmias, and the key point of ventricular rapid ablation lies in the entrance or exit of the folding ring.
Originated in the ventricular velocity of the Pu system
Case 5
The patient is male, 14 years old.
Present medical history: 1 year ago, the patient suddenly felt palpitations and discomfort after being frightened, accompanied by chest tightness and vague pain in the precordial area, and the symptoms lasted for about 20-30 minutes to resolve spontaneously, and were not diagnosed and treated. Before April, the patient had the above symptoms again after catching a cold, and the ecG of the outer hospital suggested "paroxysmal junctional tachycardia".
Figure 7 ECG: Narrow QRS wavegroup, AV separation
The patient's ventricular tachycardia originated not in the ventricular muscle, but in the Hip system, so the ECG of the ventricular tachycardia shows the above manifestations. After ablation of the lesions of the right bundle branch, the patient regained a sinus rhythm.
Multi-point pacing (MPP)
Case 6
The patient was 78 years old, and after coronary heart disease stenting, recurrent episodes of heart failure, ventricular premature, short burst ventricular tachycardia, and no obvious abnormalities were seen in coronary angiography. The patient was treated with a three-chamber pacemaker, and the patient's ventricular velocity disappeared after multi-point pacing (MPP) interrupted the retracement loop.
Figure 8 Comparison of MPP and conventional pacemaker
Note: MPP, multi-point pacing; BiV, biventricular pacing
Advantages of MPP: provide left ventricular bilocus pacing; can capture a larger area of myocardium; improve myocardial contraction; improve hemodynamics; improve CRT response rate.
The reason for the patient's disappearance of ventricular velocity after treatment is that CRTD-MPP improves acute hemodynamic changes, thoracic lead fragmentation QRS waves (fQRS) disappear, and cardiac function continues to improve.
Indications for ICD removal
Case 7
Female, 12 years old, with intermittent episodes of syncope for 1 year, ECG suggests ventricular tachycardia and ventricular fibrillation. It has been clinically confirmed that the patient's ventricular fibrillation is induced by atrial arrhythmias. After radiofrequency ablation, the patient's atrial rate disappears, followed by ICD implantation. The patient was followed up for 8 years without abnormalities and needs to be replaced or removed from the ICD?
Case 8
The patient, a 34-year-old woman, had previously been induced by anorexia with electrolyte disorders and heart failure, so she implanted an ICD, and after treatment, her weight rose to about 50Kg, and the ICD wire was removed. After discussion among global experts, it was decided to remove the wire.
2021 ESC Heart Failure Guidelines
summary
The vast majority of cases of ventricular tachycardia can be definitively diagnosed by ecG features, and understanding the mechanism of ventricular tachycardia is of great benefit to clinical treatment decisions. Spontaneous persistent ventricular rate occurs in organic heart disease, and catheter ablation is an important alternative or complement to continued monomorphic ventricular drug therapy, regardless of whether hemodynamically stable or not. As ECG and ablation techniques advance, guidelines are constantly being updated, and clinicians need to increase their knowledge reserves through continuous learning.