Cardiac resynchronisation therapy in anthracycline-induced cardiomyopathy.

INTRODUCTION: Chemotherapy-induced cardiomyopathy has been increasingly recognised as patients are living longer with more effective treatments for their malignancies. Anthracyclines are known to cause left ventricular (LV) dysfunction. While heart failure medications are frequently used, some patients may need consideration for device-based therapies such as cardiac resynchronisation therapy (CRT). However, the role of CRT in anthracycline-induced cardiomyopathy (AIC) is not well understood. METHODS: We performed a retrospective review of all patients undergoing CRT implantation at our centre from 2003 to 2019 with a diagnosis of AIC. The LV remodelling and survival outcomes of this population were obtained and then compared with consecutive patients with other aetiologies of non-ischaemic cardiomyopathy (NICM). RESULTS: A total of 34 patients underwent CRT implantation with a diagnosis of AIC with a mean age of 60.5±12.7 years, left ventricular ejection fraction (LVEF) of 21.7%±7.4%, and 11.3±7.5 years and 10.2±7.4 years from cancer diagnosis and last anthracycline exposure, respectively. At 9.6±8.1 months after CRT implantation, there was an increase of LVEF from 21.8%±7.6% to 30.4%±13.0% (p<0.001). Patients whose LVEF increased by at least 10% post-CRT implant (42.5% of cohort) survived significantly longer than patients who failed to improve their LVEF by that amount (p=0.01). A propensity matched analysis between patients with AIC and 369 consecutive patients with other aetiologies of NICM who underwent CRT implantation during the same period revealed no significant differences in improvement in LVEF or long-term survival. CONCLUSIONS: Patients with AIC undergo LV remodelling with CRT at rates similar to other aetiologies of NICM. Furthermore, AIC post-CRT responders have a favourable long-term mortality compared with non-responders.

Cardiac Resynchronization Therapy With or Without Defibrillation in Patients With Nonischemic Cardiomyopathy: A Systematic Review and Meta-Analysis.

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Machine Learning of 12-Lead QRS Waveforms to Identify Cardiac Resynchronization Therapy Patients With Differential Outcomes.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves heart failure outcomes but has significant nonresponse rates, highlighting limitations in ECG selection criteria: QRS duration (QRSd) ≥150 ms and subjective labeling of left bundle branch block (LBBB). We explored unsupervised machine learning of ECG waveforms to identify CRT subgroups that may differentiate outcomes beyond QRSd and LBBB. METHODS: We retrospectively analyzed 946 CRT patients with conduction delay. Principal component analysis (PCA) dimensionality reduction obtained a 2-dimensional representation of preCRT 12-lead QRS waveforms. k-means clustering of the 2-dimensional PCA representation of 12-lead QRS waveforms identified 2 patient subgroups (QRS PCA groups). Vectorcardiographic QRS area was also calculated. We examined following 2 primary outcomes: (1) composite end point of death, left ventricular assist device, or heart transplant, and (2) degree of echocardiographic left ventricular ejection fraction (LVEF) change after CRT. RESULTS: Compared with QRS PCA Group 2 (n=425), Group 1 (n=521) had lower risk for reaching the composite end point (HR, 0.44 [95% CI, 0.38-0.53]; P<0.001) and experienced greater mean LVEF improvement (11.1±11.7% versus 4.8±9.7%; P<0.001), even among patients with LBBB with QRSd ≥150 ms (HR, 0.42 [95% CI, 0.30-0.57]; P<0.001; mean LVEF change 12.5±11.8% versus 7.3±8.1%; P=0.001). QRS area also stratified outcomes but had significant differences from QRS PCA groups. A stratification scheme combining QRS area and QRS PCA group identified patients with LBBB with similar outcomes to non-LBBB patients (HR, 1.32 [95% CI, 0.93-1.62]; difference in mean LVEF change: 0.8% [95% CI, -2.1% to 3.7%]). The stratification scheme also identified patients with LBBB with QRSd <150 ms with comparable outcomes to patients with LBBB with QRSd ≥150 ms (HR, 0.93 [95% CI, 0.67-1.29]; difference in mean LVEF change: -0.2% [95% CI, -2.7% to 3.0%]). CONCLUSIONS: Unsupervised machine learning of ECG waveforms identified CRT subgroups with relevance beyond LBBB and QRSd. This method may assist in objective classification of bundle branch block morphology in CRT.

