3 Tesla magnetic resonance imaging in patients with cardiac implantable electronic devices: a single centre experience.

AIMS: Three Tesla (T) magnetic resonance imaging (MRI) provides critical imaging information for many conditions. Owing to potential interactions of the magnetic field, it is largely withheld from patients with cardiac implantable electronic devices (CIEDs). Therefore, we assessed the safety of 3T MRI in patients with '3T MRI-conditional' and 'non-3T MRI-conditional' CIEDs. METHODS AND RESULTS: We performed a retrospective single-centre analysis of clinically indicated 3T MRI examinations in patients with conventional pacemakers, cardiac resynchronization devices, and implanted defibrillators from April 2020 to May 2022. All CIEDs were interrogated and programmed before and after scanning. Adverse events included all-cause death, arrhythmias, loss of capture, inappropriate anti-tachycardia therapies, electrical reset, and lead or generator failure during or shortly after MRI. Changes in signal amplitude and lead impedance were systematically assessed. Statistics included median and interquartile range. A total of 132 MRI examinations were performed on a 3T scanner in 97 patients. Thirty-five examinations were performed in patients with 'non-3T MRI-conditional' CIEDs. Twenty-six scans were performed in pacemaker-dependent patients. No adverse events occurred during or shortly after MRI. P-wave or R-wave reductions ≥ 50 and ≥ 25%, respectively, were noted after three (2.3%) scans, all in patients with '3T MRI-conditional' CIEDs. Pacing and shock impedance changed by ± 30% in one case (0.7%). Battery voltage and stimulation thresholds did not relevantly change after MRI. CONCLUSION: Pending verification in independent series, our data suggest that clinically indicated MRI scans at 3T field strength should not be withheld from patients with cardiac pacemakers or defibrillators.

Comparison of cine cardiac magnetic resonance and echocardiography derived diameters of the aortic root in a large population-based cohort.

Transthoracic echocardiography (TTE) and cine cardiac magnetic resonance imaging (CMR) are established imaging methods of the aortic root. We aimed to evaluate the comparability of measurements in TTE and standard cine CMR sequences of the aortic root. Our study included 741 subjects (mean age 63.5 ± 8 years, 43.7% female) from the Hamburg City Health Study (HCHS). Subjects underwent CMR and TTE. Aortic root measurements were performed at the level of the aortic annulus (AoAn), sinus of Valsalva (SoV), and sinotubular junction (STJ) by standard cine CMR in left ventricular long axis and left ventricular outflow tract view. Measurements were performed applying the leading-edge to leading-edge (LL) convention and inner-edge to inner-edge (II) convention in TTE and the II convention in CMR. Inter correlation coefficients (ICCs) demonstrated high inter- and intraobserver reproducibility for CMR and TTE measurements of SoV and STJ (ICCs 0.9-0.98) and moderate reproducibility for AoAn (ICCs 0.68-0.91). CMR measurements of SoV and STJ showed strong agreement with TTE: while correlations were comparable (r = 0.75-0.85) bias was lower with TTE II (bias - 0.1 to - 0.74) versus TTE LL measurements (mean bias - 1.49 to - 2.58 mm). The agreement for AoAn was fair (r = 0.51-0.57) with variable bias (mean bias 0.39-3.9). Standard cine CMR and TTE derived aortic root measurements are reproducible and comparable with higher agreement for TTE II instead of LL measurements. These results support an interchangeable application of TTE and standard CMR for screening of aortic root diseases thereby possibly reducing redundant multimodality imaging.

Insights into diastolic function analyses using cardiac magnetic resonance imaging: impact of trabeculae and papillary muscles.

