The Implantable Cardioverter Defibrillator (ICD) is an implanted electronic medical device used to monitor and treat severe cardiac arrhythmias. When patients experience life-threatening arrhythmias such as ventricular fibrillation or ventricular tachycardia, the ICD can deliver immediate electrical shocks to restore normal heart rhythm. It is primarily indicated for individuals with a history of cardiac arrest, heart failure post-myocardial infarction, or those at high genetic risk for arrhythmias.
The ICD system consists of a subcutaneous pulse generator and electrode leads, implanted via endocardial or epicardial approaches. When abnormal heart rhythms are detected, the ICD initially delivers low-energy cardioversion shocks; if ineffective, it proceeds with high-energy defibrillation pulses. Modern devices feature long-lasting batteries (4-8 years), automatic defibrillation, and heart rhythm monitoring functions. Some models also integrate Cardiac Resynchronization Therapy (CRT-D).
Main indications include:
Secondary indications include a family history of sudden cardiac death or high-risk patients post-cardiac surgery, with risk stratification confirmed via electrophysiological studies.
The implantation procedure is performed under local anesthesia via catheterization, typically through a subclavicular incision to place the pulse generator, with leads inserted into the right ventricle via the vein. The procedure lasts approximately 1-3 hours, with 24-48 hours of hospitalization for observation. Device parameters are set by a cardiac electrophysiologist, including sensing thresholds, shock energy levels, and monitoring intervals, which require outpatient adjustments every 3-6 months.
ICDs can immediately terminate fatal arrhythmias, with clinical studies showing a reduction in sudden cardiac death by 60-70%. Advantages include:
Compared to traditional medication therapy, ICDs effectively respond to sudden arrhythmic events, providing life-saving intervention in real-time.
Main risks include: device infection rate of approximately 1-5%, and electrode dislodgement or lead failure rate of about 2-3%. Common side effects include:
Rare cases may involve lead perforation of the ventricular wall or thromboembolic risks, requiring periodic imaging follow-up.
Contraindications include: allergy to device materials, severe coagulopathy, uncontrolled infections, or terminal illness with life expectancy less than one year. Patients should avoid proximity to strong magnetic fields, inform healthcare providers before MRI scans, and undergo regular device function checks.
Patients on anticoagulants (e.g., warfarin) need dose adjustments to reduce bleeding risks. During radiofrequency ablation or cardiac surgery, device settings should be reprogrammed. Physical therapies should avoid direct pressure on the device site. MRI scans should be performed with 1.5T or lower machines under professional supervision.
Multiple large clinical trials (such as AVID, MADIT II) have confirmed that ICDs reduce mortality in high-risk heart failure patients by 23-31%. Long-term follow-up data show device survival rates of 70-80% after five years, establishing ICD as the standard for primary prevention of sudden cardiac death.
Alternatives include:
However, medication effects are limited and may cause side effects; ablation does not provide continuous monitoring. Therefore, ICD remains the preferred option for high-risk patients.
Patients should complete baseline tests such as ECG, blood tests, and echocardiography to evaluate cardiac function and coagulation status. The doctor may require temporary cessation or adjustment of certain medications, and fasting for 6-8 hours prior to anesthesia to reduce risks. Patients should inform the medical team of their medical history and current medications to ensure safety in treatment planning.
What dietary restrictions should be followed during atrial fibrillation treatment?During treatment, a low-salt, low-caffeine diet is recommended to reduce blood pressure fluctuations, and alcohol and stimulants should be avoided to prevent arrhythmia triggers. If anticoagulants are used, foods high in vitamin K (e.g., spinach, broccoli) should be limited to avoid affecting medication efficacy. Consulting a nutritionist for a personalized diet plan is advised.
What activity restrictions are necessary after atrial fibrillation catheter ablation?Within 24 hours post-procedure, avoid heavy lifting or excessive bending to prevent bleeding at the puncture site. Light activities can usually resume in 2-3 days, but strenuous exercise should be avoided for more than two weeks. Hot packs or hot springs should be avoided for one month post-operation to prevent affecting heart rhythm recovery. Follow medical advice for gradual return to normal activities.
How effective is long-term drug therapy for atrial fibrillation?Antiarrhythmic drugs can reduce symptom episodes by 70-80%, but about 30% of patients may need adjustments due to tolerance or side effects. New oral anticoagulants can lower stroke risk by approximately 60-70%, but require regular blood monitoring. Treatment efficacy varies among individuals and should be regularly reviewed with dose adjustments.
When should emergency medical attention be sought after atrial fibrillation treatment?If symptoms such as chest pain, difficulty breathing, dizziness, or limb weakness occur, it may indicate embolism or hemodynamic instability, requiring immediate medical attention. Patients on anticoagulants experiencing gum bleeding, bruising, or blood in stool should have their medication levels evaluated promptly. If the puncture site becomes red, swollen, or pus-filled within two weeks post-treatment, urgent intervention is necessary.
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