A Novel Quadripolar Active Fixation Left-Ventricular Pacing Lead for Cardiac Resynchronization Therapy: Initial United Kingdom Experience.

OBJECTIVES: This study sought to assess immediate and short-term performance of the Medtronic Attain Stability Quadripolar 4798 lead (Medtronic, Dublin, Ireland). BACKGROUND: Cardiac resynchronization therapy (CRT) is an established treatment for appropriately selected patients with left ventricular (LV) systolic dysfunction. The most common reason for failure to implant a lead is the lack of a suitable epicardial vein, due either to an absent vessel in the target site, an unacceptably high threshold, lead instability, phrenic nerve stimulation, or a combination of reasons. In August 2017, a novel quadripolar active fixation LV lead (Medtronic) was released. This paper reports the initial clinical experience with lead implantation and specifically immediate and short-term pacing parameters across 3 United Kingdom centers. METHODS: Consecutive patients eligible for CRT were deemed suitable for this lead. Immediate and short-term lead performance data regarding LV threshold, impedance, and displacement rates were collected at standard pacing checks (1 day, 5 weeks, 3 months, and 9 months post-implantation). RESULTS: CRT using this lead was attempted in 82 cases and was successful in 81 cases (98.8%). LV thresholds and impedance levels were 1.22 ± 0.75 V and 737 ± 319 Ω at implantation; 1.16 ± 0.71 V and 597 ± 218 Ω at day 1; 1.02 ± 0.48 V and 579 ± 148 Ω at week 6; 0.98 ± 0.49 V and 569 ± 133 Ω at 3 months; and 1.06 ± 0.48 V and 570 ± 140 Ω at 9 months. As of the publication of this paper, no LV lead has been displaced. CONCLUSIONS: CRT using the Medtronic lead was successful in more than 98% of the patients. Short-to-medium-term data regarding lead performance and stability were excellent, with zero displacements as of the publication of this paper.

Pacemaker implantation in superior vena cava obstruction: Re-canalization, venoplasty, and stenting.

Techniques to overcome challenging venous anatomy have become an increasingly important part of modern day cardiac device implantation. Complete superior vena cava (SVC) obstruction, however, is a rare and serious clinical entity, and consequently there is limited clinical experience in addressing this pathology in the context of transvenous pacemaker implantation. We present the case of a 48-year-old renal transplant patient with sick sinus syndrome and recurrent syncope, who had an upper SVC occlusion and a failed epicardial pacing system. The SVC was re-canalized and stented using techniques derived from chronic total occlusion coronary angioplasty, thus allowing successful implantation of a transvenous pacemaker lead. This case highlights the increased risk of developing central venous occlusion that exists in renal dialysis patients, and demonstrates the benefits of utilizing transferable interventional coronary and radiology techniques to overcome this pathology and facilitate pacemaker implantation. .

Safe use of MRI in people with cardiac implantable electronic devices.

MR scanning in patients with cardiac implantable electronic devices (CIEDs) was formerly felt to be contraindicated, but an increasing number of patients have an implanted MR conditional device, allowing them to safely undergo MR scanning, provided the manufacturer's guidance is adhered to. In addition, some patients with non-MR conditional devices may undergo MR scanning if no other imaging modality is deemed suitable and there is a clear clinical indication for scanning which outweighs the potential risk. The following guidance has been formulated by the British Heart Rhythm Society and endorsed by the British Cardiovascular Society and others. It describes protocols that should be followed for patients with CIEDs undergoing MR scanning. The recommendations, principles and conclusions are supported by the Royal College of Radiologists.

The 7-year teesside experience of primary prevention ICD indications following primary PCI (PPCI) and the potential impact of a change in NICE guidance.

