Catheter-tissue contact force values do not impact mid-term clinical outcome following pulmonary vein isolation in patients with paroxysmal atrial fibrillation.

PURPOSE: Catheter-tissue contact is critical for effective lesion creation in radiofrequency catheter ablation (RFCA). In a multicenter prospective study, we assessed the relationship between catheter contact force (CF) during RFCA for paroxysmal atrial fibrillation (AF) and clinical recurrences over a mid-term follow-up. METHODS: All patients underwent RFCA for paroxysmal AF by antral pulmonary vein (PV) isolation, aiming at entry and exit conduction block in all PVs. A new open-irrigated tip catheter with CF sensing (SmartTouch(TM), Biosense Webster Inc. CA) was used. All patients were followed for at least 12 months and the relationship between CF and clinical outcomes assessed. RESULTS: One year follow-up was available in 92/95 of the patients enrolled. Acute PV isolation was achieved in 100 % of the veins. Mean CF during RFCA was 12.2 ± 3.9 g. Mean force-time integral (FTI) was 733 ± 505 gs. Following the 3-month blanking period, 17 (18 %) patients experienced at least 1 atrial tachyarrhythmia relapse. There was no statistical difference in mean CF (13 ± 3.4 g vs 12 ± 4 g, p = 0.32) and mean FTI (713 ± 487 gs vs 822 ± 590 gs, p = 0.42) between patients with and without arrhythmia recurrences. Recurrences were recorded in 22 % of patients achieving a mean FTI value below the median of 544 gs and in 15 % of patients with a mean FTI value above the median (p = 0.64). CONCLUSIONS: RFCA with CF data during PV isolation for paroxysmal AF improves physician's knowledge on catheter-tissue contact. In the present dataset, however, higher CF values did not impact mid-term clinical RFCA outcome.

Impact of remote monitoring on the management of arrhythmias in patients with implantable cardioverter-defibrillator.

BACKGROUND: In the last decade, there has been an exponential increase in cardioverter-defibrillator (ICD) implants. Remote monitoring systems, allow daily follow-ups of patients with ICD. OBJECTIVE: To evaluate the impact of remote monitoring on the management of cardiovascular events associated with supraventricular and ventricular arrhythmias during long-term follow-up. METHODS: A total of 207 patients undergoing ICD implantation/replacement were enrolled: 79 patients received remote monitoring systems and were followed up every 12 months, and 128 patients were followed up conventionally every 6 months. All patients were followed up and monitored for the occurrence of supraventricular and ventricular arrhythmia-related cardiovascular events (ICD shocks and/or hospitalizations). RESULTS: During a median follow-up of 842 days (interquartile range 476-1288 days), 32 (15.5%) patients experienced supraventricular arrhythmia-related events and 51 (24.6%) patients experienced ventricular arrhythmia-related events. Remote monitoring had a significant role in the reduction of supraventricular arrhythmia-related events, but it had no effect on ventricular arrhythmia-related events. In multivariable analysis, remote monitoring remained as an independent protective factor, reducing the risk of supraventricular arrhythmia-related events of 67% [hazard ratio, 0.33; 95% confidence interval (CI), 0.13-0.82; P = 0.017]. CONCLUSION: Remote monitoring systems improved outcomes in patients with supraventricular arrhythmias by reducing the risk of cardiovascular events, but no benefits were observed in patients with ventricular arrhythmias.

Documentation of pulmonary vein isolation improves long term efficacy of persistent atrial fibrillation catheter ablation.

BACKGROUND: The aim of this study was to investigate the efficacy of catheter ablation in the treatment of persistent atrial fibrillation (AF) and the predictors of arrhythmia recurrence. METHODS: Absence of atrial tachyarrhythmia (AT) recurrence during a mid-term follow-up was correlated with several clinical and procedural characteristics in a population of 82 patients aged 20-70 years who had experienced at least one documented relapse of persistent AF during a single trial of antiarrhythmic drug therapy. Electrophysiological success of ablation was declared when all identified PVs were isolated (confirmation of entry and exit block). Patients were followed for a maximum of 24 months after the blanking period with outpatient visits, ECG recordings, 24-hour Holter monitoring, and weekly transtelephonic monitoring for 30s. RESULTS: Electrophysiological success was documented in 38/82 (46.3%) patients. During a mean follow-up of 24.7 ± 4.2 months, 69/82 (84.1%) patients presented at least one episode of AT after the 2 month blanking period. According to univariate and multivariate logistic regression analyses, only an electrophysiologically successful ablation significantly correlated with the absence of documented AT relapse (OR 5.32, 95% CL 1.02-27.72; p=.0472). CONCLUSIONS: Mid-term outcome of a single procedure of catheter ablation without the adjunction of antiarrhythmic drug therapy is poor in patients with persistent AF. Documented PV isolation is useful to increase the success rate of circumferential PV ablation even in persistent AF patients.

