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Radiofrequency Energy (radiofrequency + energy)
Selected AbstractsLinear Ablation with Duty-Cycled Radiofrequency Energy at the Cavotricuspid IsthmusPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2010STEFANIE BOLL Background: Multielectrode catheters using duty-cycled radiofrequency (RF) have been developed to treat atrial fibrillation (AF). Many of these patients also have atrial flutter. Therefore, a linear multielectrode has been developed using the same RF energy. Objective: The concept and acute results of linear ablation using duty-cycled RF were tested in the cavotricuspid isthmus (CTI). Methods: The CTI was targeted in 75 patients, in 68 (90%) among them as an adjunct to AF ablation with the same technology. A linear electrode catheter with a 4-mm tip and five 2-mm ring electrodes was connected to a generator titrating duty-cycled RF at 20,45 W up to a target temperature of 70°C in 1:1 unipolar/bipolar mode. Results: During a mean procedure time of 20 ± 12 minutes, complete CTI block was achieved by 4 ± 3 applications of duty-cycled RF in 69 (92%) patients. No more than three RF applications were necessary in 60% of patients. During the initial learning curve, standard RF had to be used in five (7%) patients. Complete block was not achieved in one patient with frequent episodes of AF. Char was observed in five (7%) patients with poor electrode cooling; consequently, the temperature ramp-up was slowed and manually turned off in the event of low-power delivery. Two groin hematomas occurred; otherwise, no clinical complications were observed. Conclusion: Multielectrode catheters delivering duty-cycled RF can effectively ablate the CTI with few RF applications with promising acute results. Further modifications are necessary to improve catheter steering and prevent char formation. (PACE 2010; 444,450) [source] Sequential Ablation of Orthodromic Atrioventricular Tachycardia and Ectopic Atrial Tachycardia with a Single Application of Radiofrequency EnergyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p1 2003NORIHIRO KOMIYA KOMIYA, N.,et al.: Sequential Ablation of Orthodromic Atrioventricular Tachycardia and Ectopic Atrial Tachycardia with a Single Application of Radiofrequency Energy. A 62-year-old woman with Wolff-Parkinson-White syndrome had two types of tachycardia; ectopic AT and orthodromic-type AVRT. A radiofrequency application 2 cm inside the coronary sinus ostium eliminated ectopic AT and accessory pathway conduction at once. (PACE 2003; 26[Pt. I]:108,109) [source] Electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia arising from para-Hisian regionINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 3 2007Y. Zhou Summary This study describes the electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia (AT) arising from para-Hisian region in 14 (6.0%) patients of a consecutive series of 224 patients patients. Inverted or biphasic P wave in V1 and uncharacteristic P wave in inferior leads were observed during tachycardia, suggesting that there isn't a characteristic P-wave morphology for para-Hisian AT. During electrophysiological study, tachycardia could be induced with programmed atrial extrastimuli in 11 patients while a spontaneous onset and offset with ,warm-up and cool-down' phenomenon were seen in other three patients. Moreover, the tachycardias were sensitive to intravenous administration of adenosine triphosphate in all patients. On the basis of these findings, the mechanism is suggestive of triggered activity or micro-reentry, but automaticity cannot be conclusively excluded. Radiofrequency energy was delivered to the earliest site of atrial activation during AT. Ablating energy was carefully titrated, starting at 5 W and increasing gradually upto a maximum of 40 W, to achieve the ceasing of tachycardia. The long-term outcome was a 100% success rate in these 14 patients and there were no irreversible complications associated with ablation. Thus, the mapping and ablation of focal AT arising from para-Hisian region is safe and effective, delivery of radiofrequency energy in a titrated manner and continuous monitoring of atrioventricular (AV) conduction advocated to minimise the risk of damage to the anterograde AV conduction. [source] ATP-Induced Dormant Pulmonary Veins Originating from the Carina Region After Circumferential Pulmonary Vein Isolation of Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2010KOJI KUMAGAI M.D., Ph.D. Dormant Pulmonary Veins from the Carina Region.,Introduction: Elimination of transient pulmonary vein recurrences (dormant PVs) induced by an ATP injection and ablation at the PV carina region is an effective strategy for atrial fibrillation (AF) ablation. The relationship between dormant PVs and the PV carina region has not been evaluated. Methods: A total of 212 consecutive symptomatic