Three hundred and fifty-three consecutive patients with permanent transvenous pacemakers

Bradyarrhythmia profile and associated diseases in 1,265 patients with cardiac pacing

Twelve hundred and sixty-five patients with implanted cardiac pacemakers were reviewed for known associated conditions and for the resulting bradycardia patterns. The group bradyarrhythmia profile was AV block in 75%, sick sinus syndrome (SSS) in 21% and combined arrhythmias in 4%. Thyroid diseases and acquired valvular disease were frequently associated with AV block especially of the Wenckebach type. Sick sinus syndrome occurred significantly more frequently in women (28%) than in men (26%). Isolated bradyarrhythmias (i.e., with no associated disease) were 22% of the entire group with a 26% incidence of SSS and with a significant association with previous gastric resection, pernicious anemia, and malabsorption compared to the groups with other associated diseases. Degenerative cardiac lesions caused by malabsorption and undiagnosed hypothyroidism in elderly women may contribute to the group of apparently isolated bradyarrhythmias.

Complications of permanent transvenous cardiac pacing: a 14-year review of all transvenous pacemakers inserted at one community hospital

Five hundred and eighty-nine consecutive transvenous pacemakers implanted between January 1, 1971 and January 1, 1985 were reviewed. A complication incidence of 17% early in the study period (1971-1977) was caused by electrode displacement and perforation. As of 1975, smaller-sized electrodes with endocardial fixation were used and were associated with a significant decrease in this complication incidence to 2% by 1985. All other complications occurring during the entire study period (1971-1985) occurred at a frequency of 3% (20/589). Infection occurred in 3 of 589 cases; there were no extrusions or erosions. No mortality was attributed to pacemaker insertion. The "twiddler" syndrome seems to be increasing in frequency. Transvenous permanent pacing can be accomplished today with a low complication rate of 5% or less. The majority of these complications are minor and can be corrected easily. Our studies suggest that the reduced complication incidence is mainly related to improved technology.

Significance of ventricular pauses of three seconds or more detected on twenty-four-hour Holter recordings

The natural history of patients with asymptomatic prolonged ventricular pauses and the indications for permanent pacing are controversial. To examine this problem, 6,470 consecutive 24-hour Holter recordings were reviewed between 1979 and 1983 for the presence of ventricular pauses of at least 3 seconds. Fifty-two patients (0.8% of total), 22 men and 30 women, were identified with an average longest pause duration of 4.1 seconds. Holter recordings were requested to evaluate syncope in 14 patients (27%), dizziness in 9 (17%) and other reasons in 29 (56%). Causes of the pauses were sinus arrest in 22 patients, atrial fibrillation with slow ventricular response in 18 patients and atrioventricular block in 12. Holter recordings were also evaluated for the presence of tachyarrhythmias. Six patients had nonsustained ventricular tachycardia and 7 had supraventricular tachycardia. Five of the 52 patients (10%) had dizziness or syncope during pauses. Twenty-six patients (50%) received permanent pacemakers. The paced (26 patients) and unpaced (26 patients) groups were similar in the length and etiology of pause, associated tachyarrhythmias, presence of bradycardia-related symptoms, prevalence of organic heart disease, medications and length of follow-up. Four patients in the paced group and 2 in the unpaced group died, yielding 3-year actuarial survival probabilities of 78% and 85%, respectively. It is concluded that ventricular pauses of 3 seconds or longer are uncommon, these pauses usually do not cause symptoms, and the presence of these pauses does not necessarily portend a poor prognosis or the need for pacing in asymptomatic patients.

