Prophylactic Pacemaker Insertion Research Articles

Do Patients with Asymptomatic Congenital Complete Heart Block Require a Pacemaker for Non-Cardiac Surgery?

The appropriate preparation of the patient with asymptomatic congenital complete heart block (CCHB) and a narrow QRS complex for elective non-cardiac surgery is controversial. Prophylactic temporary pacemaker insertion is associated with well-defined risks, and less invasive techniques exist to treat transient, hemodynamically significant intraoperative brady-arrhythmias. The present case report details the performance of general anesthesia for arthroscopic knee surgery in an adult patient with this condition without a pacemaker. Documentation of preoperative chronotropic competence with isoproterenol may be of value in deciding whether to proceed without temporary pacing capability in this setting.

A study of implanted cardiac rhythm recorders in advanced cardiac AL amyloidosis.

AL amyloidosis may respond to chemotherapy but two-thirds of patients with severe cardiac involvement die within a year of diagnosis, purportedly from tachyarrhythmias or electromechanical dissociation. We sought to characterize the nature of cardiac arrhythmias in severe cardiac AL amyloidosis using implanted cardiac rhythm recorders. Implantable loop recorders (ILRs) were inserted within 24 h of baseline evaluation at the UK National Amyloidosis Centre, into 20 consecutive patients with newly diagnosed severe cardiac AL amyloidosis and symptoms of syncope or pre-syncope. Weekly ILR recordings and additional recordings at the time of symptoms were obtained. Median (range) follow-up from baseline was 308 (10-399) days. Thirteen patients died, and median survival in the whole cohort was 61 days from device insertion. In each of eight evaluable cases, death was heralded by bradycardia, usually associated with complete atrioventricular block (CAVB), followed shortly thereafter by pulseless electrical activity. Four patients received pacemakers, a median (range) of 7 (3-38) h after development of symptomatic CAVB, but these did not prevent rapid cardiac decompensation and death in three cases. Despite 272 loop recordings, there was only one episode of non-sustained ventricular tachycardia, which was preceded by severe bradycardia. Patients who died had significantly worse global left ventricular strain on echocardiography (P = 0.029) and reduced 6 min walk distance (P = 0.048) at baseline compared with survivors. The discovery that bradyarrhythmias heralded terminal cardiac decompensation in most patients with severe cardiac AL amyloidosis supports a study of prophylactic pacemaker insertion in this patient population.

Heart Block and Temporary Pacing During Rotational Atherectomy

BackgroundRotational atherectomy (RA) performed during percutaneous coronary intervention is commonly associated with distal embolization of calcific particles resulting in conduction abnormalities. As a result, temporary pacing is often used during these procedures. It is unknown whether temporary pacing should be routinely used. MethodsWe performed an analysis of 134 consecutive patients who underwent RA at our institution between January 2011 and September 2013 for the presence of intraprocedural heart block or pacemaker activation. ResultsA temporary pacemaker was inserted in 50% of cases. Forty-two (31%) patients experienced either heart block (n = 16) or pacemaker activation (n = 26). There was no difference in baseline characteristics between those who experienced heart block or required temporary pacing, and those who did not. Interventional characteristics including burr size, maximum rotations per minute used, and maximum run duration were also similar among the groups. Only target RA vessel was associated with the presence of heart block or temporary pacing in multivariate analysis (P < 0.0001). Heart block or temporary pacing occurred in 28 (53%) of RA to the right coronary artery, 2 (5%) of the left anterior descending artery, 8 (62%) of the left-dominant circumflex artery, and 2 (18%) with RA to the circumflex artery with right-dominant circulation. Asystole occurred only in patients who underwent RA to the right coronary artery. ConclusionsHeart block or temporary pacing was more commonly associated with right coronary artery and left-dominant circumflex lesions. Prophylactic pacemaker insertion might be avoided with RA to other vessels.

