Guidelines for permanent cardiac pacemaker implantation, May 1984

Early impact of guideline publication on angiotensin-receptor neprilysin inhibitor use among patients hospitalized for heart failure

BACKGROUND

On May 20, 2016, US professional organizations in cardiology published joint treatment guidelines recommending the use of angiotensin-receptor neprilysin inhibitor (ARNI) for eligible patients with heart failure with reduced ejection fraction (HFrEF). Using data from the Get With The Guidelines-Heart Failure registry, we evaluated the early impact of this update on temporal trends in ARNI prescription.

METHODS

We analyzed patients with HFrEF who were eligible for ARNI prescription (EF ≤40%, no contraindications) and hospitalized from February 20, 2016, through August 19, 2016-allowing for 13weeks before and after guideline publication. We quantified trends in ARNI use associated with guidelines publication with an interrupted time-series design using logistic regression and accounting for correlations within hospitals using general estimating equation methods.

RESULTS

Of 7,200 eligible patient hospitalizations, 51.9% were discharged in the period directly preceding publication of the guidelines, and 48.1% were discharged after. Odds ratios of ARNI prescription at discharge were significantly higher in the postguideline period compared with the preguideline period in adjusted models (adjusted odds ratio 1.29, 95% CI 1.06-1.57, P=.01). However, there was no significant interaction between observed and expected ARNI use after guideline publication (P_interaction=.14). Results were consistent using a 6-month before and after time frame.

CONCLUSIONS

The model suggested a small increase in ARNI use in HF patients being discharged from the hospital immediately after guideline release. However, the publication of national guidelines recommending ARNI use seemed to have little influence on the adoption of this evidence-based medication in the first 3 to 6months.

Analytic Reviews: Electrophysiologic Testing in the Intensive Care Unit

The role of electrophysiologic concepts and procedures in managing patients with potentially life-threatening ar rhythmias in the intensive care unit is discussed. These patients may be survivors of sudden cardiac arrest or myocardial infarction or may be admitted for syncope or sustained or nonsustained ventricular tachycardia. The value of electrophysiologic testing is discussed in terms of the distinction between wide QRS complex tachycardias that are supraventricular or ventricular in origin and those in which preexcitation syndromes may be important. Drug-induced ventricular arrhythmias are discussed, with specific emphasis on torsades de pointes. Finally, the use of His bundle recordings in pa tients with atrioventricular conduction disturbances is discussed. The methodology of electrophysiologic test ing, including stimulation protocols and interpretation of results, is described.

Incidence and characteristics of heart block after heart surgery in pediatric patients: A multicenter study

BACKGROUND

Advanced second- or third-degree heart block has been reported with variable incidence after surgery for congenital heart disease in children. We report the incidence of heart block requiring a pacemaker and describe the risk factors for this complication in a large multicenter study.

METHODS

We performed a retrospective cohort study, using the Pediatric Health Information System database from 45 hospitals in the United States, for all children aged 18 years, discharged between January 1, 2004, and December 31, 2013, who underwent open surgery for congenital heart disease. Patients who had heart block and placement of a pacemaker during the same hospitalization were identified. Demographic characteristics, procedure and diagnostic codes, length of stay, and mortality were analyzed. Univariable and multivariable analyses were performed.

RESULTS

There were 101,006 surgeries performed. The median age of patients was 0.5 years (interquartile range, 26 days to 3.2 years), and 1% of patients (n = 990) had heart block and placement of a pacemaker. Surgeries associated with the highest incidences of heart block and placement of a pacemaker included the double switch operation (15.6%), tricuspid valve (7.8%) and mitral valve (7.4%) replacement, atrial switch with ventricular septal defect repair (6.4%), and Rastelli operation (4.8%). On multivariable analysis, after controlling for surgical complexity, other comorbidities, age at surgery, admission year, and clustering by institution, patients with heart block and placement of a pacemaker had higher odds of mortality (odds ratio, 1.67; 95% confidence interval, 1.24-2.26; P < .001).