BACKGROUND: This cardiovascular magnetic resonance (CMR) study investigates the impact of trabeculae and papillary muscles (TPM) on diastolic function parameters by differentiation of the time-volume curve. Differentiation causes additional problems, which is overcome by standardization. METHODS: Cine steady-state free-precession imaging at 1.5 T was performed in 40 healthy volunteers stratified for age (age range 7-78y). LV time-volume curves were assessed by software-assisted delineation of endocardial contours from short axis slices applying two different methods: (1) inclusion of TPM into the myocardium and (2) inclusion of TPM into the LV cavity blood volume. Diastolic function was assessed from the differentiated time-volume curves defining the early and atrial peaks, their filling rates, filling volumes, and further dedicated diastolic measures, respectively. RESULTS: Only inclusion of TPM into the myocardium allowed precise assessment of early and atrial peak filling rates (EPFR, APFR) with clear distinction of EPFR and APFR expressed by the minimum between the early and atrial peak (EAmin) (100% vs. 36% for EAmin < 0.8). Prediction of peak filling rate ratios (PFRR) and filling volume ratios (FVR) by age was superior with inclusion of TPM into the myocardium compared to inclusion into the blood pool (r2 = 0.85 vs. r2 = 0.56 and r2 = 0.89 vs. r2 = 0.66). Standardization problems were overcome by the introduction of a third phase (mid-diastole, apart from diastole and systole) and fitting of the early and atrial peaks in the differentiated time-volume curve. CONCLUSIONS: Only LV volumetry with inclusion of TPM into the myocardium allows precise determination of diastolic measures and prevents methodological artifacts.

CMR-Based Risk Stratification of Sudden Cardiac Death and Use of Implantable Cardioverter-Defibrillator in Non-Ischemic Cardiomyopathy.

Non-ischemic cardiomyopathy (NICM) is one of the most important entities for arrhythmias and sudden cardiac death (SCD). Previous studies suggest a lower benefit of implantable cardioverter-defibrillator (ICD) therapy in patients with NICM as compared to ischemic cardiomyopathy (ICM). Nevertheless, current guidelines do not differentiate between the two subgroups in recommending ICD implantation. Hence, risk stratification is required to determine the subgroup of patients with NICM who will likely benefit from ICD therapy. Various predictors have been proposed, among others genetic mutations, left-ventricular ejection fraction (LVEF), left-ventricular end-diastolic volume (LVEDD), and T-wave alternans (TWA). In addition to these parameters, cardiovascular magnetic resonance imaging (CMR) has the potential to further improve risk stratification. CMR allows the comprehensive analysis of cardiac function and myocardial tissue composition. A range of CMR parameters have been associated with SCD. Applicable examples include late gadolinium enhancement (LGE), T1 relaxation times, and myocardial strain. This review evaluates the epidemiological aspects of SCD in NICM, the role of CMR for risk stratification, and resulting indications for ICD implantation.

Concomitant implantation of Impella® on top of veno-arterial extracorporeal membrane oxygenation may improve survival of patients with cardiogenic shock.

AIMS: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support stabilizes patients with cardiogenic shock. Despite improved oxygenation and peripheral circulation, LV unloading may be impeded due to the increased afterload, resulting in a failing static left ventricle and in high mortality. METHODS AND RESULTS: We describe for the first time a large series of patients treated with the combination of VA-ECMO and Impella® compared with patients with VA-ECMO only. We retrospectively collected data on patients from two tertiary critical care referral centres. We enrolled 157 patients treated with VA-ECMO from January 2013 to April 2015: 123 received VA-ECMO support and 34 had concomitant treatment with VA-ECMO and Impella. A propensity-matching analysis was performed in a 2:1 ratio, resulting in 42 patients undergoing VA-ECMO alone (control group) compared with 21 patients treated with VA-ECMO and Impella. Patients in the VA-ECMO and Impella group had a significantly lower hospital mortality (47% vs. 80%, P < 0.001) and a higher rate of successful bridging to either recovery or further therapy (68% vs. 28%, P < 0.001) compared with VA-ECMO patients. A higher need for continuous veno-venous haemofiltration (48% vs. 19%, P = 0.02) and increased haemolysis (76% vs. 33%, P = 0.004) were reported in the study group due to higher survival. There was no difference in major bleeding rates between the two groups (VA-ECMO and Impella 38% vs. VA-ECMO 29%, P = 0.6). CONCLUSIONS: Concomitant treatment with VA-ECMO and Impella may improve outcome in patients with cardiogenic shock compared with VA-ECMO only. Nevertheless, randomized studies are needed to validate these promising results further.

