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.

Catheter ablation of idiopathic ventricular tachycardia without the use of fluoroscopy.

BACKGROUND: Catheter ablation is the treatment of choice for many patients with idiopathic ventricular tachycardia (VT). Unfortunately, conventional catheter ablation is guided by fluoroscopy, which is associated with a small but definite radiation risk for patients and laboratory personnel. The aim of our study is to assess feasibility, success rate and safety of idiopathic VT ablation procedure performed without the use of fluoroscopy. METHODS: Nineteen consecutive patients undergoing idiopathic VT ablation at our institution have been included. The ablation procedures were performed under the guidance of electroanatomical mapping (EAM) system and intracardiac echocardiography (ICE). RESULTS: Nineteen patients (mean age 38.7 years) underwent ablation procedure for idiopathic VT. Twelve (63%) had outflow tract VT, 3 (18%) fascicular tachycardia, 2 (11%) peri-tricuspidal VT, 1 (5%) peri-mitral VT, and 1 (5%) lateral left free-wall VT. The mean procedural time was 170.2 ± 45.7 min. No fluoroscopy was used in any procedural phase. Acute success rate was 100%. No complication was documented in any patients. After a mean follow up of 18 ± 4 months, recurrences occurred in 2 patients. CONCLUSIONS: In our preliminary experience idiopathic VT ablation without the use of fluoroscopy was feasible and safe, using a combination of EAM and ICE. Success rate was excellent with no complication.

Which is the best catheter to perform atrial fibrillation ablation? A comparison between standard ThermoCool, SmartTouch, and Surround Flow catheters.

INTRODUCTION: Catheter ablation (CA) is an established therapy for atrial fibrillation (AF). The SmartTouch catheter (STc) provides information about catheter tip to tissue contact force (CF). The Surround Flow catheter (SFc) provides a uniform cooling of the tip during ablation. We sought to analyze the impact of STc and SFc on CA of paroxysmal AF in terms of feasibility and acute efficacy. METHODS AND RESULTS: Sixty-three patients (mean age 57.6 ± 9.8 years, 53 males) with paroxysmal AF underwent pulmonary veins (PVs) antral isolation, by using standard ThermoCool catheter (TCc) in 21, STc in 21, and SFc in 21. Total procedural, fluoroscopy, and radiofrequency (RF) delivery times; percentage of persistently deconnected PVs after 30 min; and percentage of isolated PVs at the end of the procedure were measured. The use of both STc and SFc obtained a reduction of fluoroscopy time (TCc 34 ± 18 min, STc 20 ± 10 min, p < 0.001; SFc 21 ± 13 min, p = 0.02 vs TCc) and RF time (TCc 41 ± 13 min, STc 30 ± 14 min, p = 0.013; SFc 30 ± 9 min, p < 0.01 vs TCc). The use of STc resulted in a reduction of procedural time (TCc 181 ± 53 min, STc 140 ± 53 min, p < 0.001; SFc 170 ± 51 min, p = NS vs TCc). The percentage of isolated PVs was comparable between groups (TCc 96 % vs STc 98 % vs SFc 96 %; p = NS). The percentage of deconnected PVs at 30 min was lower in TCc (89 %) than in STc (95 %) and in SFc (95 %) group (p < 0.05). CONCLUSIONS: Both STc and SFc allowed a simplification of CA of paroxysmal AF. In addition, they reduced early PVs reconnection. Sixty-three patients with paroxysmal AF underwent ablation by standard ThermoCool, SmartTouch, or Surround Flow catheter. Both the SmartTouch and the Surround Flow significantly reduced radiofrequency and fluoroscopy times, as well as pulmonary veins reconnection rate at 30 min. Moreover, the SmartTouch reduced overall duration of the procedure.

Impact of respiration on electroanatomical mapping of the right atrium: implication for cavotricuspid isthmus ablation.