INTRODUCTION: The recovery of LV function in patients with severe LV impairment in the acute phase following primary percutaneous coronary intervention (PPCI) is not well established. The indication for a primary prevention ICD post-STEMI is dependent on which screening guidance, NICE or ESC, is followed. The potential impact of the new NICE guidance is estimated. METHODS: We performed a retrospective analysis of all patients presenting with a STEMI over a 7-year period (2005-2012) treated with PPCI to determine in-hospital mortality, LV function at index presentation, at 3 months and the predicted primary prevention ICD implantation rate using NICE (TA095) and ESC 2006 guidelines. Predicted implant rates using the new NICE guidance (TA314) and actual implantation rates were also assessed. RESULTS: 3902 patients with a mean age of 65±13 years underwent PPCI. Of those patients surviving until discharge, 332 (10%) had LVEF ≤35%. 254 of 332 patients (76%) with a severely impaired ventricle were followed up at participating centres. 210 of 254 (83%) patients had a repeat echocardiogram within 3 months post-MI; among these patients, 89 (42%) remained to have LVEF ≤35%. The number of patients fulfilling NICE and ESC criteria for primary prevention ICD implantation was 14 (16%) and 84 (94%), respectively. The actual number of patients receiving an ICD was 17 (19%). The number of patients fulfilling the new NICE (TA314) guidance was 84 (94%). CONCLUSIONS: A small proportion of patients with STEMIs undergoing PPCI have a severely impaired LV systolic function. A large proportion of these patients will have improved LV systolic function at 3 months. There is a five-fold difference in the predicted ICD implantation rates depending on which guidance is followed-NICE versus ESC. The potential impact of the new NICE (TA314) guidance on ICD implantation will be a significant increase in ICD implantation rates.

Costs of unstructured investigation of unexplained syncope: insights from a micro-costing analysis of the observational PICTURE registry.

AIMS: The observational PICTURE (Place of Reveal In the Care pathway and Treatment of patients with Unexplained Recurrent Syncope) registry enrolled 570 patients with unexplained syncope, documented their care pathway and the various tests they underwent before the insertion of an implantable loop recorder (ILR). The aims were to describe the extent and cost of diagnostic tests performed before the implant. METHODS AND RESULTS: Actual costs of 17 predefined diagnostic tests were characterized based on a combination of data from PICTURE and a micro-costing study performed at a medium-sized UK university hospital in the UK. The median cost of diagnostic tests per patient was £1114 (95% CI £995-£1233). As many patients received more than the median number of tests, the mean expenditure per patient was higher with £1613 (95% CI £1494-£1732), and for 10% of the patients the cost exceeded £3539. Tests were frequently repeated, and early use of specific and expensive tests was common. In the 12% of patients with types of tests entirely within the recommendations for an initial evaluation before ILR implant, the mean cost was £710. CONCLUSION: Important opportunities to reduce test-related costs before an ILR implant were identified, e.g. by more appropriate use of tests recommended in the initial evaluation, by decreasing repetition of tests, and by avoiding early use of specialized and expensive tests. A structured multidisciplinary approach would be the best model to achieve an optimal outcome.

Effect of right ventricular pacing lead site on left ventricular function in patients with high-grade atrioventricular block: results of the Protect-Pace study.

AIM: Chronic right ventricle (RV) apical (RVA) pacing is standard treatment for an atrioventricular (AV) block but may be deleterious to left ventricle (LV) systolic function. Previous clinical studies of non-apical pacing have produced conflicting results. The aim of this randomized, prospective, international, multicentre trial was to compare change in LV ejection fraction (LVEF) between right ventricular apical and high septal (RVHS) pacing over a 2-year study period. METHODS AND RESULTS: We randomized 240 patients (age 74 ± 11 years, 67% male) with a high-grade AV block requiring >90% ventricular pacing and preserved baseline LVEF >50%, to receive pacing at the RVA (n = 120) or RVHS (n = 120). At 2 years, LVEF decreased in both the RVA (57 ± 9 to 55 ± 9%, P = 0.047) and the RVHS groups (56 ± 10 to 54 ± 10%, P = 0.0003). However, there was no significant difference in intra-patient change in LVEF between confirmed RVA (n = 85) and RVHS (n = 83) lead position (P = 0.43). There were no significant differences in heart failure hospitalization, mortality, the burden of atrial fibrillation, or plasma brain natriutetic peptide levels between the two groups. A significantly greater time was required to place the lead in the RVHS position (70 ± 25 vs. 56 ± 24 min, P < 0.0001) with longer fluoroscopy times (11 ± 7 vs. 5 ± 4 min, P < 0.0001). CONCLUSION: In patients with a high-grade AV block and preserved LV function requiring a high percentage of ventricular pacing, RVHS pacing does not provide a protective effect on left ventricular function over RVA pacing in the first 2 years. PROTECT-PACE: ClinicalTrials.gov number NCT00461734.

