Author + information
- Received March 13, 2017
- Revision received May 2, 2017
- Accepted June 1, 2017
- Published online July 24, 2017.
- Jin Iwasawa, MDa,
- Jacob S. Koruth, MDa,
- Jan Petru, MDb,
- Libor Dujka, MDb,
- Stepan Kralovecb,
- Katerina Mzourkovab,
- Srinivas R. Dukkipati, MDa,
- Petr Neuzil, MD, PhDb and
- Vivek Y. Reddy, MDa,b,∗ ()
- aHelmsley Electrophysiology Center, Mount Sinai Medical Center, New York, New York
- bNa Homolce Hospital, Prague, Czech Republic
- ↵∗Address for correspondence:
Dr. Vivek Y. Reddy, Helmsley Electrophysiology Center, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, PO Box 1030, New York, New York 10029.
Background Saline irrigation improved the safety of radiofrequency (RF) ablation, but the thermal feedback for energy titration is absent.
Objectives To allow temperature-controlled irrigated ablation, a novel irrigated RF catheter was designed with a diamond-embedded tip (for rapid cooling) and 6 surface thermocouples to reflect tissue temperature. High-resolution electrograms (EGMs) from the split-tip electrode allowed rapid lesion assessment. The authors evaluated the preclinical and clinical performance of this catheter for pulmonary vein (PV) isolation.
Methods Using the DiamondTemp (DT) catheter, pigs (n = 6) underwent discrete atrial ablation in a temperature control mode (60°C/50 W) until there was ∼80% EGM amplitude reduction. In a single-center clinical feasibility study, 35 patients underwent PV isolation with the DT catheter (study group); patients were planned for PV remapping after 3 months, regardless of symptomatology. A control group included 35 patients who underwent PV isolation with a standard force-sensing catheter.
Results Porcine lesion histology revealed transmurality in 51 of 55 lesions (92.7%). In patients, all PVs were successfully isolated; no char or thrombus formation was observed. Compared with the control group, the study cohort had shorter mean RF application duration (26.3 ± 5.2 min vs. 89.2 ± 27.2 min; p < 0.001), shorter mean fluoroscopic time (11.2 ± 8.5 min vs. 19.5 ± 6.8 min; p < 0.001), and lower acute dormant PV reconduction (0 of 35 vs. 5 of 35; p = 0.024). At 3 months, 23 patients underwent remapping: 39 of 46 PV pairs (84.8%) remained durably isolated in 17 of these patients (73.9%).
Conclusions This first-in-human series demonstrated that temperature-controlled irrigated ablation produced rapid, efficient, and durable PV isolation. (ACT DiamondTemp Temperature-Controlled and Contact Sensing RF Ablation Clinical Trial for Atrial Fibrillation [TRAC-AF]; NCT02821351)
Pulmonary vein (PV) isolation is the mainstay of catheter ablation for patients with atrial fibrillation (AF) (1). Technological advances, such as balloon catheters to facilitate PV isolation, are increasingly being used (2,3). However, point-by-point radiofrequency (RF) ablation catheters remain the most frequently used technology, largely because of the greater flexibility of the lesion set that can be deployed. Although conceptually straightforward, placing contiguous and transmural point-by-point RF lesions around the PVs is technically challenging. This is supported by the reported near-universal presence of PV reconnections in redo-AF ablation cases and the low rate of durable PV isolation observed in the GAP-AF study (4–7). From a safety perspective, the advent of saline irrigation has decreased the incidence of thrombus and char formation on the ablation tip. However, saline irrigation on current ablation catheters also precludes temperature feedback, so these catheters are typically operated in a power control mode.