Radiation exposure during the implantation of bioabsorbable vascular scaffolds versus drug-eluting stents in non-complex coronary lesions: a matched-cohort study.

BACKGROUND: Bioabsorbable vascular scaffolds (BVS) are a novel option for the treatment of coronary lesions in patients with stable coronary artery disease or acute coronary syndromes. We aimed to identify the influence of BVS implantation on radiation exposure and procedural outcomes compared to drug-eluting stents (DES) in daily clinical practice. METHODS: A retrospective single-center study was performed in patients undergoing percutaneous coronary intervention with BVS from 2013 to 2014. Only patients with exclusive BVS implantation (N.=78 procedures) were compared with a 2:1 matched cohort of exclusive DES-treated patients in the same period (N.=156 procedures). We used a four-step protocol to reduce radiation exposure in all procedures. Furthermore, a 12-month clinical follow-up was performed. RESULTS: Patients had similar baseline characteristics due to matching. Radiation exposure (1826 vs. 2167 cGy*cm2, P=0.673), procedure time (73 vs. 65 minutes, P=0.574), target vessel revascularization (1.3 vs. 1.3%, p=1.000 for PCI; 1.3 vs. 0.6%, P=0.616 for CABG), cardiovascular death (0.0 vs. 2.6%, P=0.304) or all-cause death (0.0 vs. 3.2%, P=0.172) were similar after implantation of BVS vs. DES. However, exposure to contrast agent (166 vs. 139 mL, P=0.028) was significantly higher in the BVS group. CONCLUSIONS: The implantation of BVS in combination with a simple four-step protocol is a feasible option for interventional treatment of non-complex coronary lesions without significant impact on radiation exposure or outcome measures in daily clinical routine.

Reducing radiation exposure during invasive coronary angiography and percutaneous coronary interventions implementing a simple four-step protocol.

BACKGROUND: With an increasing number of complex and repeated percutaneous coronary interventions (PCI), radiation-induced hazards for patients and operators remain an important issue in fluoroscopy-guided procedures. Our objective was to evaluate radiation exposure during coronary angiographic procedures and assess the efficacy of a four-step program to reduce radiation exposure during coronary angiography (CAG) and PCI. METHODS AND RESULTS: A retrospective single-center analysis was performed in patients undergoing CAG or PCI in the first 6 months of 2012 vs. the first 6 months of 2014 (n = 3,107 procedures). During 2013, a four-step protocol was established in our hospital. It contained measures to reduce radiation exposure, including a frame rate reduction from 15 to 7.5 frames per second, the use of fluoroscopy storage, strict use of beam collimation, and repeat training on radiation safety. After adjustment for confounding variables, a dose-area product (DAP) reduction of 54.2% was observed subsequent to implementation of the four-step protocol. Independent predictors of DAP were age [odds ratio (OR) 1.01], body surface area (OR 5.47), prior coronary artery bypass grafting (OR 1.44), radial access (OR 1.16), PCI (OR 2.36), female gender (OR 0.91), and the implementation of the four-step program (OR 0.46). CONCLUSION: A simple four-step protocol led to a significant reduction in radiation exposure in diagnostic and interventional coronary procedures without significant drawbacks in image quality. Hence, radiation safety programs are of paramount importance and should be established to improve patient and operator safety with regard to radiation-induced hazards.

Prognostic role of subsequent atrial tachycardias occurring during ablation of persistent atrial fibrillation: a prospective randomized trial.

