Ventricular arrhythmias in patients with prior aortic valve intervention: Characteristics, ablation and outcomes.

INTRODUCTION: Data regarding ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation in patients with aortic valve (AV) intervention (AVI) is limited. Catheter ablation (CA) can be challenging given perivalvular substrate in the setting of prosthetic valves. We sought to investigate the characteristics, safety, and outcomes of CA in patients with prior AVI and ventricular arrhythmias (VA). METHODS: We identified consecutive patients with prior AVI (replacement or repair) who underwent CA for VT or PVC between 2013 and 2018. We investigated the mechanism of arrhythmia, ablation approach, perioperative complications, and outcomes. RESULTS: We included 34 patients (88% men, mean age 64 ± 10.4 years, left ventricular (LV) ejection fraction 35.2 ± 15.0%) with prior AVI who underwent CA (22 VT; 12 PVC). LV access was obtained through trans-septal approach in all patients except one patient who had percutaneous transapical access. One patient had combined retrograde aortic and trans-septal approach. Scar-related reentry was the dominant mechanism of induced VTs. Two patients had bundle branch reentry VTs. In the VT group, substrate mapping demonstrated heterogeneous scar that involved the peri-AV area in 95%. Despite that, the site of successful ablation included the periaortic region only in 6 (27%) patients. In the PVC group, signal abnormalities consistent with scar in the periaortic area were noted in 4 (33%) patients. In 8 (67%) patients, the successful site of ablation was unrelated to the periaortic area. No procedure-related complications occurred. The survival and recurrence-free survival rate at 1 year tended to be lower in VT group than in PVC group (p = .06 and p = .05, respectively) with a 1-year recurrence-free survival rate of 52.8% and 91.7%, respectively. No arrhythmia-related death was documented on long-term follow-up. CONCLUSION: CA of VAs can be performed safely and effectively in patients with prior AVI.

Characteristics and outcomes of ventricular tachycardia and premature ventricular contractions ablation in patients with prior mitral valve surgery.

BACKGROUND: Data regarding ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation following mitral valve surgery (MVS) is limited. Catheter ablation (CA) can be challenging given perivalvular substrate in the setting of mitral annuloplasty or prosthetic valves. OBJECTIVE: To investigate the characteristics, safety, and outcomes of radiofrequency CA in patients with prior MVS and ventricular arrhythmias (VA). METHODS: We identified consecutive patients with prior MVS who underwent CA for VT or PVC between January 2013 and December 2018. We investigated the mechanism of arrhythmia, ablation approach, peri-operative complications, and outcomes. RESULTS: In our cohort, 31 patients (77% men, mean age 62.3 ± 10.8 years, left ventricular ejection fraction 39.2 ± 13.9%) with prior MVS underwent CA (16 VT; 15 PVC). Access to the left ventricle was via transseptal approach in 17 patients, and a retrograde aortic approach was used in 13 patients. A combined transseptal and retrograde aortic approach was used in one patient, and a percutaneous epicardial approach was combined with trans-septal approach in one patient. Heterogenous scar regions were present in 94% of VT patients and scar-related reentry was the dominant mechanism of VT. Forty-seven percent of PVC patients had abnormal substrate at the site targeted for ablation. Clinical VA substrates involved the peri-mitral area in six patients with VT and five patients with PVC ablation. No procedure-related complications were reported. The overall recurrence-free rate at 1-year was 72.2%; 67% in the VT group and 78% in the PVC group. No arrhythmia-related death was documented on long-term follow-up. CONCLUSION: CA of VAs can be performed safely and effectively in patients with MVS.

Catheter ablation of ventricular tachycardia in patients with postinfarction left ventricular aneurysm.