Catheter-tissue contact force for pulmonary veins isolation: a pilot multicentre study on effect on procedure and fluoroscopy time.

AIMS: Catheter-tissue contact is critical for effective lesion creation in radiofrequency catheter ablation (RFCA). In a multicentre prospective study, we assessed the effect of direct contact force (CF) measurement on acute procedural parameters during RFCA of atrial fibrillation (AF). METHODS AND RESULTS: A new open-irrigated tip catheter with CF sensing (SmartTouch™, Biosense Webster Inc.) was used. All the patients underwent the first ablation procedure for paroxysmal AF with antral pulmonary vein (PV) isolation, aiming at entry and exit conduction block in all PVs. Ninety-five patients were enroled in nine centres and successfully underwent ablation. Overall procedure time, fluoroscopy time, and ablation time were 138.0 ± 67.0, 14.3 ± 11.2, and 33.8 ± 19.4 min, respectively. The mean CF value during ablation was 12.2 ± 3.9 g. Force time integral (FTI) analysis showed that patients achieving a value below the median of 543.0gs required longer procedural (158.0 ± 74.0 vs. 117.0 ± 52.0 min, P = 0.004) and fluoroscopy (17.5 ± 13.0 vs. 11.0 ± 7.7 min, P = 0.007) times as compared with those in whom FTI was above this value. Patients in whom the mean CF during ablation was >20 g required shorter procedural time (92.0 ± 23.0 vs. 160.0 ± 67.0 min, P = 0.01) as compared with patients in whom this value was <10 g. Four groin haematomas were the only complications observed. CONCLUSION: Contact force during RFCA for PV isolation affects procedural parameters, in particular procedural and fluoroscopy times, without increasing complications.

Comparison of ThermoCool® Surround Flow catheter versus ThermoCool® catheter in achieving persistent electrical isolation of pulmonary veins: a pilot study.

INTRODUCTION: Aim of this study was to compare efficacy and safety of the new ThermoCool Surround Flow® catheter (SFc) versus the ThermoCool® (TCc) in achieving persistent circumferential electrical isolation of the pulmonary veins (PVs) in patients with paroxysmal atrial fibrillation (AF). METHODS AND RESULTS: This multicenter, randomized, controlled study enrolled patients suffering from paroxysmal AF. Randomization was run in a one-to-one fashion between radiofrequency ablation by TCc or SFc. Aim of PVs ablation was documentation of electrical isolation with exit/entrance block recorded on a circular catheter. Among the 106 enrolled patients, 52 (49.0%) were randomized to TCc and 54 (51.0%) to SFc. Total volume of infused saline solution during the procedure was lower in the SFc than in TCc group (752.7 ± 268.6 mL vs 1,165.9 ± 436.2 mL, P < 0.0001). Number of identified and isolated PVs was similar in the 2 groups. Number of PVs remaining isolated 30 minutes after ablation was higher in the SFc than in TCc group (95.2% vs 90.5%, P < 0.03), mainly driven by acute ablation result in the left PVs (96.1% vs 89.7%, P < 0.04). Complications were seldom and observed only in the TCc group (0% vs 3.84%, P < 0.03). At 6-month follow-up SFc patients reported a trend toward less AF recurrences compared to those in the TCc group (22.9% vs 27.0%, P = 0.69). CONCLUSION: PV isolation by SFc lowered the rate of left PV early reconnections and reduced the volume of infused saline solution while maintaining the safety profile of AF ablation.

Different image integration modalities to guide AF ablation: impact on procedural and fluoroscopy times.

