Study design of the man and machine trial: a prospective international controlled noninferiority trial comparing manual with robotic catheter ablation for treatment of atrial fibrillation.

BACKGROUND: Pulmonary vein isolation (PVI) has become the cornerstone procedure for the treatment of symptomatic drug-resistant atrial fibrillation (AF). At the present time, circumferential PVI (CPVI) using irrigated radiofrequency (RF) is the mostly used ablation technique. However, for CPVI, precise catheter navigation and excellent catheter stability is crucial thereby requiring experienced operators. Robotic navigation systems have been introduced to facilitate catheter navigation and to improve catheter stability, therefore potentially increasing procedural success and making CPVI accessible to less experienced operators. To date, no prospective randomized trial has evaluated the efficacy and safety of CPVI using RNS compared to manually performed ablation. METHODS: In this prospective international multicenter noninferiority trial, 258 patients with either paroxysmal or short-standing persistent AF will be randomized for comparison of PVI using either manual or robotic ablation. In all patients, CPVI will be performed using irrigated RF ablation in combination with a 3D mapping system. The primary endpoint of the trial is the absence of AF or atrial tachycardia without antiarrhythmic drug therapy during 12-month follow-up. Secondary endpoints will be evaluation of periprocedural complications and procedural data such as procedure time, fluoroscopy time, as well as the incidence of esophageal injury assessed by endoscopy within 48 hours after the procedure. CONCLUSION: The "Man and Machine Trial" is the first prospective international randomized controlled multicenter noninferiority trial to compare manually performed CPVI with robotically navigated CPVI, evaluating both the safety and efficacy of the 2 techniques during a 12-month follow-up period.

Worldwide experience with the robotic navigation system in catheter ablation of atrial fibrillation: methodology, efficacy and safety.

INTRODUCTION: The Hansen Robotic system has been utilized in ablation procedures for atrial fibrillation (AF). However, because of the lack of tactile feedback and the rigidity of the robotic sheath, this approach could result in higher risk of complications. This worldwide survey reports a multicenter experience on the methodology, efficacy, and safety of the Hansen system in AF ablations. METHODS AND RESULTS: A questionnaire addressing questions on patient's demographics, procedural parameters, ablation success rate and safety information was sent to all centers where more than 50 robotic AF ablation cases have been performed. From June 2007 to December 2009, 1,728 procedures were performed at 12 centers utilizing the Hansen robotic navigation technology. The overall complication rate was 4.7% and the success rate was 67.1% after 18 ± 4 months of follow-up. In 5 low volume centers there appeared to be a learning curve of about 50 cases (complication rate 11.2% for the first 50 cases vs 3.7% for the 51-100 cases; P = 0.044) and a trend showing a decrease of complication rate with increasing case volume. However, in the remaining 7 centers no learning curve was present and the complication rate was stable over time (3.7% for the first 50 cases vs 3.6% for the 51st case thereafter; P = 0.942). CONCLUSION: The Hansen robotic system can be used for AF ablation safely. In low volume centers, there appeared to be a learning curve of the first 50 cases after which the complication rate decreased. With a higher case volume, the success rate increased.

Incidence and long-term follow-up of silent cerebral lesions after pulmonary vein isolation using a remote robotic navigation system as compared with manual ablation.

BACKGROUND: The incidence of silent cerebral lesions (SCL) after atrial fibrillation (AF) ablation is highly variable, depending on the technology used. Recently, an increased risk for SCL has been described for a novel, nonirrigated ablation tool using multielectrode phased radiofrequency (PVAC). The aim of this prospective study was to evaluate the incidence and long-term follow-up of SCL in patients undergoing robotically assisted pulmonary vein isolation (RA-PVI) as compared with manual PVI. METHODS AND RESULTS: Circumferential PVI using irrigated radiofrequency current was performed on 70 patients (41 patients with paroxysmal AF, 59%). Fifty patients underwent RA-PVI and 20 patients underwent a manual approach. Cerebral MRI was performed the day before and the day after the ablation procedure; follow-up MRI was performed on 9 of 12 (75%) patients after a follow-up period of 21 months. SCLs were found in 12 of 70 (17%) patients in this study; the incidence of SCLs was similar in patients undergoing RA-PVI as compared with manually ablated patients (n=9, 18% versus n=3, 15%; probability value=1.0). In 1 patient undergoing manual PVI (1%), an SCL with asymptomatic subarachnoid hemorrhage was detected; the bleeding completely resolved within 1 month. Transient ischemic attack occurred in 1 (1%) patient 2 days after manual PVI. After a median follow-up period of 21 months, no residual SCLs were detected. CONCLUSIONS: The incidence of SCL using the robotic navigation system was 18% in this study. Incidence and size of SCL appears to be similar after RA-PVI as compared with manual PVI. Repeat MRI showed no residual SCLs at long-term follow-up.

