PubMed Health⌕ Search

Biomedical subjects

D L Hayes

Publications and source records attributed to D L Hayes.

At least 19 recordsLinked to original sources
PubMed1992

Venous complications after insertion of a transvenous pacemaker.

We reviewed the incidence, clinical features, current diagnostic evaluations, and treatments of venous complications that can occur after implantation of a transvenous pacemaker. Of the approximately 80 published articles on the potential venous complications after implantation of a permanent transvenous pacemaker, we selected 63 that addressed the clinical features, diagnosis, and treatment of pacemaker lead-induced venous thrombosis, which occurs in approximately 30 to 45% of patients early or late after implantation of a transvenous pacemaker. Most patients with chronic deep venous thrombosis remain asymptomatic because of the development of an adequate venous collateral circulation. Clinical features of pacemaker lead-induced deep venous thrombosis, although rare, are easily recognized. They should be sought routinely during follow-up of all patients with transvenous pacemaker leads because venous obstruction can interfere with intravenously administered therapy, monitoring of central venous pressure, and revision of a pacemaker lead. Acute deep venous thrombosis is likely to be symptomatic. Early recognition and treatment of acute deep venous thrombosis may help to decrease the potential morbidity and mortality. The definitive diagnosis of pacemaker lead-induced venous thrombosis necessitates contrast-enhanced or digital subtraction venography. Management includes anticoagulation, thrombolytic therapy, surgical intervention, and, recently, percutaneous transluminal balloon venoplasty and depends on the duration, extent, and site of venous occlusion as well as the accompanying symptoms.

Cardiac Pacing, Artificial↗
PubMed1992

The next 5 years in cardiac pacemakers: a preview.

Advances in cardiac pacing continue at an astounding rate, and, occasionally, technologic capabilities are developed almost faster than they can be implemented clinically. The development and implementation of single- and dual-chamber rate-adaptive pacemakers have been the major thrusts in cardiac pacing in recent years. Rate-adaptive pacing will continue to be of primary interest in the future as investigators search for the perfect "sensor" and attempt to develop rate-adaptive pacemakers with multiple sensors. The "smart" pacemaker--that is, an autoprogramming, autodiagnostic device--will also be refined. The ultimate "smart" pacemaker would be capable of automatically adjusting output and sensing factors as well as altering the rate-adaptive variables and even changing the pacing mode in response to variations in the underlying rhythm. Other aspects of cardiac pacing that will be actively investigated include new low-threshold pacing lead designs, refinements of the single-lead pacing system capable of P-synchronous pacing, and diagnostic information that can be derived from sensors used for rate-adaptive pacing.

Cardiac Pacing, Artificial↗
PubMed1992

Follow-up of a minute ventilation rate adaptive pacemaker.

Although rate adaptive pacemakers are now frequently prescribed, there is limited information regarding long-term follow-up of patients with a pacemaker capable of rate adaptation. We have examined our patients in whom a pacemaker capable of rate adaptation via a sensor that determines minute ventilation has been implanted. After following a group of 42 patients for a mean of 13.2 months we have found this to be a reliable rate adaptive pacing system. The sensor was reliable long term, the system is easy to program, and sensor settings were changed infrequently.

Aged↗
PubMed1992

Evaluation of an in-line bipolar polyurethane ventricular pacing lead.

A study was undertaken to evaluate the performance of the Medtronic 4012 polyurethane in-line bipolar pacing electrode. One hundred twenty six patients implanted with the 4012 lead were followed by our clinic with 116 of these leads implanted at our institution. Patients were followed a minimum of every 4 months. Testing included the performance of stimulation thresholds, sensing thresholds, and provocative maneuvers to evaluate for myopotential inhibition testing a minimum of every eight months. There were 12 documented lead failures of the total 126 patients. Further analysis was limited to the ten failures occurring in the 116 leads implanted at our center. All ten failed leads utilized the suture anchoring sleeve. Six of the leads were left cephalic implants, three were right cephalic, and one was right subclavian. Manifestations of failure included: seven oversensing abnormalities, three undersensing, four loss of ventricular capture, one premature end of service, four lead impedance decreases to < 250 omega and some presentations in combination. No leads were explanted for evaluation. The Kaplan-Meier product limit method was used to estimate the time to lead failure. The probability of not experiencing a lead failure within the first 4 years of implant is estimated to be 0.9103 (SE = 0.0338). Pacemaker dependent patients implanted with the 4012 lead should be given special consideration for prophylactic replacement.

Actuarial Analysis↗
PubMed1992

Testing of work environments for electromagnetic interference.

