Indications For Pacemaker Implantation Research Articles

Intrathoracic Gadgets In The New Millennium: Primer On Pacemakers And Cardioverter-defibrillators

The invention of a simple, battery powered cardiac pacemaker by Earl Bakken and C W Lillehei in 1958 has prevented millions of untimely deaths. Major advances in pacemaker technology, including development of demand modes and rate responsiveness, have permitted these patients to lead relatively normal lives as well. Additionally, the creation of the implantable cardioverter-defibrillator by Michael Mirowski in 1985 has decreased the rate of sudden death in patients prone to tachydysrhythmias. These technologic advancements, coupled with the electronically hostile environments of the operating and procedural rooms, have complicated the job of delivering anesthetics to these patients for a variety of procedures. Much of the information that has been published regarding the care of these patients has become outdated, and new indications for implantation of pacemakers, ICDs, or both have appeared. In this primer, we attempt to provide basic information about implantable pulse generators and the care of the patient with these intrathoracic gadgets.

Intrathoracic Gadgets In The New Millennium: Primer On Pacemakers And Cardioverter-defibrillators

The invention of a simple, battery powered cardiac pacemaker by Earl Bakken and C W Lillehei in 1958 has prevented millions of untimely deaths. Major advances in pacemaker technology, including development of demand modes and rate responsiveness, have permitted these patients to lead relatively normal lives as well. Additionally, the creation of the implantable cardioverter-defibrillator by Michael Mirowski in 1985 has decreased the rate of sudden death in patients prone to tachydysrhythmias. These technologic advancements, coupled with the electronically hostile environments of the operating and procedural rooms, have complicated the job of delivering anesthetics to these patients for a variety of procedures. Much of the information that has been published regarding the care of these patients has become outdated, and new indications for implantation of pacemakers, ICDs, or both have appeared. In this primer, we attempt to provide basic information about implantable pulse generators and the care of the patient with these intrathoracic gadgets.

Intrathoracic Gadgets In The New Millennium: Primer On Pacemakers And Cardioverter-defibrillators

The invention of a simple, battery powered cardiac pacemaker by Earl Bakken and C W Lillehei in 1958 has prevented millions of untimely deaths. Major advances in pacemaker technology, including development of demand modes and rate responsiveness, have permitted these patients to lead relatively normal lives as well. Additionally, the creation of the implantable cardioverter-defibrillator by Michael Mirowski in 1985 has decreased the rate of sudden death in patients prone to tachydysrhythmias. These technologic advancements, coupled with the electronically hostile environments of the operating and procedural rooms, have complicated the job of delivering anesthetics to these patients for a variety of procedures. Much of the information that has been published regarding the care of these patients has become outdated, and new indications for implantation of pacemakers, ICDs, or both have appeared. In this primer, we attempt to provide basic information about implantable pulse generators and the care of the patient with these intrathoracic gadgets.

Standard Indications and Contraindications for Pacemaker Implantation: The 1998 ACC/AHA Guidelines

A number of new indications for pacemaker implantation were included in the new guidelines. Each of these areas will be discussed in much greater detail and context in subsequent chapters.

Influence of Cardiac Pacing Mode on Left Atrial Appendage Flow Velocity: Implication to Systemic Embolism During VVI Pacing.