Impact of risk-factor modification on arrhythmia recurrence among morbidly obese patients undergoing atrial fibrillation ablation.

BACKGROUND: Morbid obesity is associated with prohibitively high arrhythmia recurrence rates following atrial fibrillation (AF) ablation. DESIGN: This was a single-center study comprising 239 patients with morbid obesity and symptomatic paroxysmal or persistent AF undergoing AF ablation compared to 239 patients with a body mass index less than 30 kg/m2 matched based on age, sex, ejection fraction, AF type, presence and type of heart failure, and left atrial volume index. METHODS: Our primary outcome of interest was arrhythmia recurrence. RESULTS: During a mean follow-up of 29 months, arrhythmia recurrence was observed in 65% of the morbidly obese cohort compared to 27% of the control group (P < .0001). Among those with morbid obesity, sleep apnea screening, and treatment (91% vs 40%; P < .0001), blood pressure control (62% vs 53%; P = .001), glycemic control (85% vs 56%; P = .004), and weight loss more than equal to 5% (33% vs 57% in those who lost less than 5% and 83% in those who gained weight, P < .0001) were associated with lower arrhythmia recurrence. Recurrent arrhythmia was observed in one (4%) patient who accomplished all four goals, compared to 36% who achieved 3 of 4, 85% who modified 2 of 4%, and 97% of those who modified zero or one risk-factor. Risk-factor modification (RFM) was also associated with substantial reductions in the need for repeat ablation or direct-current cardioversion and arrhythmia-related hospitalization (P < .0001). CONCLUSION: RFM through pragmatic noninvasive means such as blood pressure and glycemic control, sleep apnea screening and treatment, and weight loss is associated with substantially lower rates of recurrent arrhythmia among morbidly obese patients undergoing AF ablation.

Lifestyle and Risk Factor Modification for Reduction of Atrial Fibrillation: A Scientific Statement From the American Heart Association.

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is associated with substantial morbidity, mortality, and healthcare use. Great strides have been made in stroke prevention and rhythm control strategies, yet reducing the incidence of AF has been slowed by the increasing incidence and prevalence of AF risk factors, including obesity, physical inactivity, sleep apnea, diabetes mellitus, hypertension, and other modifiable lifestyle-related factors. Fortunately, many of these AF drivers are potentially reversible, and emerging evidence supports that addressing these modifiable risks may be effective for primary and secondary AF prevention. A structured, protocol-driven multidisciplinary approach to integrate lifestyle and risk factor management as an integral part of AF management may help in the prevention and treatment of AF. However, this aspect of AF management is currently underrecognized, underused, and understudied. The purpose of this American Heart Association scientific statement is to review the association of modifiable risk factors with AF and the effects of risk factor intervention. Implementation strategies, care pathways, and educational links for achieving impactful weight reduction, increased physical activity, and risk factor modification are included. Implications for clinical practice, gaps in knowledge, and future directions for the research community are highlighted.

Effectiveness of catheter ablation of atrial fibrillation according to heart failure etiology.

BACKGROUND: Catheter ablation is an important rhythm control therapy in patients with atrial fibrillation (AF) with concomitant heart failure (HF). The objective of this study was to assess the comparative efficacy of AF ablation patients with ischemic vs nonischemic heart failure. METHODS: We conducted a retrospective, observational cohort study of patients with HF who underwent AF ablation. Outcomes were compared based on HF etiology and included in-hospital events, symptoms (Mayo AF Symptom Inventory [MAFSI]), and functional status (New York Heart Association class) and freedom from atrial arrhythmias at 12 months. RESULTS: Among 242 patients (n = 70 [29%] ischemic, n = 172 [71%] nonischemic), patients with nonischemic cardiomyopathy were younger (mean age 64 ± 11.5 vs 69 ± 9.1, P = .002), more often female (36% vs 17%, P = .004), and had higher mean left-ventricular ejection fraction (47% vs 42%, P = .0007). There were no significant differences in periprocedural characteristics, including mean procedure time (243 ± 74.2 vs 259 ± 81.8 minutes, P = .1) and nonleft atrial ablation (17% vs 20%, P = .6). All-cause adverse events were similar in each group (15% vs 17%, P = .7). NYHA and MAFSI scores improved significantly at follow-up and did not differ according to HF etiology (P = .5; P = .10-1.00 after Bonferroni correction). There were no significant differences in freedom from recurrent atrial arrhythmia at 12-months between ischemic (74%) and nonischemic patients (78%): adjusted RR 0.63, 95% confidence interval 0.33-1.19. CONCLUSIONS: Catheter ablation in patients with AF and concomitant heart failure leads to significant improvements in functional and symptom status without significant differences between patients with ischemic vs nonischemic HF etiology.

