Munger, Thomas M.

Introduction: Prior cardiac surgery, especially the presence of coronary bypass grafts, is thought to preclude percutaneous epicardial access (EpiAcc) and, due to limited catheter maneuverability, mapping and ablation. The objective of our study was to evaluate the feasibility and safety of EpiAcc in patients with prior cardiac surgery. Methods: We retrospectively analyzed all patients who underwent EpiAcc as part of an ablation procedure between 01/01/2004-06/30/2013 at Mayo Clinic, Rochester, MN. All had documented VT or recurring, symptomatic PVCs. Baseline clinical characteristics and procedural characteristics were collected. Results: Of 162 patients that underwent EpiAcc, 18 had prior cardiac surgery (mean age 61 years, all male). This included 10 CABG, 2 epicardial ICD placement, 5 valve surgery (3 aortic valve, 2 mitral valve), 2 septal myectomy, 1 aortic arch replacement, 1 myocardial bridge unroofing and 1 myocardial perforation repair (3 patients had multiple procedures). Access was successful in 12 patients (66.7%); the inferior approach was utilized in 78%. Of patients with prior CABG, successful access was attained in 6 (60%). The average procedural time was 441.6 ± 141.3 minutes. Adhesiolysis was required in 10 patients with the sheath, access wire, pigtail catheter or ablation catheter. Intra-procedural coronary angiography was performed in 8 patients. There were a total of 45 VTs/PVCs ablated in 18 patients (average 2.5 ± 1.7), mean cycle length 463.6 ± 95.9ms. Ultimately, 12 patients (66.7%) underwent endocardial only ablation, 1 (5.5%) had epicardial only ablation while 5 (27.8%) had endocardial/epicardial ablation. The procedure was deemed successful in 13 patients (72.2%). Four patients had bleeding complications (pericardial effusion, pericardial hematoma, hemoperitoneum and pericardial tamponade [the latter required repair of the RV wall]). In patients with coronary grafts, there was no evidence of acute graft disruption. Conclusions: Percutaneous epicardial access is feasible in patients with previous cardiac surgery, including CABG. However, adhesiolysis is frequently required. Although the risk of coronary graft injury is low, life-threatening complications may occur.

Introduction: Percutaneous epicardial access (EAc) is increasingly performed as part of VT/PVC ablation, especially in those that have failed prior ablation. We aimed to delineate the outcomes of EAc. Methods: We retrospectively analyzed individuals undergoing EAc for arrhythmia ablation between June 2004 and July 2014. Acute procedural success was defined as elimination/non-inducibility of the clinical arrhythmia after ablation; clinical success was defined as absence of symptoms/arrhythmia. Results: Of 175 patients, 126 (72%) were male with a mean age of 52.8±15.7 years. Eighty-three (47.4%) patients had NICM, 25 (14.3%) had ICM and 34 (19.4%) had normal hearts. Baseline EF was 44±16%. Patients had failed an average of 1.7±1.2 antiarrhythmic drugs; 139 patients (79%) had failed prior endocardial (endo) ablation (average 1.3±1.1). Six (3.4%) had prior EAc and 18 (10.3%) prior cardiac surgery. The indication for ablation was VT or PVC in 113 (64.6%) and 60 (34.3%) patients, respectively. Successful access was obtained in 168 (98%) patients. Anterior access, inferior access, or both, was utilized in 89 (52.7%), 77 (45.6%) and 2 (1.2%) patients, respectively. There were an average of 2.7±2.2 VT/PVCs identified, and 1.6±1.1 ablated. Endo, epicardial (epi) or combined ablation was performed in 58 (33.1%), 14 (8%), and 100 (57.1%) patients, respectively; 3 did not undergo ablation. Procedural success was obtained in 158 of 173 (91.3%) patients for whom data was available. At 12 months, clinical success was maintained in 62% with no difference between endo, epi or combined ablation (figure). Cardiac tamponade requiring repeat EAc occurred in 12 (6.9%) patients. There were no procedural related deaths. Conclusion: Epicardial access is feasible in almost all patients with no prior cardiac surgery, and permits acute procedural success in 91.3% of patients, most of whom had failed previous ablation. Furthermore, complications are relatively infrequent in this complex cohort.