Previous studies have shown that the incidence of thromboembolism is higher in patients with single-chamber ventricular demand (VVI) pacemakers than in patients with dual-chamber (DDD) pacemakers. However, data on left atrial appendage flow velocity in pacing patients are limited. To investigate the influence of the pacing mode on the left atrial appendage flow velocity, we studied 19 patients with permanent DDD pacemakers and measured the left atrial appendage flow velocity by transesophageal echocardiography at baseline (during DDD pacing) and after switching to VVI pacing. The indications for pacemaker implantation were second- and third-degree atrioventricular block (AVB group, n = 11) and sick sinus syndrome (SSS group, n = 8). Compared with the DDD pacing mode, there was a significant decrease in the left atrial appendage flow velocity during VVI pacing in both the SSS group (43 +/- 14 vs 23 +/- 7 cm/sec, P < 0.05) and the AVB group (59 +/- 18 vs 41 +/- 18 cm/sec, P < 0.05). In eight patients with persistent retrograde ventriculoatrial conduction during VVI pacing, the left atrial appendage flow velocity was markedly decreased (from 43 +/- 16 to 25 +/- 9 cm/sec, P < 0.05). In five (63%) of the eight patients, left atrial appendage flow velocity was less than 25 cm/sec. A reduction in left atrial appendage flow velocity when switching from DDD to VVI pacing may account for an increased risk of thrombus formation in the left atrial appendage (an increased thromboembolic risk in patients in sinus rhythm with VVI pacemakers).

Sinus Node Dysfunction

Sinus node dysfunction (SND) is the indication for pacemaker implantation in 35–50% of all patients undergoing primary pacemaker implantation [1]. SND is characterized by syncopal attacks, dizzy spells, or heart failure due to sinus arrest, sino-atrial block, or sinus bradycardia. Approximately 50% of patients with SND suffers from paroxysmal atrial ~brillation, the brady-tachy syndrome, which is associated with an increased risk of arterial thromboembolism [2]. Although it is well recognized that cardiac pacing is effective in abolishing bradycardia-related symptoms in patients with SND, the most optimal pacing mode is, however, still debated. The present review will focus upon the results of recently published prospective trials on selection of pacing mode in SND and the clinical consequences of these results.

Steroid‐Eluting Epicardial Pacing Electrodes: Six Year Experience of Pacing Thresholds in a Growing Pediatric Population

Indications for pacemaker implantation in the pediatric population often include sinus or atrioventricular node dysfunction following surgery for congenital heart defects. However, patient size, cardiac defects, and vascular and valvular concerns may limit transvenous lead utilization. Since the epicardial surface of these patients often exhibits variable degrees of fibrosis from scar tissue formation or pericardial adhesions, chronic low output (2.5/1.6 V, 0.3 ms) epicardial pacing from implant is not currently recommended in children due to frequent threshold changes and electrode exit block. As a result, pacing in children is often viewed as a less efficient system than in adults. The addition of steroid combined with newer low threshold electrode designs however stabilizes the electrode-tissue interface and eliminates postimplant changes seen with standard smooth surface electrodes potentially permitting efficient chronic pacemaker application to all patient ages. The stability of chronic low output epicardial pacing with steroid-eluting electrodes was prospectively studied in 22 patients (ages 2 days-18.5 years, median 3.5 years) for up to 6 years. Chronic pulse width thresholds were compared according to implant site and association of prior cardiac surgery. A total of 26 pacing leads were implanted. The acute implant mean pulse width threshold (2.5 V) for all the electrodes studied was 0.10 ms +/- 0.05 ms. Stable low thresholds were maintained for up to 6 years without significant variation from implant. Mean ventricular pulse width thresholds (0.12 ms +/- 0.05 ms) were significantly higher (P < 0.001) than atrial thresholds (0.06 ms +/- 0.03 ms) at implant and throughout the study period. The thresholds in the patients following cardiac surgery were comparable to those without previous cardiac surgery (P = NS). Stable low thresholds may be chronically maintained for up to 6 years for epicardial steroid-eluting electrodes irrespective of pacing site or associated cardiac surgery.

Pacing mode and long-term survival in elderly patients with congestive heart failure: 1980-1985.