It is in this context that we investigated the DiamondTemp (DT) ablation catheter (Advanced Cardiac Therapeutics, Inc., Santa Clara, California), a composite-tip, diamond-embedded, temperature-sensing, saline-irrigated RF ablation catheter. The catheter has 6 insulated thermocouples on the ablation tip surface to directly measure the tissue surface temperature, thereby potentiating temperature-guided irrigated ablation. To provide rapid diffusion of heat, the ablation tip is embedded with industrial-grade diamond, a material with a thermal diffusivity that is 2 orders of magnitude higher than platinum. Finally, instead of the standard 3.5- or 4-mm distal ablation electrode, the DT catheter distal electrode is a composite tip to provide higher resolution electrograms (EGMs). During RF delivery, the composite tip behaves as a single RF electrode. Herein, we report our pre-clinical and first-in-human clinical experience using this novel temperature-controlled irrigated RF ablation catheter.
This catheter was evaluated in 2 phases. The pre-clinical phase involved electrophysiological and histological assessment of ablation lesions created by this catheter in a series of porcine experiments. The clinical phase involved a single-center evaluation in the TRAC-AF (ACT DiamondTemp Temperature-Controlled and Contact Sensing RF Ablation Clinical Trial for Atrial Fibrillation) trial. In this prospective first-in-human study, patients underwent PV isolation with the DT catheter to treat paroxysmal AF, along with a pre-specified PV remapping procedure at ∼3 months regardless of intervening symptomatology. Thus, in addition to the acute procedural performance of the catheter, we also assessed the 3-month durability of electrical PV isolation. With regard to the procedural performance, the TRAC-AF outcomes were compared with another retrospective cohort of patients with paroxysmal AF who underwent PV isolation using a standard force-sensing irrigated catheter at Mount Sinai Hospital (New York, New York).
The preclinical experiments were approved by the Institutional Animal Care and Use Committees at Mount Sinai Hospital, and the clinical phase was approved by the human ethics committee at Homolka Hospital, Prague, Czech Republic, and by the Czech Republic Competent Authority, SUKL (State Institute for Drug Control). Written informed consent was obtained from all patients. The authors had full access to and take full responsibility for the integrity of the data, and agree to this paper as written.
The diamond-tip irrigated DT catheter is a 7.5-F externally irrigated catheter designed to deliver RF energy via a 4.1-mm catheter tip electrode (Figure 1). The tip segment consists of a composite tip electrode and 2 ring electrodes, all made of platinum-iridium. Unique to the catheter’s design, the 2-part composite ablation electrode tip is embedded with 2 industrial-grade diamonds, interconnected at the distal tip electrode, which allow rapid heat shunting by virtue of their high thermal diffusivity. This permits accurate temperature estimation along the entire length of the electrode. The distal aspect of the composite electrode is 0.6 mm and has 6 irrigation ports. By allowing effective cooling, the diamonds reduce the irrigation rate to 8 ml/min during ablation. Although the dual composite ablation tip acts as a single electrode during ablation, the 2 aspects of this tip are electrically insulated to allow for high-resolution EGM sensing separately.
Finally, there are 3 surface thermocouples at the distal end and 3 thermocouples at the proximal end to monitor the tip−tissue interface temperature during irrigated ablation (Figure 1). A custom RF generator (Advanced Cardiac Therapeutics) delivers RF energy in a temperature-control mode. The temperature recording capability was validated in a bench-top model consisting of irrigated ablation on fresh porcine hearts. Temperature sensors were inserted into the target tissue adjacent to the ablation catheter. The catheter temperature was set to 55°C and 60°C (i.e., maximum surface thermocouple temperature) with contact force (CF) between 12 and 15g, and ablation performed in temperature-control mode. In a series of 20 ablation runs, the average study catheter set temperature of 58.5°C corresponded to a mean tissue temperature of 64.2°C at 1-mm depth. This difference between the surface recording and recording at 1-mm depth was consistent with the nature of irrigated ablation that drives the hot spot of RF ablation deeper into the tissue.