Anesthetic Management for Lung Adenocarcinoma Experienced Acute Neurocardiogenic Syncope and Cardiac Arrest

Vasovagal syncope (neurocardiogenic syncope) is considered the most common cause of repetitive syncope [1]. Severe pain, emotional stress, anxiety, erect postural change in a patient who is in a hypovolemic state, invasive medical procedures such as intravenous catheter insertion, venipuncture and neuraxial anesthesia are regarded as triggering factors for this syndrome. Additionally, the resulting sympathetic tone increase and the positive inotropic state that result from the aforementioned triggers are considered potent vagal reflex responses leading to sympathetic inhibition, bradycardia, acute drop in blood pressure and ensuing syncope and circulatory collapse [2]. Generally, these conditions resolve spontaneously or treated with conservative methods, such as volume replacement, without any significant sequelae [2,3]. In this case report, the suspected vasovagal syncope that developed immediately after the transcutaneous fine-needle aspiration biopsy of the right lung nodule did not respond to the conservative therapy and abruptly progressed to fatal cardiovascular collapse with cardiac arrest, and resulted in cerebrovascular accident (CVA). Five weeks after the event, when the patient’s neurological state was stabilized, the elective lung lobectomy was performed after prophylactic pacemaker insertion and was completed safely. Herein, we report this case experience and review the literature, followed by a discussion.

244 High incidence of AV block and prophylactic pacing in familial amyloid polyneuropathy

Familial amyloid polyneuropathy (FAP) is an autosomic dominant inherited disease. FAP cardiopathy is characterized by conduction disorders, denervation, and cardiac infiltration. Because of the risk of high degree atrioventricular (AV) block and sudden death, prophylactic pacing can be suggested when there is evidence of amyloid infiltration of the AV conduction pathways. Our purpose was to estimate prevalence of AV block and pacing dependence for high risk FAP patients. In a cohort of 51 FAP patients, we performed standard ECG and electrophysiological study. Patients with conduction disorders underwent prophylactic pacing. During follow up, AV conduction was studied by using data from the Holter memories of pacemakers. Baseline characteristics of the patients are summarized on table 1. During the follow up, permanent high degree AV block occurred in 23.5% of the patients (12/51)(cf. fig. 1). Average percentage was 23 ± 35% for ventricular pacing and 18 ± 24% for atrial pacing. Paroxystic AV block was recorded for all patients but 3 (94%). Prevalence of AV conduction disorders was 283 ± 465 events per month (epm) and was distributed in 14 ± 46 epm for third degree AV block, 195 ± 386 epm for second degree AV block, 73 ± 225 epm for first degree AV block and 0.2 ± 0.7 epm for pauses. During the study, sustained atrial arrhythmias occurred in three patients. No sustained ventricular arrhythmia was recorded. Patients with FAP cardiomyopathy present high incidence of AV blocks. For FAP patients with involvement of the AV conduction pathway, prophylactic pacemaker insertion should be performed. Incidence of permanent AV block Table 1: Baseline characteristics Mean ± SD age (years) 54 ± 13 % of men 64.7% Lenght of fu (months) 34 ± 33 % Val30 Met 64% Surface ECG Conduction disorders 74% AVB type 1 38% PR interbal (ms) 191 ± 41 QRS interval (ms) 94 ± 21 Electrophysiological study corrected sinus recovery time (ms) 546 ± 438 AH interval (ms) 117 ± 43 HV interval (ms) 68 ± 11 Anterior Wenckebach point (bpm) 128 ± 33

YIA Abstracts: Best abstracts on clinical studies

YIA Abstracts: Best abstracts on clinical studies

Quantitative and Qualitative Changes in the Resting Electrocardiograph After Percutaneous Transluminal Septal Myocardial Ablation for the Treatment of Symptomatic Obstructive Hypertrophic Cardiomyopathy

Percutaneous Transluminal Septal Myocardial Ablation (PTSMA) may reduce symptoms in patients with obstructive hypertrophic cardiomyopathy. Limited quantitative and qualitative data exists on the effects of PTSMA on the resting electrocardiograph. We report repolarisation and conduction abnormalities and incidence of arrhythmia post-PTSMA. Twelve-lead electrocardiographs from subjects without pre-procedural pacemakers who underwent successful procedures (37 procedures, mean age 61+/-14 years) were analysed for rhythm, heart rate, PR and QTc intervals, QRS duration and left or right bundle branch block (RBBB, LBBB). Four subjects developed permanent complete AV block, 19 subjects developed new RBBB and two subjects developed new LBBB pre-discharge. At a median follow-up of 34 (range 1-84) months, no new AV block, ventricular arrhythmias or deaths occurred. Post-PTSMA PR, QRS and QTc intervals lengthened (PR 180+/-33 ms, 204+/-40 ms, QRS 105+/-20 ms, 132+/-27 ms and QTc 454+/-32 ms, 491+/-37 ms (pre- and post-PTSMA respectively, all p=0.001). Predictors of permanent complete AV block included female gender (p=0.013), older age (p=0.013) and pre-existing LBBB (p<0.001). Atrio-ventricular and intra-ventricular conduction disturbances are common post-PTSMA. A pre-existing LBBB is a risk factor for the development of complete AV block and may merit prophylactic pacemaker insertion.

