Dominic Rogers

A randomized double-blind crossover trial of triventricular versus biventricular pacing in heart failure

A significant proportion of patients implanted with biventricular (BiV) devices fail to respond. Clinical response may be improved by additional ventricular stimulation sites. This single‐centre, double‐blinded randomized crossover trial aimed to determine whether long‐term multisite ventricular pacing is superior to conventional BiV pacing in heart failure patients.

Effect of biventricular pacing on symptoms and cardiac remodelling in patients with end‐stage hypertrophic cardiomyopathy

Biventricular (BiV) pacing is an established therapy for heart failure in ischaemic and dilated cardiomyopathy. Its effects in end‐stage hypertrophic cardiomyopathy (HCM) are unknown.

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

AIMS 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. METHODS AND RESULTS 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. CONCLUSIONS 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.

Improving safety in the electrophysiology laboratory using a simple radiation dose reduction strategy: a study of 1007 radiofrequency ablation procedures

Background The use of fluoroscopic screening involves exposure to ionising radiation for both patients and operators. Objective To assess the effects of radiation dose reduction manoeuvres (DRM) during radiofrequency ablation (RFA) procedures. Design Prospective study of DRM. Setting Tertiary cardiac centre. Interventions Two DRM were combined: removal of the secondary radiation grid and programming an ultra-low pulsed fluoroscopy rate. These methods were assessed using an anthropomorphic phantom model to measure skin entrance dose rates. Procedures were classified as complex (ablation of atrial fibrillation, ventricular tachycardia or complex congenital heart disease arrhythmias) or simple (all other RFA). Main outcome measures Dose area product and screening times were compared for ablations performed before and after DRM. Equivalent doses to organs and malignancy risk were determined by computer modelling. Results Over a 39-month period, 1007 ablation procedures were performed (631 simple, 376 complex). Radiation dose was significantly reduced after DRM for both simple (20.4±26.9 Gycm2 vs 8.0±10.3 Gycm2, p<0.00001) and complex ablations (63.3±50.1 Gycm2 vs 32.8±31.7 Gycm2, p<0.00001) with no difference in screening times. The mean lifetime risk of fatal cancer attributable to radiation exposure per million procedures was reduced from 182 to 68 for simple ablations and from 440 to 155 for complex ablations. Conclusions Significant reductions in radiation exposure during RFA were achieved using simple DRM, corresponding to a two-thirds reduction of the risk of excess fatal malignancy.

Right atrial angiography facilitates transseptal puncture for complex ablation in patients with unusual anatomy

ObjectiveThe number of transseptal punctures performed worldwide has increased exponentially with the development of ablation therapies for atrial arrhythmias. Safe access into the left atrium in these procedures is often complicated by abnormal anatomy. We assessed the potential of right atrial angiography to facilitate transseptal puncture for atrial ablation.Methods and resultsWe examined all transseptal punctures performed for complex left atrial ablation in our centre over a 29-month period. In cases where conventional transseptal techniques failed, we performed orthogonal right atrial angiography to define cardiac anatomy and orientation. During the study period, 255 transseptal procedures were performed. Of these, 16 cases were complicated by distorted atrial anatomy, extreme cardiac rotation or unexpected location of the atria in relation to the diaphragm, preventing left atrial access using conventional fluoroscopy. The application of right atrial angiography facilitated successful transseptal puncture in all patients when use of conventional mapping catheters and fluoroscopy proved unhelpful. There were no complications relating to right atrial angiography.ConclusionThese cases highlight a number of difficulties encountered when performing transseptal punctures. Previously reported adjunctive techniques require specialised equipment, general anaesthesia or multiple catheters that may be unavailable or impede the procedure. Right atrial angiography is a simple and safe adjunct to conventional techniques to facilitate complex transseptal procedures.

An 8-year single-centre experience of cardiac resynchronisation therapy: procedural success, early and late complications, and left ventricular lead performance.

AIMS Despite the increasing number of device implants worldwide, little is known about the early and late complications of cardiac resynchronisation therapy (CRT) or the incidence of these complications in patients with different heart failure aetiologies. We aim to determine procedural success and early and late complications in CRT patients. METHODS AND RESULTS All early (<90 days) and late (>90 days) complications occurring over 490 consecutive CRT procedures in 402 patients, from a large single-centre registry between 2000 and 2009 were analysed. Mean follow-up duration was 1012 ± 610 days. In addition, procedural data and long-term left ventricular (LV) lead performance were examined. The mean age of patients was 65 ± 15 years, 31% were female. The majority of devices (70%) were CRT-defibrillators. Left ventricular lead implantation was achieved after one or more than one attempt in 96.7% of patients (first procedure was successful in 95.1%). The incidence of early and late complications was 9.4% and 6.1% respectively. Infection and lead displacement were the most common complications. Dilated cardiomyopathy (DCM) was associated with significantly more complications than ischaemic cardiomyopathy (P = 0.01) and these occurred later in the DCM population. Long-term LV lead performance was comparable with that of right atrial and ventricular leads. CONCLUSION Transvenous implantation of the LV lead is safe and achievable for CRT with high procedural success rates. For the first time we describe the late complications from CRT in different heart failure populations. This group of patients must be kept under surveillance, not only for heart failure events but also for device-related issues. The reasons for higher complication rates in DCM patients require further evaluation.