AF patients underwent circumferential PV electrical isolation (CPVEI) with a double lasso technique. They were divided into 2 groups in a retrospective review; Group 1: those given an ATP injection during an intravenous isoproterenol infusion after the CPVEI (n = 106), and Group 2: those in which it was not given after the CPVEI (n = 106). Radiofrequency energy was applied at the earliest dormant PV activation site identified using a Lasso catheter on the CPVEI line and then PV carina region if it was ineffective. Results: After a successful PVEI, 54 patients (51%) in Group 1 had PV reconnections during an ATP injection. Acute PVEI sites were observed on the carina region within the CPVEI line in the right PVs (16%) and left PVs (10%). Dormant PVs were reisolated at the carina region in the right PVs (23%) and left PVs (26%). The distribution of the dormant PV sites, except for the RIPV, significantly differed from that of the acute PVEI sites (P < 0.05). Further, AF recurred significantly in the Group 2 patients as compared to those in Group 1 during 16 ± 6.1 months of follow-up (P < 0.05). Conclusion: PV carina region origins may partly be responsible for an acute PVEI and potential recurrences. (J Cardiovasc Electrophysiol, Vol. 21, pp. 494-500, May 2010) [source] Clinical Implications of Reconnection Between the Left Atrium and Isolated Pulmonary Veins Provoked by Adenosine Triphosphate after Extensive Encircling Pulmonary Vein IsolationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2007HITOSHI HACHIYA M.D. Introduction: Dormant pulmonary vein (PV) conduction can be provoked by adenosine triphosphate (ATP) after extensive encircling pulmonary vein isolation (EEPVI). However, the clinical implication of reconnection between the left atrium (LA) and isolated PVs provoked by ATP (ATP-reconnection) remains unknown. Methods and Results: We studied the clinical consequences of ATP-reconnection during intravenous isoproterenol infusion (ISP-infusion). EEPVI severs conduction between the LA and ipsilateral PVs at their junction. Radiofrequency energy is applied at a distance from the PV ostia guided by double Lasso catheters placed within the ipsilateral superior and inferior PVs. This study comprised 82 patients (67 men, 56 ± 9 years old) with atrial fibrillation (AF) who underwent injection of ATP during ISP infusion after successful EEPVI (ATP(+) group). We compared clinical characteristics of 170 patients who underwent earlier EEPVI prior to our use of ATP injection after successful EEPVI (ATP(N/D) group) with those of ATP(+) group patients who underwent one session of EEPVI. ATP-reconnection occurred in 34 (41%) of 82 ATP(+) group patients. Additional radiofrequency applications were performed to eliminate ATP-reconnection in all ipsilateral PVs. Continuous ATP-reconnection of more than 20 seconds duration occurred in six (7.3%) of 82 patients. A total of 102 (60%) of 170 patients in the ATP(N/D) group had no recurrence of AF, whereas 60 (73%) of 82 ATP(+) group patients who underwent only one EEPVI session have had no recurrence of AF in a 6.1 ± 3.3-month follow-up period (P = 0.04). Conclusion: Radiofrequency application for provoked ATP-reconnection may reduce clinical AF recurrence. [source] Electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia arising from para-Hisian regionINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 3 2007Y. Zhou Summary This study describes the electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia (AT) arising from para-Hisian region in 14 (6.0%) patients of a consecutive series of 224 patients patients. Inverted or biphasic P wave in V1 and uncharacteristic P wave in inferior leads were observed during tachycardia, suggesting that there isn't a characteristic P-wave morphology for para-Hisian AT. During electrophysiological study, tachycardia could be induced with programmed atrial extrastimuli in 11 patients while a spontaneous onset and offset with ,warm-up and cool-down' phenomenon were seen in other three patients. Moreover, the tachycardias were sensitive to intravenous administration of adenosine triphosphate in all patients. On the basis of these findings, the mechanism is suggestive of triggered activity or micro-reentry, but automaticity cannot be conclusively excluded. Radiofrequency energy was delivered to the earliest site of atrial activation during AT. Ablating energy was carefully titrated, starting at 5 W and increasing gradually upto a maximum of 40 W, to achieve the ceasing of tachycardia. The long-term outcome was a 100% success rate in these 14 patients and there were no irreversible complications associated with ablation. Thus, the mapping and ablation of focal AT arising from para-Hisian region is safe and effective, delivery of radiofrequency energy in a titrated manner and continuous monitoring of atrioventricular (AV) conduction