The values and limitations of deductive analysis and electrophysiological testing in patients with sinoatrial arrhythmias

We reviewed the values and the limitations of deductive analysis and electrophysiological testing of sinoatrial arrhythmias (SAA). Both methods have a place in the evaluation of SAA and are complementary. Careful analysis of the surface ECG and the response of the sinus node to various tachyarrhythmias and to atrial premature beats can provide important information about the automaticity of the sinus node and sinoatrial and atriosinus conduction. Because of the sporadic nature of some SAA, the surface ECG sometimes must be supplemented by ambulatory ECG recording. This approach improves one's ability to analyze the underlying mechanism and it can also clarify the relation between the SAA and the patient's symptoms. Electrophysiological testing can be employed to reproduce certain SAA and to assess the effects of various drugs on sinus node function. This approach is superior to deductive analysis in the identification of some sinoatrial conduction abnormalities and sinus node reentry. Among the disadvantages of electrophysiological testing are its invasive character and the fact that normal electrophysiological results do not exclude sinus node dysfunction. A definitive clarification of the underlying mechanism of SAA requires direct recording of the sinus node electrogram.

Nine-year experience during 1973-1982 with 1,060 pacemakers in 805 patients

Our experience with over one-thousand pacemaker implantations resulting in almost 28,000 patient pacing months is reviewed. Data are presented regarding changing indications for pacing, experience with numerous pacemaker types, patient survival, comparative mortality of sick sinus syndrome and complete heart block, and telephone surveillance. Consistent with some previous reports, there were high one- and two-year post-implant mortality rates, and advanced age at implant was associated with decreased survival. Males had a significantly higher mortality rate. The period reported covers the transition from utilization of mercury-zinc batteries to lithium power cells and other new technology; significant differences were observed in device reliability and patient mortality when comparing these eras. Certain patients evidenced disparate survivals, the most notable difference being seen in those who received their primary implants prior to 1976 and subsequent implants of more modern units.

Porous electrodes: concept, technology and results

Porous electrodes were designed and implanted to optimize sensing and pacing performance of the cardiac pacemaker. These electrodes were manufactured to create an effective, atraumatic endocardial interface in order to (1) decrease chronic stimulation thresholds and pacemaker current drain; (2) facilitate fibrous protein tissue ingrowth for reduced electrode displacement; and (3) to create a large electrolytic surface area of contact for reduced polarization voltage, thus improving impulse and electrogram transmission. Thus far, clinical results demonstrate reduced long-term threshold and decreased current drain. Long-term advantages of porous electrodes remain to be determined.

The epicardial screw-on electrode. An analysis of 114 consecutive patients with complete one-year follow-up

This study assesses the clinical and electrode complications associated with the use of the epicardial screw-on electrode technique for permanent ventricular pacing. The records of 114 consecutive patients who received screw-on epicardial electrodes were analyzed in-hospital and at one year following implantation. We compared two techniques of implanting the screw-on electrode: 72 transmediastinal (TM) and 42 subxiphoid (SX) procedures. Baseline clinical inequalities were not apparent between the SX and TM patients. There was one operative death in the SX series and none among the TM patients. Total hospital mortality was 4% in the SX group and 2% in the TM group. In-hospital morbidity in the SX series (13/72-18%) was less than the TM group (14/42-33%), largely due to pleural entry and necessity for more frequent chest tube placement in TM patients. Electrode complications were low in both groups (3% in-hospital and 3% late; total 6/114, or 5%). Morbidity and mortality of these approaches to direct myocardial pacing remain noticeably higher than reported results of some transvenous series. Excellent electrode stability can be attained using the screw-on electrode, however, and the SX approach offers lower hospital morbidity than the TM method.

Pericardial complications of endocardial and epicardial pacing

A patient with complete atrioventricular block was fitted with a temporary endocardial pacing wire via a right subclavian percutaneous approach. The result was initially satisfactory, but within a few days radiography for left-sided chest pain showed pneumopericardium. A permanent epicardial pacing system was therefore substituted and she remained well for three months. She was then admitted for syncope: the pacemaker was failing to capture, and radiography showed pericardial and pleural effusion. A new permanent endocardial pacing system using a wedged electrode was inserted and she made an uncomplicated recovery. Pneumopericardium complicating endocardial pacing has apparently not been reported before. Presumably the electrode had penetrated both the right ventricle and the pericardium into the adjacent lung.