What Is an Implantable Cardiac Defibrillator?

The surgical technique of placing an implantable cardioverter defibrillator is a surgical term. It belongs to cardiovascular surgery / surgical arrhythmia / surgical ventricular tachyarrhythmia / ischemic ventricular tachyarrhythmia.

Surgical technique of implantable cardioverter defibrillator

This entry lacks an overview map . Supplementing related content makes the entry more complete and can be upgraded quickly. Come on!

The surgical technique of placing an implantable cardioverter defibrillator is a surgical term. It belongs to cardiovascular surgery / surgical arrhythmia / surgical ventricular tachyarrhythmia / ischemic ventricular tachyarrhythmia.

Chinese name

Surgical technique of implantable cardioverter defibrillator

Foreign name

Surgical techniques for implantable cardioverter defibrillators

Alias

Surgical technique of implantable defibrillator

Surgical technique of implantable cardioverter defibrillator

Surgical technique of implantable defibrillator; Surgical technique of implantable defibrillator; Automatic cardioversion implantation

Cardiovascular Surgery / Surgical Treatment of Arrhythmia / Surgical Treatment of Ventricular Tachyarrhythmia / Ischemic Ventricular Tachyarrhythmia

37.9401

In recent years, the use of implantable cardioverter defibrillators has been limited to ventricular tachyarrhythmias. Drug therapy is ineffective and cannot be performed with surgery or antiarrhythmic surgery, but electrophysiological examination can still induce ventricularity at the end or after surgery Tachycardia.

The surgical technique of placing an implantable cardioverter defibrillator is suitable for:

In recent years, the surgery for ischemic ventricular tachyarrhythmia has made great progress. Surgical treatments include surgical procedures, intraoperative cryoablation, and implantable cardioverter defibrillators. The surgical indications are also expanding. According to and analyze various clinical factors, a corresponding individualized surgical plan should be formulated for each case.

1. There are recurrent monomorphic ventricular tachycardia, drug treatment is not effective, left ventricular function is better, surgery should be performed.

2. Polymorphic ventricular tachycardia, due to its complex characteristics and difficult to map intraoperatively, was considered to be a contraindication for surgery. Recently, the use of an electronic computer to support the mapping system during multi-point electrode array surgery can identify one or more parts of the ventricular muscle that cause arrhythmia, even identify the type of ventricular tachyarrhythmia, and measure the origin of arrhythmia in a short time. Since then, polymorphic ventricular tachycardia is also suitable for surgical treatment.

3. Idiopathic ventricular fibrillation without any surgery can be done, all implanted cardioverter defibrillator.

The main contraindication for surgery is severe left ventricular dysfunction. If the application of drugs is not effective, implantable cardioverter defibrillator can be used. This operation has little trauma and low surgical mortality. Left ventricular function is extremely poor, and cardioverter defibrillator placement is ineffective, and heart transplantation should be considered.

In addition to the routine preparation for general open-heart cardiac surgery, the following points should be noted:

1. The purpose of preoperative electrophysiological examination is to prove that the arrhythmia is ventricular, not supraventricular tachycardia; application of stimulation techniques can induce and terminate ventricular tachycardia; determine the origin of ventricular tachycardia Site; identify and record the slow conduction area of the reentrant loop and the range of abnormal potentials.

2. Application of endocardial mapping method before surgery Endocardial electrophysiological mapping method is to use a grade 4 catheter or a multipolar catheter to place the right atrium, His bundle and left and right ventricles, and record the atrium, His bundle and Two-ventricular bipolar electrogram and activation time are used as a reference; a large-head catheter is used as a detection electrode, and the left and right ventricles are moved forward and backward at a predetermined sequence point under perspective, while performing sinus rhythm and inducing ventricular tachycardia Mapping.

(1) Pacing mapping method: During sinus rhythm, perform multi-point endocardial pacing at a frequency 10 to 20 times / min faster than your own heart rate. The electrocardiogram recorded at each point and the body surface during tachycardia Compare the 12 leads and locate the origin of ventricular tachyarrhythmias. The accuracy of this method is only 20% to 50%.

(2) Excited sequence mapping method: Find the earliest excited site during ventricular tachycardia. This potential occurs before the QRS complex on the surface electrocardiogram. However, the ventricular tachycardia reentry loop is more complicated after myocardial infarction, and the earliest activation point is not necessarily a component of the reentry loop. In this case, the earliest activation point is often located at the distal end of the block, that is, at the exit of the reentrant loop.

(3) Mapping of the slow conduction area: The slow conduction area is the basis for reentry, and it is also an ideal target for surgery and catheter ablation. Its electrophysiological characteristics are: abnormal or low amplitude fragmentation potentials can occur during local depolarization; pacing in the slow conduction zone can produce occult tow ventricular tachycardia; occult tow is accompanied by post-stimulation QRS complexes Prolongation indicates that the pacing site may be located in the slow conduction zone.

3. Preoperative echocardiography showed the size of the left ventricle, the presence or absence of wall tumors, and calculation of left ventricular function indicators. Is there any other heart disease?