advocated to minimise the risk of damage to the anterograde AV conduction. [source] Experimental Efficacy of Pericardial Instillation of Anti-inflammatory Agents during Percutaneous Epicardial Catheter Ablation to Prevent Postprocedure PericarditisJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2007ANDRE D'AVILA M.D. Introduction: Pericarditis is a potential complication of catheter-based percutaneous epicardial mapping and ablation. This study evaluates the efficacy and safety of intrapericardial instillation of anti-inflammatory agents after pericardial mapping and ablation in a porcine model of postprocedural pericarditis. Methods and Results: Twenty-five healthy swine underwent epicardial mapping and ablation after transthoracic subxyphoid puncture. After 60 minutes of continuous catheter manipulation in the pericardial space, radiofrequency energy was delivered in a linear fashion to the epicardial surfaces of both atria. The animals were randomly divided to receive the anti-inflammatory agents, Hyaluronic Acid and Triamcinolone, or control. Fourteen days after ablation, the hearts were excised and the degree of pericardial reaction/adhesions scored. The severity was uniformly graded 4 (intense) in all control animals and was characterized by intense adhesion between the parietal and the visceral pericardium obscuring tissue planes and epicardial anatomy. Hyaluronic Acid provided a mild benefit (score 3.0 ± 0.9), but 2 mg/kg of Triamcinolone significantly attenuated the inflammatory effect (all animals uniformly scored 1.0). Conclusion: In a porcine model of ablation-related pericarditis, intrapericardial instillation of 2 mg/kg of intermediate-acting corticosteroids effectively prevents post-procedure inflammatory adhesion formation. [source] Creating Continuous Linear Lesions in the Atria: A Comparison of the Multipolar Ablation Technique Versus the Conventional Drag-and-BurnJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2005WILBER W. SU M.D. Introduction: Catheter-based treatment of atrial fibrillation (AF) requires the isolation of the triggering foci as well as modification of the atria with substrate that sustains AF. The creation of linear lesions in the left atrium with standard radiofrequency ablative methods requires long procedural times with unpredictable results. Methods: The simultaneous delivery of phase-shifted radiofrequency energy from a multipolar catheter was compared to the conventional drag-and-burn technique for creating linear lesions in 10 dogs. Four atrial sites were targeted under intracardiac ultrasound and fluoroscopic guidance in each of 10 dogs. The conventional drag-and-burn technique or the multipolar phase-shifted ablation catheter was randomly applied for 60 seconds and compared. Results: Creating linear lesions using the simultaneous multipolar phase-shifted ablation catheter was on average 11.0 minutes faster (33.6 minutes vs 44.6 minutes, P < 0.01) than the drag-and-burn method. The fraction of the lesion length achieved using phase-shifted ablation compared to that intended was 23% greater (76% vs 53%, P < 0.01), and has less discontinuities (0.1 compared to 0.8 discontinuities/line, P < 0.003). There was no significant difference in either the lesion transmurality, or fluoroscopy times. Conclusion: The simultaneous delivery of phase-shifted, radiofrequency energy using a multipolar catheter is more effective and efficient in producing linear lesions than the traditional drag-and-burn technique. Using the multipolar ablative method to create linear lesions may be a useful technique in the treatment of patients with substrate-mediated atrial fibrillation. [source] Detection of Inadvertent Catheter Movement into a Pulmonary Vein During Radiofrequency Catheter Ablation by Real-Time Impedance MonitoringJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2004PETER CHEUNG M.D. Introduction: During radiofrequency ablation to encircle or isolate the pulmonary veins (PVs), applications of radiofrequency energy within a PV may result in stenosis. The aim of this study was to determine whether monitoring of real-time impedance facilitates detection of inadvertent catheter movement into a PV. Methods and Results: In 30 consecutive patients (mean age 53 ± 11 years) who underwent a left atrial ablation procedure, the three-dimensional geometry of the left atrium, the PVs, and their ostia were reconstructed using an electroanatomic mapping system. The PV ostia were identified based on venography, changes in electrogram morphology, and manual and fluoroscopic feedback as the catheter was withdrawn from the PV into the left atrium. Real-time impedance was measured at the ostium, inside the PV at approximately 1 and 3 cm from the ostium, in the left atrial appendage, and at the posterior left atrial wall. There was an impedance gradient from the distal PV (127 ± 30 ,) to the proximal PV (108 ± 15 ,) to the ostium (98 ± 11 ,) in each PV (P < 0.01). There was no significant impedance difference between the ostial and left atrial sites. During applications of radiofrequency energy, movement of the ablation catheter into a PV was accurately detected in 80% of the cases (20) when there was an abrupt increase of ,4 , in real-time impedance. Conclusion: There is a significant impedance gradient from the distal PV to the left atrium. Continuous monitoring of the real-time impedance facilitates detection of inadvertent catheter movement into a PV during applications of radiofrequency energy. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1-5, June 2004) [source] Anatomy of the Pulmonary Veins in Patients with Atrial Fibrillation and Effects of Segmental Ostial Ablation Analyzed by Computed TomographyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2003CHRISTOPH SCHARF M.D. Pulmonary Vein Anatomy.Introduction: The anatomic arrangement of pulmonary veins (PVs) is variable. No prior studies have quantitatively analyzed the effects of segmental ostial ablation on the PVs. The aim of this study was to determine the effect of segmental ostial radiofrequency ablation on PV anatomy in patients with atrial fibrillation (AF). Methods and Results: Three-dimensional models of the PVs were constructed from computed tomographic (CT) scans in 58 patients with AF undergoing segmental ostial ablation to isolate the PVs and in 10 control subjects without a history of AF. CT scans were repeated approximately 4 months later. PV and left atrial dimensions were measured with digital calipers. Four separate PV ostia were present in 47 subjects; 3 ostia were present in 2 subjects; and 5 ostia were present in 9 subjects. The superior PVs had a larger ostium than the inferior PVs. Patients with AF had a larger left atrial area between the PV ostia and larger ostial diameters than the controls. Segmental ostial ablation resulted in a 1.5 ± 3.2 mm narrowing of the ostial diameter. A 28% to 61% focal stenosis was present 7.6 ± 2.2 mm from the ostium in 3% of 128 isolated PVs. There were no instances of symptomatic PV stenosis during a mean follow-up of 245 ± 105 days. Conclusion: CT of the PVs allows identification of anatomic variants prior to catheter ablation procedures. Segmental ostial ablation results in a significant but small reduction in ostial diameter. Focal stenosis occurs infrequently and is attributable to delivery of radiofrequency energy within the PV. (J Cardiovasc Electrophysiol, Vol. 14, pp. 150-155, February 2003) [source] Randomized Comparison of Bipolar versus Unipolar Plus Bipolar Recordings During Segmental Ostial Ablation of Pulmonary VeinsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2002HIROSHI TADA M.D. Unipolar vs Bipolar Electrograms.Introduction: Segmental ostial ablation to isolate pulmonary veins is guided by pulmonary vein potentials. The aim of this prospective randomized study was to compare the utility of unipolar plus bipolar electrograms versus only bipolar electrograms as a guide for segmental ablation to isolate the pulmonary veins in patients with atrial fibrillation. Methods and Results: Isolation of the left superior, right superior, and left inferior pulmonary veins was attempted in 44 patients (35 men and 9 women; mean age 54 ± 10 years) with paroxysmal atrial fibrillation. A decapolar Lasso catheter was positioned in the pulmonary veins, near the ostium, and a conventional ablation catheter was used for segmental ablation aimed at elimination of all pulmonary vein potentials. One hundred fourteen pulmonary veins were randomly assigned for ostial ablation guided by either bipolar or unipolar plus bipolar recordings. Electrical isolation was achieved in 51 (96%) of 53 pulmonary veins randomized to the bipolar approach, and 57 (93%) of 61 pulmonary veins randomized to the unipolar plus bipolar approach (P = 0.7). In the unipolar plus bipolar group, the total duration of radiofrequency energy needed to achieve isolation, 5.5 ± 2.8 minutes/vein, was significant shorter than in the bipolar group, 7.6 ± 4.1 minutes/vein (P < 0.01). Mean procedure and fluoroscopy durations per vein were 19% to 28% shorter in the unipolar plus bipolar group. Conclusion: Segmental ostial ablation to isolate the pulmonary veins can be achieved more efficiently and with less radiofrequency energy when guided by both unipolar and bipolar recordings than by bipolar recordings alone. [source] Radiofrequency Catheter Ablation of Idiopathic Ventricular Tachycardia Originating in the Main Stem of the Pulmonary ArteryJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2002CARL TIMMERMANS M.D. Idiopathic Pulmonary Artery Ventricular Tachycardia. We report the case of a patient in whom successful radiofrequency catheter ablation of an idiopathic ventricular tachycardia (VT) originating