Dual-chamber pacing may improve short-term hemodynamics and functional class in some patients with congestive heart failure, even in the absence of conventional indications for pacemaker implantation. However, the impact of different pacing modes on survival of patients with congestive heart failure is controversial. In this retrospective study we analyzed survival data from 546 elderly patients, aged 70 years and older, who underwent implantation of a permanent dual-chamber (DDD, n = 62, DVI, n = 102) or single-chamber (VVI) pacemaker (n = 382) between 1980 and 1985. Survival was further analyzed according to the presence of absence of congestive heart failure, and pacemaker mode (DDD vs. DVI vs. VVI). Overall, dual-chamber pacing (DDD and DVI) was associated with a more favorable long-term outcome when compared with single-chamber ventricular pacing, although differences were only significant for DDD pacing (P = 0.002). When patients with and without preexisting congestive heart failure were analyzed separately, survival following dual-chamber pacing (DDD and DVI) was significantly better than survival following single-chamber pacing in patients without congestive heart failure (P = 0.03), but not in patients with preexisting heart failure (P = 0.139). When patients were analyzed according to the electrophysiological indication for pacemaker implantation, overall survival of patients with AV block (P = 0.0025) but not sinus node dysfunction (P = 0.346) was improved with dual-chamber pacing. This survival advantage in patients with AV block following dual-chamber pacing was lost in the presence of heart failure (P = 0.11). These findings suggest that dual-chamber pacing, in particular DDD pacing, improves the survival in elderly patients without preexisting congestive heart failure. In contrast to the short-term hemodynamic improvement observed in selected patients with congestive heart failure, dual-chamber pacing in elderly patients with congestive heart failure, paced for conventional indications, is not associated with improved survival when compared with single-chamber ventricular pacing.

Pacemakers and anaesthesia

Since the first permanent cardiac pacemaker was successfully implanted in 1958 there has been a vast improvement in pacemaker technology and reliability. This has been accompanied by a broadening of indications for pacemaker implantation. The initial emphasis was placed on pacemaker implantation as a life saving procedure in patients with complete heart block whose prognosis without treatment was very poor and had a mortality rate of up to 30% per year. Today the emphasis has shifted towards improving quality of life and allowing a normal lifestyle in patients whose endogenous cardiac rhythm impairs their ability to cope with the demands of day-to-day life. This article is in two major parts. The first part will introduce the pacemaker technology available, the types of pacemakers and NBG code, the indications for pacemaker treatment and the British Pacing and Electrophysiology Group (BPEG) recommendations for the selection of pacing modes for individual conditions. The second part will deal with patient management and causes of pacemaker malfunctions.

1021-59 Influence of Cardiac Pacing Mode on Left Atrial Appendage Function: Implication for the Cause of Systemic Embolism in VVI Pacing

A higher incidence of systemic embolism has been observed in patients with VVI pacing compared to DDD pacing. However, the cause of systemic embolism in VVI pacing remains unclear. Previous studies have demonstrated that thrombus formation and systemic embolization are related to left atrial appendage (LAA) dysfunction. To investigate the influence of pacing mode on LAA function, we performed transesophageal echocardiography in 16 patients (mean age 65) with permanent DDD pacemakers. The indications for pacemaker implantation were third degree atria-ventricular block (A-V block, n = 10) and sick sinus syndrome (SSS, n = 6). All had shown sinus rhythm at implantation. We measured peak LAA emptying and filling flow velocities during both DDD and VVI pacing at 60 beats/min. The data are summarized below: Peak LAA flow velocity (cm/s) p value DDD VVI A-V block (n = 10) 58 ± 18 40 ± 19 &lt;0.01 SSS (n = 6) 41 ± 13 24 ± 7 &lt;0.05 Total (n = 16) 52 ± 18 34 ± 18 &lt;0.01 Peak LAA flow velocities decreased significantly when a pacemaker was reprogrammed from DDD to VVI pacing mode, especially in patients with SSS. LAA function was impaired in VVI pacing compared with that in DDD pacing. These results suggest that impaired LAA function in VVI pacing may predispose the chamber to thrombus formation, which may playa role in the mechanism of the embolization.

Long-term results of pacemaker therapy after orthotopic heart transplantation.