BACKGROUND: While ventricular tachycardia (VT) in the setting of postmyocardial infarction left ventricular aneurysms (LVA) is not uncommonly encountered, there is a scarcity of data regarding the safety, efficacy, and outcomes of ablation of VT in this subset of patients. METHODS: Our study included consecutive patients aged 18 years or older with postmyocardial infarction LVA who presented to Mayo Clinic for catheter ablation of VT between 2002 and 2018. RESULTS: Of 34 patients, the mean age was 70.4 ± 9.1 years; 91% were male. Mean LVEF was 29 ± 9.7% and left ventricular end-diastolic dimension was 64.9 ± 6.6 mm. The site of the LVA was apical in 21 patients (62%). Fifteen patients (44%) presented with electrical storm or incessant VT. Nine patients (26%) had a history of intracardiac thrombus. All except for one patient had at least one VT originating from the aneurysm. The mean number of VTs was 2.9 ± 1.7. All patients underwent ablation at the site of the aneurysm. Ablation outside the aneurysm was performed in 13 patients (38%). Low-voltage fractionated potentials and/or late potentials at the aneurysmal site were present in all cases. Complete elimination of all VTs was achieved in 18 (53%), while the elimination of the clinical VT with continued inducibility of nonclinical VTs was achieved in a further 11 patients (32%). Two patients developed cardiac tamponade requiring pericardiocentesis. During a mean follow-up period of 2.3 ± 2.4 years, 11 patients (32%) experienced VT recurrence. Freedom from all-cause mortality at 1-year follow-up was 94%. CONCLUSION: Radiofrequency catheter ablation targeting the aneurysmal site is a feasible and reasonably effective management strategy for clinical VTs in patients with postinfarction LVA.

Catheter ablation of premature ventricular contractions originating from periprosthetic aortic valve regions.

BACKGROUND: Little is known about the ablation outcomes of premature ventricular contractions (PVCs) that originate from the periprosthetic aortic valve (PPAV) regions of patients with aortic valve replacement (AVR). METHODS AND RESULTS: Our study had 11 patients who underwent catheter ablation for PVCs arising from the PPAV regions (bioprosthetic aortic valve, n = 5; mechanical aortic valve, n = 6). The PVC characteristics, procedure characteristics, and efficacy of ablation were compared with the control group (n = 33). At baseline, the PPAV group had a lower left ventricular ejection fraction (mean [SD], 41% [12%] vs. 51% [8%]; p = .002). The rate of acute ablation success was 90.9% in the PPAV group. Ablation sites were identified above the left coronary cusp (LCC) and right coronary cusp commissure (LRCC) in one PVC, below the prosthetic valve in eight PVCs (four below LCC and four below LRCC), and within the distal coronary sinus in two PVCs. The mean procedure time, fluoroscopy time, and radiation in the PPAV group were all significantly greater than those in the control group (all p < .05). However, the number of radiofrequency ablation energy deliveries was not different. The PPAV group had a long-term success rate compared with the control group (72.7% vs. 87.9%, p = .48) and an increase of left ventricular ejection fraction from 43% to 49% after successful PVC ablation at follow-up (p < .001). Echocardiography showed no significant change in valve regurgitation after ablation. No new atrioventricular block occurred. CONCLUSION: PVCs arising from PPAV regions can be successfully ablated in patients with prior AVR, without damaging the prosthetic aortic valve and atrioventricular conduction.

Clinical implications of elective replacement indicator setting changes in patients with dual-chamber pacemaker devices.

OBJECTIVE: This study sought to determine if single-chamber operation and/or loss of rate response (RR) during elective replacement indicator (ERI) in patients with dual-chamber pacemakers lead to increased symptom burden, healthcare utilization, and atrial fibrillation (AF). BACKGROUND: Dual-chamber pacemakers often change from dual- to single-chamber pacing mode and/or lose RR functionality at ERI to preserve battery. Single-chamber pacing increases the incidence of heart failure, AF, and pacemaker syndrome suggesting these changes may be deleterious. METHODS: A retrospective analysis of 700 patients was completed. Three comparisons were analyzed: Comparison 1: mode change and RR loss versus no change; Comparison 2: RR loss only versus no change; Comparison 3: mode change only versus no change (in patients with no RR programmed at baseline). RESULTS: In Comparison 1, 121 (46%) patients with setting changes experienced symptoms (most often dyspnea and fatigue/exercise intolerance) versus 3 (4%) without setting changes (p < .0001). Similar results were noted in Comparisons 2 and 3 (p = .0016 and p = .0001, respectively). In Comparison 1, patients with setting change sought provider contact more than patients without setting changes (p = .0001). A significant difference was not noted in Comparison 2 or 3. Overall 14 (2%) patients were hospitalized, all of whom had setting changes. CONCLUSIONS: Setting changes at ERI including a change from dual- to single-chamber pacing and/or loss of RR results in a significantly increased symptom burden and increased healthcare utilization.

Defining the substrate for ventricular tachycardia ablation: The impact of rhythm at the time of mapping.