in the main stem of the pulmonary artery was performed. After successful ablation of the index arrhythmia, which was an idiopathic right ventricular outflow tract VT, a second VT with a different QRS morphology was reproducibly induced. Mapping of the second VT revealed the presence of myocardium approximately 2 cm above the pulmonary valve. Application of radiofrequency energy at this site resulted in termination and noninducibility of this VT. After 6-month follow-up, the patient remained free from VT recurrences. [source] Ablation of Atypical Atrial Flutter Guided by the Use of Concealed Entrainment in Patients Without Prior Cardiac SurgeryJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2000FRANK BOGUN M.D. Ablation of Atypical Atrial Flutter. Introduction: Mapping techniques have not been systematically evaluated with respect to atypical atrial flutter (AF) not involving the inferior vena cava isthmus. The purpose of this study was to assess prospectively the use of concealed entrainment (CE) in mapping of AF and to assess the clinical benefit of ablation of clinically relevant atypical AF. Methods and Results: In seven consecutive patients without prior cardiac surgery presenting with atypical AF, mapping was performed in the right and, if necessary, left atrium. At sites with CE, radiofrequency energy was delivered. In a posthoc analysis, the endocardial activation time, stimulus-flutter wave (F) interval, presence of split potentials and diastolic potentials, and postpacing Interval were assessed, and effective sites were compared to ineffective sites. A total of 22 forms of atypical AE either could be induced or were present at the time of the study. Eleven of the 13 targeted atypical AFs (85%) were successfully ablated. The positive predictive value of CE increased from 45% to 75% in the presence of matching electrogram-F and stimulus-F intervals or if flutter terminated during entrainment pacing, and to 88% in the presence of split atrial electrograms or diastolic potentials. During short-term clinical follow-up, none of the patients had recurrence of the ablated AE. However, the majority of patients required either medication for atrial fibrillation or repeated interventions for new forms of AF. Conclusion: Mapping and ablation of atypical AF is feasible if sites with CE can be identified. However, the clinical benefit of successful ablations in patients with atypical flutter appears to be limited. [source] Feasibility of Myxomatous Mitral Valve Repair Using Direct Leaflet and Chordal Radiofrequency AblationJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 6 2008JEFFREY L. WILLIAMS M.D., M.S. Objective: Minimally invasive repair of mitral valve prolapse (MVP) causing severe mitral regurgitation (MR) should reduce MR and have chronic durability. Our ex vivo, acute in vivo, and chronic in vivo studies suggest that direct application of radiofrequency ablation (RFA) to mitral leaflets and chordae can effect these repair goals to decrease MR. Methods: A total of seven canines were studied to assess the effects of RFA on mitral valve structure and function. RFA was applied ex vivo (n = 1), acutely in vivo using a right lateral thoracotomy and cardiopulmonary bypass (n = 3), and chronically in vivo using percutaneous access to the heart (n = 3). RFA was applied to the mitral valve and its associated chordae. Mitral valve structure and function (in vivo preparations) were then assessed. Results: Ex vivo application of RFA resulted in qualitative reduction in mitral leaflet surface area and chordal length. Acute in vivo application of RFA to canines found to have MVP causing severe MR demonstrated a 43.7,60.7% statistically significant (P = 0.039) reduction in postablation MR. Chronic, in vivo, percutaneous application of RFA was found to be feasible and the engendered alterations durable. Conclusion: These data suggest that myxomatous mitral valve repair using radiofrequency energy delivered via catheter is feasible. [source] Radiofrequency Transseptal Catheter Electrode FracturePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2010ASHOK J. SHAH M.D. Transseptal puncture is performed using a long needle advanced from the femoral approach. A radiofrequency catheter has been developed that delivers a short burst of radiofrequency energy and creates a micro puncture in the interatrial septum. We describe a case in which the distal radiofrequency electrode broke and became embedded in the interatrial septum. (PACE 2010; 33:e57,e58) [source] Exact Location of the Branching Bundle in the Living HeartPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009MASAMITSU ADACHI M.D., Ph.D. Aims: The His bundle electrogram is believed to reflect the exact location of the His bundle. However, the distinction between distal His bundle potential and proximal right bundle branch potential is challenging. The