Cardiovasc Electrophysiol Research Articles

Atrioesophageal Fistula After Cryoballoon Pulmonary Vein Isolation

The risk of atrioesophageal fistula after cryoballoon pulmonary vein isolation is thought to be much lower than after radiofrequency ablation, seeing that no data exist on this complication so far. We report for the first time on the occurrence of an atrioesophageal fistula 4 weeks after cryoballoon ablation at the site of the left inferior pulmonary vein. We suggest that even when using cryothermal ablation technique, an imaging modality to assess the proximity of esophagus and left atrium should be routinely performed to avoid this fatal complication.

Substrate Modification by Pulmonary Vein Isolation and Left Atrial Linear Ablation in Patients with Persistent Atrial Fibrillation: Its Impact on Complex‐Fractionated Atrial Electrograms

PV and Linear Ablation for CFAEs. Linear ablations in the left atrium (LA), in addition to pulmonary vein (PV) isolation, have been demonstrated to be an effective ablation strategy in patients with persistent atrial fibrillation (PsAF). This study investigated the impact of LA linear ablation on the complex-fractionated atrial electrograms (CFAEs) of PsAF patients. A total of 40 consecutive PsAF patients (age: 54 ± 10 years, 39 males) who underwent catheter ablation were enrolled in this study. Linear ablation of both roofline between the right and left superior PVs and the mitral isthmus line joining from the mitral annulus to the left inferior PV were performed following PV isolation during AF. High-density automated CFAE mapping was performed using the NAVX, and maps were obtained 3 times during the procedure (prior to ablation, after PV isolation, and after linear ablations) and were compared. PsAF was terminated by ablation in 13 of 40 patients. The mean total LA surface area and baseline CFAEs area were 120.8 ± 23.6 and 88.0 ± 23.5 cm(2) (74.2%), respectively. After PV isolation and linear ablations in the LA, the area of CFAEs area was reduced to 71.6 ± 22.6 cm(2) (58.7%) (P < 0.001) and 44.9 ± 23.0 cm(2) (39.2%) (P < 0.001), respectively. The LA linear ablations resulted in a significant reduction of the CFAEs area percentage in the region remote from ablation sites (from 56.3 ± 20.6 cm(2) (59.6%) to 40.4 ± 16.5 cm(2) (42.9%), P < 0.0001). Both PV isolation and LA linear ablations diminished the CFAEs in PsAF patients, suggesting substrate modification by PV and linear ablations. (J Cardiovasc Electrophysiol, Vol. 23, pp. 962-970, September 2012).

Late Potentials Abolition as an Additional Technique for Reduction of Arrhythmia Recurrence in Scar Related Ventricular Tachycardia Ablation

To evaluate the efficacy of radiofrequency ventricular tachycardia (VT) ablation targeting complete late potential (LP) activity. Sixty-four consecutive patients (pts) with recurrent VTs and coronary artery disease or idiopathic dilated cardiomyopathy were evaluated. Fifty patients (47 male; 66.2 ± 10.1 years) had LPs at electroanatomical mapping; 35 patients had at least 1 VT inducible at basal programmed stimulation. After substrate mapping, radiofrequency ablation was performed with the endpoint of all LPs abolition. LPs could not be abolished in 5 patients despite extensive ablation, in 1 patient because of localization near an apical thrombus, and in 2 patients because of possible phrenic nerve injury. At the end of procedure, prevention of VT inducibility was achieved in 25 of 35 patients (71.4%) with previously inducible VT; VT was still inducible in 5 of 8 patients with incomplete LP abolition; and in 5 of 42 patients (16.1%) with complete LP abolition (P < 0.01). After a follow-up of 13.4 ± 4.0 months, 10 patients (20.0%) had VT recurrences and one of them died after surgical VT ablation; VT recurrence was 9.5% in patients with LPs abolition (4/42 pts) and 75.0% (6/8 pts) in those with incomplete abolition [positive predictive value (PPV): 75%, negative predictive value (NPV): 90.4%, sensibility: 60.0%, and specificity: 95.0%, P < 0.0001); although it was 12.5% (5/40 pts) in patients without inducibility VT after the ablation, and 50% (5/10 pts) in those with inducible VT (PPV: 50%, NPV: 87.5%, sensitivity: 50.0%, and specificity: 87.5%, P = 0.008). LP abolition is an effective endpoint of VT ablation and its prognostic value compares favorably to that achieved by programmed electrical stimulation.