Background. ICD implantation for primary prevention of sudden death in patients with ischemic cardiomyopathy and left ventricular dysfunction is well established. However debate exists between the relationship between ischemia and the proarrhythmic state. Persistent ischemia may counter antiarrhythmic (AA) drug and/or device efficacy. Furthermore, the extent to which revascularization mitigates this influence of ischemia on efficacy is unknown. Methods . 704 patients enrolled in the MUSTT trial were studied. Ischemia was determined by the presence of angina within 6 weeks of enrollment and ≥ 2 reversible thallium defects. Revascularization was characterized as CABG or PTCA within 1 year of enrollment or the use of thrombolytics with the sentinal myocardial infarction (MI). We compared groups who were randomized to background medical treatment (BG Rx) verses those who were randomized to AA drug therapy in addition to EP testing (EP AARx). Results . 507 (81%) patients had ≤2 vessel CAD, whereas the remaining 19% had 3 vessel disease. 268 patients reported angina within 6 weeks of study enrollment. Thallium imaging revealed 0–1 defects in 458 (65%) and ≥2 in another 246 (35%). Those with ≥ 2 defects on Thallium and angina within 6 weeks of device implant had a significantly lower 5-year freedom from mortality in the EP AARx and BG Rx cohorts (Table ). Patients with EP AARx had an 8% lower mortality than those with BG Rx therapy alone if they received thrombolytics. However, if they did not receive thrombolytics, their mortality rate was 5% higher than the BG Rx group. Conclusion . Outcomes are worse in patients on antiarrhythmic therapy with ischemic factors compared to those on background therapy alone, particularly in the setting of recent angina. A proarrhythmic effect from antiarrhythmic drug therapy in patients with ischemia may underlie the higher mortality. ICD therapy mitigates the negative long-term effect of ischemia on mortality in those treated with AA therapy. Five Year Freedom from Mortality

Background : Lipid lowering therapy reduces mortality in patients with both ischemic and nonischemic cardiomyopathies and recently has been shown to decrease ICD shocks. Radiofrequency ablation (RFA) of recurrent VT in patients with an ICD also reduces shocks following intervention. It is unclear if statin therapy after VT RFA will further impact ICD shock rates. Methods : All patients from 1993–2005 who underwent a RFA procedure for recurrent VT at the Mayo Clinic with an ICD were included. Patient records were extracted for medical and procedural details and all ICD interrogations were reviewed for VT recurrence and therapies. Results: 63 patients (age 62±15 years) were followed over 3.9±3.6 years. Comorbid diseases included: coronary artery disease 37(58%, 34 prior myocardial infarction), ARVD/C 6(10%), nonischemic dilated cardiomyopathy 7(11%), moderate-severe valve disease 14(22%), hypertension 34(54%), and hyperlipidemia 35(56%). Ejection fraction was <0.35 in 34(56%). VT was induced in all patients (LV 55 (LVOT 1), RV 8 (RVOT 3) with multiple inducible VTs in 21(33%). VT was noninducible after RFA in 39(62%) patients. Dismissal medications included: statins 19(30%), beta blockers 40(66%), ACE/ARB 37(61%), diuretics 34(55%), and digoxin 23(37%). 5-year overall survival was 63%(95% CI 55–71). Age, diabetes, and renal insufficiency were associated with increased post ablation mortality, with no medication improving survival. 5-year survival free of ICD shocks was 31%(95% CI 24–38). Only statin therapy at discharge was associated with a decreased risk of ICD shocks [5(26%) versus 26(59%), p=0.020]. 7 additional patients received statins during follow-up, but not at discharge, of these 5(71%) had shocks. Conclusion : Statin use at discharge in patients with an ICD undergoing RFA for refractory VT significantly reduced recurrent ventricular arrhythmias and ICD shocks. Although the mechanism underlying the effects of statins on arrhythmic recurrence early after RFA requires further study, these data support aggressive therapy of the underlying substrate responsible for the VT.

Determining whether retrograde ventriculoatrial (VA) conduction is through the AV node (AVN) or an accessory pathway (AP) is critical for successful ablation of supraventricular tachycardia (SVT). With introduction of ventricular extrastimuli (VEST), retrograde right bundle branch block (retro RBBB) may occur and result in abrupt VH interval prolongation. We hypothesized when retrograde conduction is via an AP, VA interval change is less than VH interval change, whereas with retrograde AVN conduction, VA interval change is equal to or greater than VH interval change. We retrospectively reviewed the electrophysiology (EP) studies of patients undergoing ablation for AVNRT (n=55) or AVRT (n=50). The intracardiac electrograms were reviewed for induction of retro RBBB and change in VH and VA intervals during VEST. Parahisian pacing, decremental pacing, arrhythmia diagnosis and ablation outcomes were reviewed. All results were found to be reproducible between two independent observers with inter and intra observer reliability scores of 1.00 for identification of retro RBBB and greater than 0.85 for measurement of VH and VA intervals. Of 105 patients, 84 (80%) had evidence of induced retro RBBB during VEST. The average VH interval increase with induction of retro RBBB was 53.7 ms for patients with retrograde AP conduction and 54.4 ms for patients with AVN conduction (p=ns). The average VA interval increase with induction of retro RBBB was 13.6 ms with AP conduction and 70.1 ms with AVN conduction (P < 0.001). All patients with a greater VH than VA interval change had a final diagnosis of AVRT and those with a VH change less than VA change had AVNRT, yielding sensitivity and specificity of 100%. Using a cutoff of 50 ms for change in VA interval with onset of retro RBBB to diagnose AVNRT accurately identified AVNRT in 100% and AVRT in 95%. Induction of retro RBBB during VEST is common during EP studies for SVT. The relative change in the VH and VA intervals during retro RBBB accurately differentiates retrograde AVN from retrograde AP conduction with strong predictive accuracy. The use of retro RBBB based intervals is a useful technique facilitating the diagnosis of SVT in the EP laboratory, even in the absence of inducible tachycardia.

