Effect of different location of atrial lead position on nearfield and farfield electrograms in dual chamber pacemaker-defibrillators.

The normal functioning of dual chamber pacemaker-cardioverter defibrillator (AV pacer/ICD) may be affected by oversensing of the farfield R wave (FFRW) by the atrial channel. This study aimed to investigate whether placement of the AV pacer/ICD's atrial lead at a lateral (LAT) wall location compared to a medial (MED) location i.e. the appendage of the right atrium, would reduce the amplitude of FFRWs but not the nearfield atrial electrograms (AEGMs) during sinus rhythm (SR) and ventricular fibrillation (VF). In 17 patients, real time electrograms were recorded during SR and induced VF through the atrial lead initially at the MED and subsequently at the LAT location. In 10 patients the electrograms in SR were also recorded on a computerized data acquisition and recording system at different band-pass filter settings. Although FFRWs were recorded both at MED and LAT locations, they were much smaller, 3.5+/-4.1mm during SR and 1.7+/-2.2mm during VF at the LAT location. At 30-500Hz band-pass filter, lower amplitudes of FFRWs 0.14+/-0.09 mV were recorded at the LAT location. The V/A ratios of the amplitudes of FFRWs and AEGMs were smaller at the LAT location during SR and VF. The nearfield AEGMs were of similar amplitudes at the MED and LAT locations. These data indicate that lower amplitudes of FFRWs are recorded by placement of the atrial lead at the lateral wall of the right atrium. Oversensing of FFRWs may be prevented to improve functioning of the AV pacer-ICD.

Feasibility, safety, and determinants of extraction time of percutaneous extraction of endocardial implantable cardioverter defibrillator leads by intravascular countertraction method.

Previous studies of the removal of implantable cardioverter defibrillator (ICD) leads have been restricted to case reports or small series. In this report, we describe our experience in ICD lead extraction by intravascular countertraction method using Cook's extraction kit. A total of 47 high-voltage (HV) leads, 3 rate sensing (S) leads, and 2 subcutaneous arrays were removed from 42 patients (33 men, 9 women; mean age 59 years [range 14 to 81]). One HV superior vena cava (SVC) lead and 11 HV right ventricular (RV) leads were explanted by manual traction only and defined in the "lead removal" category. One S lead was removed using a femoral venous approach. The remaining 37 leads were explanted by SVC approach using extraction sheaths and defined in the "lead extraction" category. Twenty leads were extracted for "infectious" (group A) and 17 leads for "noninfectious" (group B) etiologies for which extraction times of 27.0+/-18.0 and 27.0+/-15.0 minutes (mean+/-SD), respectively, were not different. Although extraction time, 34.0+/-11.0 minutes, for leads implanted for >48 months was longer than 23.0+/-16.0, 28.0+/-18.0, and 24.0+/-14.0 minutes, for leads with implant durations of 12, 24, and 48 months, respectively, such differences were not statistically significant. The extraction time, however, was directly related to the degree of fibrosis around the lead, 39.0+/-15.0 minutes for leads with severe fibrosis compared with 13.0+/-6.0 minutes for the leads with mild fibrosis (p<0.001). Patient's age, sex, or history of coronary artery bypass graft surgery did not significantly affect extraction time. All except the initial 2 lead extractions were performed in the electrophysiology laboratory. No mortality or serious complications associated with the procedure using these methods were observed.

Efficacy and safety of catheter ablation in octogenarians.