Unexplained syncope: implications of age and gender on patient characteristics and evaluation, the diagnostic yield of an implantable loop recorder, and the subsequent treatment.

BACKGROUND: Syncope is a common clinical problem with a variety of underlying mechanisms, some of which occur more frequently in 1 of the sexes or at a certain age. HYPOTHESIS: There may be clinically significant age- and gender-related differences in patients with unexplained syncope. METHODS: Five hundred seventy patients (54% women) with unexplained syncope received an implantable loop recorder (ILR) and were followed until diagnosis or for at least 1 year. RESULTS: Women were older and more prone to severe trauma during syncope (40.8% vs 29.9%, P = 0.007), and hospitalization was more common at ≥65 years (P = 0.003) without gender difference. Muscle spasms or grand mal seizures were more common in men and at <65 years old. Carotid sinus pressure, exercise testing, coronary angiography and magnetic resonance imaging/computed tomography scans were more commonly performed in men, whereas no test was more common in women. Tilt testing, exercise test, electroencephalography, and neurological or psychiatric evaluation were more common at ≥65 years. There were no age- or gender-related differences in the diagnostic yield of the ILR, whereas patients ≥65 years old more often received specific treatment based on ILR data. CONCLUSIONS: Gender and/or age had relevance for the clinical evaluation, rate of recurrence, and subsequent specific treatment but not for the diagnostic yield of the ILR.

Current Evidence and Recommendations for Cardiac Resynchronisation Therapy.

The number of people in Europe living with symptomatic heart failure is increasing. Since its advent in the 1990s, cardiac resynchronisation therapy (CRT) has proven beneficial in terms of morbidity and mortality in selected heart failure (HF) patient populations, when combined with optimal pharmacological therapy. We review the evidence for CRT and the populations of HF patients it is currently shown to benefit, and those in which more research needs to be performed.

Early versus delayed implantation of a loop recorder in patients with unexplained syncope--effects on care pathway and diagnostic yield.

BACKGROUND: This study looked to assess the care pathway and diagnostic yield in patients who received an implantable loop recorder (ILR) after an "initial phase of the diagnostic work-up" (initial work-up) or after a "full evaluation" of unexplained syncope. METHODS AND RESULTS: Physicians classified the timing of an ILR implant in 514 patients as either following an "initial work-up" (n=128; 25%) or "full evaluation" (n=386; 75%). Patients with an "initial work-up" underwent a median (IQ range) of 8 (6-14) tests prior to ILR implant compared to 14 (10-21) tests after "full evaluation" (p<0.0001). Hospitalization and injury before implant were less common in patients with an "initial work-up": 53 vs. 75%, p<0001, and 23% vs. 39%, p<0.001, as were visits to specialists, e.g. neurologist, 32% vs. 50%, p<0.001. At one year after implant, the syncope recurrence rate was 32% in the initial work-up group and 36% in the full evaluation group, and the incidence of recurrences with an ILR-guided diagnosis was 52% and 75% respectively. Diagnoses were cardiac in 90% after "initial work-up" vs. 79% after "full evaluation". CONCLUSIONS: Patients who only underwent an "initial work-up" had fewer investigations and a lower incidence of injury or hospitalization. The diagnostic yield from the ILR was high in both groups. Patients in both groups underwent more investigations than suggested in the ESC guidelines and could have benefitted from limiting the initial evaluation before an ILR is implanted.