BACKGROUND: The role of subsequent atrial tachycardias (AT) in the context of persistent atrial fibrillation (AF) remains undetermined. This study evaluated the prognostic role of subsequent ATs for arrhythmia recurrences after catheter ablation of persistent AF. METHODS AND RESULTS: A total of 110 patients with persistent AF (63±9 years; 22 women; 61 long-lasting persistent AF) underwent pulmonary vein isolation followed by electrogram-guided ablation. After AF terminated to AT, patients were separated by the randomization protocol to receive either direct cardioversion (group A) or further ablation of subsequent ATs to sinus rhythm (group B). After a mean follow-up of 20.1±13.3 months after the first procedure, significantly more group B patients were in sinus rhythm as compared with patients in group A (30 [57%] versus 18 [34%]; P=0.02). Moreover, recurrences of AF were significantly less frequent of group B than in group A patients (10 [19%] versus 26 [49%]; P=0.001). After the last procedure (follow-up, 34.0±6.4 months), significantly more group B patients were free of AF as compared with patients of group A (49 [92%] versus 39 [74%]; P=0.01). The proportion of AT recurrences did not differ between the 2 groups after the first and final procedures. The strongest predictor for an arrhythmia-free survival after a single procedure was randomization to the procedural end point of termination to sinus rhythm by elimination of subsequent ATs (P=0.004). CONCLUSIONS: Catheter ablation of subsequent ATs increases freedom from AF but not AT, suggesting a contributing role of subsequent ATs in the mechanisms of persistent AF. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01896570.

Precision of pulmonary vein diameter measurements assessed by CE-MRA and steady-state-free precession imaging.

OBJECTIVE: Pulmonary vein (PV) diameter assessment is important for planning and follow-up of PV ablation in atrial fibrillation. Therefore, the aim of our study was to evaluate inter- and intraobserver reliability of PV diameter measurements by contrast-enhanced magnetic resonance angiography (CE-MRA) and ECG-gated 2D multislice unenhanced steady-state-free precession sequences (multislice SSFP). METHODS: Sixty PV diameters in 17 consecutive patients were measured in transverse and coronal orientation with CE-MRA and multislice SSFP by two observers. Statistics to evaluate inter- and intraobserver reliability included Bland-Altman analysis and F-test. RESULTS: Intraobserver limits of agreement (LAG) ranged between ±0.50 cm (transverse) and ±0.86 cm (coronal) for CE-MRA versus ±0.40 cm (transverse) and ±0.67 cm (coronal) for multislice SSFP. Interobserver agreement showed LAG ranging between ±0.59 cm (transverse) and ±0.83 cm (coronal) for CE-MRA versus ±0.34 cm (transverse) and ±0.75 cm (coronal) for multislice SSFP. Intra- and interobserver variances did not reveal significant differences between CE-MRA and multislice SSFP in any orientation (all p-values >0.05). CONCLUSION: Multislice SSFP and CE-MRA enable comparable precision of PV diameter measurements. However, both methods reveal a wide range of intra- and interobserver agreement, which has to be thoroughly considered in clinical use. KEY POINTS: • Unenhanced magnetic resonance imaging can now provide measurement of pulmonary vein diameters • Steady-state-free precession offers a new method of performing unenhanced MR imaging • Both unenhanced and enhanced MRI measurements show wide intra- and interobserver variation • PV diameter measurements assessed by MRI have to be interpreted with care • Nevertheless, unenhanced MRI might replace some CT examinations for pulmonary vein demonstration.

"Electrically silent" pulmonary veins connecting to the right atrium: does the atrium make the difference?

Pulmonary veins (PVs) usually drain into the left atrium (LA) and are frequently targeted for electrical isolation, since it became evident that PVs may trigger and maintain paroxysmal atrial fibrillation (AF). We present a patient with right-sided PVs anomalously connecting to the right atrium with lack of electrical PV-atrial connection. Therefore, isolation of the left veins was performed resulting in freedom from AF as shown during a midterm follow-up. These findings indicate that PV connection to the LA may be a prerequisite for the arrhythmogenic properties of the PVs causing AF.