CONCLUSIONS

The incidence of postoperative heart block requiring permanent pacemaker placement immediately after congenital heart surgery is low (1%). However, these patients have higher mortality even after adjusting for heart surgery complexity.

Cardiovascular disease in the elderly

Cardiovascular disease is the major cause of death and disability in the elderly. Atherosclerotic coronary heart disease is the most prevalent problem, followed by hypertensive cardiovascular disease. Calcific aortic stenosis is the most common haemodynamically important valvular lesion; surgical correction significantly improves the prognosis. Pulmonary embolism occurs frequently, related to immobilization and co-morbidity. Congestive heart failure is both under-diagnosed and over-diagnosed. Complete heart block and sick sinus syndrome increase with age; appropriate pacemaker therapy can improve the length and quality of life. Clinical evaluation of elderly patients is often hampered by multiple co-existing disease involving other organ systems, problems in reporting symptoms, and associated functional and structural changes of ageing that may mimic or mask cardiovascular disease. Presentations of cardiac illness often differ from those in a younger population. Most of the available data on therapy and prognosis do not apply to contemporary practice, so that clinical decisions are often extrapolated from information acquired in younger patients. Elderly patients are at high risk of complications of most diagnostic and therapeutic procedures, more related to co-morbidity than to age; they have more frequent and serious adverse drug reactions, due both to co-morbidity and to multiple medications. Age as such should not constitute a barrier to cardiac care; in the USA at least one-third of all cardiovascular procedures are performed in elderly patients. The goals of therapy are improvement in function and postponement of debilitating illness, enabling an extended active independent lifestyle.

Chronic Right Ventricular Pacing and Cardiac Performance:. The Pediatric Perspective

Cardiac stimulation from right ventricular apical or free-wall lead positions alters inter- and intraventricular impulse conduction and distorts biventricular contractility. This may contribute to eventual cellular remodeling and the development of histopathological changes which, over time, adversely affect left ventricular systolic and diastolic functions. This concept has especially important implications when pacemaker therapy is initiation in young patients. Recent studies demonstrating physiological benefits of right ventricular septal, outflow, or bundle of His pacing, in deference to the apical implant site, have gained interest to potentially prevent dysfunction and improve paced myocardial contractility. Pacing initiated in children can be expected to have more far-reaching consequences than pacing initiated in the elderly. Unfortunately, there have been limited clinical pediatric studies that evaluate precise site-specific lead locations. This current report presents a review of pacemaker applications in children, both with and without structural congenital heart defects, including the earliest applications in which patient survival was the prime concern, to more recent studies attempting to optimize physiological and histological parameters associated with pacemaker induced contractility. The past decade has seen direct evidence that right ventricular apical pacing in children contributes to adverse histological remodeling and eventual contractile dysfunction. More recent studies demonstrate that selective site pacing can be effectively applied to all children with and without structural congenital defects and shows promise in the prevention of previously documented adverse remodeling and deterioration of systemic ventricular contractility.

Report of the NASPE Policy Conference training requirements for permanent pacemaker selection, implantation, and follow-up. North American Society of Pacing and Electrophysiology

NASPE proposes and supports the concept of a two-tracked training system in cardiac pacing. Track I training will properly train physicians for the prescription of pacemakers and the monitoring of pacemaker patients, and track II training will properly prepare physicians for the implantation of pacemakers. Regardless of specialty (cardiologist or surgeon) or training venue (cardiac pacing fellowship, cardiac electrophysiology and pacing fellowship, sabbatical or mentor sponsored training), it is recommended that these minimum standards be required for hospital credentialing. NASPE also supports the voluntary institution by training program directors of core pacing training in cardiovascular disease and cardiac electrophysiology fellowships. This core training does not in itself constitute proper track I or II training for physicians interested in adequately prescribing, monitoring, or implanting cardiac pacemakers.

