Trends in complete heart block after transcatheter aortic valve replacement: A population based analysis.

OBJECTIVES: To define the national rate of complete heart block (CHB) after transcatheter aortic valve replacement (TAVR) and its impact on procedural mortality, overall cost, and length of hospital stay. BACKGROUND: CHB leading to permanent pacemaker (PPM) implantation is one of the most common complications post TAVR. National data on the temporal trend of CHB post TAVR are lacking. METHODS: We queried the 2012-2014 National Inpatient Sample databases to identify all patients who underwent TAVR. Patients with preoperative pacemakers or implantable cardioverter-defibrillators were excluded. Association between CHB and outcomes, and overall trends in rate of CHB, PPM implantation, and inpatient mortality were examined. RESULTS: Of 35,500 TAVR procedures, 3,675 (10.4%) had CHB. Overall, occurrence of CHB significantly increased from 8.4% in 2012 to 11.8% in 2014 (adjusted OR per year: 1.23; 95% confidence interval [CI]: 1.17-1.29, P trend <0.001). During the same period, PPM implantation increased from 9.5 to 13.7% (adjusted OR per year: 1.22; 95% CI: 1.16-1.28, P trend <0.001). Patients with CHB had higher odds of in-hospital mortality when compared to patients without CHB (5.9% vs. 4.2%, adjusted OR: 1.32; 95% CI: 1.12-1.56; p = 0.001). Moreover, CHB was also associated with longer length of stay (LOS) and higher hospitalization cost. CONCLUSIONS: There was a significant increase in rates of CHB and PPM implantation over the study period. Development of CHB was associated with increased in-hospital mortality, LOS, and hospitalization cost.

Postoperative heart block in children with common forms of congenital heart disease: results from the KID Database.

INTRODUCTION: Cardiac conduction system injury is a cause of postoperative cardiac morbidity following repair of congenital heart disease (CHD). The national occurrence of postoperative complete heart block (CHB) following surgical repair of CHD is unknown. We sought to describe the occurrence of and costs related to postoperative CHB following surgical repair of common forms of CHD using a large national database. METHODS AND RESULTS: Retrospective, observational analysis performed over a 10-year period (2000-2009) using the Kids' Inpatient Database (KID). Visits for patients ≤24 months of age were identified who underwent surgical repair of ventricular septal defects (VSD), atrioventricular canal defects (AVC), and tetralogy of Fallot (TOF). Patients were identified who were diagnosed with postoperative CHB, further identifying those requiring a new pacemaker placement during the same hospitalization. Costs associated with visits were calculated. There were 16,105 surgical visits: 7,146 VSD, 3,480 AVC, and 5,480 TOF. There was a decrease in postoperative mortality (P = 0.0001) with no significant change in postoperative CHB. Hospital stay and cost were higher with CHB and placement of a permanent pacemaker. Repair of AVC (OR 1.77; [1.32-2.38]) was associated with a higher rate of postoperative CHB. Length of hospital stay and total cost were significantly increased with the development of postoperative CHB and increased further with placement of a permanent pacemaker. CONCLUSION: There has been little change over time in the frequency of postoperative CHB in patients undergoing repair of VSD, AVC, and TOF. Postoperative CHB results in major added cost to the healthcare system.

Utility of the surface ECG before VDD pacemaker implantation.

BACKGROUND: VDD pacemakers may be implanted in the setting of atrioventricular block with preserved sinus function. Their main advantage over DDD pacemakers is use of a single lead. However, low-amplitude atrial electrograms (EGMs) recorded from the free-floating atrial electrode may lead to undersensing. There is currently no way of predicting EGM amplitude prior to implantation and to thus identify candidates who may be safely implanted with a VDD pacemaker. AIM: We sought to investigate whether the P-wave amplitude measured on the standard surface ECG correlates with the atrial EGM amplitude measured by the single-pass lead at implantation. METHODS: Data on 122 patients implanted with a VDD pacemaker at our institution were reviewed. Atrial EGM amplitudes measured at implantation by the single-pass lead were correlated with the maximal P-wave amplitude on the surface ECG recorded just prior to implantation. RESULTS: There was a highly significant correlation between the maximal P-wave amplitude on the surface ECG and the atrial EGM (Pearson's correlation 0.313, P<0.001). Multivariate analysis showed that maximal P-wave amplitude was independently associated with atrial EGM amplitude (p=0.003). For the overall population, an EGM amplitude of <0.9 mV was present in only 11/122 (9%) cases. An atrial EGM amplitude of <0.9 mV was found in 10/69 (14%) of patients with a maximal surface P-wave < or =0.1 mV but only in 1/53 (2%) of those with >0.1 mV (p=0.023). CONCLUSION: Low-amplitude atrial EGMs at implantation are found in a minority of patients with single-pass leads. However, patients with a maximal surface P-wave amplitude of >0.1 mV are especially unlikely to have a low atrial EGM amplitude and may be good candidates for a VDD pacemaker.

The effectiveness and cost-effectiveness of dual-chamber pacemakers compared with single-chamber pacemakers for bradycardia due to atrioventricular block or sick sinus syndrome: systematic review and economic evaluation.