After an overnight fast, percutaneous venous access was obtained in 6 pigs; transseptal puncture was performed after heparinization. A deflectable sheath was advanced into the atria, and a total of 70 ablation applications were delivered at randomly selected, disparate sites in both atria in temperature control mode to 60°C (maximum power: 50 W) until an ∼80% reduction was seen in the amplitude of the composite-tip EGM. Individual ablation lesions were anatomically defined based on electroanatomic maps, intracardiac echocardiography, and fluoroscopic guidance. The animals recovered for 7 days and then were killed. The explanted heart and surrounding tissue were subjected to gross examination, with individual lesions identified based on their anatomical position so that they could be correlated to the corresponding stored RF parameters. The explanted hearts were immersion-stained with triphenyl tetrazolium chloride. After identification, all lesions were submitted for histological analysis with hematoxylin and eosin and Masson’s trichrome staining. Lesion depth and overall myocardial thicknesses were assessed on histology.
TRAC-AF was designed as a prospective, open-label, nonrandomized, single-center study of patients with symptomatic paroxysmal AF. Patients age 18 to 75 years were entered into the study if they had paroxysmal AF refractory to at least 1 antiarrhythmic drug. Key exclusion criteria included previous PV isolation procedure, cardiac surgery in the previous 3 months, moderate-to-severe valvular disease, left ventricular ejection fraction <30%, left atrium diameter >6 cm, contraindications to long-term antithrombotic therapy, and severe pulmonary disease. Consecutive patients (the study group) underwent ablation with the DT irrigated catheter at Homolka Hospital (Prague, Czech Republic) between January 2016 and March 2016. These ablation procedures were performed by 2 operators (V.R., P.N.).
Patients were discharged the day after ablation if clinical status was stable and anticoagulation was uninterrupted. Post-procedure antiarrhythmic medications were either discontinued or reduced in dosage for 1 month, after which they were completely discontinued. There was a 1-month blanking period after ablation. The follow-up at 7 days was conducted over the phone to assess if any adverse events had occurred. Post-procedure clinic visits were performed at 3 and 6 months, including 12-lead electrocardiograms. All patients were required to wear a Holter monitor for 24 h before their first visit, followed by an event monitor for 2 weeks at 3 and 6 months.
At ∼3 months after the index procedure, patients underwent a repeat procedure to assess for PV reconnection, regardless of the intervening symptomatology. During this procedure, the durability of PV isolation was assessed with a circular mapping catheter. If PV reconnection was identified, the DT catheter was used to ablate the site(s) of breakthrough to achieve re-isolation.
As a comparator for procedural performance, we examined an additional cohort of 35 consecutive paroxysmal AF patients (the control group) who underwent ablation with a CF-sensing irrigated tip catheter (Thermocool SmartTouch, Biosense Webster Inc., Irvine, California) at Mount Sinai Hospital by a single operator (V.R.) between July 2015 and April 2016.
The study procedures were performed under either conscious sedation (n = 34) or general anesthesia (n = 3). Double transseptal punctures were performed, and the ablation catheter was placed within a deflectable sheath (Agilis, St. Jude Medical, Minneapolis, Minnesota). Intracardiac echocardiography and esophageal temperature monitoring were performed in all cases; ablation was terminated if temperatures reached 38.5°C. Ipsilateral PVs were isolated with wide-area circumferential antral ablation lesion sets guided by electroanatomic mapping (NavX, St. Jude Medical) (Figure 2). PV isolation was achieved with interrupted point-by-point ablation (dragging was not permitted in this study). As per our usual practice, a double ablation line was placed along the anterior aspect of the lesion set of the right PVs.
The contact level was assessed by the operator using traditional criteria (e.g., EGMs, catheter motion, proximity to the electroanatomical map surface, intracardiac ultrasound imaging) because CF monitoring was not available. Each lesion was delivered in a temperature control mode set to 60°C (maximum: 50 W) until a 75% to 80% reduction in the split-tip EGM amplitude occurred, followed by ablation for an additional 3 to 5 s. The goal temperature was reduced to 50°C when ablating posteriorly in proximity to the esophagus. The saline irrigation rate was 2 ml/min during mapping and 8 ml/min during ablation. Additional ablation for atrial flutter was permitted if it occurred spontaneously or was induced during the procedure.
