Search

Background: A novel 3D mapping system (KODEX‐EPD, EPD Solutions) enables catheter localization and real‐time 3D cardiac mapping. Objective: To evaluate left atrium (LA) anatomical mapping accuracy created by the KODEX‐EPD system during pulmonary vein isolation (PVI) compared with gold standard computed tomography (CT) images acquired from the same patients before the procedure. Methods: In 15 consecutive patients who underwent PVI, 3D mapping of the LA was created on the KODEX‐EPD system using the Achieve catheter. Pulmonary vein (PV), posterior wall, and appendage anatomy and diameters, were compared to the CT 3D reconstruction measured on the CARTO 3 system. Measurements were done independently by two physicians in each method. Linear correlation and agreement between CT and EPD measurements were assessed by Spearman correlation and Bland‐Altman plot. Results: Mean LA mapping time was 7.7 ± 3.6 min. Very high interobserver correlation was found for both EPD and CT measurements (Spearman r =.9). High correlation (r =.75) was found between CT and EPD measurements. Bland‐Altman plot method revealed that measurements assessed by EPD were slightly higher than those assessed by CT. Mean difference was 3.5 mm, p <.01. In 2 (13.5%) patients each, disagreement regarding the presence of a left common PV and a right middle accessory vein anatomy was seen. Conclusion: The new KODEX‐EPD mapping system allows quick and accurate mapping of the LA with high correlation to CT imaging. Some differences in left common and accessory right middle vein anatomy were seen. [ABSTRACT FROM AUTHOR]

A New CARTO Software for Ablating Ventricular Arrhythmias Introduction A new imaging software (CARTO® Segmentation Module, Biosense Webster) allows preprocedural 3-D reconstruction of all heart chambers based on cardiac CT. We describe our initial experience with the new module during ablation of ventricular arrhythmias. Methods and Results Eighteen consecutive patients with idiopathic ventricular arrhythmias or ischemic ventricular tachycardia (VT) were studied. In the latter group, a combined endocardial and epicardial ablation was performed. Of the 14 patients with idiopathic arrhythmias, 12 were ablated in the outflow tract (OT), 1 in the midseptal left ventricle, and 1 at the left posterior fascicular area; acute successful ablation was achieved in 11 (78.6%) patients. The procedure was discontinued due to close proximity of the arrhythmia origin to the coronary arteries (CA) in 2 patients. Acute successful uncomplicated ablation was achieved in all 4 patients with ischemic VT. During ablation in the coronary cusps commissures, the CARTO® Segmentation Module accurately defined the cusps anatomy. The precise anatomic location provided by the module assisted in successfully ablating when information from activation mapping was not optimal, by ablating at the opposite side of the cusps. In addition, by demonstrating the precise location of the CA, it allowed safe ablation of arrhythmias that originated in close proximity to the CA both in the OT area and the epicardium, eliminating the need for repeat angiography. Conclusions The CARTO® Segmentation Module is useful for accurate definition of the exact anatomic location of ventricular arrhythmias and for safely ablating them especially in close proximity to the CA. [ABSTRACT FROM AUTHOR]

Background A few series of focal atrial tachycardia (AT) originating from the noncoronary sinus of Valsalva (NCSV) have been reported in the literature during the last decade. Methods and Results Of 147 patients with AT referred for radiofrequency ablation (RFA), we identified nine (6%) originating in the vicinity of the NCSV. Clinical AT was induced during electrophysiological study in all patients without (n = 6) and with (n = 3) isoproterenol infusion. Mean cycle length of the induced tachycardia was 399 ± 85 ms. Mapping of the right atrium and of the left atrium (LA) was initially performed in all nine patients and in four patients, respectively. Earliest tachycardia activation occurred at the His bundle area in all cases. Earliest activations in the LA were at the low paraseptal regions. In two patients with antegrade dual atrioventricular (AV) node physiology that rendered difficult accurate distinction between atrial and ventricular activation, slow pathway ablation was necessary. A retrograde aortic approach was used for mapping the aortic cusps. The earliest local atrial activation in the NCSV preceded the atrial activation in the His area in all patients by 27 ± 8 ms. RFA was performed in all nine patients and was acutely successful in eight. Two patients required radiofrequency (RF) energy outputs of 50 W in order to terminate the arrhythmia. In one patient, successful AT ablation was associated with complete AV block requiring implantation of permanent pacemaker. Conclusions Focal AT can be successfully mapped and ablated in the NCSV. Higher than usual RF energy levels are sometimes required. Complete AV block is a possible complication. [ABSTRACT FROM AUTHOR]