Survey of the attitudes of British physicians to pacing

OBJECTIVES

To assess how the opinions of cardiologists, physicians, and general practitioners on the indications for permanent pacing compare with published guidelines, and to determine whether resources, pacing experience, and position influence referral practices.

DESIGN

Anonymous postal survey by questionnaire from St Bartholomew's Hospital, London and the King's Fund Institute, London. The questionnaire established the respondent's position, resources, and previous pacing experience. Eleven clinical and electrocardiographic situations were described and respondents were asked to decide on whether pacing was indicated. The responses received were compared with the guidelines provided by the 1984 American College of Cardiology/American Heart Association task force.

PARTICIPANTS

The 630 members of the British Cardiac Society, 1370 randomly selected general physicians, and 2000 general practitioners.

RESULTS

Patients with symptoms were more likely to be referred for pacing than symptom free patients regardless of underlying aetiology. In relatively symptom free patients the frequency with which pacing was recommended was low, even when it was unequivocally indicated on prognostic grounds. Failure to recommend pacing was unrelated to diagnostic facilities or referral difficulties. Respondents with pacing experience were more likely to recommend pacing.

CONCLUSIONS

The physicians surveyed had a conservative approach towards recommending pacing. Most physicians were influenced predominantly by symptoms and the prognostic indications for pacing were not well appreciated.

Atrial adaptive rate pacing in sick sinus syndrome: effects on exercise capacity and arrhythmias

OBJECTIVE

To test the hypotheses that adaptive rate atrial (AAIR) pacing: significantly increases maximal exercise capacity, and results in significant suppression of supraventricular and ventricular arrhythmia compared with fixed rate atrial (AAI) pacing.

DESIGN

Prospective, randomised, single blind, crossover study with maximal treadmill exercise testing and 24 hour ambulatory electrocardiographic monitoring in AAIR and AAI modes.

SETTING

Regional pacing centre.

PATIENTS

30 consecutive patients (mean SD age 65 (12) years) with sick sinus syndrome who required permanent pacing, without evidence of conduction disturbance on 12 lead electrocardiograms or 24 hour ambulatory electrocardiographic monitoring and without other cardiovascular or systemic disease.

INTERVENTIONS

Activity sensing or minute ventilation driven systems (AAI/AAIR) were implanted alternately.

RESULTS

The mean (SD) peak heart rate in AAI mode was 122(28)v 130(22) in AAIR mode (p < 0.02) for the whole group and 104(17) v 120(5) (p < 0.003) for the patients with chronotropic incompetence. Exercise time was 12.3 (4.1) minutes in AAI and 12.3 (3.8) minutes in AAIR mode (NS) in the chronotropically incompetent patients. There were no significant differences in the Borg scores at peak exercise in AAI v AAIR mode in either group. The frequency per hour of atrial and ventricular arrhythmias showed no significant differences between the two modes in either the group as a whole or in the subgroups with chronotropic incompetence.

CONCLUSION

AAIR pacing confers little benefit in sick sinus syndrome compared with AAI pacing.

The impact of pacemaker implantation on cognitive functioning in elderly patients

OBJECTIVE

To describe and quantify the impact of pacemaker implantation on cognitive functioning in the elderly.

DESIGN

Prospective case-control, non-randomized trial. Data were collected from clinical and family interviews and from a psychological test battery.

SETTING

Pacemaker clinic in a tertiary care hospital.

PARTICIPANTS

Nineteen elderly (65+ years) patients undergoing new or replacement pacemaker implantation for dysrhythmias and volunteer controls matched for age, sex, and short Mental Status Questionnaire test results, without dysrhythmia or intervention.

MAIN OUTCOME MEASURES

Subjective and clinical impressions based on family interviews; results of psychological test battery before and 6-12 months after pacemaker implantation.

RESULTS

Prior to pacemaker implantation, three patients met DSM-III criteria for dementia and two for delirium. Paced patients demonstrated deficiency in immediate memory, language, memory for less structured information, and learning of abstract materials. These deficits were due primarily to the poor performance of patients with complete heart block. Despite clinical and subjective impressions of improvement, there was no change in psychologic test performance subsequent to pacemaker implantation.