BACKGROUND: Different image integration modalities are available for atrial fibrillation (AF) ablation, but their impact on procedural and fluoroscopy times has not been evaluated yet. METHODS: Sixty patients (mean age 52.2 ± 12.0 years, 48.3% men, 75% paroxysmal AF) undergoing pulmonary vein (PV) encircling with PV disconnection for symptomatic drug-refractory AF were randomized to ablation with CARTO electroanatomical mapping (Biosense Webster, Diamond Bar, CA, USA) integrated with: (1) preprocedural magnetic resonance imaging (MRI; Group 1); (2) intracardiac echocardiography (ICE; Group 2); (3) preprocedural MRI and ICE (Group 3). RESULTS: PV disconnection was achieved in all patients. Total procedural time (Group 1: 124.7 ± 47.0; Group 2: 112.5 ± 30.4; Group 3: 108.6 ± 34.7 minutes) and total ablation time were similar between groups (P = ns). MRI integration alone required a higher fluoroscopy time (23.8 ± 6.9 in Group 1 vs 11.0 ± 2.3 and 13.9 ± 4.2 minutes in Groups 2 and 3, respectively; P < 0.005) and a longer time spent in the left atrium (109.0 ± 43.5 in Group 1 vs 78.2 ± 29.7 and 74.8 ± 34.3 minutes in Groups 2 and 3, respectively; P = 0.03) in comparison to ICE integration. Addition of MRI to ICE integration showed a tendency for a higher fluoroscopy time in comparison to ICE integration alone (P = 0.06). At a mean follow-up of 9.1 ± 2.2 months, there were no significant differences in AF recurrences among the groups (P = ns). CONCLUSION: ICE image integration significantly reduces the fluoroscopy time and the time spent in the left atrium in comparison to MRI integration alone. Addition of MRI to ICE integration does not reduce total procedural time and seems to lead to higher fluoroscopy time in comparison to ICE integration alone.

Different clinical models of CD34 + cells mobilization in patients with cardiovascular disease.

To test the role of necrosis, ischemia or both in bone marrow cells (BMC) mobilization in patients with cardiovascular disease. We studied three groups of patients: group 1, Iatrogenic Necrosis, with pure necrosis (28 patients undergoing transcatheter radiofrequency ablation); group 2, Ischemic Necrosis (30 patients with myocardial infarction); group 3, Pure Ischemia (24 patients with unstable angina). As control groups, we studied 27 patients with stable coronary artery disease (CAD), and 20 patients without CAD undergoing angiography for valvular diseases or cardiomiopathy. CD34 + cells and cytokines were evaluated at: T(0) (baseline), 48 h and 5, 7, 10, 14 days thereafter. We observed a significant increase of CD34 + cells at T(3) and T(4) only in Iatrogenic Necrosis and Ischemic Necrosis group. The peak of mobilization was observed ten days after the necrotic event (2.8 ± 1.4 vs. 5.9 ± 1.9 in the group 1, P = 0.03; and 3 ± 1.5 vs. 5.6 ± 2 in the group 2, P = 0.04; respectively). We found a good correlation between CD34 + and vascular endothelial growth factor (VEGF) and stromal derived factor (SDF-1α) peak values (r = 0.77 and r = 0.63, respectively). At multivariable analysis, myocardial necrosis (OR 3.5, 95%CI 2.2-4.2, P < 0.01), VEGF (OR 2, 95%CI 1.1-3, P = 0.01 as above versus below median value), and SDF-1α (OR 1.6, 95%CI 1.1-2.5, P = 0.02 as above versus below median value) emerged as independent predictors of C34 + cells increase. Myocardial necrosis with simultaneous elevation of VEGF and SDF-1α causes a significant CD34 + cells mobilization in patients with cardiovascular disease.

Noncontact mapping of left ventricle during CRT implant.