Abortion of myocardial infarction by primary angioplasty mainly depends on preprocedural TIMI flow.

AIMS: To define frequency and predictors of aborted myocardial infarctions (MI) after primary angioplasty. METHODS AND RESULTS: We analysed 196 consecutive patients with the clinical diagnosis of ST-elevation acute coronary syndrome (ST-ACS) admitted for primary angioplasty to one interventional facility between October 2005 and September 2006. Aborted MI was defined as a creatine increase of less than two times the upper limit of normal, combined with typical evolutionary electrocardiographic changes. Masquerading MI was diagnosed if evolutionary changes were missing or could be attributed to other causes. Thirty-four patients (17,3%) had an aborted and nine (4,6%) a masquerading MI. The main predictor of abortion was Thrombolysis In Myocardial Infarction (TIMI) flow 2 or 3 prior to procedure. The in-hospital mortality of aborted MI was 0%, the one year mortality 2.9%. Sixteen patients without prior or inter-current myocardial infarction had a preserved ejection fraction on cardiac MR at 12 months; in six patients even without any detection of late enhancement. CONCLUSIONS: There is a substantial proportion of aborted myocardial infarction after primary angioplasty, corresponding to a small or even non detectable scar formation in terms of late enhancement on cardiac MR. Preprocedural TIMI flow 2 or 3 is the main predictor of aborted MI.

Comparison of a novel, single-lead atrial sensing system with a dual-chamber implantable cardioverter-defibrillator system in patients without antibradycardia pacing indications: results of a randomized study.

BACKGROUND: Supraventricular tachyarrhythmias are the main cause for inappropriate therapy by implantable cardioverter-defibrillators (ICDs). For better rhythm discrimination, an atrial electrogram is helpful and usually obtained from an additional atrial lead, even in the absence of sinus node or atrioventricular nodal disease. An A+-ICD system with integrated atrial sensing rings mounted 15 to 18 cm from the tip of an ICD lead may obviate the need to implant a separate atrial lead. The aim of the study was to compare the novel A+-ICD and a conventional dual-chamber (DR)-ICD. METHODS AND RESULTS: Two hundred forty-nine patients with standard ICD indications but no requirement for antibradycardia pacing were randomized to receive an A+-ICD (n=124) or a DR-ICD (n=125). Implantation details, need for ICD system revision, long-term sensing, documented arrhythmia episodes, and the respective rhythm discrimination during follow-up were analyzed. The implantation time was significantly shorter in the A+-ICD group (67±30 vs 79±30 minutes, P=0.003). Mean P-wave amplitudes were 3.5±0.8 mV (A+-ICD) and 3.2±0.6 mV (DR-ICD) and remained stable during the follow-up period of 12 months. Surgical revision was necessary in 13 patients in the DR-ICD and 10 in the A+-ICD group. All 593 ventricular tachyarrhythmia episodes were correctly discriminated. Sensitivity and specificity of supraventricular tachyarrhythmia discrimination were not different between the study groups. CONCLUSIONS: The novel A+-ICD system can be implanted faster and is equivalent to a standard DR-ICD with regard to the detection of ventricular tachyarrhythmias and supraventricular tachyarrhythmias. It represents a useful alternative to obtain atrial sensing.

Outcome and treatment quality of transfer primary percutaneous intervention in older patients with acute ST-elevation myocardial infarction (STEMI).