All control group procedures were also performed under general anesthesia, using a different electroanatomical mapping system (CARTO, Biosense Webster Inc.) and a CF-sensing catheter (Thermocool SmartTouch, Biosense Webster Inc.). Automatic lesion annotation software (Visitag, Biosense Webster Inc.) was set to stability, with a minimum time of 8 s and maximum range of 2 mm, and a minimum force of 6g >50% of the time. RF energy was delivered by an interrupted point-by-point ablation technique in power-control mode (power typically at 35 W and irrigation at 30 ml/min). The goal CF during ablation was >10g. Contralateral esophageal deviation was used during these procedures (8). In instances when the esophagus was in closer proximity to the point of ablation, ablation was stopped if esophageal temperatures reached 38.5°C. As per our usual practice, a cavo-tricuspid ablation line was routinely placed.
For both the study and control groups, after confirmation of PV isolation using multipolar circular mapping catheters, 18 mg intravenous adenosine was administered. The occurrence of 1 blocked P-wave or a sinus pause confirmed an effective adenosine dose. Sites of dormant electrical conduction were recorded, and supplementary RF energy was delivered to eliminate dormant conduction.
Continuous variables are expressed as mean ± SD, and categorical variables as frequency (percentage). We used chi-square tests to compare the categorical variables, and the 2-sample Student t test was used to compare normally distributed continuous variables. The Mann-Whitney U test was used to compare the continuous variables that were not normally distributed. A p value <0.05 was considered statistically significant. Statistical analysis was performed using SPSS Statistics 23 (IBM, Armonk, New York).
A total of 70 discrete RF energy applications were delivered to the atria. When the animals were killed 7 days later, 6 lesions were not found on examination; the biophysical parameters and lesion dimensions of the remaining 64 lesions are shown in Table 1. The average lesion area, as measured on the endocardial surface, was 23.4 ± 14.1 mm2. These dimensions and transmurality rates were achieved in 13.3 ± 6.0 s of RF time (range: 5 to 32 s). The split-tip EGM amplitude reduction from baseline at the end of the lesion (Figure 3A) was noted to be 74.9 ± 12.0%. Of the 64 lesions, histological specimens were of sufficient quality for analysis in 55 lesions (30 left atria, 25 right atria). The mean tissue thickness (measured on histology) was 1.9 ± 0.9 mm (range: 0.5 to 4.2 mm), and transmural necrosis occurred in 92.7% (51 of 55 lesions) (Figure 3B). No steam pops, char formation, or increases in impedance occurred during ablation.
In the study cohort, a total of 37 patients were enrolled (Figure 4A). However, 2 patients did not undergo ablation with the DT catheter; in 1 patient, because the atrium was so extensively scarred that ablation would have been futile, and for the other, because of a technical fault with the mapping system (not the DT catheter), which resulted in the use of a balloon catheter for ablation. Thus, the analyzed patients in the study cohort included 35 patients; a corresponding group of 35 patients were included in the control cohort.
Per baseline clinical characteristics (Table 2), the mean ages of the study and control cohorts were 60 ± 10 and 63 ± 11 years, respectively; most were men. Left ventricular function was preserved, and the main comorbidity was hypertension.
In the study cohort, 13 of 35 subjects (37.1%) were in AF at the beginning of the procedure; all others were in sinus rhythm. Acute PV isolation was achieved in all patients in both groups. The shorter mean duration for each RF lesion in the study group (p < 0.001) suggested that EGM diminution occurred faster with the DT catheter (Table 3). Similarly, the RF application time for PV isolation was significantly lower for the study group than for the control group (p < 0.001). This translated to a 70% reduction in total RF time. In the study group, dormant conduction with adenosine provocation was not present in any (0%) of the 35 patients (70 PV pairs). However, in the control group, dormant conduction was unmasked in 5 of 35 patients (14%; 5 of 70 PV pairs; p = 0.024 vs. study group).