BACKGROUND: Voltage mapping is critical to define substrate during ablation. In ventricular tachycardia, abnormal potentials may be targets. However, wavefront of activation could impact local signal characteristics. This may be particularly true when comparing sinus rhythm versus paced rhythms. We sought to determine how activation wavefront impacts electrogram characteristics. METHODS: Patients with ischemic cardiomyopathy, ventricular tachycardia, and without fascicular or bundle branch block were included. Point by point mapping was done and at each point, one was obtained during an atrial paced rhythm and one during a right ventricular paced rhythm. Signals were adjudicated after ablation to define late potentials, fractionated potentials, and quantify local voltage. Areas of abnormal voltage (defined as <1.5 mV) were also determined. RESULTS: 9 patients were included (age 61.3 ± 9.2 years, 56% male, mean LVEF 34.9 ± 8.6%). LV endocardium was mapped with an average 375 ± 53 points/rhythm. Late potentials were more frequent during right ventricular pacing (51 ± 21 versus 32 ± 15, p < 0.01) while overall scar area was higher during atrial pacing (22 ± 11% vs 13 ± 7%, p < 0.05). In 1/9 patients, abnormal potentials were seen during a right ventricular paced rhythm that were not apparent in an atrial paced rhythm, ablation of which resulted in non-inducibility. CONCLUSION: Rhythm in which mapping is performed has an impact on electrogram characteristics. Whether one rhythm is preferable to map in remains to be determined. However, it is possible defining local signals during normal conduction as well as variable paced rhythms may impart a greater likelihood of elucidating arrhythmogenic substrate.

Mortality and Cerebrovascular Events After Heart Rhythm Disorder Management Procedures.

BACKGROUND: Recognition of rates and causes of hard, patient-centered outcomes of death and cerebrovascular events (CVEs) after heart rhythm disorder management (HRDM) procedures is an essential step for the development of quality improvement programs in electrophysiology laboratories. Our primary aim was to assess and characterize death and CVEs (stroke or transient ischemic attack) after HRDM procedures over a 17-year period. METHODS: We performed a retrospective cohort study of all patients undergoing HRDM procedures between January 2000 and November 2016 at the Mayo Clinic. Patients from all 3 tertiary academic centers (Rochester, Phoenix, and Jacksonville) were included in the study. All in-hospital deaths and CVEs after HRDM procedures were identified and were further characterized as directly or indirectly related to the HRDM procedure. Subgroup analysis of death and CVE rates was performed for ablation, device implantation, electrophysiology study, lead extraction, and defibrillation threshold testing procedures. RESULTS: A total of 48 913 patients (age, 65.7±6.6 years; 64% male) who underwent a total of 62 065 HRDM procedures were included in the study. The overall mortality and CVE rates in the cohort were 0.36% (95% confidence interval [CI], 0.31-0.42) and 0.12% (95% CI, 0.09-0.16), respectively. Patients undergoing lead extraction had the highest overall mortality rate at 1.9% (95% CI, 1.34-2.61) and CVE rate at 0.62% (95% CI, 0.32-1.07). Among patients undergoing HRDM procedures, 48% of deaths directly related to the HDRM procedure were among patients undergoing device implantation procedures. Overall, cardiac tamponade was the most frequent direct cause of death (40%), and infection was the most common indirect cause of death (29%). The overall 30-day mortality rate was 0.76%, with the highest being in lead extraction procedures (3.08%), followed by device implantation procedures (0.94%). CONCLUSIONS: Half of the deaths directly related to an HRDM procedure were among the patients undergoing device implantation procedures, with cardiac tamponade being the most common cause of death. This highlights the importance of the development of protocols for the quick identification and management of cardiac tamponade even in procedures typically believed to be lower risk such as device implantation.

Outcome of combined cryo- and radiofrequency-catheter ablation in patients with supraventricular tachycardias.