INTRODUCTION: Not all candidates for cardiac resynchronization therapy (CRT) are responders at follow-up. Echocardiographic parameters of dyssynchrony do not predict the response. Analysis of electrical properties of left ventricle (LV) by noncontact mapping (NCM) could be useful to better identify candidates for CRT. METHODS AND RESULTS: We studied nine consecutive patients undergoing CRT. An NCM was positioned in the LV via atrial transeptal puncture. LV activation was recorded during sinus rhythm (SR), pacing from RV, from different LV epicardial locations, and in biventricular (BIV) pacing. The corresponding invasive pressure was determined. Heparin, administered during NCM, was reversed and CRT implant was completed. An offline analysis of the data was performed in order to measure transeptal and total LV activation time, to evaluate the site of earliest and latest LV activation, and the pattern of activation. No complications occurred. Mean time of total NCM procedures was 24 + or - 7 minutes. During SR, RV, LV, and BIV pacing, respectively, a "U"-shaped LV activation pattern was found in three, seven, four, and and two patients; mean LV activation time was 58.1 + or - 7.0, 81.7 + or - 15.8, 71.1 + or - 12.4, and 65.6 + or - 7.7 ms; and mean systolic LV peak pressure was 114 + or - 21, 97 + or - 18, 103 + or - 17 and 110 + or - 15 mmHg, respectively. LV activation was influenced by a slow conduction area at the pacing site and by the duration of transeptal time. CONCLUSION: An NCM during CRT is safe and feasible. It provides an additional information on electrical activation in SR and in various modality of pacing. Further studies with larger populations are needed in order to correlate electrical to clinical outcomes.

Value of right ventricular-left ventricular interlead electrical delay to predict reverse remodelling in cardiac resynchronization therapy: the INTER-V pilot study.

AIMS: Few studies have systematically evaluated the value of intra-procedural parameters in predicting response to cardiac resynchronization therapy (CRT). We investigated whether intracardiac (electrogram) measurements of electrical delays between the positioned right ventricular (RV) and left ventricular (LV) leads at implantation could predict the mid-term CRT response. METHODS AND RESULTS: Fifty-two patients underwent CRT implantation according to standard techniques and clinical indications. The RV-LV interlead electrical delay measured during spontaneous rhythm and the difference between the pacing-induced (Deltap) RV-LV interlead electrical delays measured during RV and LV pacing were defined intraoperatively using the electrical depolarizations registered at the ventricular leads on the device programmer. At 6 months, a reduction of LV end-systolic volume > or = 15% was used to define CRT responders. Responders (62%), when compared with non-responders, showed a higher proportion of ischaemic aetiology (P = 0.007) and a lower value of DeltapRV-LV interlead electrical delay (22.1 +/- 18.4 vs. 46.3 +/- 15.0 ms, P = 0.0001). At multivariate analysis, the DeltapRV-LV interlead electrical delay was the only independent predictor of response to CRT (P = 0.001). For such a parameter, the receiving operating characteristic curve analysis identified a cut-off value of 42 ms corresponding with the highest accuracy: sensitivity 90.6%; specificity 70%; positive and negative predictive value 83% and 82%, respectively. Conversely, no difference was ascertained between responders and non-responders when RV-LV interlead electrical delay was measured during spontaneous rhythm (76.1 +/- 28.5 vs. 89.6 +/- 21.2, P = 0.078). CONCLUSION: Intraprocedural measuring of paced RV-LV interlead electrical delay obtained during RV and LV pacing predicts mid-term CRT response.

Contact versus noncontact mapping for ablation of ventricular tachycardia in patients with previous myocardial infarction.

INTRODUCTION: The aim of this study was to compare contact versus noncontact mapping for radiofrequency (RF) ablation of any sustained post-myocardial infarction (MI) ventricular tachycardia (VT). METHODS: Forty patients with tolerated VT post-MI were randomized to RF ablation with contact (group 1) or noncontact (group 2) mapping systems. In both groups ablation of tolerated VT was guided by VT activation map confirmed by concealed entrainment. When untolerated VTs were induced, ablation was performed in group 1 according to pace mapping starting from the scar border zone and in group 2 according to the VT activation map confirmed by pace mapping. RESULTS: No differences were seen between the groups in terms of acute success rate of clinical VT ablation (95% vs 100%, respectively; P = ns) and in the noninducibility of any VT at the end of the procedure (55% vs 85%, respectively; P = 0.08). Moreover, untolerated VTs were eliminated in 30% of group 1 versus 83.3% of group 2 patients (P < 0.05). The mean total procedural and fluoroscopy times were 236.4 +/- 42.7 and 29.0 +/- 7.8 minutes in group 1 and 144.5 +/- 50.8 and 23.4 +/- 5.8 minutes in group 2 (P < 0.001 and < 0.05, respectively). At a mean follow-up of 15.2 +/- 6.7 months no differences were seen in VT recurrences between groups, but noninducibility at the end of the procedure was predictive of freedom from recurrences (P < 0.001). CONCLUSION: Both systems are useful for ablation of tolerated VT. Noncontact mapping is more effective for ablation of untolerated VT and allows the reduction of procedural and fluoroscopy times. Noninducibility at the end of the procedure seems predictive of freedom from recurrences during follow-up.