With regard to other procedural characteristics, of all the individual lesions made in the study group, 76% of lesions had an impedance drop of >10 Ω (Table 3). The mean CF per ablation lesion in the control group was 24.8 ± 4.0g. In the study group, 3 patients underwent additional ablation for atrial flutter (2 atypical left atrial flutters and 1 typical cavotricuspid flutter). In the control group, 33 patients underwent cavotricuspid isthmus ablation as part of a routine strategy (i.e., empiric cavotricuspid isthmus ablation). The overall mean fluoroscopy time in the study group was also significantly lower than the control group (p < 0.001). The overall amount of saline infused through the DT catheter was only 384 ± 71 ml; the saline infused for the control group cases was not recorded.
There were no occurrences of char formation or steam pop occurrence in the study group. In this group, a mean of 5.8 RF applications per patient demonstrated a luminal esophageal temperature rise of >38.5°C. One study group patient developed a delayed pericardial effusion 8 h after the procedure; this was drained, and the patient was discharged. A few weeks later, the same patient returned with recurrent pericardial effusion that was again drained. No further accumulation occurred, and the patient did well in follow-up. The exact etiology of this effusion was unclear; during the procedure, there were no instances of audible pops, and at the end of the procedure, the intracardiac echocardiography catheter was used to document the absence of any pericardial effusion.
PV remapping and follow-up
Of the 35 study group patients, 23 (66%) agreed to undergo PV remapping, at a mean of 128 ± 57 days (range: 57 to 229 days) after the index ablation procedure. Three patients had left common veins, whereas all other subjects had 4 PVs each, resulting in a total of 89 PVs analyzed. Durable PV isolation was noted in 39 of 46 PV pairs and 80 of 89 PVs; this translated to durable isolation rates of 84.8% on a per PV pair basis and 89.9% on a per PV basis. The distribution of PV reconnections were 2 in the left superior PV, 1 left inferior PV, 2 right inferior PVs, and 4 right superior PVs. The focal areas of PV reconnection were identified in 6 of 9 PVs (Figure 4B); the precise areas of PV reconnections were not accurately determined for the other 3 PVs. On a per-patient basis, 17 of 23 patients (73.9%) demonstrated durable PV isolation during this remapping procedure.
At 6-month follow-up, AF was recorded on the event recorder in 7 of 35 patients (20%). Five of these patients with clinical recurrence were remapped; however, 19 of 20 PVs in these 5 patients had been durably isolated, suggesting a non-PV trigger for the AF. Two months following the ablation procedure, 1 patient died; a post-mortem examination indicated that the cause of death was systolic heart failure related to coronary artery disease. This was adjudicated to be unrelated to either the procedure or study catheter. No other complications were noted in any other subjects.
Irrigated RF ablation was introduced to minimize the frequency of thrombus or char formation, and the subsequent risk of embolic stroke during left-sided ablation. However, saline irrigation rendered the use of temperature as a feedback to control the titration of power during thermal RF ablation impossible. We reported the initial preclinical and first-in-human experiences with a novel catheter designed with an array of thermocouples situated directly at the tip−tissue interface to permit reintroduction of temperature-controlled, saline-irrigated RF ablation.
In the preclinical experiments, 75% reduction in voltage was achieved with 13.3 ± 6.0 s of RF, and we demonstrated a transmurality rate of 92.7%. This approach to rapid lesion creation was then tested clinically in 35 patients who underwent PV isolation; 100% acute isolation was achieved efficiently with 26.3 ± 5.2 min of RF application time per patient. There were no instances of dormant reconduction with adenosine, and the 3-month durable isolation rates on a per-vein pair and per-patient basis were 85% and 74%, respectively.