BACKGROUND: There are few data regarding the outcome of a combined cryo- and radiofrequency (RF)-catheter ablation of various types of supraventricular tachycardias (SVTs) originating from near the normal conduction system. METHODS: We analyzed all patients undergoing combined cryo- and RF- catheter ablation at Mayo Clinic, Rochester, MN as part of the ablation of SVTs with potential risks of injury to the normal conduction system. This study aimed to assess the outcome of a combined cryo- and RF-catheter ablation of various types of SVTs. RESULTS: The study population consisted of 54 patients (38 ± 17 years, 32 men). A combined cryo- and RF-catheter ablation was attempted for septal accessary pathways (APs) in 26, atrioventricular nodal reentrant tachycardia (AVNRT) in 14, atrial tachycardia (AT) in 7, and junctional ectopic tachycardia in 7 patients. Forty-one patients (76%) were successfully ablated with cryoablation, and RF ablation after an unsuccessful cryoablation ablated the SVTs successfully at the same location in 6 patients (11%). Complication occurred in 1 patient (deep vein thrombosis). The cumulative freedom from SVT rate at 30 days after the procedure was 78% and there was no significant difference in the recurrence rate among the SVTs. CONCLUSION: A combined cryo- and RF-catheter ablation is clinically effective in patients undergoing SVT ablation with the potential risk of injury to the normal conduction system.

Electrophysiologic effects and outcomes of sympatholysis in patients with recurrent ventricular arrhythmia and structural heart disease.

INTRODUCTION: Autonomic modulation has been used as a therapy to control recurrent ventricular arrhythmia (VA). This study was to explore stellate ganglion block (SGB) effect on cardiac electrophysiologic properties and evaluate the long-term outcome of cardiac sympathetic denervation (CSD) for patients with recurrent VA and structural heart disease (SHD). MATERIALS AND METHODS: Patients who had recurrent VA due to SHD were enrolled prospectively. Electrophysiologic study and ventricular tachycardia (VT) induction were performed before and after left and right SGB. VA burden and long-term outcomes were assessed for a separate patient group who underwent left or bilateral CSD for drug-refractory VA due to SHD. RESULTS: Electrophysiologic study of nine patients showed that baseline mean (SD) corrected sinus node recovery time (cSNRT) increased from 320.4 (73.3) ms to 402.9 (114.2) ms after left and 482.4 (95.7) ms after bilateral SGB (P = .03). SGB did not significantly change P-R, QRS, and Q-T intervals and ventricular effective refractory period, nor did the inducibility of VA. Nineteen patients underwent left (n = 14) or bilateral (n = 5) CSD. CSD reduced VA burden and appropriate ICD therapies from a median (interquartile range) of 2.5 (0.4-11.6) episodes weekly to 0.1 (0.0-2.4) episodes weekly at 6-month follow-up (P = .002). Three-year freedom from orthotopic heart transplant (OHT) and death was 52.6%. New York Heart Association functional class III/IV and VT rate less than 160 beats per minute were predictors of recurrent VA, OHT, and death. CONCLUSION: SGB increased cSNRT without changing heart rate. CSD was more beneficial for patients with mild-to-moderate heart failure and faster VA.

Stellate ganglion block and cardiac sympathetic denervation in patients with inappropriate sinus tachycardia.

BACKGROUND: Inappropriate sinus tachycardia (IST) remains a clinical challenge because patients often are highly symptomatic and not responsive to medical therapy. OBJECTIVE: To study the safety and efficacy of stellate ganglion (SG) block and cardiac sympathetic denervation (CSD) in patients with IST. METHODS: Twelve consecutive patients who had drug-refractory IST (10 women) were studied. According to a prospectively initiated protocol, five patients underwent an electrophysiologic study before and after SG block (electrophysiology study group). The subsequent seven patients had ambulatory Holter monitoring before and after SG block (ambulatory group). All patients underwent SG block on the right side first, and then on the left side. Selected patients who had heart rate reduction ≥15 beats per minute (bpm) were recommended to consider CSD. RESULTS: The mean (SD) baseline heart rate (HR) was 106 (21) bpm. The HR significantly decreased to 93 (20) bpm (P = .02) at 10 minutes after right SG block and remained significantly slower at 97(19) bpm at 60 minutes. Left SG block reduced HR from 99 (21) to 87(16) bpm (P = .02) at 60 minutes. SG block had no significant effect on blood pressure or HR response to isoproterenol or exercise (all P > .05). Five patients underwent right (n = 4) or bilateral (n = 1) CSD. The clinical outcomes were heterogeneous: one patient had complete and two had partial symptomatic relief, and two did not have improvement. CONCLUSION: SG blockade modestly reduces resting HR but has no significant effect on HR during exercise. Permanent CSD may have a modest role in alleviating symptoms in selected patients with IST.