Noninvasive Electrocardiographic Mapping for Prediction of Tachycardia Mechanism and Origin of Atrial Tachycardia Following Bilateral Pulmonary Transplantation

This is a case of atrial tachycardia 2 years after pulmonary transplantation. After excluding right atrial involvement, tachycardia origin was located in a scar region medial to the anastomosis of the left inferior pulmonary donor vein. Tachycardia mechanism was microreentry. Noninvasive electrocardiographic mapping performed before the ablation procedure matched with results of invasive Carto mapping and predicted both tachycardia mechanism and origin. We discuss arrhythmia mechanism found after pulmonary transplantation and benefit of noninvasive electrocardiographic mapping for procedure planning.

Isolated Subtricuspid Low‐Voltage Segment in Arrhythmogenic Right Ventricular Cardiomyopathy: Structural Characterization by Intracardiac Echocardiography

Journal of Cardiovascular ElectrophysiologyVolume 23, Issue 8 p. 882-883 EP Image Isolated Subtricuspid Low-Voltage Segment in Arrhythmogenic Right Ventricular Cardiomyopathy: Structural Characterization by Intracardiac Echocardiography ANDREA AVELLA M.D., ANDREA AVELLA M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorFEDERICA RE M.D., FEDERICA RE M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorPAOLO G. PINO M.D., PAOLO G. PINO M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorPIERGIUSEPPE DE GIROLAMO M.D., PIERGIUSEPPE DE GIROLAMO M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorFRANCESCO LAURENZI M.D., FRANCESCO LAURENZI M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorAUGUSTO PAPPALARDO M.D., AUGUSTO PAPPALARDO M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorELISABETTA ZACHARA M.D., ELISABETTA ZACHARA M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this author ANDREA AVELLA M.D., ANDREA AVELLA M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorFEDERICA RE M.D., FEDERICA RE M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorPAOLO G. PINO M.D., PAOLO G. PINO M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorPIERGIUSEPPE DE GIROLAMO M.D., PIERGIUSEPPE DE GIROLAMO M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorFRANCESCO LAURENZI M.D., FRANCESCO LAURENZI M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorAUGUSTO PAPPALARDO M.D., AUGUSTO PAPPALARDO M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this authorELISABETTA ZACHARA M.D., ELISABETTA ZACHARA M.D. Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Rome, ItalySearch for more papers by this author First published: 04 April 2012 https://doi.org/10.1111/j.1540-8167.2011.02249.x Andrea Avella, M.D., Cardiology Division, Cardiac Arrhythmia Unit and Cardiomyopathies Unit, St. Camillo-Forlanini Hospital, Via Portuense 332, 00149, Rome, Italy. Fax: +39-06-58704520; E-mail: andrea.avella@tin.it J Cardiovasc Electrophysiol, Vol. 23, pp. 882-883, August 2012 No disclosures. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume23, Issue8August 2012Pages 882-883 RelatedInformation

“Largest Amplitude Ablation” is the Optimal Approach for Typical Atrial Flutter Ablation: A Subanalysis from the AURUM 8 Study

The recently proposed "maximum voltage-guided" (MVG) technique for radiofrequency catheter ablation of atrial flutter targets high-voltage electrograms along cavotricuspid isthmus (CTI) to ablate the functionally important anatomic muscle bundles alone, without drawing a complete anatomic line across the CTI. This innovative approach may shorten ablation time and procedure duration. Within the multicenter AURUM 8 study, which compared 8-mm gold- and Pt-Ir-tip catheters in atrial flutter ablation, we made a post hoc comparison of procedural data from 72 patients treated with MVG technique with data from 281 patients undergoing anatomic CTI ablation (unmatched) and with data from 72 patients selected from among those 281 patients such that they were matched with the MVG group with respect to selected baseline parameters and catheter type (matched). The MVG technique markedly reduced (P < 0.001) ablation time (mean 6.9 minutes vs 10.9/9.7 minutes [unmatched/matched]), number of lesions (8.3 vs 13.7/12.9), fluoroscopy time (9.5 minutes vs 20.6/17.9 minutes), procedure duration (59 minutes vs 93/86 minutes), and energy delivered (19 kJ vs 34/30 kJ) compared with anatomic CTI ablation. The incidence of charring was higher for MVG than for anatomic ablation technique (31.9% vs 18.5/15.3%, P < 0.05), where Pt-Ir tip catheters were 6-fold more susceptible to charring than gold-tip catheters (P < 0.001), likely because of a lower thermal conductivity of the Pt-Ir material. The acute success rate was slightly better for MVG than for anatomic ablation technique (97.2% vs 92.2/91.7%, P = n.s.). Major procedural parameters are remarkably improved with MVG technique. Gold-tip catheters are substantially less susceptible to charring and may therefore be preferred over Pt-Ir-tip catheters for MVG ablation technique.