Atrial fibrillation ablation in patients with transthyretin cardiac amyloidosis.

AIMS: Atrial fibrillation (AF) occurs in as many as 70% of patients with transthyretin cardiac amyloidosis (ATTR CA). The aim of our study was to investigate the impact of AF ablation on freedom from recurrent arrhythmia, hospitalization for AF or heart failure (HF), and mortality. METHODS AND RESULTS: This was a retrospective observational cohort study of 72 patients with ATTR CA and AF, of whom 24 underwent AF ablation and were matched in a 2:1 manner based on age, gender, ATTR CA stage, New York Heart Association functional class, ejection fraction, and date of AF diagnosis with 48 patients with ATTR CA and AF undergoing medical management. During a mean follow-up of 39 ± 26 months, 10 (42%) patients remained free of recurrent arrhythmia following ablation. Ablation was significantly more effective in those with Stage I or II ATTR CA, with 9/14 (64%) patients with Stage I or II ATTR CA remaining free of recurrent arrhythmia compared to only 1/10 (10%) patients with Stage III disease (P = 0.005). Death occurred in 7 (29%) patients in the ablation group compared to 36 (75%) in the non-ablation arm (P = 0.01). Rates of ischaemic stroke were similar in both groups. Ablation was associated with a significant reduction in the frequency of hospitalization for HF/arrhythmia (1.7 ± 2.4 hospitalizations vs. 4 ± 3.5, P = 0.005). On Cox proportional hazards analyses, ablation was associated with improved survival (hazard ratio 0.38, 95% confidence intervals 0.17-0.86; P = 0.02). CONCLUSION: Atrial fibrillation ablation is associated with reduced mortality in ATTR CA and is most effective when performed earlier during the disease process.

Predictors of long-term outcomes greater than 10 years after cardiac resynchronization therapy implantation.

BACKGROUND: Cardiac resynchronization therapy (CRT) is indicated in patients with medically refractory heart failure and wide QRS duration. While much is known about predictors of left ventricular (LV) remodeling after CRT implantation and short-term mortality, limited data exist on long-term outcomes after CRT placement. METHODS: We retrospectively reviewed all patients undergoing CRT implantation at our center between 2003 and 2008 and examined mortality using institutional electronic records, social security death index, and online obituary search. We included only patients with preimplant echoes with LV ejection fraction (LVEF) 35% or below. Variable selection was performed using stepwise regression and models were compared using goodness-of-fit criteria. A final model was validated with the bootstrap regression method. RESULTS: Out of the 877 CRT patients undergoing implantation during this time, 287 (32.7%) survived longer than 10 years. Significant (P < .05) predictors of survival in our multivariate model were age, left ventricular diastolic diameter, sex, presence of nonischemic vs ischemic cardiomyopathy, QRS duration, atrial fibrillation, BNP levels, and creatinine levels at the time of CRT implantation. A model using the odds ratios from these variables had a receiver operating curve with an area under the curve score of 0.816 (standard error, 0.019) at predicting survival or freedom from LVAD or heart transplant for longer than 10 years after CRT implantation. The specificity for factors 3 or above and 5 or above was 68% and 77%, respectively. CONCLUSION: A large proportion of patients are still alive 10 years after CRT implantation. Variables at the time of CRT implant can help provide prognostic information to patients and electrophysiologists to determine the long-term benefit and survival of patients after CRT implantation.

Impact of Bariatric Surgery on Atrial Fibrillation Type.