Fragmentation of QRS complex during ventricular pacing is associated with ventricular arrhythmic events in patients with left ventricular dysfunction.

BACKGROUND: QRS fragmentation (fQRS) during baseline ventricular conduction, a myocardial fibrosis marker, is associated with increased risk of ventricular tachyarrhythmias but may not manifest unless ventricular activation change is provoked. We examined the association of fQRS during right ventricular (RV) pacing with death and ventricular tachyarrhythmia in patients with left ventricular (LV) dysfunction undergoing electrophysiology study (EPS). METHODS AND RESULTS: Study participants had LV dysfunction (ejection fraction < 50%) undergoing EPS from January 2002 to May 2014 at Mayo Clinic in Rochester, Minnesota. fQRS during RV stimulation involved >2 notches on R/S waves identified in ≥2 contiguous standard electrocardiographic leads representing anterior, inferior, or lateral ventricular segments. Primary outcomes were ventricular tachyarrhythmias that were symptomatic or required intervention and total and cardiac deaths. In all, 528 patients participated (mean age, 65 years; male sex, 80%). Of them, 312 (59%) had ischemic cardiomyopathy and mean (SD) left ventricular ejection fraction (LVEF) of 33.2% (9.5%); 457 (87%) had implantable cardiac devices (implanted defibrillator, n  =  380). Mean (SD) follow-up was 3.2 (3.0) years. fQRS during RV pacing was observed in 292 patients (60%) in any ventricular segment. Patients with fQRS during RV pacing had 2.5 higher rate of ventricular tachyarrhythmia events than patients with no fQRS (hazard ratio [95% CI], 2.45 [1.5-4.2]; P < 0.01), after correcting for baseline ventricular conduction defect and QRS duration, LVEF, inducible sustained ventricular tachycardia, diabetes mellitus, chronic kidney disease, and ischemic cardiomyopathy. CONCLUSIONS: RV stimulation can unmask fQRS, and it is associated with increased risk of ventricular tachyarrhythmia in LV dysfunction.

Impact of sedation vs. general anaesthesia on percutaneous epicardial access safety and procedural outcomes.

Aims: Patient movement while under moderate/deep sedation may complicate percutaneous epicardial access (EpiAcc), mapping and ablation. We sought to compare procedural outcomes in patients undergoing EpiAcc under sedation vs. general anaesthesia (GA) for ablation. Methods and results: Patients undergoing EpiAcc between January 2004 and July 2014 were included. Safety, procedural, and clinical outcomes were compared between patients undergoing EpiAcc under sedation or GA for ventricular tachycardia or premature ventricular complex ablation. Between January 2004 and July 2014, 170 patients underwent EpiAcc (mean age, 53.2 ± 15.8 years; average ejection fraction, 44.3 ± 15.3%). The majority (122 [72%] patients) were male. GA was used in 69 (40.6%). There was no difference in route of access (more often anterior, 53.0%) or the rate of successful access (96% overall) between groups. Similarly, the site of ablation (endocardial vs. epicardial vs. combined endocardial/epicardial) was similar between groups. Complications were equally seen between groups-the most frequent event/complication was pericardial effusion, occurring in 10.6% of patients. Finally, procedural and clinical success rates between GA and sedation groups were comparable (93 vs. 91% and 44 vs. 51%, respectively, P > 0.05). Conclusions: Choice of anaesthesia for EpiAcc does not appear to significantly affect safety and procedural or clinical outcomes. For patients in whom anaesthesia may pose increased risk, it is reasonable to obtain epicardial access under sedation.

Effect of Ventricular Arrhythmia Ablation in Patients With Heart Mate II Left Ventricular Assist Devices: An Evaluation of Ablation Therapy.

