Marcoen F. Scholten

Comparison of monophasic and biphasic shocks for transthoracic cardioversion of atrial fibrillation

Objective: To compare the efficacy of cardioversion in patients with atrial fibrillation between monophasic damped sine waveform and rectilinear biphasic waveform shocks at a high initial energy level and with a conventional paddle position. Design: Prospective randomised study. Patients and setting: 227 patients admitted for cardioversion of atrial fibrillation to a tertiary referral centre. Results: 70% of 109 patients treated with an initial 200 J monophasic shock were cardioverted to sinus rhythm, compared with 80% of 118 patients treated with an initial 120 J biphasic shock (NS). After the second shock (360 J monophasic or 200 J biphasic), 90% of the patients were in sinus rhythm in both groups. The mean cumulative energy used for successful cardioversion was 306 J for monophasic shocks and 159 J for biphasic shocks (p < 0.001). Conclusions: A protocol using monophasic waveform shocks in a 200–360 J sequence has the same efficacy (90%) as a protocol using rectilinear biphasic waveform shocks in a 120–200 J sequence. This equal efficacy is achieved with a significantly lower mean delivered energy level using the rectilinear biphasic shock waveform. The potential advantage of lower energy delivery for cardioversion of atrial fibrillation needs further study.

The learning curve associated with the introduction of the subcutaneous implantable defibrillator

Abstract Aims The subcutaneous implantable cardioverter defibrillator (S-ICD) was introduced to overcome complications related to transvenous leads. Adoption of the S-ICD requires implanters to learn a new implantation technique. The aim of this study was to assess the learning curve for S-ICD implanters with respect to implant-related complications, procedure time, and inappropriate shocks (IASs). Methods and results In a pooled cohort from two clinical S-ICD databases, the IDE Trial and the EFFORTLESS Registry, complications, IASs at 180 days follow-up and implant procedure duration were assessed. Patients were grouped in quartiles based on experience of the implanter and Kaplan–Meier estimates of complication and IAS rates were calculated. A total of 882 patients implanted in 61 centres by 107 implanters with a median of 4 implants (IQR 1,8) were analysed. There were a total of 59 patients with complications and 48 patients with IAS. The complication rate decreased significantly from 9.8% in Quartile 1 (least experience) to 5.4% in Quartile 4 (most experience) (P = 0.02) and non-significantly for IAS from 7.9 to 4.8% (P = 0.10). Multivariable analysis demonstrated a hazard ratio of 0.78 (P = 0.045) for complications and 1.01 (P = 0.958) for IAS. Dual-zone programming increased with experience of the individual implanter (P < 0.001), which reduced IAS significantly in the multivariable model (HR 0.44, P = 0.01). Procedure time decreased from 75 to 65 min (P < 0.001). The complication rate and procedure time stabilized after Quartile 2 (>13 implants). Conclusion There is a short and significant learning curve associated with physicians adopting the S-ICD. Performance stabilizes after 13 implants.

Outcome in patients with an ICD incorporating cardiac resynchronisation therapy: Differences between primary and secondary prophylaxis

The incidence of ventricular tachyarrhythmias in ICD patients with cardiac resynchronisation therapy (CRT‐D) is not well studied.

Comparison of radiofrequency versus cryothermy catheter ablation of septal accessory pathways

Approximately 30% of all accessory pathways are located in the “septal” area. As these pathways are close to the atrioventricular node, there is an increased risk of right bundle branch block or inadvertent complete atrioventricular block during catheter ablation.1 Lesions created by radiofrequency (RF) energy inevitably involve some degree of tissue disruption and are irreversible. As cryothermy energy has the ability to reversibly show loss of function of tissue with cooling (“ice mapping”) at less negative temperatures, and progressive ice formation at the catheter tip causes adherence to the adjacent tissue, this ablation method potentially has advantages over RF for safe ablation of septal accessory pathways.2–4 In this retrospective study we compare transvenous RF with cryoablation in patients with septal accessory pathways. Between January 2000 and October 2001, 15 patients were treated with RF and the next consecutive nine patients with cryoablation for septally located accessory pathways. The final classification of the accessory pathways was made according to the successful ablation site on fluoroscopy. A standard electrophysiological study was performed and, after confirmation of the presence of an accessory pathway, transvenous RF or cryoablation was carried out. Mapping was performed beginning at the anteroseptal region at the His deflection down to the coronary os and further to the right posterior region. For both energy forms standard techniques were used to identify prospective ablation sites. For cryoenergy procedures, initially ice mapping was done by cooling to −30°C for a maximum of 80 seconds with the use of a 7 French cryocatheter (Freezor, curve 3, CryoCath Technologies Inc, Montreal, Quebec, Canada). …

Gender differences in psychological distress and quality of life in patients with an ICD 1-year postimplant

Gender differences in patient‐reported outcomes in patients with an implantable cardioverter defibrillator (ICD) have been researched, but findings are inconclusive and mostly based on cross‐sectional study designs. To gain a better insight into potential determinants of psychological distress and health‐related quality of life (HQOL), we examined the relationship between gender and patient‐reported outcomes in patients with an ICD in the first year after ICD implantation.