The objectives of this study were to identify: (1) the indications for pacemaker implantation; (2) the long-term survival; (3) the percentage of bradyarrhythmias below 50 beats/min persisting for more than 3 months; and (4) the variables predicting persistent bradyarrhythmias following orthotopic heart transplantations. During the recent decade (August 1, 1981 through December 31, 1991), 237 patients underwent orthotopic heart transplantation at our institution. Twenty-six recipients (11%) showed evidence of a symptomatic bradyarrhythmia due to sinus node dysfunction (n = 25) or complete heart block (n = 1), which required insertion of a permanent pacing device. During a mean follow-up period of 17.2 months (range 3 to 57 months), five patients (19%) died and one was lost to follow-up. Actuarial survival at 1 and 4 years were 81% and 65%, respectively, as compared to 79% and 69%, respectively, in patients without permanent pacemakers. Holter monitoring after 3 months (n = 25) and 1 year (n = 14) showed a spontaneous heart rate below 50 beats/min in six (24%) and three patients (18%), respectively. None of the tested variables predicted the necessity of initial pacemaker implantation. However, in patients requiring permanent pacing for a period longer than 3 months, ischemic time of the donor heart was found to be significantly longer as compared to the other patients (221 +/- 76 min vs 137 +/- 91 min, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency and mechanism of bradycardia in cardiac transplant recipients and need for pacemakers

Orthotopic cardiac transplantation is occasionally complicated by unexplained bradyarrhythmias. Sinus node injury as a consequence of operation or acute rejection has anecdotally been linked to the development of bradycardia early after transplantation. These arrhythmias are empirically managed by pacemaker implantation, the indications for which remain poorly defined. This retrospective study examined the 20-year experience of our institution with bradyarrhythmias after transplantation to determine the predisposing factors and indications for pacemaker implantation. Forty-one of 556 patients in our cardiac transplant program (7.4%) received permanent pacemakers between 1969 and 1989. The predominant rhythm disturbances were junctional rhythm (46%), sinus arrest (27%) and sinus bradycardia (17%). Most patients were asymptomatic (61%), and presented in the early post-transplant period (73%). Four possible predisposing factors were evaluated: (1) graft ischemic time, (2) rejection history, (3) use of bradycardia-inducing drugs, and (4) anatomy of blood supply to the sinoatrial (SA) node. No significant differences existed between patients with and without pacemakers with regard to the first 3 variables. However, after transplantation angiograms showed that prevalence of abnormal SA nodal arteries was greater in patients with than without pacemakers (p < 0.02). Pacemaker follow-up at 3, 6 and 12 months showed persistent bradycardia (60 to 90 beats/min) in 88, 75 and 50% of patients, respectively. The most common pacemaker complication (15%) was lead displacement at time of biopsy. These results suggest that disruption of the SA nodal blood supply may be an important predisposing factor in the development of bradycardias.

Pacemakers in children: An update

This report reviews recent pacemaker technological advances as they apply to infants, children, and adolescents. Indications for pacemaker implantation in children have evolved since the 1984 Joint Task Force Guidelines. Recent data show that pacemaker implantation should be strongly considered in patients who have (1) asymptomatic congenital complete AV block with a mean heart rate less than 50 beats/min or other evidence of junctional instability; (2) congenital AV block with long QT interval; or (3) congenital long QT syndrome with bradyarrhythmias, or when conventional beta-blocker therapy is unsuccessful. Permanent pacemaker implantation is not necessarily an effective prophylactic measure against sudden death in patients following their operation who are receiving drug therapy for atrial tachyarrhythmias, and so is not absolutely indicated. New developments in lead technology have made transvenous lead systems more feasible for pediatric use. Because epicardial leads are required for small infants and for cosmetic reasons in some older children, design improvements are needed to enhance epicardial lead performance. Rate-responsive pacing is an acceptable alternative to dualchamber pacing for augmenting exercise tolerance, and for children with sinus node dysfunction it is the preferred pacing mode. Pacemakers with automatic antitachycardia capabilities and with noninvasive electrophysiology features are valuable in children with atrial tachyarrhythmias. New data suggest that chronic atrial pacing also may be effective in controlling atrial tachyarrhythmias. New developments in pacemaker systems for the young parallel those for the older population, but differences between adult and pediatric patients demand ongoing increased participation by pediatric cardiologists.