The aim of this study was to evaluate the outcome and treatment quality of transfer percutaneous coronary intervention (PCI) in older patients with acute STEMI. In this prospective study all patients with diagnosed acute (pain-to-balloon≤12 h) STEMI transferred to our institution for primary PCI (n=400) between January 2005 and October 2007 were under investigation. Overall 125 older patients with age ≥70 years were included (mean age 77.5±4.9 years; 77 males). Pre-hospital delays were more common in older patients with longer pain-to-balloon: median (range)=85 (5-629) vs. 66 (1-688) p=0.031, and pain-to-first medical-contact-times: median: 206 (84-711) vs. 172 (45-720); p=0.001. A trend towards a higher (non-significant) rate of major 5/125 (5%) vs. 5/275 (1.8%), p=0.195 and minor 10/125 (8%) vs. 14/275 (5.1%). p=0.256 bleeding complications in older patients was evident. In-hospital mortality was significantly higher in older patients compared to the younger patients group: 13/125, 10.4% vs. 8/275, 2.9%, p=0.002). Overall mortality at 30-day follow-up was 11.2% in older and 3.3% in younger patients: 14/125 vs. 9/275, p=0.002. Transfer PCI is an effective treatment strategy for older patients with acute ST-elevation myocardial infarction. Overall-30-day mortality in older STEMI-patients transferred for primary PCI is comparably low.

Remote robotic catheter ablation for atrial fibrillation: how fast is it learned and what benefits can be earned?

INTRODUCTION: Recently, results describing pulmonary vein isolation (PVI) on patients using a robotic navigation system (RNS) in a high-volume center specialized in pulmonary vein isolation were published. The main purpose of this prospective study was to evaluate the learning curve of new users of RNS in a community hospital and to address the effectivity of RNS in electrophysiological settings with fewer patients. Radiation times, procedural times, feasibility, and safety with the RNS were assessed. METHODS: PVI using the RNS was performed on 100 consecutive patients with symptomatic paroxysmal (n = 56, 56%) or persistent atrial fibrillation (AF). To assess the learning curve of practitioners with first-time use of RNS, patients were divided into four groups of 25 patients each (Q1-Q4). Procedural times as well as radiation times, complications, and outcome after a 6-month follow-up period were assessed for each quartile. All patients were ablated by the same physician. RESULTS: Comparing the four patient groups, a continuous and significant reduction of procedural and radiation times was seen in the first 75 patients (Q1-Q3), whereas no further improvement was seen in the consecutive patients (Q3-Q4). One pericardial tamponade occurred in the course of 100 patients (1%). Overall success rate after a 6-month follow-up period was 74% in patients with paroxysmal and persistent AF. Comparing the four quartiles there was a higher but non-significant number of patients with freedom of atrial fibrillation after a 6-month follow-up in the subsequent groups (Q2-Q4) when compared to group 1. CONCLUSIONS: This data suggest that RNS is feasible and safe when performed in a community hospital with a significant reduction of radiation times and procedure times within the first 75 patients and with similar success and complication rates as compared to high-volume centers.

Primary angioplasty for any patient with ST-elevation myocardial infarction? Guideline-adherent feasibility and impact on mortality in a rural infarction network.

AIMS: The aim of this study was to assess the guideline-adherent feasibility of area-wide primary angioplasty in rural German surroundings and its impact on reperfusion and outcome in patients with acute ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: All consecutive patients with acute STEMI (n = 347) admitted to any of the hospitals (5 non invasive and 1 invasive with established 24 h/7 days primary angioplasty service) in a 350.000 inhabitant rural area during the year 2002 (n = 184) and 2005 (n = 163) were included in this registry. In 2002, emergency medical services transferred acute STEMI patients to the nearest emergency room, where reperfusion therapy (fibrinolysis or primary angioplasty) was organised. In 2005, all patients were transferred directly to the cathlab bypassing any emergency room when possible. Primary angioplasty increased from 53 to 89% (p < 0.01), fibrinolysis decreased from 27 to 2% (p < 0.01) and the no revascularisation rate from 21 to 9% (p < 0.01). Onset of pain to balloon time in primary angioplasty was reduced from median 339 to 191 min (p < 0.01), median first medical contact to balloon time in 2005 was 101 min. Overall, 6-month mortality decreased from 19 to 10% (p = 0.03). CONCLUSIONS: After transition to a uniform primary angioplasty concept, an increase in overall reperfusion rates and a decrease in time delays could be observed in a rural German infarction network.

Oesophageal temperature monitoring and incidence of oesophageal lesions after pulmonary vein isolation using a remote robotic navigation system.