Clinical Outcome of Single- versus Dual-Chamber ICDs Objective To compare the clinical outcomes of a single- versus dual-chamber ICD for primary prevention of sudden cardiac death in a large, national ICD registry. Methods Data were collected from the prospective Israeli ICD Registry. Baseline characteristics and clinical outcomes including mortality, admissions for heart failure (HF), and ICD therapy were compared between the two groups. Results A total of 1,125 subjects, 37% with a single-chamber and 63% with a dual-chamber ICD, constructed the baseline cohort. Approximately 80% had ischemic heart disease (IHD). Mean follow-up was 22 months, mean ejection fraction was 30%, and mean QRS width was 103 milliseconds in both groups. During follow-up, there were no significant differences in the rate of mortality, admissions for HF, appropriate or inappropriate therapy, or in time to any of the clinical outcomes. Using multivariate analysis, single-chamber ICD was not associated with increased risk of death or admission for HF. In a subgroup of patients with IHD, single-chamber ICD was associated with a higher rate of inappropriate therapy. Conclusions In this large retrospective population-based cohort, dual-chamber ICD showed no benefit in reducing the incidence of death or HF admissions, whereas in a subgroup of patients with IHD, single-chamber ICD was associated with increased inappropriate therapy. Further prospective studies are necessary to assess the benefit of dual-chamber ICD in reducing the rate of inappropriate therapy. [ABSTRACT FROM AUTHOR]

Ablation Effectiveness and Biophysical Parameters Background There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT). Methods and Results Data were collected from consecutive patients undergoing VT ablation with open-irrigation. Complete data were available for 372 lesions in 21 patients. The frequency of biophysical parameter changes were: >10Ω reduction (80%), bipolar EGM reduction (69%), while loss of capture was uncommon (32%). Unipolar injury current was seen in 72% of radiofrequency applications. Both EGM reduction and impedance drop were seen in 57% and a change in all 3 parameters was seen in only 20% of lesions. Late potentials were eliminated in 33%, reduced/modified in 56%, and remained after ablation in 11%. Epicardial lesions exhibited an impedance drop (90% vs. 76%, P = 0.002) and loss of capture (46% vs. 27%, P < 0.001) more frequently than endocardial lesions. Lesions delivered manually exhibited a >10Ω impedance drop (83% vs. 71%, P = 0.02) and an EGM reduction (71% vs. 40%, P < 0.001) more frequently than lesions applied using magnetic navigation, although loss of capture, elimination of LPs, and a change in all 3 parameters were similarly observed. Conclusions VT ablation is inefficient as the majority of radiofrequency lesions do not achieve more than one targeted biophysical parameter. Only one-third of RF applications targeted at LPs result in complete elimination. Epicardial ablation within scar may be more effective than endocardial lesions, and lesions applied manually may be more effective than lesions applied using magnetic navigation. New technologies directed at identifying and optimizing ablation effectiveness in scar are clinically warranted. [ABSTRACT FROM AUTHOR]

Introduction: The usefulness of unipolar electrograms (EGMs) has been reported in assessing lesion transmurality and conduction block along ablation lines. It is unknown whether unipolar and bipolar EGM characteristics predict exit block during pulmonary vein isolation (PVI) procedures. Methods and Results: Twenty patients (63 ± 7 years; 14 males [70%]) undergoing PVI with a circular mapping catheter (CMC) placed outside each PV ostium were retrospectively studied. After entrance block was achieved, pacing at each bipole around the CMC was performed to assess for absence of atrial capture (exit block). Bipolar EGMs recorded before pacing were examined for voltage, duration, fractionation, and monophasic morphology. Unipolar EGMs were examined for positive and negative amplitude, PQ segment elevation, fractionation, and monophasic morphology. The association of these parameters with atrial capture (absence of exit block) at each site was analyzed. After achievement of entrance block, only 23 of 64 PV antra (36%) exhibited exit block. Unipolar EGMs at sites with persistent capture were more likely to be fractionated and had larger negative deflections. Bipolar EGMs at sites with persistent capture showed higher amplitude, longer duration, were more likely to be fractionated, and were less likely to be monophasic. In a multivariate logistic regression model, bipolar and unipolar fractionation, bipolar duration, and lack of bipolar monophasic morphology were independently associated with persistent atrial capture. Conclusion: Specific unipolar and bipolar EGM characteristics are associated with left atrium capture after PV antral isolation. These parameters might be useful in predicting the need for further ablation to achieve exit block. (PACE 2012; 35:1294-1301) [ABSTRACT FROM AUTHOR]

