The effect of hyperpotassemia on the idioventricular pacemaker in complete A-V heart block and comparison with its effect on the heart rate in normal sinus rhythm An experimental study in dogs

Data are presented relative to the effects of varying degrees of hyperpotassemia on the atrial and ventricular rates in the presence of normal sinus rhythm and with complete A-V heart block. In the initial or moderately advanced stages of hyperpotassemia with serum levels up to 9.2 mEq./L. there is only a slight change in the atrial and ventricular rates in the presence of normal sinus rhythm. However, in the presence of complete A-V heart block the ventricular rate shows a decrease of 51 per cent (± 3.61 per cent) from the control rate with serum potassium levels up to 7.75 mEq./L. (± 0.22 mEq./L.). The possible relationship between these elevated serum potassium levels and the occurrence of Stokes-Adams seizures in patients with complete A-V heart block is discussed.     

Alcohol septal ablation complicated by complete heart block and permanent pacemaker failure.

Alcohol septal ablation is a novel catheter-based technique for the treatment of obstructive hypertrophic cardiomyopathy. Complete heart block complicates the procedure in 7%-30% of cases and necessitates the prophylactic insertion of a temporary pacing wire in all patients who do not have a permanent pacemaker. We describe a case of alcohol septal ablation complicated by complete heart block and failure to capture by both a permanent pacemaker and an implantable cardioverter defibrillator (ICFD) with pacing capabilities.     

Increased healthcare utilization associated with complete atrioventricular block in pacemaker patients

Purpose

The purpose of the current study is to characterize and quantify the impact of complete atrioventricular block (cAVB) on heart failure hospitalization (HFH) and healthcare utilization in pacemaker (PM) patients.

Methods

Patients ≥?18 years implanted with a dual-chamber PM from April 2008 to March 2014 were selected from the MarketScan® Commercial and Medicare Supplemental claims databases. Patients with ≤?1-year continuous MarketScan enrollment prior to and post-implant, and those with prior HF diagnosis were excluded. Patients were dichotomized into those with cAVB, defined as a 3rd degree AVB diagnosis or AV node ablation in the year prior to PM implant, versus those without any AVB (noAVB). Post-implant HFH and associated costs were compared based on inpatient claims.

Results

The study cohort included 21,202 patients, of which 14,208 had no AVB and 6994 had cAVB, followed for 2.39 and 2.27 years, respectively. Patients with cAVB were associated with a significantly increased risk of cumulative HFH (HR 1.59 [95% CI 1.35–1.86] p?<?0.001) and significantly higher costs ($636 [609–697] vs $369 [353–405] per pt-year, p?<?0.001) compared to those with no AVB.

Conclusions

Among dual-chamber PM patients without prior HF, cAVB is associated with a significantly increased risk of HFH and greater HF-related healthcare utilization. Identifying patients at high risk for HF in the setting of RV pacing, and potentially earlier use of biventricular or selective conduction system pacing, may reduce HF-related healthcare utilization.

     

Comparison of dual chamber and ventricular rate responsive pacing in patients over 75 with complete heart block.

OBJECTIVE--To compare symptoms and exercise tolerance during dual chamber universal (DDD) and ventricular rate response (VVIR) pacing in elderly (> or = 75) patients. DESIGN--Randomised, double blind, crossover study. SETTING--Regional cardiac department. PATIENTS--Twenty elderly patients (mean age 80.5 (1) years) with high grade atrioventricular block and sinus rhythm. Patients with pre-existing risk factors for the pacemaker syndrome and chronotropic incompetence were excluded. INTERVENTION--After four weeks of VVI pacing following pacemaker implantation, patients underwent consecutive two week periods of VVIR and DDD pacing. MAIN OUTCOME MEASURES--Patient preference, symptom scores, "daily activity exercises," and perceived level of exercise (Borg score). RESULTS--Eleven patients preferred DDD mode to either VVI or VVIR mode. Mean (SE) total symptom scores during VVI, VVIR, and DDD pacing were 5.9 (1.1), 6.1 (1.0), and 3.5 (0.9) respectively (P < 0.01). The corresponding mean (SE) pacemaker syndrome symptom scores were 4.8 (0.7), 5.2 (0.8), and 2.9 (0.8) (P < 0.05). Symptom scores during VVI and VVIR pacing were not significantly different. Exercise performance and Borg scores were significantly worse during VVI pacing compared with VVIR or DDD pacing but did not significantly differ between VVIR and DDD modes. CONCLUSIONS--In active elderly patients with complete heart block both DDD and VVIR pacing are associated with improved exercise performance compared with fixed rate VVI pacing. The convenience and reduced cost of VVIR systems, however, may be offset by a higher incidence of the pacemaker syndrome. In elderly patients with complete heart block VVIR pacing results in suboptimal symptomatic benefit and should not be used instead of DDD pacing.     