RF-based PV isolation
Currently available approaches to PV isolation using RF can be broadly separated into 2 categories: 1) point-by-point RF ablation to create peri-venous circumferential lesions sets (9); and 2) “1-shot” PV isolation approaches using either balloons or multipolar catheters (9–12). Although 1-shot ablation approaches are less dependent on operator expertise, they are largely limited by their ostial level of PV isolation and their inability to target discrete non-PV sites (13). Conversely, point-by-point irrigated RF ablation has the flexibility to provide both a wide antral isolation and the ability to perform extra PV ablation. However, this approach is almost universally delivered in a power-control mode, which is widely acknowledged to be laborious. Despite advances, such as force sensing and use of indirect lesion assessment tools (e.g., force−time integral and ablation index), PV isolation requires significant time and skill. Furthermore, an unacceptably high incidence of chronic PV reconnections remains: ∼70% of patients had PV reconnections at ∼3 months post-ablation in the GAP-AF study (7). Inadequate rates of durable PV isolation in the post-force sensing era can be explained by either discontinuous lesion placement and/or inadequate lesion formation. The latter, in particular, is sensitive to creating consistently wide and deep enough lesions. It is reasonable to speculate that improvements in lesion formation would translate into improvements in the durability of PV isolation. In addition, if such lesions can be formed quickly, the currently laborious point-by-point ablation technique may change to a more efficient approach.
In this study, we evaluated a unique catheter design that allowed for reliable measurement of catheter−tissue interface temperatures despite the presence of an irrigated tip, which is now broadly accepted to be essential for any left-sided ablation (Central Illustration). Interface temperatures reflect the degree of catheter-tissue coupling and can therefore provide an estimate of the tissue temperature within a lesion. Therefore, by design, temperature could be made part of a feedback loop (temperature control) to allow automated titration of power based on catheter−tissue coupling. This has potential advantages over the current approach of empiric power-controlled ablation. That is, fixed power in the setting of varying CF and catheter stability may result in inconsistent lesions. With the dynamic nature of force and stability, automated titration of power in conditions of excessive or poor catheter−tissue contact and stability should result in more efficient, reliable, and safe lesion formation.
This catheter also has 2 additional features to improve ablation efficiency: 1) a diamond heat shunt tip ablative segment; the high thermal diffusivity of diamond allows for both rapid detection of temperature changes to improve temperature feedback, as well as homogenous and improved cooling of the tip; and 2) a composite tip for EGM recording; this high-resolution EGM might be better at monitoring lesion formation. This composite-tip EGM helps the operator to determine when to terminate ablation and minimize collateral injury. From a safety standpoint, both steam pop or perforation and char formation are related to higher tip temperatures; accordingly, it is expected these will be less frequent with temperature control.
Although our data were limited by the relative thinness of porcine atria, we demonstrated a high rate (93% sections) of transmurality without pop or char formation. This was achieved using a strategy of discontinuing RF once significant EGM reduction was achieved. The ability to achieve transmurality in ∼13 s indicated that adequate lesion formation could be rapidly achieved with good safety in thin tissues. The efficiency of combining temperature-controlled power titration with composite-tip EGM reduction is highlighted in Figure 5—a porcine “drag” lesion in which an endocardial ablation line was placed between the superior and inferior vena cavas. Together, these data provided the experimental basis for the clinical phase of evaluation.
In the TRAC-AF clinical study, despite significantly reduced RF times, we demonstrated that acute PV isolation was achieved in 100% of cases without any evidence of dormant conduction upon adenosine challenge, which underscored the overall efficiency of temperature-controlled RF delivery (mean duration for each RF lesion was 18 s). The RF times in the study arm (26.3 ± 5.2 min) were 70% lower than our control arm (89.2 ± 27.2 min).