A simple infection-control protocol to reduce serious cardiac device infections

AIM Device infection is a serious complication and is considered procedure-related if occurring within 12 months of an intervention. We analysed the effectiveness of a simple infection-control protocol (ICP) at reducing cardiac device infections (CDIs) in a tertiary referral centre. METHODS AND RESULTS Prior to the introduction of a new ICP, we retrospectively analysed all simple and complex device implants, related procedures, and infections over a 3-year period. A new protocol was implemented from November 2007, including antibiotic prophylaxis determined by risk stratification, improved glycaemic control, specific skin preparation, and closure techniques, as well as different diathermy settings. Follow-up data for all patients were collected. Risk factors for infection were compared between pre- and post-intervention groups to ensure that the populations were comparable. A cost analysis of CDI and a review of the commonly identified micro-organisms were also undertaken. One thousand seven hundred and ninety-eight procedures were performed between November 2004 and November 2007 and 981 procedures between November 2007 and May 2009. There were no significant differences in the risk factors for infection between the two groups. Following the introduction of the ICP, there was a 54% reduction in the incidence of CDI from 1.3 to 0.6% (P < 0.03; CI 0.25, 1.36). Most patients with CDI had negative blood cultures or grew Staphylococcus sp. The average cost was £30 958.40 per infection incident and the cost of the new ICP was minimal. CONCLUSIONS A significant reduction in CDI can be achieved with the introduction of a simple ICP with substantial cost savings.

Successful coronary sinus lead replacement despite total venous occlusion using femoral pull through, two operator counter-traction and subclavian venoplasty.

The majority of patients presenting for lead extraction have indications for a replacement lead. Venous stenosis is common in recipients of pacing leads and can impede ipsilateral lead replacement. Recanalization through an existing tract after lead extraction allows successful lead placement but may require complex hybrid lead extraction and revascularization techniques. We present a case in which a combination of femoral lead extraction with complete guidewire pull-through, two operator external counter-traction and subclavian venoplasty was used to successfully replace a coronary sinus lead in a patient with total subclavian venous occlusion.

A heart without hormones.

A 65-year-old man was referred by his general practitioner for an ECG at our hospital after a single episode of syncope occurring at rest. He had felt light-headed immediately before collapsing but had had no other symptoms. The ECG showed sinus rhythm at 68 beats per min, with striking prolongation of the QT interval (corrected for heart rate) 503 ms and he was admitted for cardiac monitoring and investigation. He had not previously had any similar epi sodes, palpitations, or chest pain. There was no relevant medical, family, or drug history. Clinical examination was unremarkable, and routine serum bio-chemistry was normal (sodium 139 mmol/L, potas sium 4·1 mmol/L, calcium 2·24 mmol/L, magnesium 0·87 mmol/L). Echocardiography showed good biven-tricular function with no valvular abnormality. Thyroid function tests showed secondary hypothyroidism with low free thyroxine (4·2 pmol/L) and normal thyrotropin concentrations (2·87 mIU/L). On subsequent questioning, our patient gave a history of lethargy, reduced libido, erectile dys function, and loss of body hair. A pituitary profi le showed low concentrations of luteinising hormone (0·1 IU/L), follicle-stimulating hormone (0·8 IU/L), testos-terone (<0·1 nmol/L), and cortisol (17 nmol/L). Serum prolactin was slightly high at 740 mIU/L.A diagnosis of panhypopituitarism was made and treatment with hydrocortisone and, subsequently, levo-thyroxine was started. MRI of the head (fi gure) showed a well-circumscribed mass occupying the sellar and suprasellar regions with expansion of the sella turcica. No arrhythmias were seen during 5 days of cardiac monitoring and our patient was discharged on pituitary replacement therapy. At review 2 weeks later, the QT interval had normalised at 430 ms, and no further episodes of syncope had occurred. He subsequently underwent successful resection of a pituitary macro-adenoma, and at 12 month follow up was symptom free.The QT interval on the ECG, corrected for heart rate by use of Bazett’s formula, represents ventricular depolarisation and repolarisation, a process mediated by

Is CRT pro-arrhythmic? A comparative analysis of the occurrence of ventricular arrhythmias between patients implanted with CRTs and ICDs

Aim and Hypothesis: Despite the proven symptomatic and mortality benefit of cardiac resynchronization therapy (CRT), there is anecdotal evidence it may be pro-arrhythmic in some patients. We aimed to identify if there were significant differences in the incidence of ventricular arrhythmias (VAs) in patients undergoing CRT-D and implantable cardioverter-defibrillators (ICD) implantation for primary prevention indication. We hypothesized that CRT is unlikely to be pro-arrhythmic based on the positive mortality and morbidity data from large randomized trials. Methods and Results: A retrospective analysis of device therapies for VA in a primary prevention device cohort was performed. Patients with ischemic (IHD) and non-ischemic (DCM) cardiomyopathy and ICD or CRT+ICD devices (CRT-D) implanted between 2005 and 2007 without prior history of sustained VA were included for analysis. VA episodes were identified from stored electrograms and defined as sustained (VT/VF) if therapy [anti-tachycardia pacing (ATP) or shocks] was delivered or non-sustained (NSVT) if not. Of a total of 180 patients, 117 (68% male) were in the CRT-D group, 42% IHD, ejection fraction (EF) 24.5 ± 8.2% and mean follow-up 23.9 ± 9.8 months. 63 patients (84% male) were in the ICD group, 60% IHD, EF 27.7 ± 7.2% and mean follow-up 24.6 ± 10.8 months. Overall, there was no significant difference in the incidence of VA (35.0 vs. 38.1%, p = 0.74), sustained VT (21.3 vs. 28.5%, p = 0.36) or NSVT (12.8 vs. 9.5%, p = 0.63) and no significant difference in type of therapy received for VT/VF: ATP (68 vs. 66.6%, p = 0.73) and shocks (32 vs. 33.3%, p = 0.71) between the CRT-D and ICD groups, respectively. Conclusion: In patients with cardiomyopathy receiving CRT-D and ICDs for primary prophylaxis, there was no significant difference in the incidence of VA. From this single center retrospective analysis, there is no evidence to support cardiac resynchronization causing pro-arrhythmia.