BACKGROUND: Obesity is an independent risk factor for atrial fibrillation (AF) and is associated with a higher AF burden. Recently, weight loss has been found to be associated with a significant reversal in AF type. Bariatric surgery (BS) is associated with reductions in inflammation, left atrial and ventricular remodeling, sleep apnea, blood pressure, and improved glycemic control, all of which may reduce AF burden. In this study, we sought to determine the impact of BS on AF type. METHODS: We studied AF type before and after BS in 220 morbidly obese patients (body mass index, ≥40 kg/m2). All patients underwent extended outpatient cardiac rhythm monitoring within 12 months of BS and at least 1 year after BS. RESULTS: There was a significant reduction in body mass index following BS from 49.7±9 to 37.2±9 kg/m2. Weight loss was the greatest in the gastric bypass group with a mean percentage weight loss of 25% compared with 19% in patients who underwent sleeve gastrectomy and 16% following gastric banding (P<0.0001). Significant reductions in CRP (C-reactive protein), NT-proBNP (N-terminal pro-B-type natriuretic peptide), HbA1C (glycated hemoglobin), and systolic blood pressure were observed in all 3 groups. Reversal of AF type occurred in 71% of patients following gastric bypass, 56% of patients who underwent sleeve gastrectomy, and 50% of patients following gastric banding (P=0.004). On Cox proportional hazards analyses, percentage weight loss was significantly associated with AF reversal (P=0.0002). CONCLUSIONS: BS is associated with significant reductions in weight, inflammatory markers, blood pressure, and AF type, and the beneficial effects appear to be the greatest in those undergoing gastric bypass surgery. This study further exemplifies the importance of weight loss and risk factor modification in AF management.

Baseline Right Ventricular Dysfunction Predicts Worse Outcomes in Patients Undergoing Cardiac Resynchronization Therapy Implantation.

INTRODUCTION: Cardiac resynchronization therapy (CRT) has been shown to improve survival in patients with systolic heart failure, wide QRS duration, and left-bundle-branch-block. However, CRT outcomes stratified by right ventricular (RV) function at implant have not been well studied. METHODS: We retrospectively reviewed patients at Cleveland Clinic who underwent CRT implantation (n = 777) from 2003 to 2011 with a diagnosis of heart failure, echocardiography with both pre-CRT left ventricular ejection fraction (LVEF) ≤35% and available post-CRT echocardiography at 6 months post-implant. CRT response was defined as LVEF improvement ≥5%. Patients were separated into 2 groups: normal or mild RV dysfunction (n = 570) labeled Normal RV; moderate to severe dysfunction (n = 207) labeled RV DYSFXN based on qualitative echocardiography assessment. Survival was calculated as time from CRT implant to death, left ventricular assist device implant, or heart transplant. RESULTS: CRT response was significantly higher in patients with Normal RV (67%) compared with patients with RV DYSFXN (56%; P = .006). Kaplan-Meier analysis showed that CRT patients with Normal RV had significantly greater survival compared with patients with RV DYSFXN (P < .001). In multivariable Cox regression accounting for a priori covariates, RV DYSFXN was associated with worse survival (HR 1.41 [95% CI: 1.14-1.75], P = .002) and lower CRT response (HR 0.66 [95% CI: 0.44-0.97], P = .03). CONCLUSION: Baseline RV dysfunction at CRT implant is an important predictor of worsened left ventricular remodeling and survival in CRT patients.

Cardiac devices in patients with transthyretin amyloidosis: Impact on functional class, left ventricular function, mitral regurgitation, and mortality.

BACKGROUND: The aim of our study was to investigate outcomes of patients with ATTR (amyloidosis and transthyretin) CA (cardiac amyloidosis) and implantable devices with respect to left ventricular ejection fraction (LVEF), mitral regurgitation (MR), New York Heart Association (NYHA) functional class, and mortality. METHODS: This was a retrospective observational cohort study of 78 patients with ATTR CA and implantable devices. During a mean follow-up of 42 months we investigated the impact of right ventricular (RV) pacing burden and biventricular (BiV) pacing on LVEF, MR severity, NYHA functional class, and mortality. RESULTS: Worsening MR occurred in 11% of patients with a RV pacing % <40% compared to 62% of those with a RV pacing burden >40% (P = .002). Similarly, worsening LVEF occurred in 26% of patients who were RV paced <40% and 89% of those who were RV paced >40% of the time (P < .0001) and worsening in NYHA functional class occurred in 22% and 89%, respectively (P < .0001). Improvement in LVEF, NYHA functional class, and MR severity occurred in 78%, 67%, and 67%, respectively, in those with BiV devices. Death occurred in 67% of patients in the cardiac resynchronization therapy group compared to 68% of those with a RV pacing burden <40% and 92% of those with a RV pacing burden >40%. CONCLUSION: A higher RV pacing burden is associated with deleterious remodeling and congestive heart failure in patients with ATTR CA, whereas BiV pacing is associated with improvements in LVEF, NYHA class, and degree of MR. BiV pacing should be considered in patients with ATTR CA and an indication for pacing. However, further larger prospective studies will need to be performed.