Video-assisted thoracoscopic left ventricular pacing in patients with and without previous sternotomy.

BACKGROUND: Left ventricular epicardial lead placement via video-assisted thoracoscopy (VAT) is a recognized surgical technique to achieve cardiac resynchronization therapy (CRT) when conventional lead placement has failed. Its role in patients with previous sternotomy is uncertain. We describe our experience in a cohort of patients including those with previous sternotomy. METHODS: This was a retrospective review of consecutive patients undergoing VAT lead implantation for CRT in a single center between 2004 and 2011. All patients fulfilled conventional criteria for CRT and were followed up at 4 to 6 weeks and then at 3-month intervals. Clinical and pacing parameters were compared at baseline and at the latest review. RESULTS: Thirty-two patients (27 men; mean age, 67 ± 9 years) underwent VAT left ventricular lead implantation. Mean follow-up duration was 704 ± 450 days. Ten patients (31%) had undergone previous sternotomy. Thoracoscopic lead implantation was successful in 31 patients (97%): 1 patient with two previous sternotomies required conversion to open thoracotomy due to bleeding with multiple adhesions. Satisfactory implantation pacing thresholds of 2 volts or less at 0.5 ms were achieved in all patients. Despite a longer operative time in those with previous sternotomy, all clinical and pacing outcomes, including complications, clinical response to CRT, and long-term pacing variables were similar between the groups. CONCLUSIONS: VAT left ventricular lead placement appears safe and effective in selected patients with previous sternotomy, including coronary artery bypass operations, with postoperative outcomes comparable with those patients without previous sternotomy.

Use of an implantable loop recorder to increase the diagnostic yield in unexplained syncope: results from the PICTURE registry.

AIMS: To collect information on the use of the Reveal implantable loop recorder (ILR) in the patient care pathway and to investigate its effectiveness in the diagnosis of unexplained recurrent syncope in everyday clinical practice. METHODS AND RESULTS: Prospective, multicentre, observational study conducted in 2006-2009 in 10 European countries and Israel. Eligible patients had recurrent unexplained syncope or pre-syncope. Subjects received a Reveal Plus, DX or XT. Follow up was until the first recurrence of a syncopal event leading to a diagnosis or for ≥1 year. In the course of the study, patients were evaluated by an average of three different specialists for management of their syncope and underwent a median of 13 tests (range 9-20). Significant physical trauma had been experienced in association with a syncopal episode by 36% of patients. Average follow-up time after ILR implant was 10±6 months. Follow-up visit data were available for 570 subjects. The percentages of patients with recurrence of syncope were 19, 26, and 36% after 3, 6, and 12 months, respectively. Of 218 events within the study, ILR-guided diagnosis was obtained in 170 cases (78%), of which 128 (75%) were cardiac. CONCLUSION: A large number of diagnostic tests were undertaken in patients with unexplained syncope without providing conclusive data. In contrast, the ILR revealed or contributed to establishing the mechanism of syncope in the vast majority of patients. The findings support the recommendation in current guidelines that an ILR should be implanted early rather than late in the evaluation of unexplained syncope.

Early invasive versus conservative treatment in patients with failed fibrinolysis--no late survival benefit: the final analysis of the Middlesbrough Early Revascularisation to Limit Infarction (MERLIN) randomized trial.