AIMS: Oesophageal lesions (EL), a potential complication after pulmonary vein isolation (PVI), have been described recently. A new remote robotic navigation system (RNS; Hansen Medical) provides enhanced catheter stability along with more effective lesion placement. The aim of this prospective study was to evaluate temperature monitoring and incidence of EL when using RNS with an irrigated tip radiofrequency catheter for PVI. METHODS AND RESULTS: Circumferential PVI using RNS was performed in 73 patients (pts) with paroxysmal (n = 46, 63%) and persistent atrial fibrillation. An oesophageal temperature probe was placed in 58 (79.5%) pts and was integrated in the 3D-map (NavX). Power was limited to 25 W at the posterior wall, and in the case of an increase in temperature power was limited to 20 W. Endoscopy was performed in 42 pts within 24 h after PVI. In 44 of 58 (75.9%) pts, a significant rise in temperature (>39 degrees C) was observed. In 6 of 42 (14.3%) pts, an EL was found during endoscopy. In patients with EL, the body mass index (BMI) was significantly lower than in pts without EL (24.1 +/- 2.0 vs. 29.0 +/- 5.8, P = 0.047). The BMI of all patients with EL was <26, whereas all patients without EL had a BMI above 26. The EL showed brisk healing after re-endoscopy within 2 weeks in all pts. CONCLUSION: In patients undergoing PVI using the RNS, the incidence of EL is 14.3% when using power settings comparable to settings used in manual ablation. Patients with lower BMI (<26) are at higher risk for EL.

Persistent iatrogenic atrial septal defect after a single-puncture, double-transseptal approach for pulmonary vein isolation using a remote robotic navigation system: results from a prospective study.

AIMS: Persistent iatrogenic atrial septal defect (iASD) after transseptal puncture for pulmonary vein isolation (PVI) has been described recently as a complication of PVI. No data exists evaluating systematically the incidence and clinical implications of iASDs after PVI using a remote robotic navigation system (RNS) with sheaths with a distinct larger outer diameter. METHODS AND RESULTS: In this prospective study, 40 patients with either paroxysmal (n = 22, 55%) or persistent symptomatic atrial fibrillation were treated with circumferential PVI using an RNS. In all patients, a single-puncture, double-transseptal approach was used to access the left atrium. Transoesophageal echocardiography was performed before and the day after PVI as well as after a 3 and 6 months follow-up (FU). The day after ablation an iASD was detected in 38 of 40 (95%) patients with a mean diameter of 3.45 +/- 1.5 mm. At 6-month FU, the iASDs were closed in 30 of 39 (78.9%) patients. During the 6-month FU period, no patient died or suffered from cerebral or cardiac embolism. CONCLUSION: After a single-puncture, double-transseptal approach for PVI using the RNS, iASDs show a high spontaneous closure rate of 78.9% after a 6-month FU period. Persistent iASDs following PVI with the RNS are not associated with an increased rate of paradoxical embolism or with relevant shunting.

Ablation within the sinus of Valsalva for treatment of supraventricular and ventricular tachycardias: what is known so far?

Whenever common ablation strategies for treatment of cardiac arrhythmias fail, the search for alternative concepts becomes essential. Since it has been proven that the sinus of Valsalva (soV) is situated in close proximity to small regions of the myocardium, difficult to access via endocardial ablation, catheter ablation within the soV has become an established treatment option for patients with supraventricular and ventricular tachycardias. Although ablation within the soV is increasingly practiced, larger studies investigating the feasibility and safety of this approach remain rare. In this review, the authors summarize the currently available literature with special focus on safety issues, energy sources, success rates, and other distinctive aspects of ablation strategies within the soV.

Catheter ablation within the sinus of Valsalva--a safe and effective approach for treatment of atrial and ventricular tachycardias.

