Paul A. Scott

The Extent of Left Ventricular Scar Quantified by Late Gadolinium Enhancement MRI Is Associated With Spontaneous Ventricular Arrhythmias in Patients With Coronary Artery Disease and Implantable Cardioverter-Defibrillators

Background—Characterization of sudden cardiac death (SCD) risk remains a challenge in the application of implantable cardioverter-defibrillator (ICD) therapy. Late gadolinium enhancement cardiac MRI (LGE-CMR) can accurately identify myocardial scar. We performed a retrospective, single-center observational study to evaluate the association between the extent and distribution of left ventricular scar, quantified using LGE-CMR, and the burden of ventricular arrhythmias in patients with coronary artery disease and ICDs. Methods and Results—All patients included (2006 to 2009) had undergone LGE-CMR before ICD implantation. Scar (defined as myocardium with a signal intensity ≥50% of the maximum in scar tissue) was characterized in terms of percent scar, scar surface area, and number of transmural left ventricular scar segments. The end point was appropriate ICD therapy. Sixty-four patients (mean age, 66±11 years; male sex, 51) were included. During 19±10 months follow-up, appropriate ICD therapy occurred in 19 (30%) patients. In Cox regression analyses, both percent scar (hazard ratio per 10%, 1.75; 95% CI, 1.09 to 2.81; P=0.02) and number of transmural scar segments (hazard ratio per segment, 1.40; 95% CI, 1.15 to 1.70; P=0.001) were significantly associated with the occurrence of appropriate ICD therapy. Conclusions—In this pilot study, the extent of myocardial scar characterized by LGE-CMR was significantly associated with the occurrence of spontaneous ventricular arrhythmias. We hypothesize that scar quantification by LGE-CMR may prove a valuable risk stratification tool for the occurrence of ventricular arrhythmias, which may have implications for patient selection for ICD therapy.

Brain natriuretic peptide for the prediction of sudden cardiac death and ventricular arrhythmias: a meta-analysis.

The risk stratification of patients for sudden cardiac death (SCD) remains a challenge. Brain natriuretic peptide (BNP) predicts overall mortality in heart disease but it is unclear how well it predicts SCD. We therefore performed a meta‐analysis of studies evaluating the accuracy of BNP to predict SCD and ventricular arrhythmias (VA).

Late gadolinium enhancement cardiac magnetic resonance imaging for the prediction of ventricular tachyarrhythmic events: a meta-analysis

Approaches to the risk stratification for sudden cardiac death (SCD) remain unsatisfactory. Although late gadolinium enhancement cardiac magnetic resonance imaging (LGE‐CMR) for SCD risk stratification has been evaluated in several studies, small sample size has limited their clinical validity. We performed this meta‐analysis to better gauge the predictive accuracy of LGE‐CMR for SCD risk stratification.

Non-steroidal anti-inflammatory drugs and cardiac failure: meta-analyses of observational studies and randomised controlled trials

To determine the risks of cardiac failure with non‐steroidal anti‐inflammatory drugs (NSAIDs) and the specific risks with Cox‐2 specific NSAIDs (COXIBs).

Targeted left ventricular endocardial pacing using a steerable introducing guide catheter and active fixation pacing lead

AIMS Cardiac resynchronization therapy via the coronary sinus (CS) is not always possible. Left ventricular (LV) endocardial lead placement is a potential alternative. The purpose of this study was to assess the feasibility of endocardial LV pacing using a steerable lead introducer and active fixation polyurethane lead. METHODS AND RESULTS Endocardial LV lead placement was attempted in nine patients (seven males, age 48-77 years) in whom transvenous CS lead placement had failed. Trans-septal puncture and septal dilatation were performed via the femoral route. A steerable introducer catheter was advanced across the septal puncture site from the right or left subclavian vein into the LV. An active fixation polyurethane lead was then implanted into the high postero-lateral aspect of the LV endocardial wall. All patients were anticoagulated following implant. Successful LV lead placement was achieved in eight patients. There were no acute complications and no embolic events during follow-up (1-32 months). All implanted patients responded well with either improvement in New York Heart Association class or maintenance of symptomatic improvement that had previously been conferred by LV epicardial pacing. CONCLUSION Targeted LV endocardial pacing is a potential alternative to CS pacing and warrants a trial to characterize long-term benefits and risks.