Radiofrequency ablation of paroxysmal atrial fibrillation by mesh catheter.

INTRODUCTION: Pulmonary veins isolation usually requires a multielectrode catheter for mapping in addition to the ablation catheter. We describe our experience with a new multipolar catheter designed for simultaneous mapping and ablation (MESH, Bard). METHODS AND RESULTS: We tested the catheter in 15 patients (mean age 61.1 +/- 7.9; eight men) scheduled for paroxysmal atrial fibrillation ablation. The catheter was positioned in front of the pulmonary vein ostia. A pulmonary vein potential was demonstrated in 63.5% of the veins, which were disconnected with a mean of 1.6 radiofrequency applications with a mean time of 351 +/- 125.8 s (range 180-650) for each vein. Mean procedural time was 93 +/- 17.1 min (range 65-120), and fluoroscopy time was 13.7 +/- 4.0 (range 5-15) min. No complications occurred during and after or procedures. CONCLUSION: Pulmonary veins disconnection with MESH ablator catheter is feasible with short procedural and X-ray exposure time. Further studies are needed to compare this new device to standard multipolar mapping catheters in order to evaluate its ability to correctly identify pulmonary vein potentials and to compare its safety and efficacy.

Paroxysmal atrial fibrillation ablation with the multipolar mapping and ablation catheter (Mesh-Bard).

Pulmonary veins (PVs) ablation is a valid treatment option for atrial fibrillation. The standard approach for PVs isolation usually requires two catheters or an electroanatomical reconstruction of the left atrium. We describe our initial experience with a single device for mapping and ablating in a patient referred to our center for the relapsing of atrial fibrillation 3 years after a previous ablation procedure. The newly available catheter MESH was safe and effective to quickly isolate two reconnected PVs.

Radiofrequency atrial fibrillation ablation based on pathophysiology: a diversified protocol with long-term follow-up.

BACKGROUND: The optimal approach and long-term results of radiofrequency catheter ablation of atrial fibrillation (AF) are still unknown. We report our experience with respect to an ablation protocol diversified on a patient's AF pathophysiology with long-term follow-up. METHODS: Seventy-two patients with paroxysmal/persistent drug-resistant AF were selected. Patients with apparently normal hearts (group 1, n = 20) underwent electrophysiological disconnection of pulmonary veins (PVs) presenting a clear PV potential, whereas those with even initial cardiopathy (group 2, n = 52), underwent PV encircling. RESULTS: Sinus rhythm was maintained at 6 months in 85% of group 1 and 71% of group 2 patients. After 42 months of follow-up, including 15.2% re-do procedures, 85% of group 1 and 77% of group 2 patients were in sinus rhythm, including patients with anti-arrhythmic drugs (AADs). The long-term success rate without AADs was 75% and 46% for each group, respectively. Age and the 6-month success of the procedure were predictive of sinus rhythm maintenance during follow-up. CONCLUSIONS: An ablation protocol diversified on AF pathophysiology assured, at 3 years of follow-up, sinus rhythm maintenance in 85% of patients with a normal heart and in 77% of those with even initial cardiopathy. The 6-month result of the ablation procedure remained stable over time.

Radiofrequency ablation of atrial fibrillation: is the persistence of all intraprocedural targets necessary for long-term maintenance of sinus rhythm?

