EV-ICD vs CRT-D: Device Selection in Young High-Risk Cardiac Patients
Device Selection in Young High-Risk Cardiac Patients: Why EV-ICD for One, CRT-D for the Other?
The arrhythmia team led by Dr. Yonghui Zhao at Fuwai Central China Cardiovascular Hospital (Henan Provincial Cardiovascular Hospital) recently completed device implantation in two young, high-risk patients. Both faced a risk of sudden cardiac death, but the core clinical problems differed, and so did the choice of device.
Inherited arrhythmias and cardiomyopathies are important causes of syncope and sudden cardiac death in young people. These patients have a long life expectancy, so device safety, durability, and quality of life matter greatly. A single standard approach is not suitable for every patient.
Case 1: 27-Year-Old Woman With Long QT Syndrome, Treated With EV-ICD
The patient had long QT syndrome with a QTc above 500 ms and a family history of ventricular tachycardia and sudden death. This placed her at high risk of malignant arrhythmias.
The team considered three device options:
- Transvenous ICD: The leads sit in the vessels and heart chambers for the long term, with risks of lead failure, vascular injury, and infection.
- Subcutaneous ICD: There are no intracardiac leads, but the device has no anti-tachycardia pacing (ATP) capability, so ventricular tachycardia can only be terminated by shock.
- EV-ICD (extravascular ICD): The lead is placed substernally, outside the vessels and heart chambers, while ATP is preserved.
Because she is expected to need protection for decades, the team chose an EV-ICD after multidisciplinary evaluation.
Before surgery, thin-slice CT was used to plan the substernal tunnel path. During surgery, the lead was placed in the substernal space, and the pulse generator was placed in a pocket on the lateral chest wall. Ventricular fibrillation induction testing was performed, and sensing, pacing, and defibrillation parameters were all satisfactory. The procedure was completed uneventfully.
Case 2: 23-Year-Old Man With Hypertrophic Cardiomyopathy, High-Grade AV Block, and LBBB, Treated With CRT-D
The patient had genetic hypertrophic cardiomyopathy with high-grade atrioventricular (AV) block, complete left bundle branch block (LBBB), and a left ventricular ejection fraction (LVEF) of 30%. He had ventricular dyssynchrony and a risk of malignant ventricular arrhythmias.
Treatment needed to achieve three goals at once: correct the conduction disorder, improve cardiac function, and prevent sudden death.
- A conventional pacemaker treats bradycardia but cannot prevent sudden death.
- Right ventricular pacing alone may worsen dyssynchrony.
- An ICD alone prevents sudden death but cannot correct dyssynchrony or improve heart failure.
After echocardiography, Holter monitoring, and coronary venous anatomy assessment, the team selected CRT-D (cardiac resynchronization therapy with defibrillator). Coronary sinus venography was performed, atrial, right ventricular, and left ventricular leads were implanted, and the pulse generator was placed in a submuscular pocket under the pectoralis major. Pacing, sensing, and defibrillation tests were all satisfactory. Coronary venous anatomy variation is common in hypertrophic cardiomyopathy and can make lead placement more challenging.
Key Takeaways
The two patients were of similar age but had different underlying diseases.
- The first patient needed long-term sudden death prevention with fewer lead-related complications, which favored EV-ICD.
- The second patient needed simultaneous management of conduction disease, dyssynchrony, heart failure, and arrhythmic risk, which favored CRT-D.
Device selection should be based on the underlying disease, anatomy, and expected lifespan, rather than a single standard approach.
It is worth noting that long-term follow-up data for EV-ICD remain limited, and its long-term safety requires further study.
About the Department
The department offers leadless pacing, CRT(D), ICD, subcutaneous ICD, and EV-ICD implantation, and tailors device selection to each patient's underlying disease, anatomy, and expected lifespan.