4. Preoperative coronary angiography and left ventricular angiography can show the scope and severity of coronary artery stenosis, as well as the location and function of left ventricular infarction, in order to choose left ventricular cryoablation and coronary artery bypass grafting or implantable heart rhythm Turn over the defibrillator.

5. It is still controversial that the application of amiodarone can increase surgical mortality and postoperative complications. This problem depends in part on the design of the surgery, as postoperative low cardiac output is limited to cases where certain operations are performed with cardiac arrest. Cox proposes that ventricular tachycardia is performed under an extracorporeal heartbeat at room temperature, and amiodarone has no effect on the postoperative course. In the case of simultaneous coronary artery bypass grafting or heart valve surgery, first perform ventricular tachycardia under the heart beat, and then perform other operations while the heart is beating. In this case, Stop amiodarone for at least 4 weeks.

1. Transthoracic implantable cardioverter defibrillator

The thoracotomy can be performed through a midline chest incision, a left thoracic lateral incision, and a subxiphoid incision.

(1) Mid-thoracic incision: After coronary artery bypass grafting, the lower part of the pericardial incision is intermittently loosened and sutured to remove extrapericardial fat. A pair of defibrillation sheet electrodes are placed on the surface of the right atrium and the left ventricle. The pericardium is fixed and sutured to prevent movement. Avoid damaging coronary arteries, myocardium, and coronary artery grafts when placing defibrillation sheet electrodes. The end of the sheet electrode is buried behind the rectus abdominis muscle on the left side of the front abdomen. A perceptual and pacing system is also to be established. The long-term threshold is better than the epicardial lead system by direct puncture into the right ventricular bipolar lead through the left jugular or innominate vein. Place the pacing lead through the tunnel behind the rectus abdominis. An implantable cardioverter defibrillator was placed behind the left rectus abdominis muscle and connected to each lead. Then test the defibrillator system.

(2) Left thoracotomy incision: Patients who have had surgery in the past or failed to insert an implantable cardioverter defibrillator lead through a vein can be left through a small incision on the left anterolateral side and placed in a front defibrillator after the sternal adhesion is separated Isolate the pericardium from the diaphragm muscle and put it into the rear defibrillation sheet electrode, so as not to damage the right ventricle, the coronary artery and its transplanted blood vessels, and the phrenic nerve. The wire was placed under the ribs through the diaphragm attachment site and placed in the extraperitoneal space below the ribs. A bipolar wire is inserted through the subclavian vein or innominate vein, and its end is placed in the extraperitoneal space through a tunnel. After a patch and pacing lead test, an implantable cardioverter defibrillator connected to the extraperitoneal space buried behind the left rectus abdominis muscle.

Separate the right sternal bone into the anterior sheet electrode (AP), separate the pericardium in the mediastinum muscle and place the posterior sheet electrode (PP), and do not damage the phrenic nerve, but the posterior sheet electrode is often placed on the left phrenic nerve (PN) surface . The sheet electrode lead (PL) was inserted into the extraperitoneal space of the left rectus abdominis muscle through the rib (R) and tunnel. Placing bipolar electrodes through veins and placing ICDs in the same inferior xiphoid incision as shown in Figure 6.55.3.1.2-1 is easier to place epicardial sheet electrodes. It should be noted that the sheet electrodes are placed accurately to avoid overlapping.

2. Implantable cardioverter defibrillator without open chest

Since the development of this technology in 1993, it has developed to the fourth generation of open chest implantable cardioverter defibrillators. The transvenous lead system has a 100 cm length with three fin-shaped electrode leads. It integrates frequency, sensing, defibrillation and pacing functions. The lead is inserted through the subclavian vein and fixed to the apex of the right ventricle. . The distal porous head electrode is the cathode for sensing and pacing. The other two spring electrodes, one on the proximal side and the other on the far side. The distal electrode has two functions, the cathode is used for defibrillation and pacing, and the anode is sensed; the proximal electrode is used for defibrillation. An implantable cardioverter defibrillator can be placed under the left upper chest muscle.

When installing a defibrillator, it is important to determine the defibrillation threshold. The conventional defibrillation threshold is adjusted to 8 to 25J. After the pulse generator was connected to the lead, it induced ventricular tachycardia or ventricular fibrillation, and recorded the entire process, including the automatic discharge of the implantable cardioverter defibrillator and termination of arrhythmia. When ventricular tachyarrhythmia occurs, it usually only needs to be terminated at 25J. Occasionally more than one electric shock is needed, from arrhythmia to termination time between 11 to 30 seconds. The implantable cardioverter defibrillator discharges a total of 5 times during one working cycle. If 5 consecutive times are invalid, the pulse will not be issued. If the heart rhythm is corrected to 35s sinus rhythm and ventricular tachycardia or ventricular fibrillation occurs again, the implantable cardioverter defibrillator is still counted as the first discharge. According to the second discharge meter in the same working cycle.

3. Heart transplant

In cases where the left ventricular function is particularly poor and the implantable cardioverter defibrillator is ineffective, heart transplantation is used.