aim of this study was to pinpoint the location of the branching point of the His bundle, and to compare that site with the site of recording of the largest His bundle electrogram (LH) during sinus rhythm. Methods: We hypothesized that the site of earliest His activation (EH) during retrograde conduction via the left bundle branch is the branching point. We studied 15 nonconsecutive patients (mean age = 40 ± 22 years; eight men). We performed a programmed stimulation from right ventricular apex until retrograde right bundle branch block appeared. At that point we measured (1) the distance between antegrade LH site and retrograde EH site and (2) the atrial-to-ventricular amplitude ratio (A/V ratio) at both sites. Results: EH was recorded at the proximal electrode of the His bundle catheter in all patients. Mean distance between EH and LH was 9.8 ± 2.5 mm. The mean A/V ratios at the EH site and the LH site were 1.01 ± 0.42 and 0.08 ± 0.06, respectively. Discussion: This study showed that the EH site is located approximately 10-mm proximal to the LH site. The mean A/V ratio at the EH site during sinus rhythm is approximately 1.0. These observations suggest that the majority of His potentials reflect proximal right bundle activation. Before delivering radiofrequency energy in the para-Hisian area, attention should be paid to the presence of a His potential and to the A/V ratio, rather to the amplitude of the His electrogram. [source] Left Atrial Catheter Ablation Promotes Vasoconstriction of the Right Coronary ArteryPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2007EIJI YAMASHITA M.D. Background: Multiple cardiac ganglia are present in the left atrial (LA) region, and marked changes in autonomic nervous activity can occur after left atrial catheter ablation (CA) for atrial fibrillation (AF). Vasospastic angina involving the inferior wall of the left ventricle has been reported as a complication shortly after LACA. Methods: We studied 20 patients with drug-refractory AF who underwent LACA, performed to encircle the left- and right-sided pulmonary veins, 1 to 2 cm from their ostia under fluoroscopic guidance. Quantitative coronary angiography was performed before and after LACA, and we analyzed the minimal lesion diameter (MLD) of the proximal segment of the coronary arteries, and the basal tone, the baseline percent constriction versus maximal dilation after nitroglycerin administration. Results: No significant difference was observed in MLD or basal tone of the left coronary arteries after LACA. However, in the right coronary artery (RCA), the basal MLD was smaller (P < 0.01) and the basal tone was greater (P< 0.05) after than before LACA. No correlation was found between the baseline MLD or tone of the RCA and total amount of radiofrequency energy delivered or procedure duration. In 75% of RCA, the baseline MLD was smaller after than before LACA, which was significantly higher (P < 0.01) than observed in the left coronary arteries (38%). Conclusion: Vasoconstriction was promoted in the RCA shortly after LACA, which may explain the variant angina reported after LACA. [source] Atrial Electrogram Amplitude and Efficacy of Cavotricuspid Isthmus Ablation for Atrial FlutterPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2003MEHMET OZAYDIN Large atrial electrogram amplitudes recorded in the cavotricuspid isthmus (CTI) may reflect thick atrial musculature. For this reason, in patients with atrial flutter, the efficacy of an application of conventional radiofrequency energy may be related to the amplitude of the local atrial electrogram. In 100 consecutive patients (mean age 59 ± 13 years) with atrial flutter, contiguous applications of radiofrequency energy were delivered in the CTI. The criterion for complete CTI block was the presence of widely split double potentials (>110 ms) along the entire ablation line during pacing from the coronary sinus and posterolateral right atrium. The atrial electrogram amplitude was measured before and after applications of radiofrequency energy at sites of gaps in the ablation line. Complete CTI block was achieved in 90 (90%) of the 100 patients. The mean atrial electrogram amplitudes at gap sites where an application of radiofrequency energy did and did not result in complete block were 0.36 ± 0.42 and 0.67 ± 0.62 mV, respectively (P < 0.01). The positive and negative predictive values (for complete block) of a ,50% decrease in electrogram amplitude after an application of radiofrequency energy were 100% and 35%, respectively. The mean atrial electrogram amplitude is larger at CTI sites where complete isthmus block cannot be achieved with conventional radiofrequency energy. The efficacy of conventional radiofrequency ablation may be improved by identifying areas in the CTI where the voltage is relatively low. (PACE 2003; 26:1859,1863) [source] Pulsed Radiofrequency: Current