Late complications in patients with pectoral defibrillator implants with transvenous defibrillator lead systems: high incidence of insulation breakdown.

As the majority of ICDs with transvenous leads are now implanted in the pectoral region, complications associated with the technique are being identified. To determine the incidence of lead complications in patients with transvenous defibrillator leads and ICDs implanted in the pectoral region, 132 unselected consecutive patients with transvenous defibrillator leads had ICDs implanted in the pectoral region. Three lead systems were used: (1) lead system 1 (45 patients) consisted of a transvenous pacing sensing lead and a superior vena cava coil with a submuscular patch used for defibrillation; (2) lead system 2 (36 patients) utilized a CPI Endotak lead system; and (3) lead system 3 (51 patients) utilized a Medtronic Transvene lead system. Patients were followed for 3-54 months (cumulative 2,269, mean 18 months). The average duration of follow-up with the three systems was 32, 12 and 11 months, respectively. At 30 months follow-up, all three lead systems had a low incidence of complications. However, there was a 13% overall incidence (45% actuarial incidence) of erosion of the insulation of the pacing sensing lead of system 1 at 50 months of follow-up. All lead complications were seen in patients with ICDs whose weights were > 195 g and volumes > 115 cc. The erosion was probably a consequence of the pressure by the large ICD against the lead in the pectoral pocket. Follow-up with lead systems 2 and 3 is relatively short (average 12 months) but no lead erosions were seen. Pectoral implantation of ICDs with long transvenous leads and large generators is associated with a moderate risk of late complications in the form of insulation breaks caused by pressure of the generator against the leads. The use of less redundant leads coupled with smaller ICDs will probably eliminate this complication.

Use of single lead VDD pacing in children.

The development of transvenous ventricular pacing leads with proximal electrodes capable of atrial sensing and the recent availability of smaller generators has created the opportunity to treat children with complete AV block and normal sinus node function with a transvenous single lead VDD pacing system. Studies in adults have demonstrated this system to be efficacious with low complication rates. Transvenous single lead VDD pacemakers were implanted in ten children, aged 5-15 years, between December 1993 and April 1996, in our institution. The indications were complete AV block with severe bradycardia in 5 patients, second-degree or complete AV block following congenital heart surgery in 3, complete AV block with long QT syndrome in 1, and second-degree AV block and syncope in 1. There were no complications related to the procedure in any case. P and R wave amplitudes were measured and thresholds were determined intraoperatively on all patients. Amplitudes and thresholds were remeasured on seven patients with a mean follow-up of 17 months; Holter monitors were performed on seven patients with mean follow-up of 16 months. P and R wave amplitudes were generally diminished at follow-up compared to initial values but remained within an acceptable range for all patients. Four patients required reprogramming after pacemaker insertion, 1 received an atrial lead for dual chamber pacing, 1 required reposition for lead dislodgment, and 1 patient required a new lead for an inadequate ventricular pacing threshold. No patient had evidence of failure to sense or capture as evaluated by Holter monitoring at last follow-up. Single lead VDD pacing systems can be successfully used in properly selected children with high degree or complete AV block with normal sinus node function.

Incidence of malposition of polyvinylchloride and red rubber left-sided double-lumen tubes and clinical sequelae.

Currently, fiberoptic bronchoscopy (FB) is recommended for correct positioning of double-lumen endobronchial tubes (DLTs) because of the high incidence of malpositions not appreciated by clinical signs. The aims of this study were to assess whether clinical signs allow accurate confirmation of adequate positioning with left red rubber (RR) or polyvinyl-chloride (PVC) double-lumen tubes and to compare the incidence of malpositions between the two tubes. Another goal was to assess whether these malpositions, not appreciated by clinical assessment, adversely affected outcome. Twenty-one adult patients scheduled for elective thoracic surgery were randomly assigned to the RR (11 patients) or PVC group (10 patients). After endobronchial intubation, the position of the tubes was adjusted until clinically satisfactory lung separation had been achieved. A single investigator performed all the FB assessments were performed in the supine (SUP) and lateral positions. The anesthesiologists responsible for the clinical evaluation were "blinded" to the bronchoscopic findings. While in the SUP position, the tube was "too deep" to permit visualization of the carina during tracheal bronchoscopy in 5 patients (2 RR, 3 PVC). In 17 of 21 (10 RR, 7 PVC), the bronchial cuff could not be visualized, although in 1 patient (RR group), the cuff was overinflated and bulged out to partially obstruct the right main bronchus orifice. Bronchial bronchoscopy showed 4 of 11 patients in the RR group in whom the left upper lobe orifice was occluded compared with 1 only in the PVC group.(ABSTRACT TRUNCATED AT 250 WORDS)

Myopotential interference with DDD pacemakers: endocardial electrographic telemetry in the diagnosis of pacemaker-related arrhythmias.

Skeletal myopotentials may inhibit the output of unipolar demand ventricular pacemakers, resulting in protracted episodes of asystole in susceptible patients. The new DDD-mode pacemakers have, in addition to a unipolar ventricular lead, a unipolar atrial lead to enable atrioventricular sequential or atrial synchronous function. During clinical investigation of a new dual-unipolar cardiac pacing system programmed to operate in the DDD mode (Pacesetter AFP models 281 and 283), 6 patients were noted (5 men and 1 woman, aged 22 to 68 years) who manifested paroxysmal acceleration of ventricular pacing rate approaching the maximal tracking rate. Two patients also had abrupt slowing or cessation of ventricular output. With the use of atrial electrographic recordings (obtained with telemetry), the following mechanisms of rate change were found: myopotential tracking, myopotential inhibition, interference-mode asynchronous operation, sudden increases in sinus rate, and pacemaker-mediated reentrant tachycardia. In all patients, reprogramming of the implanted devices, based on telemetered atrial electrography, resulted in disappearance of the arrhythmias and loss of symptoms while maintaining the DDD pacing mode. Thus, several mechanisms of rhythm disturbances are peculiar to dual-chamber cardiac pacing systems that use unipolar electrodes. Endocardial telemetry combined with extensive programming capability offers the best opportunity for proper diagnosis and management of these problems.

Combined left ventricular aneurysm and coronary artery bypass surgery: long-term results of 100 consecutive patients.

Forty-four percent of 2,367 patients who had operations for the complications of coronary atherosclerosis between 1971 and 1977 were noted to have major left ventricular wall motion abnormalities. Of this group, 100 patients required left ventricular aneurysm resections or plications (4.2%). There were 85 men and 15 women. Their average age was 52 years (range, 30 to 68 years). Concomitant coronary artery bypass grafting was required in 95 patients. The operative mortality was 7% and the actuarial survival at six years was 78%. Patients were followed for an average of 31 months (range, 3 to 72 months). Eighty-eight percent of the survivors had excellent or good results with improvement of their functional status to the New York Heart Association classes I and II. Age, congestive heart failure, and poor residual left ventricular function had an adverse effect on the outcome of these patients. Concomitant coronary artery bypass grafting seems to have favorably influenced their outcome and functional recovery. Surgical judgment is of great importance in selecting which patients require left ventricular aneurysm resection.