Early mortality in prophylactic implantable cardioverter-defibrillator recipients: development and validation of a clinical risk score

AIMS To reduce sudden cardiac death, implantable cardioverter-defibrillators (ICDs) are indicated in patients with ischaemic and non-ischaemic dilated cardiomyopathy and a left ventricular ejection fraction (LVEF) ≤35%. Current guidelines do not recommend device therapy in patients with a life expectancy <1 year since benefit in these patients is low. In this study, we evaluated the incidence and predictors of early mortality (<1 year after implantation) in a consecutive primary prevention population. METHODS AND RESULTS Analysis was performed on a prediction and validation cohort. The primary endpoint was all-cause mortality at 1 year. The prediction cohort comprised 861 prophylactic ICD recipients with ischaemic cardiomyopathy or dilated cardiomyopathy from the Academic Medical Center (Amsterdam) and Thorax Center Twente (Enschede). Detailed clinical data were collected. After multivariate analysis, a risk score was developed based on age ≥75 years, LVEF ≤ 20%, history of atrial fibrillation, and estimated glomerular filtration rate (eGFR) ≤30 mL/min/1.73 m(2). Using these predictors, a low (≤1 factor), intermediate (2 factors), and high (≥3 factors) risk group could be identified with 1-year mortality of, respectively, 3.4, 10.9, and 38.9% (P< 0.01). Afterwards, the risk score was validated in 706 primary prevention patients from the Erasmus Medical Center (Rotterdam). One-year mortality was, respectively, 2.5, 13.2, and 46.3% (all P< 0.01). CONCLUSION A simple risk score based on age, LVEF, eGFR, and atrial fibrillation can identify patients at low, intermediate, and high risk for early mortality after ICD implantation. This may be helpful in the risk assessment of ICD candidates.

Left Ventricular Lead Placement Within a Coronary Sinus Side Branch Using Remote Magnetic Navigation of a Guidewire: A Feasibility Study

Background: A novel magnetic navigation system (MNS) allowing remote guidance of catheters and guidewires might assist in implantation of left ventricular (LV) pacing leads.

Transthoracic defibrillation of short-lasting ventricular fibrillation: a randomised trial for comparison of the efficacy of low-energy biphasic rectilinear and monophasic damped sine shocks.

Background — Biphasic rectilinear shocks are more effective than monophasic shocks for transthoracic atrial defibrillation and for ventricular arrhythmias during electrophysiological testing.We undertook the present study to compare the efficacy of 100 J rectilinear biphasic waveform shocks with 150 J monophasic damped sine waveform shocks for transthoracic defibrillation of true ventricular fibrillation during defibrillation threshold testing (DFT).The second aim of the study was to analyse the influence of patch positions on the efficacy of defibrillation. Methods — 50 episodes of 14 patients (age ranging from 37 to 82 years) who underwent DFT testing were randomised for back-up shocks with either a sequence of 100 and 200 J biphasic waveform, or a sequence of 150 and 360 J conventional monophasic shocks. A binary search protocol was used at implantation and before hospital discharge. Patients were also randomised to an anteroposterior position versus a right-anterior-apical position. A crossover was performed between implantation and pre-hospital discharge for biphasic versus monophasic sequence as well as for the 2 different positions. Results — After failed internal shocks, 27 episodes were treated with biphasic, and 23 with monophasic shocks. The first attempt by the external device did not terminate 11 episodes (2 biphasic, 9 monophasic).The first shock efficacy was significantly greater with biphasic than with monophasic shocks (p > 0.02). The overall success rate was 93% with biphasic shocks and 64% with monophasic shocks. In multivariate regression analysis including patch position, arrhythmia duration, type of waveform, testing order and session, only waveform was associated with successful defibrillation (p>0.02). Conclusion — For transthoracic defibrillation of ventricular fibrillation, low-energy rectilinear biphasic shocks are more effective than monophasic shocks.The position of the defibrillation shock pads has no influence on the biphasic shock efficacy, but anteroposterior pad position is more effective using monophasic shocks.

Intracardiac echocardiography during interventional procedures

BACKGROUND As non-surgical percutaneous interventions are increasingly considered for many cardiac conditions, high quality near field continuous imaging is warranted, in order to optimize the results, and to prevent and detect complications. Transesophageal echocardiography is the standard imaging technique, however general anesthesia and endotracheal intubation is required during prolonged monitoring of percutaneous interventions. Intracardiac echocardiography is a novel emerging tool that allows a view within the cardiac chambers and the large vessels and can be employed by the interventional cardiologist. METHOD In our department, a phased array, multi-frequency, four-way steerable catheter (AcuNaV - Siemens) was used for anatomic and haemodynamic cardiac assessment and for guidance and monitoring during non-coronary percutaneous interventions. In total 135 patients underwent intracardiac echocardiographic investigation, 4 during diagnostic heart catheterization, 6 during percutaneous coronary intervention with the use of a new left ventricular assist device, the Impella Recover LP 2.5 system, 26 during percutaneous transluminal septal myocardial ablation (10 patients were reevaluated with intracardiac echocardiography at 6 months), 50 during interatrial communication closure, 4 during percutaneous left atrial appendage transcatheter occlusion, 7 during percutaneous balloon valvuloplasty, 1 during percutaneous aortic valve replacement and 27 during pulmonary vein ablation. All patients tolerated the procedure very well with no catheter related complications. However, there were two complications, which were due to the guidewire and the sheath, an inferior vena cava dissection and a femoral vein dissection, respectively. CONCLUSION Phased array intracardiac imaging is a safe technology, which facilitates non-surgical interventions by providing high quality images. It eliminates the need for general anesthesia and thus increases the patient comfort.

Visualization of a coronary sinus valve using intracardiac echocardiography

Cannulation of the coronary sinus (CS) is sometimes difficult due to the presence of anatomical anomalies. Fluoroscopy is of limited value in visualizing these variations. This case is the first to demonstrate how intracardiac echocardiography (ICE) allows visualization of a valve, which is one of the causes of problematic cannulation of the CS. Based on information obtained by ICE an appropriate catheter could be selected.