Guidelines for Cardiac Pacing

ABSTRACT Cardiac pacing has enjoyed rapid growth since it became technically available about 25 years ago. Its indications since then have broadened to include virtually every known arrhythmia. Criteria for pacing, published by the American College of Cardiology and the American Heart Association in 1983, and since then adapted with modification by Medicare, divide indications for implantation of pacemakers into the following three classes: (1) pacing clearly required, (2) some disagreement about necessity, and (3) contraindicated.Guidelines for Cardiac Pacing is a videotape moderated by William C. Roberts, MD, editor in chief, American Journal of Cardiology. Panel members are Drs Leonard S. Dreifus, Seymour Furman, Paul C. Gillette, Jerry C. Griffin, David L. Hayes, and Paul A. Levine. Intermedics has produced Guidelines for Cardiac Pacing to clarify certain controversial gray areas concerning the use of pacemakers in patients with congenital heart block, acquired heart block, sinoatrial block, and hypersensitive carotid sinus

Progress in Cardiac Pacing

Cardiac pacing therapy has evolved rapidly since the first device was implanted 26 years ago. 1 Technologic progress has provided the clinician with microprocessor-based multiprogrammable pulse generators, long-lived power sources, and reliable atrial and ventricular lead systems. Along with these developments, the indications for singleand dual-chamber pacing have broadened considerably since the early pacemakers were implanted for complete heart block. They now include the bradyarrhythmic manifestations of the sick sinus syndrome and some types of tachycardias. 2-4 As a result, the number of patients in the United States with pacemakers is over 500,000 and growing. 5 The practicing physician is thus very likely to encounter patients who either have or need a pacing system. In the past, the physician caring for a patient was concerned primarily with establishing the indications for pacemaker implantation. Now pacing therapy must be individualized to match the patient's needs with the most suitable pacing mode

The clinical significance of an exercise test during His-bundle electrocardiography.

In 39 patients with an average age of 47±17 years (14 to 75 years) submaximal exercise was performed in addition to atrial pacing (AP) during necessaryHis-bundle Ecg (HBE) diagnostic procedure. AP induced a rate dependent AH prolongation without alterations of the HV time. During the exercise stress test (bicycle ergometer) the AH interval decreased from 113±32 msec to 87±23 msec significantly, whereas the HV time increased from 45±8 msec at rest to 51±9 msec significantly in 32 patients. In contrast, 5 patients revealed AH prolongation or decrease of the HV time during exercise. In 12 patients treated with an iv. injection of 0.8 mg prindolol the AH intervals were prolonged compared with the pre-medication phase, whereas the HV times remained unchanged. Again exercise induced a decrease of the AH intervals, but the exercise induced HV prolongation in the pre-medication phase could not be reproduced after administration of the betablocker. Therefore we suggest that alterations of the conduction velocities of the AV-node (AVN) as well as the His-Purkinje system are the result of the relative influences of the direct sympathetic effect mainly on the AVN and the indirect parasympathetic tonus as the result of the carotid sinus reflex mechanism with its negative dromotropic effect, predominantly on the His-Purkinje system (HPS). The stress HBE is discussed as an additional diagnostic provocative test for clarifying the indication of pacemaker implantation especially in patients with conduction disturbances.

Quantitation of the gain in mortality in life-time after pacemaker treatment.