BACKGROUND: Early (30 days) and midterm (6 months) clinical outcomes in trials comparing rescue angioplasty (rescue percutaneous coronary intervention [rPCI]) with conservative treatment of failed fibrinolysis complicating ST-segment elevation myocardial infarction have shown variable results. Whether early rPCI confers late (up to 3 years) clinical benefits is not known. METHODS: The MERLIN trial compared rPCI and a conservative strategy in patients with failed fibrinolysis complicating ST-segment elevation myocardial infarction. Three hundred seven patients with electrocardiographic evidence of failure to reperfuse at 60 minutes were included. Patients in cardiogenic shock were excluded. Thirty-day and 1-year results have been reported. Results of 3 years of follow-up are presented. RESULTS: Three-year mortality in the conservative arm and rPCI, respectively, was 16.9% versus 17.6% (P = .9, relative difference [RD] -0.8, 95% CI [-9.3 to 7.8]). Death rates were similar (3.9% vs 3.2%) between 1- and 3-year follow-up, respectively. The incidence of the composite secondary end point of death, reinfarction, stroke, unplanned revascularization, or heart failure was significantly higher in the conservative arm (64.3% vs 49%, P = .01, RD 15.3, 95% CI [4.2-26]). There was no significant difference in the rate of reinfarction (0.7% vs 0.7%) or heart failure (1.3% vs 2.7%) between 1 and 3 years between the conservative and rPCI arms, respectively. The incidence of subsequent unplanned revascularization at 3 years was significantly higher in the conservative arm (33.8% vs 14.4%, P < .01, RD 19.4, 95% CI [10-28.7]), most of which occurred within 1 year; the rates between 1 and 3 years were 3.9% in the conservative arm versus 2% in the rPCI arm. There was a trend toward fewer strokes in the conservative arm at 3 years (conservative arm 2.6% vs rPCI 6.5%, P = .1, RD -3.9%, 95% CI [-9.4 to 0.8]), with similar stroke rates (1.3% vs 1.3%) between 1- and 3-year follow-up. CONCLUSIONS: Rescue angioplasty did not confer a late survival advantage at 3 years. The composite end point occurred less often in the rPCI arm mainly because of fewer unplanned revascularization procedures in the early phase of follow-up. The highest risk of clinical events in patients with failed reperfusion is in the first year, beyond which the rate of clinical events is low.

A randomized trial of prophylactic antiarrhythmic agents (amiodarone and sotalol) in patients with atrial fibrillation for whom direct current cardioversion is planned.

UNLABELLED: Antiarrhythmic agents enhance maintenance of sinus rhythm (SR) after direct current cardioversion (DCC) for atrial fibrillation but there are few comparative trials. BACKGROUND: The aims of the study were (1) to establish whether patients successfully cardioverted to SR are more likely to stay in SR over 6 months if taking amiodarone or sotalol, and if so, to establish whether one agent is better than the other; (2) to establish whether taking amiodarone or sotalol is better at achieving chemical cardioversion within the 6 weeks before DCC; and (3) to establish whether DCC is more likely to be successful on a drug. METHODS: Randomized, prospective, nonblinded, controlled study of treatment with either amiodarone (n = 27), sotalol (n = 36), or no antiarrhythmic agent (n = 31). RESULTS: Chemical cardioversion occurred in 7 patients in the amiodarone group (A), 7 patients in the sotalol group (S), but none in the no-antiarrhythmic group (N). A total of 33 (92%) patients in the sotalol group, 22 (81%) patients in the amiodarone group, and 23 (74%) patients in the no-antiarrhythmic group were in SR after cardioversion. Of the original cohort of patients, 17 (63%) patients in the amiodarone group remained in SR at 6-month follow-up, compared with 14 (39%) in the sotalol group and 5 (16%) in the no-antiarrhythmic group (A vs N, P < .0002, P < .0006B [after Bonferroni correction]; A vs S, P = .05, P = .15B; and S vs N, P = .03, P = .09B). CONCLUSIONS: Amiodarone and sotalol achieved chemical cardioversion before planned electrical cardioversion in 26% and 19% of patients, respectively. After successful cardioversion, amiodarone appears better than sotalol at maintaining SR at 6 months.

A prospective, randomized trial to determine the early and late reactions after the use of iopamidol 340 (Niopam) and iobitridol 350 (Xenetix) in cardiac catheterization.