Impact of a Recent Lead Recall on Utilization of Implantable Cardioverter Defibrillators: Data from the NCDR ICD Registry™

Underutilization of ICDs is well documented. It has been hypothesized that device recalls, and the resultant negative publicity, may contribute. To determine if the October 2007 recall of the Medtronic Fidelis lead was associated with a decrease in volume of ICD procedures in the United States, we analyzed data submitted to the ICD Registry™ between July 2006 and December 2008. Time-series analyses were performed comparing actual and predicted implant volumes following the recall, using monthly data from July 2006 to September 2007 to establish a trend line. Observed data points falling outside the 95% CIs from the trend line were considered statistically significant. The study cohort includes 173,616 implantations in 658 hospitals. Before October 2007, an average of 5,952 devices, 4,910 for primary prevention, were implanted per month. Following the recall, the average monthly number of implants was modestly lower at 5,623 (P = 0.05), 4,601 for primary prevention (P = 0.01.) However, as volume was decreasing prior, in time-series analysis, the observed monthly implant volume for primary prevention devices differed from expected based on the trend line for only 1 month. The proportion of Medtronic implants declined from 51.1% in the 15 months prior to the recall to 45.8% in the 15 months of the recall or after (P < 0.01), falling outside the 95% CI of the trend line for 3 months in time-series analysis. A recent well-publicized lead recall had minimal impact on ICD utilization either overall or for primary prevention.

Psychopathology and Symptoms of Atrial Fibrillation: Implications for Therapy

Current guidelines recommend that the choice of AF management strategy be guided by the symptomatic status of the patient when in AF. However, little is known regarding what drives AF symptoms. Several limited studies suggest that psychological distress may be linked with AF symptom severity. A total of 300 patients with documented AF completed a questionnaire assessing general health and well-being, including a comprehensive psychological assessment as well as disease-specific measures of AF symptom severity. AF burden was determined by 1-week continuous looping monitor in a subset of patients. Analysis of covariance was used to determine the association between individual measures of depression, anxiety, and somatization disorder symptom severity with measures of general health status and AF-specific symptom severity, adjusting for important confounders. Patients with worsened severity of depression, anxiety, or somatization disorder symptoms had an associated increase in the severity of symptoms attributed to AF regardless of AF severity scale used (P < 0.0001 for each measure of psychological distress). This association persisted after adjusting for important confounders. Increasing severity of depression and anxiety symptoms were also associated with increased visits to medical care for AF management. Our study demonstrates the consequence of psychological distress on AF-specific symptom severity and healthcare resource utilization. Psychological well-being may strongly influence symptom severity and healthcare utilization. An assessment of psychological distress may be an important adjunct to standard AF management that warrants further study, particularly if symptom relief is the primary goal.

Effects of Nonsystemic Ventricular Pacing in Patients with Transposition of the Great Arteries and Atrial Redirection