The clinical strategy used in the control arm involved ablation until a pre-determined endpoint based on the automatic lesion annotation software. Furthermore, we typically included redundant lesions along sites of thick atrial tissue (such as anterior to the right PVs), poor stability, and sites of frequent reconnections. This led to our control arm demonstrating significantly longer RF times than those observed in other contemporary paroxysmal AF ablation studies, such as the TOCCASTAR (TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation) and the Heartlight (CardioFocus, Marlborough, Massachusetts) multicenter clinical trials (47 and 50 min, respectively) (Figure 6) (3,14). However, even if we were to compare the study arm with these other studies, the RF time reductions (44% and 47%) were still substantial. Furthermore, and most importantly, during the remapping study, 39 of 46 PV pairs (84.8%) or 80 of 89 PVs (89.9%) remained electrically isolated, translating to 17 of 23 patients (73.9%) with durable PV isolation. These data compared favorably with other remapping studies, such as the EFFICAS II (TactiCath Prospective Effectiveness Pilot Study) study, in which 85% of PVs were durably isolated during a long-term remapping study (15).
Importantly, from a safety perspective, there were no instances of thrombus or char detected on the ablation catheter tip, nor any observed instances of audible pops. However, 1 patient developed delayed tamponade 8 h after the procedure. Although this effusion was, of course, related to the ablation procedure, it was curious that there was no evidence of peri-cardial effusion at the end of the procedure by intracardiac echocardiographic imaging.
This was a nonrandomized comparison, and therefore, it was subject to potential bias. Because of its nonrandomized design, it was unknown if fixed power (35 W) and short duration (∼18 s) might have resulted in similar outcomes. In addition, this was a small study from a single center, and the study patients underwent the procedure by a single expert operator; therefore, the generalizability of the results was limited. Further experience with this catheter in multicenter studies is needed to more accurately determine its efficacy and safety. Also, the 3-month time point for the remapping study did not address the possibility of PV reconnection at later time points.
Catheter tip−surface thermocouples permitted safe and effective temperature-controlled, saline-irrigated RF ablation. Using this power titration strategy, the first-in-human TRAC-AF clinical series demonstrated that rapid and durable PV isolation was achievable. These data usher back an era of facile, efficient temperature-controlled irrigated RF ablation during PV isolation.
COMPETENCY IN PATIENT CARE AND PROCEDURAL SKILLS: Irrigation facilitates RF ablation and reduces embolic events by cooling the catheter tip during thermal energy transfer, but it also impedes temperature-guided titration of energy delivery to endocardial tissue. Application of surface thermocouples at the tip of an irrigated catheter improved temperature-controlled energy titration, which enabled safe and effective ablation.
TRANSLATIONAL OUTLOOK: Randomized studies are needed to compare the outcomes of ablations procedures performed with temperature-guided catheters and conventional instruments.
Drs. Koruth and Neuzil have received research grant support from Advanced Cardiac Therapeutics, Inc. Dr. Reddy has served as a consultant to and has received research grant support from Advanced Cardiac Therapeutics, Inc. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Andrea Natale, MD, served as Guest Editor for this paper.
- Abbreviations and Acronyms
- atrial fibrillation
- contact force
- pulmonary vein
- Received March 13, 2017.
- Revision received May 2, 2017.
- Accepted June 1, 2017.
- 2017 American College of Cardiology Foundation
- Calkins H.,
- Kuck K.H.,
- Cappato R.,
- et al.
- Dukkipati S.R.,
- Cuoco P.,
- Kutinsky I.,
- et al.
- Ouyang F.,
- Antz M.,
- Ernst S.,
- et al.
- Kuck K.H.,
- Hoffman B.A.,
- Emst S.,
- et al.
- Van Belle Y.,
- Janse P.,
- Rivero-Ayerza M.J.,
- et al.
- Reddy V.Y.,
- Neuzil P.,
- Themistoclakis S.,
- et al.
- Scaglione M.,
- Caponi D.,
- Anselmino M.,
- et al.
- Reddy V.Y.,
- Neuzil P.,
- d’Avila A.,
- et al.
- Reddy V.Y.,
- Dukkipati S.R.,
- Neuzil P.,
- et al.
- Kautzner J.,
- Neuzil P.,
- Lambert H.,
- et al.