A challenge for pacemaker therapists is whether a patient working in an environment with the potential for electromagnetic interference (EMI) can return to their work after a pacemaker has been implanted. Common practice has been to prohibit pacemaker patients from using electric welding machines. Twelve work environments and a new method for monitoring the pacemaker rhythm in the presence of EMI were tested. The new method uses a special memory called the event record found in several Siemens Pacesetter pacemaker models. Surface ECGs with a marking system, intracardiac electrograms, and a digital monitor were used to verify the results with event records. The results from several sources of EMI are reported. Twenty-one in vivo and in vitro tests were performed in the work environments of 12 patients. Event records were useful and accurate both in vivo and in vitro. Electric are welding machines up to 225 A did not affect these pacemakers. Arc welding machines using 1,000 A or more inhibited the in vitro test system within 1 or 2 meters of the weld or power generator. Electric welding machines with high frequency voltage superimposed on the welding current affected the pacemaker when it was within 2 meters of the power unit and 1 meter of the weld. Very large industrial degaussing coils affected pacemakers within 2 meters. The test method using event records was found to be an effective addition to monitoring the pacemaker. These results are specific for the pacemaker models tested. Such testing allows the physician to make a knowledgeable decision regarding return to work for the pacemaker patient in a high EMI environment.

Electricity↗
PubMed1992

A multicenter experience with a bipolar tined polyurethane ventricular lead.

A multicenter study was undertaken to determine the failure rate of a specific polyurethane bipolar tined pacing lead, the Medtronic 4012 pacing lead. Six centers in the United States and Canada implanted 1,190 Medtronic 4012 pacing leads. The study was designed to determine the probability and clinical manifestations of lead failure. Only failures compatible with an insulation problem were included. The probability of a 4012 lead failure by Kaplan-Meier analysis was 20.9% at 6 years after implantation. Failures were manifested as sensing abnormalities, failure to capture, early battery depletion, and significant decrease in measured impedance compared with the previous impedance measurements. Of the 95 definite lead failures, 16 (16.8%) were associated with symptoms similar to those experienced before pacemaker placement. The observed failure rate is unacceptable, and strong consideration should be given to replacing the 4012 pacing lead in pacemaker-dependent patients and closely monitoring nondependent patients.

Aged↗
PubMed1992

Timing cycles of permanent pacemakers.

A clear understanding of the components of the pacemaker timing cycles is crucial to understanding and interpreting paced electrocardiograms. The information given in this article provides basic rules for timing cycles for pacing modes currently in use and pacing modes less frequently used but of importance in understanding current timing cycles. Although understanding basic timing cycles allows interpretation of most paced electrocardiograms, manufacturer-dependent variations of the timing cycle operation make it necessary to be intimately familiar with the design of each pacemaker to be interpreted.

Bradycardia↗
PubMed1991

Advances in pacing therapy for bradycardia.

Advances have been made rapidly in the field of cardiac pacing. The most significant technologic advance is that of pacemakers capable of rate-adaptive pacing. Multiple types of sensors are now used for rate-adaptive pacing; some are commercially available and many are undergoing clinical investigation. In the near future, clinical investigation will begin on pacemakers that incorporate dual simultaneous sensors for rate-adaptive pacing. Significant improvement has been made in electrode design. Electrodes with low thresholds allow improved battery longevity. Steroid-eluting leads have proven reliable and capable of avoiding the early threshold rise seen with other electrodes. Standardization of pacemaker connector dimensions is now under way. The International Standards Organization has established the guidelines for connector standardization, and the guidelines have been adopted by the major manufacturers. The ultimate "smart" pacemaker would be capable of autoprogramming most or all of its programmable features. Many autoprogramming features have already been incorporated, and several others such as automatic programming of output and sensitivity are under investigation.

Bradycardia↗
PubMed1991

Standardized informal exercise testing for programming rate adaptive pacemakers.

It is essential that patients with pacemakers capable of rate modulation undergo some form of exercise testing to assure appropriate rate modulation. Informal exercise testing is a reasonable and less expensive alternative to formal treadmill testing. Empiric adjustment of the rate response parameters by assessing the patient's rate response while walking at a self-determined casual and brisk pace has been used. However, no normals exist to determine the appropriate rate response for a "casual" and "brisk" walk. Volunteers were tested with metronome-guided casual and brisk walks in an effort to standardize the informal exercise and determine expected heart rate response for these levels of activity. Results of the metronome-guided rate response in normal volunteers may be useful in determining the appropriate rate response for pacemaker patients when tested in such an informal manner.

Adult↗
PubMed1991

Antitachycardia pacemaker treatment of postoperative arrhythmias in pediatric patients.