BACKGROUND: Several approaches have been developed for radiofrequency catheter ablation of atrial fibrillation, but the correct intraprocedural end point is still under debate, and few data exist about the destiny of ablation lesions over time. The aim of the present study was to evaluate the long-term maintenance of intraprocedural end points of ablation procedures. METHODS AND RESULTS: Inclusion criteria were (1) a previous ablation procedure of pulmonary vein (PV) encircling performed for drug-refractory persistent atrial fibrillation; (2) a "complete" intraprocedural end point, which consisted of voltage abatement inside the lesions, PV disconnection, and exit-block pacing from inside the lesions, attained in all PVs; and (3) stable sinus rhythm documented during a minimum follow-up of 2.5 years after the procedure. Twenty volunteers were selected (12 males, mean age 59+/-7 years) and underwent a repeat electrophysiological study. After a follow-up of 36.4+/-4.7 months, complete voltage abatement was maintained around 32 PVs (40.0%), PV disconnection persisted in 12 (37.5%) of the previously isolated PVs, and exit block was present in 39 PVs (48.7%). Ten patients who underwent a redo ablation procedure because of recurrences of atrial fibrillation were used as the control group. Differences in intraprocedural end-point maintenance between the 2 groups were not statistically significant. CONCLUSIONS: Common intraprocedural end points such as voltage abatement, PV disconnection, and exit block persist only in a limited number of patients, even when the outcome is favorable during follow-up. Further investigation will be required to determine whether such data will have implications for ablation strategies.

[Cardiac resynchronization therapy and reduction of mortality in heart failure: a proven association]. / Terapia di resincronizzazione e riduzione di mortalità nello scompenso cardiaco: un'associazione provata.

Cardiac resynchronization therapy (CRT) is currently used for treatment of refractory heart failure and is effective in reducing symptoms and increasing quality of life and exercise tolerance. Data from the literature also show that CRT may prolong event-free survival and reduce heart failure mortality. This therapy is also highly cost-effective as compared to optimized medical treatment. The reduction of the risk of death occurs in both nonischemic and ischemic heart failure, although in this latter group CRT benefit seems to be less. It is still controversial whether a back-up defibrillator should be implanted to all patients undergoing CRT. Finally, left ventricular reverse remodeling occurring after 3 to 6 months of treatment predicts long-term benefit of CRT on mortality.

Sedation with midazolam for electrical cardioversion.

BACKGROUND: Electrical cardioversion (ECV) usually requires the assistance of the anesthesiology team. To avoid this dependence, previous studies have considered the use of sedation with benzodiazepines administered by cardiologists. We describe our experience with intravenous Midazolam during cardioversion. METHODS: We performed 280 ECV in 202 patients sedated with intravenous Midazolam, without anesthesiology supervision. In scheduled cardioversions, we tested two protocols of Midazolam administration: a bolus of 3 mg, followed by 2 mg each minute until necessary, and a loading dose of 0.09-0.1 mg/kg. In cardioversions performed during electrophysiology studies or defibrillator implant, Midazolam was administered by small repeated doses during the entire procedure. RESULTS: Midazolam was effective to obtain adequate sedation in 99% of cases. All patients had amnesia with regards of the cardioversion. A loading dose of Midazolam allowed a shortening of the procedural time without serious adverse events. Intubation or the assistance of an anesthetist was never necessary. CONCLUSION: Sedation with Midazolam for ECV is effective and well tolerated, with some cautions discussed. A loading dose of Midazolam is well tolerated and further reduces the procedural time.

A clinical and health-economic evaluation of pulmonary vein encircling ablation compared with antiarrhythmic drug treatment in patients with persistent atrial fibrillation (Catheter Ablation for the Cure of Atrial Fibrillation-2 study).

AIMS: Catheter Ablation for the Cure of Atrial Fibrillation 2 study is a prospective, randomized trial aimed to demonstrate the efficacy of catheter ablation with combined lesions in the right and left atria, in preventing atrial fibrillation (AF) recurrences among patients with recurrent persistent AF refractory to one antiarrhythmic drug, in comparison with the best pharmacological therapy. METHODS AND RESULTS: Enrolment is limited to patients aged between 18 and 70 years who have experienced at least one documented relapse of persistent AF during antiarrhythmic drug therapy. One hundred and twenty-six patients will be randomized to ablation or antiarrhythmic drug therapy in a 2 : 1 manner. In the ablation group, the patients will undergo right and left atrial linear ablation. Control group patients will be treated with the best antiarrhythmic drug. After an initial blanking period of 2 months patients will be followed for 24 months. Primary endpoint of the study is the absence of documented persistent atrial tachyarrhythmias relapse during the first 24 months after the blanking period. Enrolment is scheduled in 14 centres in Italy, UK, Austria, and Finland. Seventy-two patients have currently been enrolled. CONCLUSION: This study will provide important data about the efficacy of catheter ablation in comparison with antiarrhythmic drugs for the treatment of persistent AF.