BACKGROUND: Patients with advanced heart failure (HF) are predisposed to ventricular arrhythmias (VAs), particularly following implantation of a left ventricular assist device (LVAD). There is minimal evidence for appropriate management strategies. OBJECTIVES: This study aimed to compare the burden of VA and response to ablation performed either before or following LVAD implantation. METHODS: We created a retrospective cohort of patients who underwent both VA ablation and Heart Mate II (Thoratec, Pleasanton, CA, USA) LVAD implantation at Mayo Clinic (Rochester, MN, USA). Patients were stratified based on whether they underwent VA ablation before (pre-LVAD) or after LVAD (post-LVAD) implantation. Descriptive analyses assessed 6-month arrhythmia burden in relation to LVAD implantation and VA ablation. RESULTS: A total of 9 patients underwent both LVAD implantation and VA ablation. There were 3 and 6 patients, respectively, in the pre-LVAD and post-LVAD cohorts. Among patients in the pre-LVAD cohort, the median number of VAs tended to increase after ablation (9 vs. 72) and decreased after LVAD implantation (72 vs. 63). Similarly among patients in the post-LVAD cohort, the median burden of VAs increased after LVAD implantation (1 vs. 22) and the median burden decreased after ablation (22 vs. 13). Two of 6 patients had substrate related to the LVAD inflow cannula site, while other substrate was not related directly to the cannula. CONCLUSIONS: In patients with progressive HF and LVAD implantation, ablation is associated with reduced VA rates. In LVAD patients, most VAs arise from substrate unrelated to the inflow cannula site.

Acute Sinus Node Dysfunction after Atrial Ablation: Incidence, Risk Factors, and Management.

BACKGROUND: Many patients with atrial fibrillation (AF) or atrial flutter (Aflutter) have concomitant sinus node dysfunction (SND). Ablation may result in injury to the sinus node complex or its blood supply resulting in sinus arrest and need for temporary pacing. We sought to characterize patients who develop acute SND (ASND) during/immediately after AF/Aflutter ablation. METHODS: We performed a retrospective analysis of AF/Aflutter ablation patients between January 1, 2010 and February 28, 2015 to characterize those who required temporary pacemaker (TPM) implantation due to ASND (sinus arrest, sinus bradycardia <40 beats/min, or junctional rhythm with hemodynamic compromise) following atrial ablation. RESULTS: Of 2,151 patients, eight patients (<0.5%) with ASND manifesting as sinus arrest (n = 2), severe sinus bradycardia (n = 2), and junctional rhythm with hemodynamic compromise (n = 4) were identified (all male, age 66 ± 9.9 years, 4/8 [50%] persistent AF). AF ablation was performed in four, atypical Aflutter in one, and AF/Aflutter in three patients. The ablation set consisted of: pulmonary vein (PV) isolation (n = 6), roof line ablation (n = 6), mitral annulus-left inferior PV line ablation (n = 5), left atrial appendage-mitral annulus ablation (n = 1), cavotricuspid isthmus ablation (n = 5), and isolation or ablation near the superior vena cava (SVC, n = 4). Patients with peri-SVC ablation were more likely to develop ASND (P = 0.03). All patients received TPM; six received permanent pacemaker before discharge, performed 3.5 days postablation (range 2-6 days). At 3-month device interrogation, all patients were atrially paced >50%. CONCLUSION: ASND is a rare complication of atrial ablation. It may be more common when peri-SVC ablation is performed and may necessitate permanent pacemaker implantation.

Electrophysiologic characteristics of ventricular arrhythmias arising from the aortic mitral continuity-potential role of the conduction system.

INTRODUCTION: Catheter ablation of ventricular arrhythmia (VA) at the fibrous aortic mitral continuity (AMC) has been described, yet the nature of the arrhythmogenic substrate remains unknown. METHODS: Procedural records of 528 consecutive patients undergoing ablation of VA at Mayo Clinic, Rochester, MN, were reviewed. The electrocardiographic and electrophysiologic characteristics of patients with successful ablation at the AMC were analyzed to characterize the underlying arrhythmogenic substrate. RESULTS: Of the 21 patients (mean age 53.2 ± 13.4 years, 47.6% male) who underwent ablation of VA at the AMC with acute success, prepotentials (PPs) were found at the ablation sites preceding the ventricular electrogram (VEGM) during arrhythmias in 13 (61.9%) patients and during sinus rhythm in 7 (53.8%) patients. VAs with PPs were associated with a significantly higher burden of premature ventricular complexes (PVCs; 26.1 ± 10.9% vs. 14.9 ± 10.1%, P = 0.03), shorter VEGM to QRS intervals (9.0 ± 28.5 milliseconds vs. 33.1 ± 8.8 milliseconds, P = 0.03), lower pace map scores (8.7 ± 1.6 vs. 11.4 ± 0.8, P = 0.001), and a trend toward shorter V-H intervals during VA (32.1 ± 38.6 milliseconds vs. 76.3 ± 11.1 milliseconds, P = 0.06) as compared to those without PP. A strong and positive correlation was found between V-H interval and QRS duration during arrhythmia in those with PPs (B = 2.11, R(2) = 0.97, t = 13.7, P < 0.001) but not in those without PPs. CONCLUSION: Local EGM characteristics and relative activation time of the His bundle suggest the possibility of conduction tissue as the origin for VA arising from the fibrous AMC. Specific identification and targeting of PPs when ablating VAs at this location may improve procedural success.