Scar burden is an independent and incremental predictor of cardiac resynchronisation therapy response.

Objective: Determine the prognostic impact of scar quantification (scar %) by cardiac magnetic resonance (CMR) in predicting heart failure admission, death and left ventricular (LV) function improvement following cardiac resynchronisation therapy (CRT), after controlling for the presence of left bundle branch block (LBBB), QRS duration (QRSd) and LV lead tip location and polarity. Methods: Consecutive patients who underwent CMR between 2002 and 2014 followed by CRT were included. The primary endpoint was death or heart failure admission. The secondary endpoint was change in ejection fraction (EF) ≥3 months after CRT. Cox proportional hazards, linear regression models and change in the area under the receiver operating characteristic curve (AUC) were used. Results: A total of 84 patients were included (63% male, 51% with ischaemic cardiomyopathy). After adjusting for clinical factors, presence of LBBB and QRSd and LV lead tip location and polarity, greater scar % remained associated with a higher risk for clinical events (HR=1.06; 95% CI 1.02 to 1.10; p<0.001) and a smaller improvement in EF (slope: -0.61%; 95% CI -0.93% to 0.29%; p<0.001). When adding scar % to QRSd and LBBB, there was significant improvement in predicting clinical events at 3 years (AUC increased to 0.831 from 0.638; p=0.027) and EF increase ≥10% (AUC 0.869 from 0.662; p=0.007). Conclusion: Scar quantification by CMR has an incremental value in predicting response to CRT, in terms of heart failure admission, death and EF improvement, independent of the presence of LBBB, QRSd, LV lead tip location and polarity.

Long term outcomes in patients with chronic right ventricular pacing upgraded to cardiac resynchronization therapy.

INTRODUCTION: In patients with chronic systolic heart failure and frequent right ventricular pacing (RVP), upgrade to cardiac resynchronization therapy (CRT) has become common practice despite a lack of randomized clinical trials. We aimed to evaluate long term outcomes in patients upgraded to CRT from chronic RVP compared with de novo CRT implants. METHODS AND RESULTS: We reviewed medical charts on consecutive patients with a left ventricular ejection fraction (LVEF) ≤ 35% and a QRSd ≥ 120 ms undergoing CRT. Survival free of left ventricular assist device (LVAD) and a heart transplant was compared amongst patients on the basis of pre-CRT QRS morphology. Improvement in LVEF was also compared across groups. A total of 1260 patients met inclusion criteria of whom 233 were upgraded from chronic RVP. Over a mean follow up 6.5 ± 4.0 years there were 821 endpoints (27 LVAD, 30 heart transplants, and 764 deaths). In a multivariate Cox regression model, upgraded patients had worse outcomes (HR 1.3(1.1-1.7) P = .007) compared with those with native LBBB and similar outcomes to patients with non-LBBB(HR 0.96(0.76-1.21) P = .7). The survival curve for chronic RVP parallels native LBBB for approximately 2.5 years before dropping sharply. Patients with chronic RVP derive similar improvements in LVEF compared with those with LBBB and superior improvements compared with those with non-LBBB. CONCLUSIONS: Despite achieving similar levels of LVEF improvement, patients with systolic heart failure with chronic RVP undergoing upgrade to CRT have inferior long term outcomes compared with patients with native LBBB. Long term outcomes with CRT in patients with chronic RVP, RBBB, and IVCD are similar.

Machine Learning Prediction of Response to Cardiac Resynchronization Therapy: Improvement Versus Current Guidelines.