Ventricular pacing may add additional risk for right ventricular (RV) dysfunction in patients with transposition of the great arteries (TGA) and atrial redirection. The aim of our study was to evaluate the effects of long-term nonsystemic ventricular pacing on cardiac function, dyssynchrony, and clinical performance in patients with systemic RV. Forty-six adults with TGA and atrial redirection, of whom 11 were permanently paced at the nonsystemic ventricle, underwent assessment of clinical status and exercise stress testing, as well as echocardiography to assess parameters of RV function and dyssynchrony. In paced patients, median NYHA functional class was II, which was significantly higher than in nonpaced patients (median class I; P = 0.002). Maximum performance and peak oxygen consumption on exercise testing were significantly lower in paced patients when compared with nonpaced patients (100 ± 30 vs 120 ± 32 W and 22 ± 6 vs 27 ± 7 mLO(2)/kg/min, respectively; P < 0.05 for both). On echocardiography, RV shortening fraction (27 ± 11 vs 33 ± 10%), RV ejection fraction (39 ± 7 vs 44 ± 10%) and RV dP/dt(max) (891 ± 470 vs 1,024 ± 318 mmHg/s) were significantly lower (P < 0.05 for all) in paced versus nonpaced patients. Inter- and intraventricular dyssynchrony was most pronounced in the paced group (99 ± 10 vs 25 ± 9 ms and 70 ± 29 vs 21 ± 15 ms, respectively; P < 0.001 for both). Long-term pacing of the nonsystemic ventricle in patients with atrial switch for TGA was associated with significantly impaired functional status, exercise capacity, and systemic ventricular function.

Superiority of Gold versus Platinum Irrigated Tip Catheter Ablation of the Pulmonary Veins and the Cavotricuspid Isthmus: A Randomized Study Comparing Tip Temperatures and Cooling Flow Requirements

In order to optimize power delivery into the myocardium during radiofrequency ablation (RFA) without overheating the electrode tip, active cooling of the tip electrode as well as electrode tips made of gold have evolved. Recently, an externally irrigated gold tip electrode ablation catheter has been developed to combine the advantages of these 2 technologies. We sought to investigate the procedural parameters tip temperature, delivered power and cooling flow requirements of the irrigated gold tip catheter in comparison to the conventional irrigated platinum iridium (Pt) tip catheter in pulmonary vein isolation (PVI) and cavotricuspid isthmus (CTI) ablation. Sixty patients referred for first PVI were randomized into ablation with irrigated gold tip catheter versus irrigated Pt tip catheter. Forty-nine patients received ablation of CTI following PVI. Mean and standard deviation from all measurements were calculated for each patient. During RFA of pulmonary veins, mean catheter tip temperature was significantly lower in the gold group (35.4 ± 0.9 °C vs 38.2 ± 0.8 °C, P < 0.001), and total amount of delivered energy was higher (1303.1 ± 81.1 W vs 1223.7 ± 115.6 W, P = 0.004). During CTI ablation, necessary saline flow was almost 2.5-fold lower in the gold group (22.5 ± 5.9 mL/min vs 52.5 ± 9.7 mL/min, P < 0.001), accompanied by significantly lower tip temperature (39.1 ± 0.6 °C vs 40.5 ± 1.4 °C, P < 0.001). The irrigated gold tip electrode allows to deliver significantly more energy at a lower electrode tip temperature in RFA of PV and CTI in comparison to the irrigated Pt tip electrode. The required saline flow during CTI ablation is much lower than in Pt.

Disparate Activation of the Coronary Sinus and Inferior Left Atrium During Atrial Tachycardia After Persistent Atrial Fibrillation Ablation: Prevalence, Pitfalls, and Impact on Mapping

Persistent atrial fibrillation (AF) ablation may lead to partial disconnection of the coronary sinus (CS). As a result, disparate activation sequences of the local CS versus contiguous left atrium (LA) may be observed during atrial tachycardia (AT). We aimed to evaluate the prevalence of this phenomenon and its impact on activation mapping. AT occurring after persistent AF ablation were investigated in 74 consecutive patients. Partial CS disconnection during AT was suspected when double potentials with disparate activation sequences were observed on the CS catheter. Endocardial mapping facing CS bipoles was performed to differentiate LA far-field from local CS potentials. A total of 149 ATs were observed. Disparate LA-CS activations were apparent in 20 ATs after magnifying the recording scale (13%). The most common pattern (90%) was distal to proximal endocardial LA activation against proximal to distal CS activation, the latter involving the whole CS or its distal part. Perimitral macroreentry was more common when disparate LA-CS activations were observed (67% vs 29%; P = 0.002). Partial CS disconnection also resulted in "pseudo" mitral isthmus (MI) block during LA appendage pacing in 20% of patients as local CS activation was proximal to distal despite distal to proximal activation of the contiguous LA. Careful analysis of CS recordings during AT following persistent AF ablation often reveals disparate patterns of activation. Recognizing when endocardial LA activation occurs in the opposite direction to the more obvious local CS signals is critical to avoid misleading interpretations during mapping of AT and evaluation of MI block.