PURPOSE: Cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFL) has become the preferred treatment for this arrhythmia. The aims of this study were to assess the impact of respiratory gating (RG) on electroanatomical mapping of CTI and to assess the efficiency of CTI ablation guided by the Carto3® system equipped with the new respiration gating software. METHODS: Forty-four consecutive patients (mean age, 60 ± 13 years; 25 male) undergoing cavotricuspid ablation for symptomatic common AFL were randomly assigned to CARTO™ mapping with or without enabling RG module (Group A, RG OFF, Group B, RG ON). RESULTS: A significant reduction in mean RA volume, CTI central length and CS ostium maximum diameter has been observed in the RG maps. The mean total procedural, fluoroscopy and radiofrequency (RF) time were 102.9 ± 35.3, 10.6 ± 3.3, 22.9 ± 14.2 min in group A and 75.3 ± 21.7, 3.6 ± 4.5, 10.4 ± 5.7 min in group B, respectively (p < 0.05). CONCLUSIONS: Electroanatomical mapping systems' accuracy may be strongly influenced by respiration movements. The current study showed that automatic respiratory gated acquisition resulted in a better visualization of CTI, and this determines a relevant reduction in fluoroscopy and RF times.

Catheter ablation of right atrial ganglionated plexi in patients with vagal paroxysmal atrial fibrillation.

BACKGROUND: Catheter ablation of ganglionated plexi (GP) in the left atrium has been proposed in different subgroup of patients with atrial fibrillation (AF). Anatomic studies found a high prevalence of GP in the posterior surface of the right atrium (RA). Experimental data suggested the potential role of right atrial GP in the AF initiation and maintenance. The aim of our study was to assess the efficacy of GP ablation in RA in patients with vagal AF. METHODS AND RESULTS: Thirty-four patients without structural heart diseases were randomly assigned for a selective ablation procedure targeted on the elimination of vagal reflex evoked by high frequency stimulation or an extensive approach at anatomic sites of GP. All patients underwent Holter ECG and heart rate variability evaluation at baseline and at 3, 6, 12, and 18 months of follow-up. At a mean follow-up of 19.7±5.2 months, AF recurred in 5 of 17 patients with anatomic ablation and in 13 of 17 patients with a selective approach (P=0.01). No patient had major complications. After ablation, heart rate variability parameters showed a significant parasympathetic (and sympathetic) denervation in the first 6 months, which was more prominent in patients with anatomic GP ablation and in those without AF recurrence. CONCLUSIONS: This study demonstrates that in a selected population of vagal paroxysmal AF, the anatomic ablation of GPs in the RA is effective in about 70% of patients. These results confirm that atrial vagal denervation can abolish AF, as suggested by experimental and clinical data.

Noncompacted ventricular myocardium: characterization by intracardiac echo.

We report a patient with clinical manifestation of arrhythmias and evidence of noncompacted myocardium in both left and right ventricular apex. The diagnosis was made with intracardiac echo performed during the electrophysiologic study. This method has allowed the diagnosis of noncompaction of the ventricular myocardium due to its high resolution. Color Doppler showed trabecular recesses in communication with the ventricular cavity that could not be identified with transthoracic echocardiography.

The new electroanatomical Carto3 mapping system: three-dimensional right ventricular fast anatomical map resolution in comparison to magnetic resonance image.

Three-dimensional mapping systems are required in some electrophysiological procedures in order to allow nonfluoroscopic catheter navigation, reconstruction of electrophysiological mechanisms, particularly of complex arrhythmias, and to facilitate catheter ablation. Accuracy in three-dimensional reconstructions of cardiac chambers is crucial to increase the effectiveness and safety of electrophysiological procedures. We report on the feasibility of the anatomical reconstruction of the right ventricular chamber by means of the new Carto3 system. The three-dimensional anatomical reconstruction of the right ventricle was compared to the magnetic resonance image of the same chamber.

Intracardiac echocardiography and electroanatomic mapping in diagnosis of arrhythmogenic right ventricular dysplasia.