Intravenous administration of magnesium and potassium solution lowers energy levels and increases success rates electrically cardioverting atrial fibrillation.

BACKGROUND: External biphasic electrical cardioversion (CV) is a standard treatment option for patients suffering from acute symptoms of atrial fibrillation (AF). Nevertheless, CV is not always successful, and thus strategies to increase the success rate are desirable. OBJECTIVE: The purpose of this study was to evaluate the effect of intravenously administered K/Mg solution on the biphasic CV energy threshold and success rate to restore sinus rhythm (SR) in patients with AF. METHODS: The study consisted of 170 patients with persistent AF. The patients were randomly assigned to undergo biphasic CV either with (n = 84) or without (n = 86) pretreatment with K/Mg solution. An energy step-up protocol of 75, 100, and 150 W (J) was used. RESULTS: Biphasic CV of AF was effective in 81 (96.4%) patients in the pretreatment and 74 (86.0%) patients in the control group (P = 0.005). The effective energy level required to achieve SR was significantly lower in the pretreated group (140.8 ± 26.9 J vs 182.5 ± 52.2 J, P = 0.02). No K/Mg-solution-associated side effects such as hypotension or bradycardia were observed. CONCLUSION: Administration of K/Mg solution positively influences the success rate of CV in patients with persistent AF. Furthermore, significantly less energy is required to successfully restore SR and therefore K/Mg pretreatment may facilitate SR restoration in patients undergoing CV for AF.

A standardized education protocol significantly reduces traumatic injuries and syncope recurrence: an observational study in 316 patients with vasovagal syncope.

AIMS: The aim of this study was to assess the role of a non-pharmacological approach on the frequency of traumatic injuries and syncope recurrence in patients with vasovagal syncope and normal hearts. We report the experience in our syncope centre with a standardized education and teaching protocol for patients with vasovagal syncope. The treatment of vasovagal syncope is often complex and discouraging. Besides medical options, behaviour modification is a main component of therapy but has no statistical evidence to support its use. METHODS AND RESULTS: Between January 1999 and September 2006, we prospectively enrolled all patients with vasovagal syncope. The patients were counselled about the benign nature of their disease. Specific recommendations were made according to a standardized education protocol established at our syncope centre. A pre-/post-study was conducted to investigate the effectiveness of our approach on syncope recurrence and frequency of injury as the study endpoints. Complete follow-up data were available from 85% of the study population (316 of 371) after a mean time of 710 ± 286 days (mean age 50 years; standard deviation ± 18 years, 160 female). Eighty-seven patients (27.5%) had a syncope recurrence with 22 suffering an injury during syncope. During the follow-up period, the syncope burden per month was significantly reduced from 0.35 ± 0.03 at initial presentation to 0.08 ± 0.02 (P< 0.001). The frequency of traumatic syncope was significantly lower at the time of recurrence compared with the initial presentation (25 vs. 42%; McNemar's test P= 0.02). CONCLUSION: A standardized education protocol significantly reduces traumatic injuries and syncope recurrence in patients with vasovagal syncope.

Coronary angiography and intervention during hypothermia can be performed safely without cardiac arrhythmia or vasospasm.