Journal of Cardiovascular Electrophysiology-2011

Journal of Cardiovascular ElectrophysiologyVolume 23, Issue 3 p. 231-231 Journal of Cardiovascular Electrophysiology—2011 Eric N. Prystowsky M.D., Eric N. Prystowsky M.D.Search for more papers by this author Eric N. Prystowsky M.D., Eric N. Prystowsky M.D.Search for more papers by this author First published: 13 March 2012 https://doi.org/10.1111/j.1540-8167.2012.02309.x J Cardiovasc Electrophysiol, Vol. 23, p. 231, March 2012. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume23, Issue3March 2012Pages 231-231 RelatedInformation

Cardiac Resynchronization Therapy in an Infant with Double Outlet Right Ventricle and Mechanical Dyssynchrony

Cardiac resynchronization therapy (CRT) is commonly used in adults with heart failure, poor left ventricular ejection fraction (LVEF), and wide QRS complex. CRT has rarely been applied in young patients. We report the case of a 10-month-old infant with congenital heart disease, postsurgical complete atrioventricular block, and severe refractory heart failure. The patient showed a significant clinical improvement and was withdrawn from the heart transplant list 2 months after epicardially established CRT.

Incidence of Asymptomatic Cerebral Microthromboembolism After Atrial Fibrillation Ablation Guided by Complex Fractionated Atrial Electrogram

The incidence of cerebral thromboembolism after pulmonary vein isolation (PVI) ranges from 2% to 14%. This study investigated the incidence of cerebral thromboembolism after complex fractionated atrial electrogram (CFAE) ablation with or without PVI. One hundred consecutive atrial fibrillation (AF) patients (50 paroxysmal and 50 persistent, including 10 longstanding) who underwent CFAE ablation combined with (n = 41, PVI+CFAE group) or without (n = 59, CFAE group) PVI were studied. Coronary angiography (CAG) was conducted with AF ablation in 5 cases in which coronary artery stenosis was suspected on 3D-computed tomography. PVI was performed before CFAE ablation without circular catheter during AF. After termination of AF, additional ablation was performed to complete PVI with a circular catheter. All patients underwent cerebral magnetic resonance imaging (MRI) including diffusion-weighted MRI and T2-weighted MRI the day after ablation. New thromboembolism was detected in 7.0%, and there was no significant difference between the 2 strategies (7.3% in PVI+CFAE group, 6.8% in CFAE group). CHADS2 score (1.6 ± 1.0 vs 0.8 ± 0.9, P < 0.05), left atrial volume (LAV; 83.8 ± 27.1 vs 67.8 ± 21.8, P < 0.05), and left ventricular ejection fraction (LVEF, 53.1 ± 9.2 vs 65.1 ± 9.7, P < 0.01) were significantly different when comparing patients with or without thromboembolism. In multivariate analysis, LVEF (odds ratio [OR], 0.92; 95% confidence interval [CI], 0.84-0.99; P < 0.05) and concomitant CAG (OR 18.82; 95% CI, 1.77-200.00; P < 0.05) were important predictors of new cerebral thromboembolism. The incidence of cerebral microthromboembolism after CFAE ablation was not greater than previous reports in PVI. Cautious management is required during AF ablation, especially in the patients with low LVEF.

Atrial Electrical and Structural Remodeling Associated with Longstanding Pulmonary Hypertension and Right Ventricular Hypertrophy in Humans