Clinical and Biological Literature AvailablePAIN MEDICINE, Issue 5 2006Alex Cahana MD, DAAPM ABSTRACT Objective., Pulsed radiofrequency, where short bursts of radiofrequency energy are applied to nervous tissue, has been used by pain practitioners as a non- or minimally neurodestructive technique, alternative to radiofrequency heat lesions. Clinical advantages and mechanisms of this treatment remain unclear. The objective of this study was to review current clinical and laboratory data. Design., We systematically searched the MEDLINE database (PubMed) and tables of contents of electronically available pain journals. Reference lists of relevant reports and international scientific pain congress abstract books were also hand searched. Only those reports on pulsed radiofrequency were withheld. Results., The final analysis yielded 58 reports on the clinical use of pulsed radiofrequency in different applications: 33 full publications and 25 abstracts. We also retrieved six basic science reports, five full publications, and one abstract. Conclusions., The accumulation of these data shows that the use of pulsed radiofrequency generates an increasing interest of pain physicians for the management of a variety of pain syndromes. Although the mechanism of action has not been completely elucidated, laboratory reports suggest a genuine neurobiological phenomenon altering the pain signaling, which some have described as neuromodulatory. No side effects related to the pulsed radiofrequency technique were reported to date. Further research in the clinical and biological effects is justified. [source] Evaluation of Radiofrequency Thermal Ablation Results in Inferior Turbinate Hypertrophies by Magnetic Resonance ImagingTHE LARYNGOSCOPE, Issue 4 2007Tarik Sapci MD Abstract Objectives: Nasal obstruction caused by inferior turbinate hypertrophies is one of the most frequent problems in otolaryngology. Treatment of this disease may involve medical and surgical methods. Thermal ablation with radiofrequency energy has become quite popular in the recent years as one of the surgical methods used when medical therapy is not adequate. Study Design: Prospective, clinical trial. Methods: Thermal ablation with radiofrequency energy was used in this study on the inferior turbinates of 21 patients who had nasal obstruction caused by inferior turbinate hypertrophy only. The results were evaluated subjectively by preoperative and postoperative patient- and physician-assigned visual analogue scales and objectively by magnetic resonance imaging (MRI) investigation. Results: By the end of the postoperative week 10, 64.76% recovery was detected according to the patient evaluation, and 40.75% recovery was detected according to the physician evaluation. Measurement of the average volumes of the inferior turbinates by MRI revealed a 8.70% postoperative reduction. The most significant change was detected in the anterior-posterior length measurement performed in the axial plane. Conclusions: These results suggest that thermal ablation with radiofrequency energy is an easily applied, efficient, and reliable technique in treatment of the inferior turbinate hypertrophy, and that anterior-posterior length measurement in the axial section of the inferior turbinate by MRI, which is thought as an objective evaluation method, could be an efficient diagnostic tool in detecting the efficiency of radiofrequency on inferior turbinate. [source] The 2-year symptomatic and urodynamic results of a prospective randomized trial of interstitial radiofrequency therapy vs transurethral resection of the prostateBJU INTERNATIONAL, Issue 3 2001R.G. Hindley Objective To assess the 2-year symptomatic and urodynamic results of a prospective randomized trial of interstitial radiofrequency therapy of the prostate (IRFT) vs transurethral resection of the prostate (TURP). Patients and methods Patients with lower urinary tract symptoms (LUTS) and urodynamic evidence of bladder outlet obstruction (BOO) were randomized to undergo IRFT or TURP and were followed up using the International Prostate Symptom Score (IPSS) and urodynamic assessment for 2 years. Results At 2 years there was a clinically relevant reduction in the IPSS in the IRFT (20 to 9) and TURP groups (22 to 4). There was also a statistically significant reduction in the detrusor pressure at maximum urinary flow in both groups, but the reduction in the IRFT group was probably not sufficient to explain the observed symptomatic improvements solely from a reduction in BOO. Conclusion IRFT can produce a sustained improvement in LUTS for at least 2 years. However, such improvements are unlikely to be entirely the result of a reduction in BOO. The effects of radiofrequency energy may, at least partly, be independent of any thermal effect and depend instead on neuromodulation of lower urinary tract nerves. [source] | ||||||||||