CONCLUSIONS

Impaired cognitive functioning is not always clinically apparent but appears common in patients with cardiac dysrhythmias; it is not altered 6-12 months after pacemaker implantation.

Follow-Up of a Respiratory Rate Modulated Pacemaker

The efficacy of 27 respiration sensitive rate modulated pacemakers (Biorate RDP-3 Biotec) implanted in the left pectoral area was evaluated every 3 months during a mean follow-up period of 29 months (range 10-50 months). Rate modulation function was unchanged other than for three patients in whom the auxiliary leads became displaced. Two implants lost ventricular sensing in this nonprogrammable model. In all but the three patients, Holter monitoring demonstrated pacing rate variation corresponding to daily activity. Stress test duration increased from 8.2 +/- 1.5 minutes (in fixed rate VVI rate) to 12.83 +/- 2.0 minutes (in the VVIR mode) (P less than 0.05). Right arm movement increased the pacing rate by 5 +/- 3 beats/min (NS), while the left arm movement increase was 30 +/- 5 beats/min (P less than 0.05). Mental, arithmetic, and nifedipine tests did not change the rate modulated pacing rate. The system responded to a change in respiratory rate by an increase in stimulation rate. A satisfactory response in sensitivity and velocity was present only with medium-high workloads. Interference with rate modulation occurred with movement of the arm ipsilateral to the implanted pulse generator.

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.

Cardiac pacemaking in Hong Kong: report of a survey of general practitioners and internists

A questionnaire study was carried out among cardiologists, internists, general practitioners, and final year medical students in Hong Kong concerning cardiac pacemaking. The response rate was 11.2%. Salient results include the misconception on the part of 40% and 12% of physicians, that general anesthesia and thoracotomy respectively, are commonly required for permanent pacing and that the procedure is associated with significant mortality (14.2% of physicians). Most would offer permanent pacing to patients with symptomatic complete atrioventricular block, but advanced age appeared to be considered as a barrier to permanent pacemaking. There was confusion about the need to pace asymptomatic sick sinus syndrome and bundle branch conduction diseases. Oral isoprenaline was still used to treat bradycardia by 16.6% of physicians. A similar deficiency in knowledge was found among the students. It is suggested that misunderstanding of cardiac pacing is common and may be a reflection of the lack of emphasis in undergraduate teaching. This deficiency may have prevented some patients from receiving the benefits of permanent pacing.

Incidence of unwarranted implantation of permanent cardiac pacemakers in a large medical population

Because of allegations that the implantation of many permanent cardiac pacemakers has been unjustified, we reviewed the indications for all new pacemakers implanted at 30 hospitals in Philadelphia County between January 1 and June 30, 1983, and paid for by Medicare. Complete chart data were evaluated for 382 implants. We determined whether the indications for implantation were appropriate and adequately documented on the basis of standard clinical practice. Implants were classified as possibly indicated primarily because of inadequate diagnostic evaluation (63 percent) or inadequate documentation of an accepted indication (36 percent). Implants were classified as not indicated primarily because a rhythm abnormality was incorrectly identified as a justifiable indication (84 percent). We found that 168 implants (44 percent) were definitely indicated, 137 (36 percent) possibly indicated, and 77 (20 percent) not indicated. Unwarranted implantation was both prevalent (73 percent of hospitals had an incidence of 10 percent or more) and independent of the type of hospital (university teaching, university-affiliated, and community hospitals). The additional tests most often required to clarify the need for a pacemaker in inadequately evaluated cases included electrophysiologic studies (37 percent) and ambulatory monitoring (31 percent). We conclude that in a large medical population in 1983, the indications for a considerable number of permanent pacemakers were inadequate or incompletely documented.