Pulmonary hypertension (PH) is common to a range of cardiopulmonary conditions and is associated with atrial arrhythmias. However, little is known of the isolated atrial effects of PH and right atrial dilatation (RA) in humans. To avoid the confounding effects of PH-associated disease states, we performed detailed electrophysiological (EP) and electroanatomic (EA) mapping of the RA in patients with idiopathic PH. Eight PH patients (mean pulmonary arterial [PA] pressure 39.0 ± 15.8 mmHg) and 16 age-matched controls (mean PA pressure 11.5 ± 4.1 mmHg, P < 0.0001) were studied. Corrected sinus node recovery times (cSNRT), atrial effective refractory periods (ERPs), conduction delay at the crista terminalis (CT), and inducibility of atrial fibrillation (AF) were evaluated. EA mapping (pacing cycle length 600 and 300 milliseconds) was performed to determine RA global and regional voltage, conduction velocities, atrial activation times, fractionated electrograms and double potentials. Patients with PH demonstrated a prolongation in cSNRT without significant change in atrial ERP and an increase in AF inducibility. PH was associated with lower tissue voltage (1.8 ± 0.4 mV in PH vs 2.2 ± 0.4 mV in controls, P = 0.02), increased low voltage areas (13.7 ± 8.2% in PH vs 6.2 ± 3.7% in controls, P < 0.01) and the presence of electrically silent areas. Conduction velocities were slower (global 67.3 ± 5.6 cm/s vs 92.8 ± 4.0 cm/s, P < 0.001) and fractionated electrograms and double potentials were more prevalent (14.7 ± 4.4% vs 6.3 ± 4.1, P < 0.01) in PH compared with controls, respectively. Idiopathic PH is associated with RA remodeling characterized by: generalized conduction slowing with marked regional abnormalities; reduced tissue voltage; and regions of electrical silence. These changes provide important insights into the isolated effects of PH fundamental to a range of clinical conditions associated with AF.

AF News

Journal of Cardiovascular ElectrophysiologyVolume 23, Issue 2 p. 228-229 AF News Shih-Ann Chen MD., Shih-Ann Chen MD. EditorSearch for more papers by this author Shih-Ann Chen MD., Shih-Ann Chen MD. EditorSearch for more papers by this author First published: 11 January 2012 https://doi.org/10.1111/j.1540-8167.2011.02254.x Shih-Ann Chen, M.D., Division of Cardiology, Taipei Veterans General Hospital, 201 Sector 2, Shih-Pai Road, Taipei, Taiwan, R.O.C. Fax: 886-2-2873-5656; E-mail: epsachen@ms41.hinet.net J Cardiovasc Electrophysiol, Vol. 23, pp. 228-229, February 2012. No disclosures. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume23, Issue2February 2012Pages 228-229 RelatedInformation

Visually Guided Sequential Pulmonary Vein Isolation: Insights into Techniques and Predictors of Acute Success

Pulmonary vein isolation (PVI) is a challenging procedure most often requiring sophisticated technical aids such as electroanatomical mapping, double transseptal access, and the use of a circular mapping catheter. We sought to develop a PVI strategy solely based on visual guidance with a single ablation device as well as a single transseptal puncture using the endoscopic ablation system (EAS). In 35 patients with drug-refractory atrial fibrillation (18 male, mean age: 62 ± 9 years) ablation was performed. PVI was achieved in 96 of 137 PVs (70%) purely by visually guided circular ablation. Predictors of acute isolation were the degree of PV occlusion by EAS as well as the number of catheter repositionings but not total ablation energy or the number of laser applications. Conduction gaps were detected at sites with suboptimal occlusion as well as esophageal temperature elevations. Further EAS ablation resulted in a 98% acute isolation rate. Mean procedure and fluoroscopy times were 154 ± 38 minutes and 16 ± 6 minutes, respectively. Between the first and last 12 cases, a reduction in procedure times (175 ± 48 minutes vs 138 ± 26 minutes; P = 0.05) was observed. One pericardial tamponade and 1 right-sided phrenic nerve palsy occurred. During a median follow-up of 266 days (q-q3: 218-389), 27 of 35 patients (77%) remained free of any tachyarrhythmia recurrence off antiarrhythmic drugs. Sequential PVI based solely on endoscopic visual information with a single device and a single transseptal puncture is feasible. Optimal PV occlusion and few controlled repositionings facilitate PVI.

Electrical Inhomogeneities of Guinea Pig Atrial Tissue in High Resolution Optical Potential Mapping

Inhomogeneities in the tissue are a determining factor for cardiac function and can be either structural or functional. Using the voltage sensitive fluorescent dye di-4-ANEPPS on incubation stained guinea pig preparations allows to map the tissue's response to externally applied electric shocks. Previous work on ventricular muscle preparations revealed a membrane potential morphology that could be relevant during defibrillation [1]. Using a two pulse stimulus protocol we are able to map the excitation response to a short triggering field pulse and to consequently map the membrane potential morphology resulting from a second field pulse, which is applied in the depolarized state and is attributed to the interaction of the electric field with the tissue. This approach is now carried over to atrial preparations. A custom developed object-positioning and image-stitching method allows for wide view analysis of the atrial tissue structure. Objective-magnifications of 10x, 20x, 40x and 63x enable a multi-scale based analysis with resolutions up to 15 micrometers. This is augmented with information from transmitted light microscopy so that it is possible to correlate the membrane potential patterns with the visible structure of the atrial tissue, providing further insight into atrial excitation and conduction.[1] Windisch,H. et al. (2007) Quantification of shock-induced microscopic virtual electrodes assessed by subcellular resolution optical potential mapping in guinea pig papillary muscle. J Cardiovasc Electrophysiol; 18(10):1086-1094