OBJECTIVES: To determine whether catheter ablation is safe and effective in patients over the age of 80. BACKGROUND: There is a tendency to withhold invasive therapy in the elderly until it has been proven safe and effective. METHODS: Over a two-year period from February 1, 1996 to February 1, 1998, 695 consecutive patients underwent 744 catheter ablation procedures of supraventricular and ventricular arrhythmias. These patients were divided into three groups based on age: > or =80 years, 60 to 79 years and <60 years. Acute ablation success, using standard criteria and complication rates for these three groups were determined. RESULTS: There were 37 patients > or =80 years, 275 patients 60 to 79 years and 383 patients <60 years old. The overall acute ablation success rate for the entire group was 95% with no difference in rates among the three groups (97%, > or =80 years; 94%, 60-79 years; 95%, <60 years). The percentage of patients undergoing His bundle ablation was greatest in the > or =80-year-old group (43% vs. 19% vs. 2%, p < 0.01), and the percentage of patients undergoing accessory pathway ablation was greatest in the <60-year-old patients (0% vs. 4% vs. 25%, p < 0.01). The overall complication rate for the entire group was 2.6%, and there was only one major/life-threatening complication. There was no difference in complication rates among the groups (0%, > or =80 years; 2.2%, 60 to 79 years; 3.1%, <60 years). Based on the sample size, the 95% confidence interval is 0% to 7.8% for an adverse event in the octogenarian. CONCLUSIONS: Catheter ablative therapy for the arrhythmias attempted in the very elderly appears to be effective with low risk. Ablation results appear to be comparable with those noted in younger patients.

Amiodarone-associated hemoptysis.

Amiodarone is a benzofuran derivative with a chemical structure similar to thyroxine. Originally introduced to treat angina pectoris, amiodarone was found to have antiarrhythmic properties, and in 1985, was approved in the United States for treatment of life-threatening ventricular arrhythmias. It is now used for various ventricular and supraventricular arrhythmias refractory to conventional first-line medications, and as a result, side effects have been observed with increased frequency. The most severe and potentially life-threatening of these side effects is the development of pulmonary toxicity. Typically, amiodarone pulmonary toxicity (APT) is manifested by acute pneumonitis and chronic fibrosis. Amiodarone-associated hemoptysis (AAH) is a rare occurrence. The authors describe a case of AAH successfully treated with cessation of drug and steroid therapy.

Temporary epicardial atrial pacing electrodes: duration of effectiveness based on position.

BACKGROUND: To investigate the duration of effectiveness in the postoperative period of temporary epicardial atrial pacing electrodes on the right atrium, based on position. METHODS: The function of temporary epicardial atrial pacing electrodes were examined in 55 patients undergoing coronary artery bypass grafting from March 20, 1996, to July 31, 1996, at Allegheny University Hospitals, Hahnemann Division, Philadelphia, PA. There were 41 male and 14 female patients. The mean age was 71 years (range 35 to 86 years). Two atrial and two ventricular temporary epicardial pacing electrodes were placed at the termination of cardiopulmonary bypass. One atrial electrode was placed on the body of the right atrium at the junction of the superior vena cava (body electrode); the other was passed through the pursestring of the atrial cannulation site (appendage electrode). RESULTS: The mean thresholds for the atrial body electrodes on the operative day and postoperative days 1 and 2 were 4.96, 6.67, and 6.80 mA, respectively. The mean thresholds for the atrial appendage electrodes were 5.98, 7.50, and 8.59 mA, respectively. CONCLUSIONS: Temporary epicardial atrial pacing electrodes are more effective when the wires are placed in the atrial body of the right atrium than if they are wrapped within the pursestring of the right atrial appendage. As a result of these findings, the common practice of placing the pacing wire through pursestring tissue should be abandoned.

Management of infected implantable cardiac defibrillators.

BACKGROUND: The implantable cardiac defibrillator (ICD) was introduced clinically in 1980 for the management of ventricular arrhythmias. METHODS: From January 31, 1989, through May 29, 1996, 329 ICD devices were implanted at Allegheny University Hospital, Hahnemann Division, Philadelphia, Pennsylvania. All device-related infections were examined. RESULTS: Fifteen patients (5%) experienced infection of the generator component of the ICD. There were 14 male and 1 female patients with a mean age of 62 years (range, 38 to 79 years). All infections involved the generator with or without other component involvement. Complete removal of the system was performed in 7 patients, partial removal in 5, and the entire system was left intact in 3. In 4 patients (27%), further procedures were performed to remove additional infection. Three patients (20%) died during the hospital stay. CONCLUSIONS: Infection of ICD devices is a devastating event. We favor complete removal of the ICD generator and all the components when possible. Partial removal of the ICD unit (ie, generator only) is reserved for patients in whom the risk of complete removal is too high and infection is confined to the generator only.