BACKGROUND: Ablation of the aortic sinus of Valsalva in adults for ectopic atrial tachycardia (EAT) and ventricular tachycardia (VT)/premature ventricular complexes (PVCs) has been reported in only a very few patients. Limited data exist concerning the safety of aortic ablation. OBJECTIVE: The purpose of this study was to confirm aortic wall and aortic valve integrity after ablation and to evaluate for potential cerebral embolism due to thrombus formation at aortic wall lesions. METHODS: From January 2006 to August 2007, 21 patients with EAT (n = 6) or VT/PVCs (n = 15) originating from the sinus of Valsalva underwent successful ablation. The aortic wall structure was evaluated using transesophageal echocardiography (TEE) and magnetic resonance imaging (MRI) the day after ablation and at 6-month follow-up for all patients. To rule out cerebral embolism due to postablation thromboembolic events, a cerebral MRI was performed immediately after ablation in six patients and at 6-month follow-up in all patients. Ablation success was defined by 24-hour Holter monitoring before hospital discharge and after 6 months. RESULTS: Aortic wall integrity was confirmed in all patients by TEE and MRI. Cerebral MRI showed evidence of silent cerebral ischemia in one patient. Aortic valve thickening was detected in one patient by TEE. CONCLUSION: Ablation in the aortic sinus of Valsalva is a safe and effective approach for atrial tachycardia or VT/PVCs. The incidence of silent ischemia needs further evaluation.

Advances in remote monitoring of implantable pacemakers, cardioverter defibrillators and cardiac resynchronization therapy systems.

Unlike the standard quarterly or semi-annual direct ambulatory device interrogations procedures, state-of-the-art implantable electronic cardiovascular devices (IECD) enable their wireless remote interrogation and monitoring, and automatically send reports and special alerts on a daily basis. This allows physicians to respond more proactively to changes in patient or device status, more appropriately triage patient care, and more efficiently perform the post-implant ambulatory follow-ups. This review presents the-state-of the-art technology of remote IECD monitoring and summarizes the main clinical observations published through June 2008. Cardiovascular remote monitoring systems made by several manufacturers are currently in various phases of development, clinical investigation, and medical applications. Data collected in several completed and ongoing studies strongly suggest that this new technology will make important contributions, particularly with respect to the facilitation of IECD follow-ups, enhancement of patient safety and quality of life, and lowering of medical costs. Further technological advances and a more clear understanding and appreciation of the clinical and economic benefits of telecardiology, will likely increase sharply the use of remote IECD monitoring in upcoming years.

Persistent iatrogenic atrial septal defect after pulmonary vein isolation : incidence and clinical implications.

INTRODUCTION: Pulmonary vein isolation (PVI) is widely practiced for treating atrial fibrillation. Transseptal access is necessary with one or even more transseptal sheaths to perform PVI. METHODS: In this prospective study, 31 patients were examined with transesophageal echocardiography before, immediately after and in a 3-, 6- and 12-month follow-up period for evaluation of iatrogenic atrial septal defect (iASD). All patients underwent PVI with double transseptal puncture. RESULTS: An iASD was detected in 27/31 patients (87%) with a maximum diameter of 1.0 mm. After 3 months, the iASDs were completely closed in 26/27 (96.3%) patients. In 1/27 (3.7%) patients, there was an iASD detectable even after 12 months. Clinically no patient suffered from cerebral or cardiac embolism in the follow-up period. CONCLUSIONS: We were only able to find small iASDs with left to right shunting after PVI but none with right to left shunting. iASDs following PVI show a high spontaneous closure rate already at 3 months of follow-up and are not associated with an increased rate of paradoxical embolism.

Short-term heart rate turbulence analysis versus variability and baroreceptor sensitivity in patients with dilated cardiomyopathy.

New methods for the analysis of arrhythmias and their hemodynamic consequences have been applied in risk stratification, in particular to patients after myocardial infarction. This study investigates the suitability of short-term heart rate turbulence (HRT) analysis in comparison to heart rate and blood pressure variability as well as baroreceptor sensitivity analyses to characterise the regulatory differences between patients with dilated cardiomyopathy (DCM) and healthy controls. In this study, 30 minutes data of non-invasive continuous blood pressure and ECGs of 37 DCM patients and 167 controls measured under standard resting conditions were analysed. The results show highly significant differences between DCM patients and controls in heart rate and blood pressure variability as well as in baroreceptor sensitivity parameters. Applying a combined heart rate-blood pressure trigger, ventricular premature beats were detected in 24.3% (9) of the DCM patients and 11.3% (19) of the controls. This fact demonstrates the limited applicability of short-term HRT analyses. However, the HRT parameters showed significant differences in this subgroup with ventricular premature beats (turbulence onset: DCM: 1.80+/-2.72, controls: - 4.34+/-3.10, p<0.001; turbulence slope: DCM: 6.75+/-5.50, controls: 21.30+/-17.72, p=0.021). Considering all (including HRT) parameters in the subgroup with ventricular beats, a discrimination rate between DCM patients and controls of 88.0% was obtained (max. 6 parameters). The corresponding value obtained for the total group was 86.3% (without HRT parameters). Comparable classification rates and high correlations between heart rate turbulence and variability and baroreflex parameters point to a more universal applicability of the latter methods.