Ventricular tachycardia as a late complication of blunt chest trauma has never been reported. We present a case of combined endocardial and epicardial delineation of the right ventricular arrhythmogenic substrate, where other causes of cardiomyopathy were excluded. The epicardial scar was more extensive than endocardial scar, and the central isthmus was likely intramural. A history of blunt chest trauma should be considered in patients with right ventricular cardiomyopathy. (PACE 2012; 35:e127-e130) [ABSTRACT FROM AUTHOR]

Electrophysiological properties of the atrial endocardium compared to epicardium are not well understood. The purpose of this study was to compare the electrophysiological properties and vulnerability to arrhythmia induction from these regions. Transseptal endocardial and percutaneous epicardial mapping were performed in a porcine model (n = 7). Two opposing 4-mm electrophysiological catheters were positioned endocardially and epicardially. A circular mapping catheter (CMC) was positioned at the ostium of the common inferior pulmonary vein (CIPV) recording left atrial (LA)-PV potentials. Endocardial and epicardial effective refractory periods (ERPs) at two basic cycle lengths (CLs) of 600 and 400 ms were recorded from four anatomic locations (CIPV, LA appendage, right superior PV, and LA posterior wall). Atrial repetitive response (ARR) induction was also tested from endocardial and epicardial sites. Overall, 254 ERP measurements (mean 36.3 per animal) and 84 induction attempts (mean 12 per animal) were performed. The ERP was significantly shorter in the epicardium compared to the endocardium at basic CL of 400 ms (P = 0.006) but not at CL of 600 ms (P = 0.2). In addition, only the epicardium demonstrated ERP shortening when the CL of the basic drive was shortened (P = 0.03). ARR could be induced more often from the epicardium (P = 0.002) and fibrillatory activity with epicardial/endocardial dissociation was recorded (n = 3). Also, the earliest PV activation site on the CMC was noted to be different in 16.5% of cases during epicardial and endocardial pacing. The electrophysiological characteristics of the atrial epicardium are different from the endocardium with a shorter ERP and more frequent ARR induction by programed stimulation. (PACE 2011; 37-46) [ABSTRACT FROM AUTHOR]

Objective Data on low molecular weight heparin (LMWH) and induction of hyperkalemia is scarce. Therefore, we conducted a prospective study evaluating potassium levels before and after three days of treatment with the LMWH Enoxaparin. Methods Patients treated with the LMWH Enoxaparin in the standard therapeutic dosages were included. Levels of potassium, sodium, urea, creatinine, AST, ALT bicarbonate, pH and platelet counts were examined before and after three days of LMWH treatment. Plasma renin activity (PRA) and aldosterone levels were examined in a subgroup of patients. Potassium levels were correlated with disease states and medications known to affect potassium homeostasis. Results Ninety-seven consecutive patients were enrolled in the study, however, 12 patients were excluded from analysis; therefore 85 patients comprised the study group. The most common reason for exclusion (in 9 patients) was the absence of a second potassium result. We found an increase in potassium levels from 4.26±0.04 mmol/L at baseline to 4.43±0.04 mmol/L on the third day of treatment (mean±SE), with potassium levels exceeding 5.0 mmol/L in 9% of treated patients. There was no life threatening or symptomatic hyperkalemia. PRA and aldosterone levels did not change significantly during the treatment period. There was no correlation between the increase in potassium levels and diabetes mellitus or treatment with angiotensin converting enzymes inhibitors, angiotensin receptor blockers, β-blockers and non-potassium sparing diuretics. Conclusions Potassium levels increase on the third day of treatment with the LMWH Enoxaparin. This effect may be aldosterone independent. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article reports on a electrophysiology study of a nine-year-old child who presented with syncope and wide complex tachycardia. The discussion topics include dilated cardiomyopathy, infraHisian conduction system disease, ventricular tachycardia, atrioventricular node reentry tachycardia (AVNRT), and diagnosis of bundle branch (BB) reentry.