Transcatheter closure of perimembranous ventricular septal defect

The author's reply: The letter from Melbourne by Dumitrescu et al reporting complete heart block occurring in 3 of 36 patients after transcatheter closure of perimembranous ventricular septal defect adds weight to the concern expressed about this complication.1 Most disturbing is the detection of new‐onset heart block more than 3 years after the interventional catheter procedure. This supports the view that steroid treatment in the immediate postimplantation period will not necessarily prevent the late development of this important complication. The age or size of the affected patients at the time of device implantation is not stated, but all were children. Interventional catheterisation occlusion of a perimembranous ventricular septal defect in children, whether using the existing asymmetric Amplatzer occluder or other occlusive devices, should be performed with caution, and only as part of a prospective clinical trial or with submission of data to a registry. Continuing follow‐up of patients who have undergone the procedure is required. There is a responsibility to alert patients and their families to seek advice should relevant symptoms suggesting bradycardia occur, and also to report further experience of heart block should this be recognised. If similar experience of late‐onset heart block becomes widespread, the question of prophylactic pacemaker insertion may even need consideration.

Prophylactic pacemaker use to allow β-blocker therapy in patients with chronic heart failure with bradycardia

Although the benefits of beta-blocker therapy for patients with congestive heart failure (CHF) are independent of pretreatment heart rate, patients with chronic systolic heart failure and low resting heart rates are often excluded from beta-blocker therapy. We investigated the effectiveness and cost-effectiveness of prophylactic pacemaker insertion to facilitate beta-blocker use in these patients. A Markov model simulated the natural history of a cohort of clinically stable patients with CHF (ejection fraction < or = 35%, mean age 60 years) with resting heart rates of < 68 beat/min. Two strategies were evaluated: (1) conventional therapy (conventional)-the risks for death and hospitalization were derived from the angiotensin-converting enzyme inhibitor arm of the SOLVD treatment trial; and (2) pacemaker insertion with atrial pacing and carvedilol therapy (pacemaker-carvedilol)-risk reductions for death and CHF-related hospitalizations for carvedilol compared with conventional therapy were derived from the US Carvedilol Heart Failure Study. We assumed full carvedilol benefits for 2 years, declining benefits for the next 3 and no additional benefits after 5 years, whereas pacemaker-related adverse events persisted. In the base case, the pacemaker-carvedilol strategy increased mean survival by 1.3 years at an incremental cost of $7800, for an incremental cost-effectiveness of $6100 per year of life saved. Results were most sensitive to theoretical pacing-induced harm, changes in hospitalization cost, and reductions in beta-blocker benefits. Prophylactic pacemaker insertion to facilitate beta-blocker treatment in patients with CHF with low resting heart rates has the potential to produce clinical benefits in a highly cost-effective manner.

Risk of right bundle-branch block and complete heart block during pulmonary artery catheterization.

The need for the prophylactic insertion of a pacemaker before pulmonary artery catheterization in patients with pre-existing left bundle-branch block (LBBB) is controversial. To determine the incidence of new right bundle-branch block (RBBB) and complete heart block during bedside pulmonary artery catheterization, 293 patients undergoing 307 pulmonary artery catheterizations were prospectively studied. Nine patients had pacemaker rhythms and 19 patients had an RBBB on their precatheterization ECGs and therefore were excluded from analysis. In the remaining 279 pulmonary artery catheterizations, eight (3%) were associated with the development of a new RBBB. None of the 14 patients with a pre-existing LBBB developed complete heart block. The incidence of complete heart block during pulmonary artery catheterization of patients with previous LBBB was not higher than the incidence of RBBB in patients without underlying conduction defects. Because of the rare but grave consequences of RBBB in patients with pre-existing LBBB, we recommend the use of standby external pacemakers and equipment for transvenous pacemaker insertion in these patients during pulmonary artery catheterization. We do not recommend prophylactic pacemaker insertion.

Chronic bundle branch block and use of temporary transvenous pacemakers during coronary arteriography.