BACKGROUND: Cardiac resynchronization therapy (CRT) has significant nonresponse rates. We assessed whether machine learning (ML) could predict CRT response beyond current guidelines. METHODS: We analyzed CRT patients from Cleveland Clinic and Johns Hopkins. A training cohort was created from all Johns Hopkins patients and an equal number of randomly sampled Cleveland Clinic patients. All remaining patients comprised the testing cohort. Response was defined as ≥10% increase in left ventricular ejection fraction. ML models were developed to predict CRT response using different combinations of classification algorithms and clinical variable sets on the training cohort. The model with the highest area under the curve was evaluated on the testing cohort. Probability of response was used to predict survival free from a composite end point of death, heart transplant, or placement of left ventricular assist device. Predictions were compared with current guidelines. RESULTS: Nine hundred twenty-five patients were included. On the training cohort (n=470: 235, Johns Hopkins; 235, Cleveland Clinic), the best ML model was a naive Bayes classifier including 9 variables (QRS morphology, QRS duration, New York Heart Association classification, left ventricular ejection fraction and end-diastolic diameter, sex, ischemic cardiomyopathy, atrial fibrillation, and epicardial left ventricular lead). On the testing cohort (n=455, Cleveland Clinic), ML demonstrated better response prediction than guidelines (area under the curve, 0.70 versus 0.65; P=0.012) and greater discrimination of event-free survival (concordance index, 0.61 versus 0.56; P<0.001). The fourth quartile of the ML model had the greatest risk of reaching the composite end point, whereas the first quartile had the least (hazard ratio, 0.34; P<0.001). CONCLUSIONS: ML with 9 variables incrementally improved prediction of echocardiographic CRT response and survival beyond guidelines. Performance was not improved by incorporating more variables. The model offers potential for improved shared decision-making in CRT (online calculator: http://riskcalc.org:3838/CRTResponseScore ). Significant remaining limitations confirm the need to identify better variables to predict CRT response.

Should fast pathway ablation be reconsidered in typical atrioventricular nodal re-entrant tachycardia?

INTRODUCTION: Atrioventricular nodal re-entry tachycardia (AVNRT) is the most common, regular narrow-complex tachycardia. The established treatment is catheter ablation of the AV nodal slow pathway (SP). However, in a select group of patients with long PR intervals in sinus rhythm, SP ablation can lead to AV block due to the absence of robust anterograde conduction through the fast pathway (FP). This report aims to demonstrate that AV nodal FP ablation is a reasonable approach in patients with AVNRT and poor or absent anterograde FP conduction. METHODS AND RESULTS: Standard electrophysiology study techniques were used in the electrophysiology laboratory. Catheter ablations were performed using radiofrequency energy. Mapping of intracardiac activation was performed with electroanatomical mapping systems. Outcomes were assessed acutely during the procedure and during routine clinical follow-up. Six patients with first-degree AV block and recurrent AVNRT who underwent ablation of their tachycardia at our institution are presented. One patient underwent ablation of AV nodal SP resulting in high-degree AV block necessitating pacemaker implantation. The remaining five patients underwent ablation of the AV nodal FP guided by electroanatomical mapping of the earliest atrial activation in tachycardia. These five had successful treatment of the tachycardia with preservation of anterograde AV nodal conduction. Mapping and ablation approach to eliminate retrograde FP conduction are described. CONCLUSION: In select patients with AVNRT and poor anterograde FP conduction, retrograde FP ablation is reasonable and is less likely to result in AV block and pacemaker dependency.

Management and outcomes in mitral valve prolapse with ventricular arrhythmias undergoing ablation and/or implantation of ICDs.

BACKGROUND: While there is an association between isolated mitral valve prolapse (MVP) and sudden cardiac arrest (SCA), the baseline characteristics and outcomes of patients with isolated MVP who experience ventricular arrhythmias (VAs) and then subsequently undergo catheter ablation and/or implantable cardioverter defibrillator (ICD) implantation are unknown. METHODS: We performed a retrospective review of all patients at the Cleveland Clinic with isolated MVP between 1997 and 2016 who underwent VA catheter ablation or secondary prevention ICD implantation. RESULTS: Of 617 screened patients, we identified 43 patients with isolated MVP and significant VA who underwent ICD placement (n = 13, 30%) or catheter ablation (n = 30, 70%). Both leaflets were most commonly involved (n = 22, 52%) with posterior MVP being next most common (n = 15, 36%). The most common foci of VA origin was the left ventricular papillary muscle (n = 9, 27%). Ablation was successful in the majority of cases (n = 20, 65%). At a mean follow-up of 2.5 years, 11 patients (26%) had recurrent VT. CONCLUSIONS: Patients with isolated MVP and VA were more likely to have bileaflet prolapse and at least moderate mitral regurgitation. VA originated more commonly from left-sided foci. While ablation was acutely successful in the majority of cases, there was still a moderate rate of VA recurrence. There is still more study needed on factors that will predict malignant VAs and management of these VAs in the MVP population.