Successful percutaneous epicardial access in challenging scenarios.

BACKGROUND: This case-series highlights strategies used for successful epicardial access in challenging cases. Percutaneous epicardial access has become a valuable tool for mapping and ablating arrhythmias. However, this technique can be especially difficult in certain circumstances and is frequently avoided. METHODS: All cases of epicardial access for ablation from our institution were reviewed searching for exceptionally difficult cases in patients with complex pericardial and thoracic anatomy. The successful strategies are characterized in this report. RESULTS: Among 144 patients who underwent an epicardial ablation procedure between January 2004 and June 2013, four required unconventional approaches for epicardial access for ventricular tachycardia ablation. Two patients (one with previous cardiac surgery and one with prior pericardial effusion) had substantial fibrous pericardial adhesions with no virtual pericardial space and required adhesiolysis. One patient, status postpartial colectomy, underwent computed tomography-guided intercostal epicardial access due to the presence of bowel throughout the subdiaphragmatic space in the upper abdomen. The fourth patient had partial congenital absence of the pericardium and underwent epicardial access through the creation of a subxiphoid window. All epicardial accesses were successful and performed without major complication. CONCLUSIONS: With precise procedural planning and cardiac imaging, percutaneous epicardial access is feasible even in patients with significant anatomical challenges.

Pericardial effusion following drain removal after percutaneous epicardial access for an electrophysiology procedure.

OBJECTIVES: To determine the frequency and predictors of pericardial effusion following epicardial sheath removal. BACKGROUND: Pericardial effusion can occur following cardiac surgical or interventional procedures including percutaneous epicardial access (EpiAcc), which is increasingly used as part of electrophysiology ablation procedures. METHODS: A retrospective analysis of the Mayo Clinic comprehensive electronic medical record was performed from all patients who underwent planned EpiAcc as part of an electrophysiology ablation procedure between January 1, 2004 and June 30, 2013. RESULTS: Of 144 patients (mean age 51.3 ± 15.5 years, 68% male) who underwent planned EpiAcc as part of an electrophysiology ablation (95.8% pericardial access success rate), seven (4.9%) developed a postoperative pericardial effusion requiring repeat EpiAcc. Inferior access was utilized in 74 (51.4%) patients. Patients with pericardial effusion tended to be younger (41.1 years vs 51.8 years, P = 0.08) and were more likely to have undergone inferior approach access (85.7% vs 49.6%, P = 0.06) than those who did not develop postoperative pericardial effusion. Seventy-one percent of patients with postoperative pericardial effusion versus 32.1% of patients without postoperative pericardial effusion had a preprocedure ejection fraction ≥55% (P = 0.03). There were no procedural-related deaths, and no difference in mortality between groups. CONCLUSIONS: Postoperative pericardial effusion requiring repeat access/drainage was relatively infrequent, occurring in 4.9% of patients shortly after epicardial procedures. While the majority occur early and therefore require close observation, some patients may present in a delayed manner.

Obesity does not increase complication rate of percutaneous epicardial access.

INTRODUCTION: Percutaneous epicardial access for ablative therapies is an increasingly common technique utilized for refractory ventricular arrhythmias. There are, however few known data on obesity and complication rates associated with this procedure. METHODS AND RESULTS: We retrospectively reviewed the charts of subjects undergoing epicardial access at Mayo Clinic between January 2004 and June 2013. Baseline clinical and echocardiographic data were collected for each subject, who was then classified into body mass index (BMI) categories as underweight, normal weight, overweight, and obese based on a BMI of <18.5, 18.5-24.99, 25-29.99, and ≥30, respectively. Events and complications were recorded, and procedural and clinical success rates were determined. There was no statistically significant difference in access approach, procedural or clinical outcomes, or complications among the BMI categories. Note that 95.1%, 91.7%, and 93.1% derived procedural success among the normal weight, overweight, and obese categories, respectively (P value = 0.81). Similarly, there was no difference in clinical outcomes with success rates of 68.3%, 66.7%, and 75.9% between the respective groups (P value = 0.54). At 5 years, there was a trend toward increased mortality among obese individuals (28.8%) compared to normal weight (8.8%) and overweight (9.8%) patients (P value = 0.139). CONCLUSION: Percutaneous epicardial access, mapping, and ablation can be performed in obese individuals with similar outcomes to those of lower weight category. Obesity should not preclude the use of percutaneous epicardial access when clinically indicated.