1. Through epicardial and endocardial mapping under cardiac pulsation during operation to determine the origin of the arrhythmia, local endocardial resection and cryoablation must be performed until the ventricular tachycardia cannot be induced. Avoid the use of cardiac arrest surgery, so this method has a high recurrence rate. A cardiac pacing lead was placed at the end of the operation.

2. Sub-endocardial resection cannot be performed on the aortic and mitral valve annulus and the muscles around the papillary muscle. Only cryoablation can be applied to avoid valve insufficiency.

3. After repeated tachycardia and subendocardial resection and cryoablation, 5% ~ 10% of cases still can induce ventricular tachyarrhythmia, and implantable cardioverter defibrillation should be placed during the operation. Device system. If this system is not installed, amiodarone should be applied after surgery.

4. Before the application of amiodarone, it is necessary to perform antiarrhythmic surgery under cardiac beat during operation to prevent low cardiac output syndrome after operation. In cases where cardiac arrest is accompanied by coronary artery bypass grafting or heart valve surgery, amiodarone should be stopped for at least 4 weeks before surgery.

5. Early repair of ventricular aneurysm by Jatine and Dor without intraoperative mapping. Recently, Dor and Rasteger reported that the medial wall angioplasty under the guidance of mapping has received satisfactory results. In the future, we must pay attention to accurate intraoperative mapping so that the effect of this operation can be further improved.

6. Of the patients who placed an implantable pacing defibrillator, about 12% of the cases had an extremely high defibrillation threshold, and 25J could not terminate the arrhythmia. Some patients with high defibrillation thresholds are related to hypokalemia or taking amiodarone. After correcting electrolytes and adjusting drugs, the threshold can be lowered. The threshold can also be lowered by replacing a large sheet electrode or changing the superior vena cava spring electrode to a sheet electrode or adjusting the position of the lead. For a few particularly difficult patients, a high-output pulser needs to be implanted.

After returning to the monitoring room, the ECG, arterial pressure, left atrial pressure, right atrial pressure, and pulmonary arterial pressure, and arterial oxygen saturation were continuously monitored. Blood gas analysis and cardiac output were performed intermittently. Most of the patients undergoing surgery were elderly, with poor lung compliance and muscle tone. They maintained mechanical assisted breathing for 2 to 3 days and sucked sputum in time. After disabling the ventilator, intermittently atomize and turn your back to help expel sputum and prevent respiratory infections. When the venous transfusion reaches a hematocrit of 35%, plasma is input to prevent blood viscosity from affecting hemodynamics and complications such as thromboembolism, and control the amount of blood. Low-dose dopamine and / or dobutamine and nitroglycerin are routinely applied after surgery. Apply powerful antibiotics to prevent infection. Digitalis and diuretics were used to treat heart failure, and drugs such as dopamine and dobutamine were gradually stopped.

1. Low cardiac output syndrome In the past, circular endocardium ventriculotomy was used, and the incidence of this complication was very high. At present, the scope of surgery is reduced, and subendocardial resection or cryoablation is used under the guidance of mapping. This syndrome gradually decreases. Postoperative application of dopamine and / or dobutamine to support myocardial contractility and timely application of sodium bicarbonate to correct metabolic acidosis can cure most low cardiac output syndromes. A few cases require intra-aortic capsule counterpulsation.

2. Heart failure patients have heart dysfunction before surgery, and often have different degrees of heart failure after surgery. Digitalis and diuretics were routinely applied after surgery. Check the blood potassium concentration intermittently to prevent hypoarrhythmia from causing arrhythmia.

3. Ventricular tachycardia occurs in about 2% to 38% of patients with recurrent ventricular tachyarrhythmias after surgery. Early after surgery, antiarrhythmic drugs such as amiodarone can be used. Immediate or late recurrence of ventricular tachyarrhythmias requires implantable cardioverter defibrillators.

4. Some complications can occur in the early and late stages of a buried implantable cardioverter defibrillator.

5. Early postoperative complications

(1) The pulse generator sac can produce effusion or blood, which can usually subside on its own. It is not recommended to use puncture pumping to increase the chance of infection. Perform puncture drainage.

(2) Placement of the sheet electrode of the implantable cardioverter defibrillator, such as near the anastomosis of coronary artery bypass graft surgery, can cause vascular rupture. Such serious complications should be urgently re-operated.

(3) After placement of an implantable cardioverter defibrillator, femoral artery embolism and cerebral infarction can occur. The patient had a history of atrial fibrillation for more than 2 years, and the defibrillation was converted to sinus rhythm during the operation. Anticoagulation was applied after the operation.

(4) When endocardial spring electrodes and frequency sensing electrodes are used, thrombus formation of the subclavian vein may occasionally occur.

6. Late complications The most common late complications are infections. Bag infection requires removal of all implantable cardioverter-defibrillator defibrillators, and the manufacture of a bag into a new device. If the infection is not serious, you can also try to remove the pulse generator, keep the lead, and give a sufficient amount of antibiotic treatment.