An automatic antitachycardia pulse generator (Intertach 262-12) was implanted in each of six pediatric patients (mean age, 10 years) with drug-resistant and persistent postoperative supraventricular arrhythmias. Four had bradycardia-tachycardia syndrome, two after a Mustard procedure for transposition of the great arteries, one after a Senning procedure for the same anomaly, and one after a Fontan procedure for univentricular heart with transposition of the great arteries. Of the two remaining patients, one had atrial flutter after a modified Fontan procedure for univentricular heart and one had intra-atrial reentry tachycardia after a modified Fontan procedure for double-outlet right ventricle with pulmonary stenosis. During a mean follow-up interval of 31 months after implantation, pacemakers were activated on multiple occasions and functioned appropriately in all six patients. Complications necessitated six invasive interventions in three patients: erosion or infection of the system, adaptor fracture, and connector block fracture on one occasion each and lead dislodgment on three occasions. Four of the six patients continued to take drugs at the end of this study; however, all patients had their drug therapy reduced and one was taking digoxin only. The number of hospital admissions decreased after implantation. Despite a number of technical challenges, this newer multiprogrammable antitachycardia pacemaker appears to be a valuable addition to the treatment of refractory postoperative supraventricular tachyarrhythmias in pediatric patients.

Adolescent↗
PubMed1990

Venous obstruction due to permanent transvenous pacemaker electrodes: treatment with percutaneous transluminal balloon venoplasty.

Transvenous placement of permanent pacemaker leads is currently the most common method for permanent cardiac pacing. Venous abnormalities, in particular venous stenosis or thrombosis (or both) frequently have been described, although most patients remain asymptomatic because of the development of an adequate venous collateral circulation. Venous obstruction often first becomes apparent during pacemaker lead revision, when difficulty passing the new pacing lead is encountered. In this report, we present two cases of venous stenosis and thrombosis due to permanent transvenous pacemaker electrodes and the use of percutaneous transluminal balloon venoplasty to relieve the venous obstruction.

Aged↗
PubMed1990

Facilitation of the subclavian-introducer technique with contrast venography.

The subclavian-introducer technique is a rapid and easily performed method of obtaining venous access for implanting permanent pacemaker electrodes. Although this technique has facilitated the participation of nonsurgeons in pacemaker implantation, the potential for complications is increased over the venous cutdown approach. This is particularly true in difficult cases, such as those with prior lead implants, venous thrombosis, or anomalous venous return. This article describes the use of contrast venography for facilitating an otherwise "blind" subclavian venipuncture. This method should make use of the subclavian-introducer technique safer.

Catheterization, Peripheral↗
PubMed1990

Quantitative analysis of Wenckebach behavior in DDD pacemakers.

Wenckebach-type behavior in P-synchronous pacing modes allows a gradual transition into 2:1 block. As this behavior is dependent on precise timing intervals, it can be quantitated with mathematical equations. In this report, equations for quantitating the Wenckebach escape rate and the (N + 1)/N block points have been derived. These equations were then used to produce plots of Wenckebach escape rates for given AV intervals, atrial refractory periods, and atrial rates. These equations were validated utilizing a DDD pulse generator interfaced with a patient simulation device. The predicted values for the Wenckebach escape rate and ratio (n = 33) correlated highly with the observed values (r = 0.99, P less than 0.0001, and r = 0.97, P less than 0.0001, respectively) thereby validating the derived equations. This quantitative analysis has allowed a close look at the pacing behavior between the maximum tracking rate and the 2:1 block point. These equations may be clinically useful for assessing whether a nontriggering P wave resulted from Wenckebach type block or atrial undersensing and for the more complicated interval analysis in DDDR pacing with rate responsive AV delays and postventricular atrial refractory periods.

Computer Simulation↗
PubMed1989

Advantage of discrepant upper rate limits in a DDDR pacemaker.

The latest cardiac pacing mode to become available is the dual-chamber, rate-modulated mode (referred to as DDDR), which restores both rate responsiveness and atrioventricular synchrony in patients with sinus node dysfunction and atrioventricular block. This pacing mode combines dual-chamber and single-chamber rate-modulated technologies. Thus, it is necessary to program both a maximum tracking rate and a maximum sensor rate, as in dual-chamber and single-chamber rate-modulated devices, respectively. These two upper rate limits are usually programmed to equivalent values. The case described herein illustrates one advantage of programming discrepant upper rate limits. The rapid tracking of supraventricular tachycardias was prevented by lowering the maximum tracking rate to 100 ppm. A maximum sensor rate of 140 ppm still allowed an adequate rate response during activity.

Aged↗
PubMed1989

Utility of rate histograms in programming and follow-up of a DDDR pacemaker.

Dual-chamber, rate-modulated pacing (DDDR) is the newest available pacing mode. To optimize programming of the rate response options for such a pacemaker, the physician must adopt an organized follow-up method, including use of some type of exercise testing to assess the programmed options of the pacemaker. Because the patient may achieve a substantial "training effect" after a rate-modulated pacing device has been implanted, the device probably should be reprogrammed at 1 month or after implantation. Programming and follow-up can be considerably facilitated by the use of pacemaker-generated "rate histograms," which conveniently display the distribution of rate responses to various levels of activity.

Adult↗