A retrospective analysis of 217 consecutive patients with chronic bundle branch blocks undergoing cardiac catheterization was done to evaluate the need for temporary transvenous pacing during coronary arteriography. In patients without temporary right ventricular pacemakers (n = 185), only one episode of high-grade atrioventricular block occurred during coronary arteriography which required the urgent use of temporary pacing. All other bradyarrhythmias, including five episodes of transient asystole (greater than 3-sec pause) and four episodes of atrioventricular block (second degree or higher) were successfully managed without pacemaker utilization. Patients with prophylactic right ventricular pacemakers (n = 32) had a greater prevalence of ventricular fibrillation than those without pacing electrodes located in the right ventricle (2% vs. 9% respectively; P less than 0.05). These findings suggest that routing prophylactic pacemaker insertion during coronary arteriography in patients with chronic bundle branch block is not warranted and may place the patient at risk for developing iatrogenic ventricular arrhythmias.

Cardiac arrhythmias associated with prophylactic pacing during coronary angiography

Data from 518 consecutive cardiac catheterizations were analyzed to test the value of prophylactic pacemaker insertion during coronary angiography and to compare the incidence of arrhythmic complications in patients with and without pacemakers. In patients without pacing (n = 273), 1 episode of ventricular fibrillation occurred, which responded promptly to defibrillation. Sinus bradycardia (fewer than 30 beats/min for 10 seconds) was recorded in 74 patients (27%) and required treatment in 30 (11%). No patient required or would have benefited from pacemaker placement. Of the 245 patients with prophylactic pacemakers, there was an increased incidence of all ventricular (9 vs 1; p < 0.013) and supraventricular (5 vs 0; p < 0.046) arrhythmias. Pacemaker-associated induction of ventricular fibrillation occurred in 2 patients and was clearly related to electrical stimulation during a normally nonvulnerable period of the cardiac cycle. In conclusion, routine prophylactic pacemaker insertion during coronary angiography is not warranted in patients with normal sinus rhythm and normal atrioventricular conduction. More information is needed to determine if pacing is needed in patients with conduction system disease.

Electrophysiologic studies in patients with bundle branch block.

A total of 401 patients with chronic bundle branch block underwent electrophysiologic studies and were followed for a mean of approximately 30 months. Patients with an infranodal conduction time (H-Q) greater than or equal to 70 ms had a significantly higher incidence of progression to spontaneous second-degree or third-degree atrioventricular (AV) block (12%) compared with those with H-Q less than 70 ms (3.5%). The incidence of AV block was 25% for those with H-Q greater than or equal to 100 ms. Although the incidences of all deaths and cardiac deaths were higher for the H-Q greater than or equal to 70 ms group, there was no statistically significant difference in the incidence of sudden deaths in the two groups. A subgroup of 77 patients underwent prophylactic pacemaker insertion based on the presence of transient neurologic symptoms and/or a prolonged H-Q interval. We found no significant difference in the incidence of relief of symptoms or incidence of cardiac or sudden deaths between paced and unpaced groups. A subgroup of 25 patients with syncope underwent ventricular stimulation studies and ventricular tachycardia was induced in 14. We conclude that a markedly prolonged H-Q interval (greater than or equal to 100 ms) may be of value in detection of spontaneous AV block. Prophylactic pacing is of no value in either relief of symptoms or prolongation of life. Complete electrophysiologic studies, including ventricular stimulation studies, are indicated for patients with bundle branch block and syncope.

Bundle branch block in acute myocardial infarction

The management of patients with acute myocardial infarction complicated by bundle branch block is a significant clinical problem and represents 8% to 13% of patients with acute infarction. This study reviews the records of 606 patients with myocardial infarction admitted to our coronary care unit. Forty-seven (8%) had complete bundle branch block. The risk of developing high-degree AV block in these 47 patients was reviewed. There are no established therapeutic guidelines for patients with pre-existing bundle branch block and left bundle branch block in acute myocardial infarction. We found a high risk of progression in patients with pre-existing bifascicular block in the presence of anterior wall infarction (25%) as well as in patients with left bundle branch block with acute anterior wall infarction (100%). On the basis of our data and careful review of the literature, we recommend prophylactic pacemaker insertion in these high-risk groups.