Distinguishing ventricular arrhythmia originating from the right coronary cusp, peripulmonic valve area, and the right ventricular outflow tract: utility of lead I.

INTRODUCTION: Outflow tract ventricular arrhythmia (OTVA) can be complicated to target for ablation when originating from either the periaortic or pulmonary valve (PV) region. Both sites may present with a small R wave in lead V1. However, the utility of lead I in distinguishing these arrhythmia locations is unknown. METHODS AND RESULTS: Thirty-six consecutive patients (mean age 41 ± 14 years, 13 male) underwent catheter ablation for OTVA. OTVA origin was determined from intracardiac electrogram tracings and electroanatomic maps. Observers blinded to results measured QRS waveform amplitude and duration from standard 12-lead ECG tracings. Measurements with highest diagnostic performance were modeled into an algorithm. Sites of successful ablation were anterior right ventricular outflow tract (RVOT; n = 6), posterior RVOT (n = 4), PV (n = 18), and right coronary cusp (RCC; n = 8). Highest performing surface ECG discriminators were from lead I to V1 vectors: RCC, lead I R wave ≥ 1.5 mV, and V1 R wave ≥2.0 mV (sensitivity 87%, specificity 93%); PV, V1 R wave > 0 mV, and lead I R/(R+S) ≤ 0.75 (sensitivity 78%, specificity 72%); anterior RVOT, V1 R wave = 0 mV, and lead I R/(R+S) <0.4 (sensitivity 67%, specificity 97%); posterior RVOT, V1 R wave > 0 mV, and lead I R/(R+S) > 0.75 (sensitivity 75%, specificity 84%). Sequential algorithmic application of these criteria resulted in an overall accuracy of 72% in predicting site of OTVA origin. CONCLUSIONS: A relatively large R wave in lead I is seen with RCC origin but not PV origin. A sequential algorithm has limited but potentially significant value beyond assessment of lead I in approaching OTVA.

A prospective randomized trial of single- or dual-chamber implantable cardioverter-defibrillators to minimize inappropriate shock risk in primary sudden cardiac death prevention.

AIMS: Dual-chamber implantable cardioverter-defibrillators (ICDs) may improve specificity and reduce the risk of inappropriate shocks, and enhance atrial arrhythmia (AT/AF) detection to permit stroke prevention compared with single-chamber ICDs, but at additional expense and risk. METHODS AND RESULTS: Patients (n = 100) receiving primary prevention ICDs at two USA and two Israeli centres were randomized to dual-chamber or single-chamber devices between December 2008 and December 2010 and were followed for 1 year. Programming in both groups included: delayed detection to avoid therapy for non-sustained episodes; high detection cut-off rates to avoid treating slower, better tolerated arrhythmias; minimized right ventricular pacing; and routine use of supraventricular-ventricular tahcycardia discriminators and antitachycardia pacing. The primary outcome was the proportion of patients with inappropriate shocks. One patient in each group (2%) received inappropriate shocks (P = 1.00). Death occurred in two patients in the single-chamber arm, and in none of the patients in the dual-chamber arm (P = 0.15). New AT/AF was detected in 12 patients (24%) in the dual-chamber group, vs. no patients in the single-chamber group (P < 0.001). Among US participants, the mean cost of dual- vs. single-chamber ICD implantation was $16 579 vs. $14 249, respectively (P < 0.001); there was no difference in the quality of life (EQ-5D index difference 0.013, P = 0.769; EQ VAS difference 3.3, P = 0.49). CONCLUSION: When optimal programming is utilized, inappropriate shocks are rare in primary prevention patients with both single- and dual-chamber ICDs. The routine use of dual-chamber ICDs increases the expense without reducing inappropriate shocks or improving the quality of life at 1 year. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00787800.