PURPOSE: Mild therapeutic hypothermia is a neuroprotective procedure after cardiac arrest. Therefore, it is increasingly used. Likewise, there is a growing demand for coronary angiography and percutaneous coronary interventions under hypothermia. Case studies suggested that hypothermia may be associated with coronary vasospasm, heart rhythm events and platelet dysfunction. In this study, it was evaluated whether vasospasm, arrhythmia or bleeding occur to a relevant degree during cardiac catheterization under concomitant hypothermia. METHODS: In this prospective, single-center, open-label, non-interventional study, 29 patients after resuscitation for cardiac arrest were treated with mild hypothermia and underwent cardiac catheterization (coronary angiography n = 11, coronary angiography plus percutaneous intervention n = 18). The incidence of vasospasm, cardiac arrhythmia and relevant bleeding at the puncture site were evaluated. RESULTS: Mean temperature at cardiac catheterization was 33.9 ± 0.76°C. The mean heart rate was 82 ± 26 bpm at hospital admission and 67 ± 17 bpm under hypothermia (p < 0.05). There was no patient with relevant bradycardia beyond the expected hypothermia-induced rate reduction during the procedure. There were no unexpected ventricular tachycardias or episodes of ventricular fibrillation which might have been attributed to hypothermia. Twenty-nine of 29 patients (100%) were free from coronary vasospasm. There was no patient with a relevant bleeding at the puncture site. Potassium levels were low in 52% of the patients, even after resuscitation, which was partially attributed to hypothermia. CONCLUSION: Coronary angiography and percutaneous coronary interventions under mild therapeutic hypothermia were safe in this small cohort and were performed without hypothermia-induced vasospasm, relevant rhythm events or bleeding complications. This result has to be confirmed in a large series of patients.

Long-term single- and multiple-procedure outcome and predictors of success after catheter ablation for persistent atrial fibrillation.

BACKGROUND: Stepwise ablation is an effective treatment for persistent atrial fibrillation (AF), although it often requires multiple procedures to eliminate recurrent arrhythmias. OBJECTIVE: This study evaluated single- and multiple-procedure long-term success rates and potential predictors of a favorable single-procedure outcome of stepwise ablation for persistent AF. METHODS: This study comprised 395 patients with persistent AF (duration 16 months) undergoing de novo catheter ablation using the stepwise approach. Procedural success was defined as the absence of any arrhythmia recurrence. Patient characteristics and electrophysiological parameters were analyzed with respect to single- and multiple-procedure outcomes. RESULTS: After a follow-up of 27 ± 7 months, 108 (27%) patients were free of arrhythmia recurrences with a single procedure. After 2.3 ± 0.6 procedures, 312 (79%) patients were free of arrhythmia with concomitant antiarrhythmic treatment in 38% (23% on ß-blocker). Female gender, duration of persistent AF, and congestive heart failure were predictive for the outcome after first ablation. However, the strongest predictors for single-procedure success were longer baseline AF cycle length (CL) and procedural AF termination. Moreover, procedural AF termination during the index procedure also predicted a favorable outcome after the last procedure, while the existence of congestive heart failure was associated with an increased risk for eventual arrhythmia recurrences. CONCLUSIONS: Single-procedure long-term success is anticipated in approximately a quarter of patients undergoing de novo ablation of persistent AF. Baseline AFCL emerged as the strongest predictor of single-procedure success, while AF termination during index ablation predicts the overall outcome. However, an overall success rate of 79% is achievable with multiple procedures.

[Three-dimensional reconstruction and remote navigation for catheter-guided atrial fibrillation ablation. Does it influence procedural outcomes?]. / Dreidimensionale Rekonstruktion und Remote-Navigation für die kathetergeführte Ablation von Vorhofflimmern : Verbesserung des prozeduralen Outcomes?

Catheter ablation of atrial fibrillation has evolved as a widely accepted therapy approach and is now also incorporated in the current guidelines.A major limitation consists of the limited three-dimensional visualization of the complex three-dimensional structures in the left atrium since most procedures have routinely been performed using fluoroscopy alone. Another unsolved problem is the limited durability of lesions sets performed with radiofrequency ablation and therefore somewhat disappointing long-term ablation results besides fluoroscopy exposition for patient and operator as required for safe catheter manipulation.In the recent years we have gained substantial insight with respect to arrhythmia mechanism. At the same time new techniques and developments have become available to improve catheter ablation results.The present article summarizes the available opportunities with respect to three-dimensional mapping including CT/MRI image integration and gives an overview of the robotic and magnetic systems available for catheter ablation.