"Double" potentials define linear lesion conduction block using a novel mapping/linear lesion ablation catheter.

INTRODUCTION: A novel mapping/ablation catheter using a coaxially ablation electrode (E) that is moveable between distal and proximal ring electrodes along its shaft was used to create a linear lesion over the cavotricuspid isthmus (CTI) and bidirectional block in 32 patients (21 men; age 38-79 years) undergoing ablation for counterclockwise atrial flutter. METHODS AND RESULTS: Two bipolar electrograms (E1 and E2) were recorded: between E and the distal ring electrode and between E and the proximal ring electrode. Interpole distance varied for both as the E traversed the slide shaft. Given the catheter's concept, these bipoles are orientated exactly along the line of lesion creation. Prior to ablation, unitary bipolar electrograms were recorded along the catheter slide shaft position. As the CTI lesion was created (E moved along the catheter slide shaft in 2-mm steps with radiofrequency energy delivered to achieve 65 degrees C for 60 sec at each), double potentials (DP) were observed. Interpotential distance became maximal with completion of the linear lesion and bidirectional block. DPs were noted in all these procedures. With pacing from the low septal right atrium at bidirectional block creation, interpotential timing was 140.9 +/- 15 msec and from the low right atrial free wall was 145.13 +/- 18 msec. In sinus rhythm, DP interpotential timing was less (35.13 +/- 9 msec) as activation fronts arrived from both septal and anterior atrial aspects. CONCLUSION: Bipolar recordings from the coaxially moveable electrode catheter provide unique electrogram data. DPs recorded during and after linear lesion creation can define conduction block across that lesion without the need for additional mapping catheters or complex mapping technology.

Recurrence-plot-based measures of complexity and their application to heart-rate-variability data.

The knowledge of transitions between regular, laminar or chaotic behaviors is essential to understand the underlying mechanisms behind complex systems. While several linear approaches are often insufficient to describe such processes, there are several nonlinear methods that, however, require rather long time observations. To overcome these difficulties, we propose measures of complexity based on vertical structures in recurrence plots and apply them to the logistic map as well as to heart-rate-variability data. For the logistic map these measures enable us not only to detect transitions between chaotic and periodic states, but also to identify laminar states, i.e., chaos-chaos transitions. The traditional recurrence quantification analysis fails to detect the latter transitions. Applying our measures to the heart-rate-variability data, we are able to detect and quantify the laminar phases before a life-threatening cardiac arrhythmia occurs thereby facilitating a prediction of such an event. Our findings could be of importance for the therapy of malignant cardiac arrhythmias.

Heart rate variability before the onset of ventricular tachycardia: differences between slow and fast arrhythmias.

BACKGROUND: We tested whether or not heart rate variability (HRV) changes can serve as early signs of ventricular tachycardia (VT) and predict slow and fast VT in patients with an implantable cardioverter defibrillator (ICD). METHODS AND RESULTS: We studied the ICD stored 1000 beat-to-beat intervals before the onset of VT (131 episodes) and during a control time without VT (74 series) in 63 chronic heart failure ICD patients. Standard HRV parameters as well as two nonlinear parameters, namely 'Polvar10' from symbolic dynamics and the finite time growth rates 'Fitgra9' were calculated. Comparing the control and the VT series, no linear HRV parameter showed a significant difference. The nonlinear parameters detected a significant increase in short phases with low variability before the onset of VT (for time series with less than 10% ectopy, P<0.05). Subdividing VT into fast (cycle length 270 ms) events, we found that the onset of slow VT was characterized by a significant increase in heart rate, whereas fast VT was triggered during decreased heart rates, compared to the control series. CONCLUSIONS: Our data may permit the development of automatic ICD algorithms based on nonlinear dynamic HRV parameters to predict VT before it starts. Furthermore, they may facilitate improved prevention strategies.