Transseptal left ventricular endocardial pacing reduces dispersion of ventricular repolarization.

Background:  Cardiac resynchronization therapy (CRT) may be proarrhythmic in some patients. This may be due to the effect of left ventricular (LV) epicardial pacing on ventricular repolarization. The purpose of this study was to evaluate the effect of endocardial versus epicardial LV biventricular pacing on surface electrocardiogram (ECG) parameters that are known markers of arrhythmogenic repolarization.

Extraction of pacemaker and implantable cardioverter defibrillator leads: a single-centre study of electrosurgical and laser extraction.

AIMS Both electrosurgical dissection (EDS) and laser tools are effective in the extraction of chronic implanted endovascular leads. It is unclear which is superior. We undertook a retrospective single-centre study to assess this. METHODS AND RESULTS In our institution from 2000 to 2004, all extractions requiring an ablative sheath were performed using the EDS system. In 2004, an excimer laser system was acquired, which became the first choice. Consecutive patients undergoing extraction requiring an ablative sheath (EDS or laser) were studied. From 2000 to 2007, 140 leads were extracted from 74 patients (EDS 31 and laser 43). Procedural success was non-significantly higher in the laser vs. the EDS group (95 vs. 87%). In the EDS group, one patient suffered tamponade requiring surgery; in the laser group, one patient suffered a significant pericardial effusion treated conservatively. There were no deaths. Procedure and fluoroscopy times were similar between groups. More patients were referred for primary surgical extraction in the EDS vs. the laser era (7 vs. 0, P = 0.003). CONCLUSION Lead extraction using an ablative sheath is safe and effective. In our small study, there were no significant differences between EDS and laser sheaths in terms of success, time, or safety.

Rates of upgrade of ICD recipients to CRT in clinical practice and the potential impact of the more liberal use of CRT at initial implant.

Background:  Many implantable cardioverter defibrillator (ICD) recipients may develop indications for cardiac resynchronization therapy (CRT) during follow‐up. However, the actual upgrade rate during follow‐up in clinical practice is not known.

Varying implantable cardioverter defibrillator referral patterns from implanting and non-implanting hospitals

AIMS To assess the impact of hospital type on implantable cardioverter defibrillation (ICD) prescription rates. METHODS AND RESULTS The Wessex Cardiothoracic Unit is a regional implanting centre serving eight district general hospitals (DGHs). We audited all new ICD implants performed in our institution over 4 years. Hospitals implanting or referring patients elsewhere were excluded. We categorized patients into three different groups depending on local hospital type-regional centre (one hospital), DGH with a device specialist (one hospital), DGH without a device specialist (two hospitals). For each hospital type, we assessed the overall implant rate based on local population. There were 459 new ICD implants; of which 381 were included in the analysis. Implant rates were higher in areas whose local hospital was a regional centre (103/million/year), when compared with DGHs with (49/million/year) or without a device specialist (48/million/year). This disparity was greatest with respect to coronary artery disease primary prevention indications-implant rates 29, 14, and 9/million/year, respectively. CONCLUSIONS ICD implant rates are affected by hospital type and are significantly higher in regional centres when compared with DGHs. To increase ICD implant rates, the widespread implementation of clinical pathways to identify prospective primary prevention patients may be needed.

Left Ventricular Scar Burden Specifies the Potential for Ventricular Arrhythmogenesis: An LGE-CMR Study

Late Gadolinium Enhancement and Arrhythmias. Introduction: The extent of left ventricular (LV) scar, characterized by late gadolinium enhancement cardiac MRI (LGE‐CMR), has been shown to predict the occurrence of ventricular arrhythmias in implantable cardioverter defibrillator (ICD) recipients. However, the specificity of LGE‐CMR for sudden cardiac death (SCD) versus non‐SCD is unclear. The aim of this retrospective, observational study was to evaluate this relationship in a cohort of ICD recipients.