OBJECTIVES: To estimate the effectiveness and cost-effectiveness of dual-chamber pacemakers versus single-chamber atrial or single-chamber ventricular pacemakers in the treatment of bradycardia due to sick sinus syndrome (SSS) or atrioventricular block (AVB). DATA SOURCES: Electronic databases and relevant Internet sites. Contact with device manufacturers and experts in the field. REVIEW METHODS: A systematic review was carried out of randomised controlled trials (RCTs). The quality of selected studies was appraised using standard frameworks. Meta-analyses, using random effects models, were carried out where appropriate. Limited exploration of heterogeneity was possible. Critical appraisal of economic evaluations was carried out using two frameworks. A decision-analytic model was developed using a Markov approach, to estimate the cost-effectiveness of dual-chamber versus ventricular or atrial pacing over 5 and 10 years as cost per quality-adjusted life-year (QALY). Uncertainty was explored using one-way and probabilistic sensitivity analyses. RESULTS: The searches retrieved a systematic review of effectiveness and cost-effectiveness published in 2002, four parallel group RCTs and 28 cross-over trials. Dual-chamber pacing was associated with lower rates of atrial fibrillation, particularly in SSS, than ventricular pacing, and prevents pacemaker syndrome. Higher rates of atrial fibrillation were seen with dual-chamber pacing than with atrial pacing. Complications occurred more frequently in dual-chamber pacemaker insertion. The cost of a dual-chamber system, over 5 years, including cost of complications and subsequent clinical events in the population, was estimated to be around 7400 pounds. The overall cost difference between single and dual systems is not large over this period: around 700 pounds more for dual-chamber devices. The cost-effectiveness of dual-chamber compared with ventricular pacing was estimated to be around 8500 pounds per QALY in AVB and 9500 pounds in SSS over 5 years, and around 5500 pounds per QALY in both populations over 10 years. Under more conservative assumptions, the cost-effectiveness of dual-chamber pacing is around 30,000 pounds per QALY. The probabilistic sensitivity analysis showed that, under the base-case assumptions, dual-chamber pacing is likely to be considered cost-effective at levels of willingness to pay that are generally considered acceptable by policy makers. In contrast, atrial pacing may be cost-effective compared with dual-chamber pacing. CONCLUSIONS: Dual-chamber pacing results in small but potentially important benefits in populations with SSS and/or AVB compared with ventricular pacemakers. Pacemaker syndrome is a crucial factor in determining cost-effectiveness; however, difficulties in standardising diagnosis and measurement of severity make it difficult to quantify. Dual-chamber pacing is in common usage in the UK. Recipients are more likely to be younger. Insufficient evidence is currently available to inform policy on specific groups who may benefit most from pacing with dual-chamber devices. Further important research is underway. Outstanding research priorities include the economic evaluation of UKPACE studies of the classification, diagnosis and utility associated with pacemaker syndrome and evidence on the effectiveness of pacemakers in children.

Cost-effectiveness of dual-chamber pacemaker therapy: does single lead VDD pacing reduce treatment costs of atrioventricular block?

AIMS: Implantation of single-lead VDD pacemakers is an established alternative to DDD pacing in patients with atrioventricular block. This study compares the long-term costs of both systems. METHODS AND RESULTS: Three hundred and sixty patients with atrioventricular block received VDD or DDD pacemakers in alternating order. Primary costs of implantation included: devices, leads and operation material, surgeons, nurses, medical technicians, and hospitalization. The mean cost of an uncomplicated DDD pacemaker implantation was defined as 1000 virtual cost-units (CU). Costs of pacemaker related complications or re-operations as well as upgrades from VDD to DDD devices were considered secondary costs and assessed during a mean follow-up period of 42+/-15 months. Pacing efficacy was assessed by event-free survival with maintained atrioventricular synchronized pacing mode. Costs of pacemaker devices were not different (639+/-26 CU in VDD vs 641+/-32 CU in DDD, ns). However, due to lower costs of lead hardware (102+/-10 CU in VDD vs 133+/-14 CU in DDD, P<0.001) and shorter implantation procedures (44.3+/-5.1 min vs 74.4+/-13.5 min, P<0.001), costs of an uncomplicated implantation were 8.9% lower in the VDD group (911+/-35 CU vs 1000+/-39 CU, P<0.001). A smaller complication rate in the VDD group led to a 16.1% reduction of secondary costs (26+/-17 CU year(-1)vs 31+/- 25 CU year(-1), P=0.024). Event-free survival did not differ between groups (83.4% in VDD vs 84.9% in DDD, ns). CONCLUSION: Use of single-lead VDD pacemakers achieves significant reduction of implantation and follow-up costs without loss of therapeutic efficacy compared to conventional DDD systems.

Cost benefit analysis of single and dual chamber pacing for sick sinus syndrome and atrioventricular block. An economic sensitivity analysis of the literature.

The benefits of dual (DDD) over single chamber pacing (VVI) have been demonstrated in haemodynamics, exercise capacity, quality of life and reduced complications in atrioventricular block and sick sinus syndrome. The literature was reviewed to provide complication rates for dual and VVI pacing. Cost calculations were based on United Kingdom 1991 prices. Over a 10-year period, a computer model calculated the incidence and prevalence of atrial fibrillation, stroke, permanent disability, heart failure and mortality in six patient categories: sick sinus syndrome paced VVI, sick sinus syndrome upgraded to DDD, sick sinus syndrome paced DDD from outset, atrioventricular block paced VVI and those upgraded to DDD and atrioventricular block paced initially DDD. Calculations were based on intention to treat. The 10 year survival with DDD vs VVI pacing was 71% vs 57% in sick sinus syndrome and 61% vs 51%, respectively, in atrioventricular block. In both indications the prevalence of heart failure in the 10 year survivors was 60% lower with DDD pacing. In sick sinus syndrome patients paced VVI, 36% had severe disability while only 8% experienced this with DDD pacing. For atrioventricular block the figures were, respectively, 22% vs 3%. The difference in 10 year cumulative cost between VVI and DDD is 13 times the purchase price of a VVI pulse generator for sick sinus syndrome and 7 times for atrioventricular block. In the third year after implantation the cumulative costs of DDD were lower than for VVI for both indications. Dual chamber pacing for both indications, sick sinus syndrome and atrioventricular block, is both clinically and cost effective.