BACKGROUND: Intravascular contrast agents presently used in modern digital catheter laboratories during cardiac catheterization are superior to older agents as regards patient tolerance. There are, however, significant differences between these agents. PURPOSE: The aim of this study was to determine the incidence of early (< 24 hours) and late (> 24 hours to 7 days) reactions to 2 contrast agents currently used during cardiac catheterization: iopamidol 340 (Niopam) and iobitridol 350 (Xenetix). METHODS: This was a prospective, randomized, double-blinded trial. Two thousand and nineteen patients undergoing cardiac catheterization received one of the following contrast agents: iopamidol 340 (Niopam) and iobitridol 350 (Xenetix). Reactions that were possibly related to the contrast agents were recorded during hospital admission (early reaction) and after discharge (late reaction) by means of a questionnaire. RESULTS: The baseline characteristics were matched in both the groups. There was no significant difference in the incidence of heat sensation experienced between the 2 groups, (p = 0.1). Early non-heat reactions occurred in 3.2% of patients receiving iopamidol 340 (Niopam) and 3.6% of those receiving iobitridol 350 (Xenetix), (p = 0.65). Electrocardiographic changes were recorded in 0.7% of patients who received iopamidol 340 (Niopam), and 2.6% of those who received iobitridol 350 (Xenetix), (p = < 0.01). Seven patients (0.8%) receiving iobitridol 350 suffered ventricular fibrillation requiring DC cardioversion compared with none in the iopamidol 340 group (p = < 0.01). Late reactions (post discharge symptoms) occurred in 13.9% of those receiving iopamidol 340 (Niopam) and 18.5% of those receiving iobitridol 350 (Xenetix) (p = 0.02). CONCLUSIONS: Iobitridol 350 (Xenetix) was associated with more ECG changes and, importantly, ventricular fibrillation, than iopamidol (Niopam). There were no features to suggest other benefits from iobitridol 350. These results suggest that iopamidol 340 is a preferable contrast agent in cardiac catheterization.

A randomized trial of rescue angioplasty versus a conservative approach for failed fibrinolysis in ST-segment elevation myocardial infarction: the Middlesbrough Early Revascularization to Limit INfarction (MERLIN) trial.

OBJECTIVES: We sought to compare emergency coronary angiography with or without rescue percutaneous coronary intervention (PCI) with conservative treatment in patients with failed fibrinolysis complicating ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Most patients with STEMI receive fibrinolytic therapy and aspirin. The management of failed fibrinolysis is unclear. METHODS: A total of 307 patients with STEMI and failed fibrinolysis were randomized to emergency coronary angiography with or without rescue PCI or conservative treatment. RESULTS: Thirty-day all-cause mortality was similar in the rescue and conservative groups (9.8% vs. 11%, p = 0.7, risk difference [RD] 1.2%, 95% confidence interval [CI] -5.8 to 8.3). The composite secondary end point of death/re-infarction/stroke/subsequent revascularization/heart failure occurred less frequently in the rescue group (37.3% vs. 50%, p = 0.02, RD 12.7%, 95% CI 1.6 to 23.5), driven by less subsequent revascularization (6.5% vs. 20.1%, p < 0.01, RD 13.6%, 95% CI 6.2 to 21.4). Re-infarction and clinical heart failure were less common in the rescue group (7.2% vs. 10.4%, p = 0.3, RD 3.2%, 95% CI -3.3 to 9.9; and 24.2% vs. 29.2%, p = 0.3, RD 5.7%, 95% CI -4.3 to 15.6, respectively). Strokes and transfusions were more common in the rescue group (4.6% vs. 0.6%, p = 0.03, RD 3.9%, 95% CI 0.5 to 8.6; and 11.1% vs. 1.3%, p < 0.001, RD 9.8%, 95% CI 4.9 to 19.9, respectively). Left ventricular function at 30 days was the same in the two groups. CONCLUSIONS: Rescue angioplasty did not improve survival by 30 days, but improved event-free survival, almost completely due to a reduction in subsequent revascularization. Rescue angioplasty was associated with more strokes and more transfusions and did not result in preservation of left ventricular systolic function at 30 days.