Introduction: Left atrial appendage (LAA) flow depends largely on left ventricular compliance and may play a role in mediating the regulation of left atrial volume-pressure relationships. Hypothesis: We hypothesize that LAA emptying flow velocity (LAAEV) is a predictive factor of long-term outcomes (e.g. recurrent AF, stroke, and survival) after cardioversion for non-valvular AF. Method: We identified 3,251 consecutive patients with non-valvular AF who underwent successful TEE-guided electrical cardioversion (ECV) at our institution between May 2000 and March 2012. Successful ECV was defined as sinus rhythm at time of discharge from the cardioversion unit. Patients were monitored following their ECV procedure for first documentation of recurrent AF, stroke or death. Multivariate Cox proportional hazards models were used to identify independent predictors of long-term outcomes. Patients with >= moderate valvular regurgitation or stenosis were excluded. Results: Among the 3,251 patients who were successfully cardioverted to sinus rhythm, the mean (±SD) LAAEV was 38.43±23 cm/s and the median was 33 cm/s, (interquartile range [IQR], 20-50). Patients with LAAEV <=33 cm/s had higher CHA 2 DS 2 -VASc score (2.6±1.2 vs. 1.9±1.3, P =.009), larger LAVI (52.0±20.9 cc/m 2 vs. 43.3±13.6 cc/m 2 , P <.001) than those with LAAEV >33 cm/s. Pre or post-procedure antiarrhythmic drug use was similar between the two groups. During 1-year follow-up, patients with LAAEV <=33 cm/s had significantly higher rate of AF recurrence than those with LAAEV >33 cm/s (55% vs 45%, P <.001). Likewise, during a mean follow-up of 4.9±3.6 years, similar patterns in 5-year rates were observed for first recurrence of AF (81% vs 73%, P <.001), stroke (7% vs 4%, P =.003) and mortality (31% vs 23%, P <.001) for LAAEV <=33 vs > 33cm/s, respectively. Stepwise multivariate Cox regression analysis revealed that LAAEV <=33 cm/s, age, CHA 2 DS 2 -VASc score were independent predictors of AF recurrence, stroke and mortality. Conclusions: LAA emptying flow velocity is an effective and convenient method for risk stratification of patients undergoing cardioversion for AF. Our data showed that patients with reduced LAAEV have an increased risk for AF recurrence, stroke and death following electrical cardioversion.

Background: Data regarding ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation following MVS is limited.) 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 catheter ablation (CA) in patients with prior mitral valve surgery (MVS) and ventricular arrhythmias (VA). Methods: We identified consecutive patients with prior MVS who underwent CA for VT or PVC between January 2013- December 2018. We investigated the mechanism of arrhythmia, ablation approach, peri-operative complications, and outcomes. Results: In our cohort of 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 1patient. Heterogenous scar regions were present in 94% of VT patients and scar-related reentry was the dominant mechanism of VT. Clinical VA substrates involved the peri-mitral area in 6 patients with VT and 5 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

Background The temporal incidence of high‐grade atrioventricular block (HAVB) after transcatheter aortic valve replacement (TAVR) is uncertain. As a result, periprocedural monitoring and pacing strategies remain controversial. This study aimed to describe the temporal incidence of initial episode of HAVB stratified by pre‐ and post‐TAVR conduction and identify predictors of delayed events. Methods and Results Consecutive patients undergoing TAVR at a single center between February 2012 and June 2019 were retrospectively assessed for HAVB within 30 days. Patients with prior aortic valve replacement, permanent pacemaker (PPM), or conversion to surgical replacement were excluded. Multivariable logistic regression was performed to assess predictors of delayed HAVB (initial event >24 hours post‐TAVR). A total of 953 patients were included in this study. HAVB occurred in 153 (16.1%). After exclusion of those with prophylactic PPM placed post‐TAVR, the incidence of delayed HAVB was 33/882 (3.7%). Variables independently associated with delayed HAVB included baseline first‐degree atrioventricular block or right bundle‐branch block, self‐expanding valve, and new left bundle‐branch block. Forty patients had intraprocedural transient HAVB, including 16 who developed HAVB recurrence and 6 who had PPM implantation without recurrence. PPM was placed for HAVB in 130 (13.6%) (self‐expanding valve, 23.7% versus balloon‐expandable valve, 11.9%; P <0.001). Eight (0.8%) patients died by 30 days, including 1 unexplained without PPM present. Conclusions Delayed HAVB occurs with higher frequency in patients with baseline first‐degree atrioventricular block or right bundle‐branch block, new left bundle‐branch block, and self‐expanding valve. These findings provide insight into optimal monitoring and pacing strategies based on periprocedural ECG findings.

AbstractBackgroundLittle 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 ResultsOur 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.ConclusionPVCs arising from PPAV regions can be successfully ablated in patients with prior AVR, without damaging the prosthetic aortic valve and atrioventricular conduction.

AbstractObjectiveThis 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).BackgroundDual‐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.MethodsA 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).ResultsIn 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.ConclusionsSetting 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.