Persistence of pulmonary vein isolation after robotic remote-navigated ablation for atrial fibrillation and its relation to clinical outcome.

AIMS: A robotic navigation system (RNS, Hansen™) has been developed as an alternative method of performing ablation for atrial fibrillation (AF). Despite the growing application of RNS-guided pulmonary vein isolation (PVI), its consequences and mechanisms of subsequent AF recurrences are unknown. We investigated the acute procedural success and persistence of PVI over time after robotic PVI and its relation to clinical outcome. METHODS AND RESULTS: Sixty-four patients (60.7 ± 9.8 years, 53 male) with paroxysmal AF underwent robotic circumferential PVI with 3-dimensional left atrial reconstruction (NavX™). A voluntary repeat invasive electrophysiological study was performed 3 months after ablation irrespective of clinical course. Robotic PVI was successful in all patients without complication (fluoroscopy time: 23.5 [12-34], procedure time: 180 [150-225] minutes). Fluoroscopy time demonstrated a gradual decline but was significantly reduced after the 30th patient following the introduction of additional navigation software (34 [29-45] vs 12 [9-17] minutes; P < 0.001). A repeat study at 3 months was performed in 63% of patients and revealed electrical conduction recovery in 43% of all PVs. Restudied patients without AF recurrence (n = 28) showed a significantly lower number of recovered PVs (1 (0-2) vs 2 (2-3); P = 0.006) and a longer LA-PV conduction delay than patients with AF recurrences (n = 12). Persistent block of all PVs was associated with freedom from AF in all patients. At 3 months, 67% of patients were free of AF, while reablation of recovered PVs led to an overall freedom from AF in 81% of patients after 1 year. CONCLUSION: Robotic PVI for PAF is safe, effective, and requires limited fluoroscopy while yielding comparable success rates to conventional ablation approaches with PV reconduction as a common phenomenon associated with AF recurrences.

Correlation of right ventricular dysfunction parameters and pulmonary vascular obstruction score in acute pulmonary embolism in a porcine model.

This paper aims to non-invasively determine right ventricular dysfunction parameters (RVDP) in acute pulmonary embolism (APE) and to correlate these parameters with a computed tomography (CT)-based pulmonary artery obstruction score (OS). In seven domestic pigs, magnetic resonance imaging (MRI) was performed before (n = 7) and after (n = 5) APE was induced. Analysis of relative changes in right ventricular stroke volume (RVSV%), output (RVO%), end-systolic (RVESV%), end-diastolic volume (RVEDV%), and heart rate (HR%) was performed. Additionally, for the determination of the OS, all animals underwent contrast-enhanced CT-pulmonary angiography. The CT-based OS correlated strongly with RVSV% (r = 0.9576; p = 0.0104) and RVO% (r = 0.9703; p = 0.0061). Contrarily, almost no correlation could be demonstrated for the OS and the increase of RVESV % (r = 0.3850; p = 0.5222), RVEDV% (r = 0.1830; p = 0.7683), and HR% (r = 0.5494; p = 0.3375). The results of this experimental study underline that the CT-based OS correlates with RVDP as determined by cardiac MRI and might be a helpful tool for the severity assessment in APE.

Reduced fluoroscopy during atrial fibrillation ablation: benefits of robotic guided navigation.

