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Introduction Left ventricular non-compaction (LVNC) is a rare cardiomyopathy thought to result from intrauterine arrest of myocardial compaction which has been associated with and increased risk of sudden cardiac death (SCD). However, appropriate identification of at-risk individuals and risk-stratification is lacking, particularly in patients diagnosed during adulthood. We sought to identify high-risk patients wtih LVNC in order to guide therapy. Hypothesis That patients with decreased left ventricular ejection fraction (LVEF) would have worse outcomes than those with preserved left ventricular function. Methods We reviewed outcomes in all patients diagnosed with LVNC at Mayo Clinic between 2001 through 2006. Data were prospectively entered into a centralized database and retrospectively analyzed. Mortality was compared to age and sex matched population rates. Results A total of 80 patients were diagnosed with LVNC during this interval. After exclusion of pediatric patients (n = 21), 59 adult patients (62% male; age 46 ± 19 years, range 18–83) were analyzed. There were 4 deaths in this group (none due to stroke, mortality 18% at 2 years) during follow-up (mean 13.0 ± 13.5 months, range 0–52). Overall survival of patients with LVNC was worse than age and sex matched controls (Minnesota population p < 0.001). This was also noted in patients with LVEF > 35% (n = 35, p = 0.02). Overall LVEF was 41 ± 16% but was lower in patients who died compared to survivors (26 ± 10% vs. 42 ± 15%; Hazard ratio = 2.0 for a decrease in ejection fraction of 10%, p = 0.12). There were no deaths in patients with LVEF > 50% (n = 17). Conclusion Survival of adults with LVNC is worse than expected for age and sex. A decrease in ejection fraction is associated with increased risk of death in this population. These data suggest that patients diagnosed with LVNC and reduced LVEF may benefit from ICD implantation, whereas patients with a normal LVEF may be observed.

Radiofrequency (RF) ablation for cardiac arrythmias is an established curative therapy. However, catheter-tip coagulum formation leading to thromboembolic stroke is a persistent problem despite heparinization. Recent studies demonstrated an up to 70% incidence of thrombus formation on the catheter tip during ablation and a 10 % incidence of thromboembolic events. Catheter tip thrombus can impede the delivery of RF energy to the tissue, resulting in reduced efficacy and longer procedure times. Here we report on a novel method to prevent coagulum formation on ablation catheters by delivering a negative charge to the catheter tip to repel negatively charged fibrinogen molecules during RF ablation. A novel circuit was built with a charge delivery unit using a 9 voltage battery to deliver a fixed offset direct current charge, placed in parallel to the RF delivery unit for negative charge placement during RF delivery. In in-vivo canine experiments (n=50) standard 6/4, 8/5 ablation catheters and catheters with abraded tips were advanced from right femoral veins into atria and ventricles under intra-cardiac echo (ICE) and biplane fluoroscopic guidance. The dogs received 1 of 2 therapies: no RF energy delivered with and without negative charge delivery, RF energy delivery with and without negative charge delivery. The presence of thrombus was identified with ICE. The catheter tips were examined also macroscopically with visual inspection and also with field emission scanning electron microscopy (FESEM). FESEM of the catheter tips showed surface coverage of fibrin clot of the catheter tip to be 90 % for non-charged catheters compared to 0 % (p< 0.01) in negatively-charged catheters. There was no significant difference in surface coverage of fibrin clot between negatively-charged catheters with the abraded tips (98.8%) and non-charged catheters with smooth tips (90.7 %, p=ns). Clot volume formed on the catheter tip decreased with increased amount of charge. Application of a negative charge did not affect the quality of the intracardiac electrograms or induce malignant ventricular arrhythmias. Negative charge delivery during RF ablation is feasible and safe and can eliminate coagulum formation, potentially reducing thromboembolic complications.

Background: Although multiple macroreentrant atrial flutters are seen in postoperative patients with congenital heart disease, cavotricuspid isthmus (CVTI) dependent flutter remains a fairly common arrhythmia in this group. When a Fontan or atrial switch (Mustard/Senning) type of procedure is performed, a portion of the CVTI is excluded from catheter access obtainable via a systemic venous route. We evaluated different techniques to access this excluded portion and completely ablate CVTI dependent flutter. Methods/Results: Between 1990 and 2007, 140 patients with surgically corrected congenital heart disease underwent an ablation procedure at our institution. Their records were reviewed to identify those with prior Fontan or atrial switch procedure who had documented CVTI dependent flutter requiring ablation. Data collected included methods of catheter access, circuits observed or induced, the location and number of ablation lines, immediate and long-term success, and complications. Results: Sixteen patients were identified (14, Fontan; 2, Mustard). In 12/16 (75%) patients bidirectional block of CVTI dependent flutter could not be achieved by right atrial (venous approach) ablation alone. In 7 of those, the excluded portion of the CVTI was targeted for ablation. This was accomplished by a retrograde transaortic approach via an interventricular communication then through the right atrioventricular valve (5 patients). Another retrograde transaortic approach was used with the catheter crossing the left atrioventricular valve then an atrial septal communication (one patient). A third approach involved an antegrade transconduit puncture (one patient). In all 7 patients, successful ablation of CVTI dependent flutter with bidirectional block was achieved. Post-procedure, one patient had temporary AV block requiring pacemaker placement. Follow-up was available on 4/7 patients (3 to 22 months, mean 10 months) with no documented recurrence of their CVTI dependent flutter. Conclusion: Even when surgical procedures exclude a portion of the CVTI, complete ablation for typical atrial flutter with resulting bidirectional block can be achieved via “non-traditional” approaches targeting the surgically excluded arrhythmogenic tissue.