A total of 140 patients given permanent pacemaker 1963--73 were followed during three years with regard to survival. Indication of pacemaker implantation was AV block in 82% and disturbed consciousness in 84%. The first half of the series had a survival equal to that of the second half. The survival was 86, 73 and 64% and the excess mortality, which is above normal, was 9, 16 and 20% after one, two and three years, respectively. Concepts of fractional life-time and death-time were developed. These express the proportion of the total observation time that is life and death, respectively. The fractional life-time was 0.80 and the fractional death-time 0.20. The excess death-time was 0.12 (12%) of the total observation time. Mortality, survival, life-time and death-time were compared in three studies, the present one and two from Denmark. The great similarities were obvious. An estimation of the unpaced survival during three years, based on studies of AV block before the pacemaker era, indicated the great benefit of pacemaker treatment.

Permanent Cardiac Pacemakers in Alaska Natives With Complete Heart Block

Sixteen Alaska natives have been followed up after permanent cardiac pacemaker implantation, from July 1965 to May 1970. The indication for pacemaker implantation was persistent symptomatic complete heart block. The longest follow-up period was 57 months. The average follow-up period per patient was 17 months. There was no mortality during this time with a small number of pacemaker failures or complications. Many of the patients returned to live in remote villages. The success of this program indicates that permanent pacemakers can be used in patients who live in rural settings, far from hospital centers, as long as appropriate follow-up methods are employed.

Physiological studies and clinical experience in patients with synchronous and asynchronous pacemakers

Summary Physiological studies and clinical experience in 34 patients in whom synchronous or asynchronous pacemakers were implanted were analyzed. Studies were performed defining the hemodynamic abnormalities in complete heart block, the beneficial effect of increasing ventricular rate, and the further beneficial effect of atrial and ventricular synchronization. Complete heart block with Adams-Stokes attacks, and complete heart block with profound lethargy and congestive heart failure were the main indications for pacemaker implantation. The average age at the time of implantation was 68 years. Two patients died in the hospital. There were five late deaths due to the following causes: infection (1), electrode breakage (1), coronary artery disease (2), and unknown (1). Eighty per cent of the patients are surviving to date with improved cardiac function and are relieved of their Adams-Stokes attacks. The main problems were related to unit failure (5 patients) and wire breakage (7 patients).

Information on Merit Awards

<h3>Objective</h3> Pacing technology and care have improved notably over the past decade, justifying an update on the long-term prognosis and pre-implantation determinants of prognosis of bradycardia pacemaker (PM) recipients. <h3>Design</h3> Prospective cohort study. <h3>Setting</h3> 23 Dutch pacemaker centres <h3>Patients</h3> Pre-implantation characteristics of 1517 patients receiving a first bradycardia PM between 2003–2007 were studied in relation to survival. <h3>Interventions</h3> None; patients were followed up during routine clinical practice. <h3>Main outcome measures</h3> Cause and time to death. <h3>Results</h3> At the end of a mean follow-up of 5.8 (SD 1.1) years, 512 patients (33%) died, mostly of non-cardiac cause (67%). There were two PM related deaths. Survival rates were 93%, 81%, 69%, and 61% after 1, 3, 5 and 7 years, respectively. PM recipients without concomitant cardiovascular disease at implantation showed survival rates comparable to age and sex matched controls. Predictors at time of implantation associated with cardiac mortality were: age, coronary artery disease (CAD), diabetes, heart failure, valve disease, and the indication for PM implantation. Predictors for all cause mortality were: male gender, age, body mass index, CAD, cardiac surgery, diabetes, heart failure, and maintained atrioventricular synchrony. <h3>Conclusions</h3> A pre-implantation history of heart failure, CAD, and diabetes are the most important predictors for worse prognosis in PM recipients. Without baseline heart disease, survival rates equal that of the general population, suggesting that the prognosis of contemporary PM recipients is mainly determined by comorbid diseases and a bradycardia pacing indication as such does not influence survival. <h3>Clinical Trial Registration</h3> ClinicalTrials.gov Identifier: NCT00135174.