Effect of Cardiac Resynchronization Therapy on Left Ventricular Remodeling in Patients With Cardiac Sarcoidosis.

Cardiac resynchronization therapy (CRT) has been shown to be beneficial in patients with medically refractory heart failure. Although it has been found to be effective in a wide range of etiologies for nonischemic cardiomyopathy, its role in improving remodeling and survival of patients with cardiac sarcoidosis (CS) remains undefined. We performed a retrospective review of all patients at our institution with CS who underwent implantation of a CRT device from 2007 to 2017. The outcomes of this population were compared with the outcomes of a cohort of patients with nonischemic cardiomyopathy with an etiology other than sarcoidosis. Nineteen patients in our institution with CS underwent CRT implantation during the time period. This group was compared with 311 consecutive patients with other etiologies of nonischemic cardiomyopathy who underwent CRT implantation. CRT improved left ventricular ejection fraction (LVEF) from 28.8% to 35.9% (p <0.05) in CS, whereas it improved LVEF from 25% to 36.6% (p <0.01) in non-CS group (difference in means of 0.13). CRT significantly improved diastolic and systolic LV diameters, mitral regurgitation, and right ventricular systolic function in non-CS patients but failed to improve same parameters in CS patients. In conclusion, CRT significantly improved LVEF in patients with CS. There is no significant evidence that survival outcomes of CRT patients with CS are significantly worse than other etiologies of nonischemic cardiomyopathy.

Effect of PR interval prolongation on long-term outcomes in patients with left bundle branch block vs non-left bundle branch block morphologies undergoing cardiac resynchronization therapy.

BACKGROUND: Although the influence of QRS duration (QRSd) and/or bundle branch block morphology on outcomes of cardiac resynchronization therapy (CRT) have been well studied, the effect of PR interval remains uncertain. OBJECTIVE: The purpose of this study was to evaluate the impact of PR prolongation (PRp) before CRT on long-term outcomes, specifically taking into account bundle branch block morphology and QRSd. METHODS: We extracted clinical data on consecutive patients undergoing CRT. Multivariate models were constructed to analyze the effect of PRp (≥200 ms) on the combined endpoint of death, heart transplant, or left ventricular assist device. Kaplan-Meier curves were constructed stratifying patients based on bundle branch block and QRSd (dichotomized by 150 ms). RESULTS: Of the 472 patients who met inclusion criteria, 197 (41.7%) had PR interval ≥200 ms. During follow-up (mean 5.1 ± 2.6 years) there were 214 endpoints, of which 109 (23.1%) occurred in patients with PRp. In multivariate analysis, PRp was independently associated with worsened outcomes (hazard ratio 1.34, 95% confidence interval 1.01-1.77, P = .04). When stratified by bundle branch block morphology, PRp was significantly associated with worsened outcomes (log-rank P <.001) in patients with LBBB but not in those with non-LBBB (log-rank P = .55). Among patients with LBBB, stratified by QRSd, patients without PRp had improved outcomes compared to those with PRp independent of QRSd (log-rank P <.001). CONCLUSION: PRp is an independent predictor of impaired long-term outcome after CRT among patients with LBBB but not in non-LBBB patients. Notably, among LBBB patients, PRp is a more important predictor than QRSd in assessing long-term outcomes.

Rhythm control in heart failure patients with atrial fibrillation: contemporary challenges including the role of ablation.

Because nonpharmacological interventions likely alter the risks and benefits associated with rhythm control, this paper reviews the role of current rhythm control strategies in atrial fibrillation. This report also focuses on the specific limitations of pharmacological interventions and the utility of percutaneous ablation in this growing population of patients with concomitant atrial fibrillation and heart failure.