Focal Initiation of Sustained and Nonsustained Ventricular Tachycardia in a Canine Model of Ischemic Cardiomyopathy

To define the role of focal and reentrant mechanisms underlying nonsustained (NSVT) and sustained ventricular tachycardia (SuVT) induced by programmed stimulation, 3-dimensional cardiac mapping was performed in 8 dogs with heart failure (HF) created by multiple intracoronary microsphere embolizations. Continuous recording from 232 intramural sites throughout the left and right ventricles and the interventricular septum was performed during programmed stimulation in the absence and presence of isoproterenol (Iso, 0.1 μg/kg/min). Sinus beats and the last extrastimuli preceding induced VT conducted with total activation times (TA) of 51 ± 10 and 111 ± 8 milliseconds, respectively, that did not change during Iso infusion (47 ± 4 and 109 ± 5 milliseconds, P = NS). NSVT was induced in 75% of HF dogs; SuVT was induced in 38%. In all cases, initiation and maintenance of SuVT and NSVT arose by a focal mechanism. Compared to NSVT, SuVT had a shorter coupling interval (CI; 150 ± 7 vs 186 ± 16, P < 0.05) and a predilection for certain critical subendocardial initiation sites (that were initiation sites for only 29% of NSVT beats). After 21-30 beats, acceleration of SuVT by a focal mechanism to a CI less than 120 milliseconds led to functional conduction delay (TA increasing from 111 ± 3 to 137 ± 3 milliseconds, P < 0.0001), intramural reentry, and transition to ventricular fibrillation. Thus, initiation of SuVT in a model of ischemic HF is due to a focal mechanism. However, subsequent acceleration of this focal mechanism can ultimately lead to functional conduction delay and development of intramural reentry.

Thoracic Spinal Cord Stimulation Improves Cardiac Contractile Function and Myocardial Oxygen Consumption in a Porcine Model of Ischemic Heart Failure

Prior experimental studies show that thoracic spinal cord stimulation (SCS) improves left ventricular (LV) ejection fraction (LVEF). The mechanism of this improvement in the LV contractile function after SCS and its effects on the myocardial oxygen consumption remains unknown. We performed thoracic SCS (T1-T2 level) followed by 4 weeks of rapid ventricular pacing in 9 adult pigs with ischemic heart failure (HF) induced by myocardial infarction (MI). At 24 hours off-pacing, detailed echocardiogram and invasive hemodynamic assessment were performed to determine LV contractile function and myocardial oxygen consumption. Serum norepinephrine level was measured before and after SCS. SCS was performed on 2 occasions for 15 minutes, 30 minutes apart (recovery) with 50 Hz frequency (pulse width 0.2 millisecond, 90% of motor threshold at 2 Hz output). Echocardiogram revealed significant decrease in LVEF (33.8 ± 1.8% vs 66.5 ± 1.7%, P < 0.01) after induction of MI and HF. Compared with MI and HF, acute SCS significantly increased LVEF and +dP/dt (all P < 0.05). Withdrawal of SCS during recovery decreased +dP/dt, but not LVEF that increased again with repeated SCS. Myocardial oxygen consumption also significantly decreased during SCS compared with MI and HF (P = 0.006) without any change in serum norepinephrine level (P = 0.9). Speckle tracking imaging showed significant improvement in global and regional circumferential strains over the infarcted mid and apical regions, decreased in time to peak circumferential strain over the lateral and posterior wall after SCS, and the degree of intraventricular dyssynchrony during SCS compared with MI and HF (P < 0.05). In a porcine model of ischemic HF, acute SCS improved global and regional LV contractile function and intraventricular dyssynchrony, and decreased myocardial oxygen consumption without elevation of norepinephrine level.