on behalf of the European 7219 Jewel ICD InvestigatorsBackground-A newly developed classification system relates adverse events to the surgical procedure or the function of the implantable defibrillator. Methods and Results-Adverse events were monitored during prospective clinical evaluation of the Medtronic model 7219Jewel ICD and were classified according to the definitions of the ISO 14155 standard for device clinical trials into 3 groups: severe and mild device-related and severe non-device-related adverse events. In addition, events were related to the surgical procedure, treatment with the device, or cardiac function. Seven hundred seventy-eight patients were followed up for an average of 4.0 months after ICD implantation. In total, 356 adverse events were observed in 259 patients. At 1, 3, and 12 months after ICD implantation, 99%, 98%, and 97% of the patients, respectively, survived; 95%, 93%, and 92%, respectively, were free of surgical reintervention; and 79%, 68%, and 51%, respectively, were free of any adverse event. Twenty patients died: 6 deaths were related to the surgical procedure, 12 deaths were considered unrelated to ICD treatment, and 2 patients died of an unknown cause. Of 111 nonlethal severe adverse device effects, 47 required surgical intervention, 19 times for correction of a dislodged lead. Inappropriate delivery of therapy was observed 128 times in 111 patients, and the events were typically resolved by reprogramming or drug adjustment. Nine of these required rehospitalization. Conclusions-Approximately 50% of patients experience an adverse event within the first year after ICD implantation.The observed adverse event rate depends on the definitions and the prospective monitoring. The incidence of inappropriate therapy emphasizes the need for improved detection algorithms and for quality-of-life evaluations, especially when considering ICD treatment in high-risk but arrhythmia-free patients. (Circulation. 1998;98:663-670.)

The implanted device nearly eliminates sudden arrhythmic death in patients with documented, potentially fatal ventricular tachyarrhythmias. Automatic tiered therapy is highly effective to restore sinus rhythm, provided that an integrated two-zone tachycardia detection algorithm is used, assigning lower tachycardia rates to overdrive pacing and/or cardioversion and higher tachycardia rates to defibrillation. In general, spontaneous VTs can be terminated by automatic overdrive pacing, and painful or disturbing countershock therapies are not required to terminate the majority of spontaneous VT episodes.

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Paroxysmal atrioventricular (AV) block was induced by exercise in an otherwise healthy young man. The only abnormalities demonstrated at comprehensive cardiac evaluation were: 1) angiographic systolic narrowing of the left anterior descending coronary artery, and 2) reversible radionuclide hypoperfusion of the septum during exercise. It is postulated that ischemia of the conduction system due to systolic milking of the left anterior descending coronary artery was responsible for the paroxysmal AV block in this patient.

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the neural network approach can be useful in situations where causal relations between the electrocardiogram and underlying mechanism are partly undefined.

One of the possible complications of subclavian vein puncture is entry into the subclavian artery. If this is not recognized, a pacemaker lead may be placed arterially. Since this may lead to systemic emboli, the pacemaker lead must be removed. This case report describes a patient in whom an atrial lead was inadvertently placed in the ascending aorta, where it had good sensing values but poor atrial capture threshold values. This lead was subsequently removed and hemostasis was achieved with intraarterial balloon compression via the brachial artery.