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: One million patients around the world have had total hip arthorplasty with 35% of them having metal-on-metal implants. Although there have been some case reports of cobalt cardiotoxicity from arthroprosthetic cobaltism resulting in dilated cardiomyopathy, incidence of cardiomyopathy and mortality in these patients is unknown. Objective: We therefore sought to determine the incidence of new onset cardiomyopathy (EF <40%) and associated mortality, in patients with metal hip arthroplasty. Methods: We retrospectively examined the records of the patients form our institutional total hip arthroplasty registry (Metal on Metal: MoM, Metal on Polyethylene: MoP, Ceramic on Ceramic: CoC and Ceramic on Polyethylne: CoP). Among 122 patients with baseline and follow up echocardiograms, cobalt and chromium levels were available in 12 patients, none of which developed incident cardiomyopathy. Results: The mean age of the population with metal group (MoM and MoP) was 53 years, predominantly males. During the follow up period of 10 years, the cumulative incidence (KM curve probabilities) of low EF <=40% in our study population was 14% in metal group as compared to 5% in non-metal group (CoC and CoP), (p value 0.51). At 15 years of follow up, among 122 patients, there were16 deaths in the metal group (81) and only 2 deaths in the non-metal group (41) (p value 0.15). Conclusions: In conclusion, although the incidence of cardiomyopathy as well as mortality is low in patients with metal hip arthroplasty and not significantly, further studies maybe needed to assess its effect on diastolic dysfunction.

Background: Worldwide, approximately one million patients have had total hip arthroplasty with 35% being cobalt and chromium Metal-on-Metal (MoM) or Metal-on-Polythelene (MoP) implants. Animal models have suggested that cobalt and chromium can affect all chambers, but there seems to be an atrial predilection. There are several case reports of metal containing hip arthroplasty causing atrial arrhythmias but the true incidence of atrial fibrillation associated with metal hip arthroplasty remains undefined. Objective: We sought to determine the incidence of atrial fibrillation in patients with metal containing hip arthroplasty. We also examined the association between serum cobalt and chromium levels and arrhythmias in this cohort and all cause mortality. Methods: We retrospectively examined the records of patients from the Mayo Clinic total hip arthroplasty registry (Metal group - Metal-on-Metal: MoM and Metal-on-Polyethylene: MoP, Non-Metal group - Ceramic-on-Ceramic: CoC and Ceramic-on-Polyethylne: CoP) to obtain demographic data, comorbidities, laboratory, ECG, and echocardiographic data. Out of a total of 1756 patients, Cobalt and Chromium levels were available in 138 patients. Results: The mean age of patients with metal containing hip replacement was 50 years and were predominantly male. During a follow up period of 10 years, the incidence of atrial fibrillation in our study population was 8% in metal group compared to 2% (p=0.11) in non-metal group. There was no association between cobalt or chromium levels with the incidence of atrial fibrillation. All-cause mortality was significantly higher in metal group versus non-metal group (p=0.005). Conclusion: The incidence of atrial fibrillation was relatively more in patients with metal versus non-metal hip arthroplasty but there was no association of serum cobalt or chromium levels with incidence of atrial fibrillation in the subset of patients. In addition, all-cause mortality was significantly higher in the metal group suggesting potential toxic effects of metal containing hip arthroplasty.

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

Introduction: Several chemotherapy agents, especially anthracyclines, are associated with the development of non-ischemic cardiomyopathy. When chemotherapy-induced cardiomyopathy (CHIC) is associated with left bundle branch block (QRS >150 ms) and a left ventricular ejection fraction (LVEF) of 35% or lower, cardiac resynchronization therapy (CRT) is often utilized to improve cardiac function and relieve symptoms. Hypothesis: CRT is associated with improvement in left ventricular strain in patients with CHIC. Methods: The study included 22 patients with CHIC and 44 age- and gender-matched controls with other types of NIC who underwent CRT implantation between 2004 and 2017. LVEF, left ventricular global longitudinal strain (GLS), systolic strain rate (SRS), and early diastolic strain rate (SRE) were assessed at baseline and 6-18 months after CRT. CRT response was defined as LVEF improvement by >5% after CRT. Results: CRT responders had a significant improvement in left ventricular GLS as compared to CRT non-responders in the control group, but not in the CHIC group (Table 1). The mean change in LVEF after CRT was similar between the CHIC and control groups (10 ± 10% versus 11 ± 11%, p= 0.67). The mean change in GLS after CRT was also similar between the two groups (-2.15 ± 4.32 versus -3.57 ± 4.02, p= 0.19). The proportion of patients whose LVEF increased by more than 5% was similar between the two groups (59% in the CHIC group versus 68% in the control group, p= 0.46). The mean changes in LV myocardial systolic and early diastolic strain rates were similar between the CHIC and control groups. Mean SRS decreased by 0.13 ± 0.14 in the CHIC group and by 0.34 ± 1.28 in the control group (p=0.45). Mean SRE increased by 0.06 ± 0.18 in the CHIC group and by 0.07 ± 0.22 in the control group (p=0.86). Conclusions: CRT is associated with improvement in left ventricular strain in patients with CHIC. Prospective studies are needed to further evaluate the echocardiographic strain outcomes of CRT in CHIC.