Value of the H-Q interval in patients with bundle branch block and the role of prophylactic permanent pacing

His bundle electrograms were obtained in 313 patients with chronic bundle branch block who were followed for a mean period of almost 3 years. The infranodal conduction time (H-Q interval) was < 55 ms in 97 patients (Group I), 55 to 69 ms in 99 patients (Group II), and > 70 ms in 117 patients (Group III). There was a higher incidence of organic heart disease in patients in Group III, but the groups were otherwise comparable. On follow-up study, mortality and the incidence of sudden death were similar among the groups, but patients in Group III had a greater incidence of progression to high degree atrioventricular block (HDB) than did those in Groups I and II (14 of 117 [12%] versus 4 of 97 [4%] and 2 of 99 [2%], p < 0.0, rmrespectively). High degree block was found in 4 of 17 (24%) patients with an H-Q interval (H-Q) ≥ 100 ms. Sixty-two patients underwent permanent prophylactic pacemaker insertion at the discretion of the referring physician and were compared with 231 patients who did not. Paced patients had a higher incidence of transient neurologic symptoms and prolonged H-Q, but the groups were otherwise comparable. On follow-up study, mortality and the incidence of sudden death were similar among the groups, but symptom relief was significantly more common among patients with pacemakers. In conclusion, in our population (1) H-Q ≥ 70 ms was an independent risk factor for progression to HDB, (2) H-Q ≥ 100 ms identified a subgroup at particularly high risk, and (3) prophylactic pacemakers relieved neurologic symptoms but did not prolong life.

Prophylactic permanent pacemakers for patients with chronic bundle branch block

His bundle recordings were obtained in 189 patients with chronic bundle branch block, and the patients were followed for a mean of approximately 20 months. Forty patients underwent prophylactic pacemaker insertion (group II) and 149 did not (group I). There was no significant difference between the two groups at the time of entry into the study with regard to mean age, serum cholesterol or the incidence of smoking, diabetes, hypertension, coronary artery disease or congestive heart failure. The patients in group II had a significantly higher incidence of transient neurologic symptoms (30 of 40,75 per cent, versus 79 of 149, 53 per cent, p < 0.05) and longer mean infranodal conduction time (79 ± 25 versus 61 ± 20 msec, p < 0.001). Eleven patients died before symptom relief could be assessed. More paced patients (group II) had relief of neurologic symptoms compared with the unpaced group (18 of 25, 72 per cent, versus 36 of 73, 49 per cent), but the difference was not quite statistically significant (0.1 < p > 0.05). There was no significant difference between the two groups in the total mortality or the incidence of sudden death. Nineteen of 21 sudden deaths occurred in patients with coronary artery disease and/or congestive heart failure. In conclusion, (1) prophylactic pacemaker insertion in a subset of largely symptomatic patients with chronic bundle branch block and long H-Q time did not protect against sudden death; the incidence of this complication appears to be related to the type and severity of underlying heart disease; (2) presenting neurologic symptoms may be an inadequate guide to assess the need for permanent pacing in bundle branch block.

Chronic right bundle branch block and left posterior hemiblock: Clinical, electrophysiologic and prognostic observations

Twenty-one patients with long-term right bundle branch block and left posterior hemiblock were studied electrophysiologically and then followed up prospectively. The group consisted of 19 men and 2 women aged 61 ± 2.7 years (mean ± standard error of the mean). The majority of patients had either hypertensive cardiovascular disease (48 percent) or primary conduction disease (33 percent). Initial electrophysiologic studies revealed A-H intervals of 58 to 152 msec (mean 98 ±7.7) and H-V intervals of 40 to 80 msec (mean 52 ± 2.1). Six patients (29 percent) had prolonged H-V intervals. The follow-up period ranged from 91 to 1,231 days (mean 671 ± 68). Three of 21 patients (14 percent) needed a permanent pacemaker after development of the following symptomatic conduction disease: sinoatrial block on day 3 of follow-up; second degree atrioventricular (A-V) block, site undetermined, on day 118; and second degree A-V block proximal to the His bundle on day 398. One patient died suddenly (on day 571), and two others died of noncardiac causes.In conclusion, combined right bundle branch block and left posterior hemiblock was associated with less trifascicular disease than reported previously. The clinical course of most of the patients was benign and the incidence of sudden death was relatively small. Symptomatic conduction disease occurred but could be definitely related to trifascicular disease in only one patient. These short-term data suggest that prophylactic pacemaker insertion is not routinely indicated in patients with chronic right bundle branch block and left posterior hemiblock.