Effect of local lidocaine anesthesia on ventricular escape intervals during permanent pacemaker implantation in patients with complete heart block

Transient asystole is often noted during the course of permanent pacemaker implantation in patients with complete heart block. Since subcutaneous lidocaine is frequently used as the local anesthetic agent for permanent pacemaker implantation, the effect of this drug on ventricular escape intervals was studied. Ventricular escape intervals after transient cessation of pacing were studied in 9 patients with complete heart block before and 10, 30, and 45 minutes after subcutaneous lidocaine administration for permanent pacemaker implantation. The total lidocaine dose ranged from 170 to 400 mg (1.9 to 9.5 mg/kg of body weight). Therapeutic blood levels were achieved in 7 patients. The mean ventricular escape interval before lidocaine was 1.83 +/- 0.32 seconds, which increased to 2.58 +/- 1.35, 2.96 +/- 1.06, and 2.68 +/- 1.27 seconds at 10, 30, and 45 minutes after lidocaine (p less than 0.02). The mean maximal escape interval before lidocaine was 2.06 +/- 0.30 seconds, which increased to 3.80 +/- 1.44 seconds (p less than 0.01), a mean increase of 84%. The percent increase in maximal escape interval was related directly to the peak lidocaine level achieved. After lidocaine administration, 5 patients had asystole greater than 4 seconds and 1 required resumption of pacing. Thus, subcutaneous lidocaine contributes to the occurrence of asystole seen during permanent pacemaker implantation. It is advisable to limit the amount of lidocaine administered during permanent pacemaker implantation to the minimum necessary to achieve adequate local anesthesia. Strong consideration should be given to the use of a temporary pacemaker in patients with complete heart block during permanent pacemaker implantation even in the absence of previous asystole.     

Polymyositis and complete heart block.

The development of complete heart block is described in a patient with polymyositis. The implantation of a permanent pacemaker has controlled the heart block, but the progression of the underlying disease despite treatment with relatively high dosage of corticosteroids makes the outlook uncertain.     

Polymyositis and complete heart block.

The development of complete heart block is described in a patient with polymyositis. The implantation of a permanent pacemaker has controlled the heart block, but the progression of the underlying disease despite treatment with relatively high dosage of corticosteroids makes the outlook uncertain.     

Acute and chronic effects of cardiac resynchronization in patients developing heart failure with long-term pacemaker therapy for acquired complete atrioventricular block.

AIMS: We assessed the effects of cardiac re-synchronization therapy (CRT) in patients who developed otherwise unexplained heart failure (HF) during right ventricular apical (RVA)-pacing for acquired complete atrioventricular block (CAVB). METHODS AND RESULTS: Eighteen consecutive CAVB patients with HF during RVA-pacing were assessed with haemodynamic studies immediately and 12 months after CRT-upgrade. Ten patients had idiopathic CAVB and 13 showed normal left ventricular (LV) function at RVA-pacemaker implantation. HF developed after 81 +/- 10 months. RVA-pacing duration correlated (r = 0.49, P < 0.05) with LV ejection fraction (LVEF) deterioration. Biventricular- (BiV) and LV-pacing acutely improved the systolic function comparably, but only BiV improved diastolic function. One-year post-CRT-initiation, New York Heart Association classification improved 35 +/- 3% (P < 0.05) and the number of hospitalizations decreased 85 +/- 3% (P < 0.0001). CRT decreased LV end-diastolic diameter (LVEDd) 7 +/- 2% (P < 0.01) and increased LVEF by 23 +/- 7% (P < 0.01). The CRT-induced reduction in LVEDd tended to be greater in patients with RVA-pacing for < 5 years vs. > 5 years (7.7 +/- 2.5 vs. 3.6 +/- 1.0 mm, P = 0.08). CONCLUSION: CRT-upgrade improves the cardiac function and symptoms in CAVB patients with HF progression related to RVA-pacing. Because adverse LV-remodelling may be partly irreversible, consideration should be given to BiV- and LV-pacing upgrade as soon as possible after the indications appear, and prospective studies of the optimal timing of CRT-upgrade may be useful.