Outpatient pacemaker procedures

Over a 46-month period 181 pacemaker procedures were performed from an outpatient practice. Patients were admitted, operated on and discharged all within a 24-hour period. There were no pacemaker emergencies, major complications or emergency readmissions. The outpatient approach to permanent pacemaker procedures was not limited by the type of pacemaker procedure, pacemaker dependence, patient age or sex. The feasibility and safety of outpatient procedures is demonstrated.

Pacing in children and young adults with nonsurgical atrioventricular block: comparison of single-rate ventricular and dual-chamber modes

A prospective comparison of physiologic response to single-rate ventricular and dual-chamber atrioventricular pacing was conducted in 14 pediatric patients (age 1 to 24 years, median 14) with symptomatic nonsurgical second- or third-degree atrioventricular block. All patients were studied acutely during cardiac catheterization before and after 1 hour of both pacing modes. Following pacemaker implant, eight patients were reevaluated after 1 month of each mode with symptom questionnaire, resting ECG, resting echocardiogram, and Doppler cardiac output measurement at rest and at peak treadmill exercise. Cardiac outputs (mean +/- standard error) increased acutely (n = 14) with both ventricular (32 +/- 12%) and dual-chamber (39 +/- 10%) pacing over intrinsic rhythm values (p less than 0.01 in both). During chronic pacing (n = 8), symptoms were reported only with the ventricular mode. Dual-chamber synchronous pacing was associated with improved mean resting shortening fraction and cardiac output, slower mean resting sinus rate (89 +/- 5 compared to 73 +/- 4 bpm (p less than 0.02), and a 23% increase in mean excerise cardiac output (4.2 +/- 0.4 compared to 3.4 +/- 0.3 L/min/m2) compared to single-rate ventricular pacing. Exercise-induced dysrhythmias occurred only with ventricular pacing. This study demonstrates that pediatric patients with nonsurgical atrioventricular block can compensate for loss of atrioventricular synchrony at rest but exhibit improved cardiac function with chronic dual-chamber atrioventricular compared to single-rate ventricular pacing.

DDD pacing: clinical considerations

DDD pacemakers offer a physiologic form of pacing for selected patients by incorporating atrioventricular synchrony over a wide range of atrial rates. Selection of a patient for DDD pacing necessitates a thorough knowledge of the individual functions of the DDD pacemaker, the limitations of DDD pacing, and the patient's own electrical and physiologic needs. Continuing developments in cardiac pacing include further reduction of the possibility of pacemaker-mediated tachycardia, increased matching to metabolic needs, and advancement of telemetric technology and electrophysiologic testing.

Noninvasive assessment of pacemaker hemodynamics by Doppler echocardiography: importance of left atrial size

The relative decrease in cardiac output with ventricular pacing versus "physiologic" modes was measured noninvasively using Doppler echocardiography in 26 patients. Standard echocardiographic measurements of left ventricular size (diastolic diameter), left ventricular function (shortening fraction) and left atrial size were examined to determine which of these variables might best identify patients more likely to benefit from maintenance of atrioventricular (AV) synchrony. Decreases in relative cardiac output, expressed as reduction in the Doppler-derived flow velocity integral, with loss of AV synchrony ranged from 0 to 43% (mean decrease 21%). There was no correlation between left ventricular size or function and effect of pacing mode on relative cardiac output. There was, however, correlation between left atrial size and sensitivity to pacing mode. Patients with normal left atrial size were significantly more sensitive to loss of AV synchrony. In this subgroup, the decrease in flow velocity integral with ventricular pacing was 32 +/- 11% compared with only 11 +/- 13% in patients with left atrial enlargement. Thus, Doppler echocardiography is useful in assessing optimal pacing mode in the individual patient. Echocardiographically measured left atrial size may identify patients in whom physiologic pacing may be major benefit.

Pacemaker therapy

This article reviews the indications for pacemaker implantation and the techniques and devices currently in use. The management of patients who require permanent pacemakers and the potential complications involved are discussed. The article concludes with a brief synopsis of temporary pacing.