BACKGROUND: Recently, a nonmagnetic robotic navigation system (RN, Hansen-Sensei) has been introduced for remote catheter manipulation. OBJECTIVE: To investigate the influence of RN combined with intuitive 3-dimensional mapping on the fluoroscopy exposure to operator and patient during pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) in a prospective randomized trial. METHODS: Sixty patients were randomly assigned to undergo PVI either using a RN guided (group 1; n = 30, 20 male, 62 +/- 7.7 years) or conventional ablation approach (group 2; n = 30, 14 male, 61 +/- 7.6 years). A 3-dimensional mapping system (NavX) was used in both groups. RESULTS: Electrical disconnection of the ipsilateral pulmonary veins (PVs) was achieved in all patients. Use of RN significantly lowered the overall fluoroscopy time (9 +/- 3.4 vs 22 +/- 6.5 minutes; P < 0.001) and reduced the operator's fluoroscopy exposure (7 +/- 2.1 vs 22 +/- 6.5 minutes; P < 0.001). The difference in fluoroscopy duration between both groups was most pronounced during the ablation part of the procedure (3 +/- 2.4 vs 17 +/- 6.3 minutes; P < 0.001). The overall procedure duration tended to be prolonged using RN without reaching statistical significance (156 +/- 44.4 vs 134 +/- 12 minutes, P = 0.099). No difference regarding outcome was found during a midterm follow-up of 6 months (AF freedom group 1 = 73% vs 77% in group 2 [P = 0.345]). CONCLUSION: The use of RN for PVI seems to be effective and significantly reduces overall fluoroscopy time and operator's fluoroscopy exposure without affecting mid-term outcome after 6-month follow-up.

Interactive real-time mapping and catheter ablation of the cavotricuspid isthmus guided by magnetic resonance imaging in a porcine model.

AIMS: We investigated the feasibility of real-time magnetic resonance imaging (RTMRI) guided ablation of the cavotricuspid isthmus (CTI) by using a MRI-compatible ablation catheter. METHODS AND RESULTS: Cavotricuspid isthmus ablation was performed in an interventional RTMRI suite by using a novel 7 French, steerable, non-ferromagnetic ablation catheter in a porcine in vivo model (n = 20). The catheter was introduced and navigated by RTMRI visualization only. Catheter position and movement during manipulation were continuously visualized during the entire intervention. Two porcine prematurely died due to VT/VF. Anatomical completion of the CTI ablation line could be achieved after a mean of 6.3+/-3 RF pulses (RF energy: 1807+/-1016.4 Ws/RF pulse, temperature: 55.9+/-5.9 degrees C) in n = 18 animals. In 15 of 18 procedures (83.3%) a complete CTI block was proven by conventional mapping in the electrophysiological (EP) lab. CONCLUSION: Completely non-fluoroscopic ablation guided by RTMRI using a steerable and non-ferromagnetic catheter is a promising novel technology in interventional electrophysiology.

Favorable outcome using an abbreviated procedure for catheter ablation of AVNRT: results from a prospective randomized trial.

INTRODUCTION: Radiofrequency catheter ablation aiming slow pathway modulation is a widely established procedure with high success and low recurrence rates in patients with atrioventricular nodal reentry tachycardia (AVNRT). However, the necessity of a waiting period following successful slow pathway modulation to increase the long-term success rates has not been systematically evaluated thus far. METHODS AND RESULTS: This prospective study comprised 138 consecutive patients (mean age 50.3 +/- 15.1 years) with AVNRT. These patients were randomly assigned to two groups: in group I (n = 70), a waiting period of 30 min was part of the procedure, whereas in group II (n = 68), the procedure ended without a waiting period. Electrophysiological standard parameters, i.e., ERP of RA, fast and slow pathway, RV as well as antegrade and retrograde AV node conduction capacity, were assessed prior to and after the ablation. During a follow-up period of 22.8 +/- 5.9 months, four patients in group I and three patients in group II developed recurrence of AVNRT (4.9%; P = 0.4). The mean procedure time was 115.1 +/- 23.6 min in the group with and 88.9 +/- 23.3 min in the group without waiting period (P = 0.009). No high degree AV-node conduction block was observed during the study. CONCLUSION: In the present study we could show that no long-term benefit results from a 30 min waiting period for patients who underwent an acutely successful catheter ablation for AVNRT. We therefore conclude that a 30-min waiting period can be omitted in standard procedures, thus resulting in significant shorter procedure durations.