A 48-year-old man with an episode of syncope and family history of sudden cardiac death was evaluated. The ECG showed negative T waves from V1 to V3 with evidence of epsilon-wave. Magnetic resonance imaging showed replacement with fibrofatty tissue in midapical regions of free wall of the right ventricle with dyskinesia. Transthoracic echocardiography revealed only mild enlargement of the middle right ventricular cavity. A programmed ventricular stimulation induced only an unsustained monomorphic ventricular tachycardia. Intracardiac echocardiography showed mild right ventricular enlargement and outflow dilatation (26 mm), microaneurysms with systolic bulging along the apical segment of the right ventricle. Bipolar voltage mapping, performed by the Carto system, detected a circumscribed low potential (<1.5 mV) area at the same level of the right ventricular apex. Cardiovascular imaging improves the detection of abnormal myocardial areas. Further studies are warranted to support this hypothesis.

Integration of MR images with electroanatomical maps: feasibility and utility in guiding left ventricular substrate mapping.

PURPOSE: The purpose of the study is to evaluate the feasibility and utility of magnetic resonance (MR) image and electroanatomic (EA) maps integration in guiding detailed left ventricle (LV) anatomical and substrate mapping, identifying the most accurate registration strategy. METHODS: Twenty-five patients with dilated ischemic or non-ischemic cardiomyopathy were enrolled. We first verified the feasibility and accuracy of EA mapping and MR image integration using four different strategies (15 patients). Different EA maps were performed according to the strategy in exam: aortic map, collected from the descending portion of the arch to the ascending one; partial or complete LV map, reconstructed with a minimum of 40 widely distributed points or 200 points, respectively. We then evaluated the utility in LV substrate mapping of the most accurate integration method identified (ten patients). RESULTS: Strategy III, based on aortic map and a partial LV map, allowed us to obtain an accurate integration with MR images of aorta and LV with a lower number of EA LV points; we therefore used this strategy during phase II of the study. Both mean LV end diastolic volume and long- and short-axis LV end diastolic diameters obtained by MR were not significantly different compared with Carto measurements. Eighty-eight percent of the segments with transmural/subendocardial scar detected by delayed enhanced MR were localized on bipolar voltage maps projected on MR-integrated images. CONCLUSION: This study shows that integration strategy III represents the optimal registration method. Its clinical utility consists on guiding the catheter roving inside the chamber, mapping all areas of the LV and optimizing scar reconstruction.

Pain perception during esophageal warming due to radiofrequency catheter ablation in the left atrium.

PURPOSE: We investigated the relationship among esophageal warming, pain perception, and the site of radiofrequency (RF) delivery in the left atrium (LA) during the course of catheter ablation of atrial fibrillation. Such a procedure in awake patients is often linked to the development of visceral pain and esophageal warming. As a consequence, potentially dangerous complications have been described. METHODS: Twenty patients undergoing RF ablation in the LA were studied. An esophageal probe (EP) capable of measuring endoesophageal temperature (ET) was positioned before starting the procedure. The relative position of the EP and the tip of the ablator were evaluated through fluoroscopy imaging before starting each RF delivery, during which the highest value of the temperature was collected. After RF withdrawal, the patients were asked to define the intensity of the experienced pain by using a score index ranging from 0 (no pain) to 4 (pain requiring immediate RF interruption). RESULTS: The mean ET value during ablation was 39.59 +/- 4.71 degrees C. The EP proximity to the ablator's tip showed a high correlation with the development of the highest ET values (Spearman's rank correlation coefficient r = 0.49, confidence interval (CI) 0.55-0.41). Moreover, the highest values of pain intensity were reported when the RF was delivered to the atrial zones close to the EP projection (r = 0.50, CI 0.55-0.42) and when the highest ET levels were reached (r = 0.38, CI 0.30-0.45). CONCLUSIONS: Pain perception in LA ablation is significantly related to esophageal warming and is higher when the RF is delivered near the esophagus. It seems advisable to perform ET monitoring in sedated patients to avoid short- and long-term jeopardizing of the esophageal wall.