Search

Chronic right ventricular (RV) pacing can induce left ventricular (LV) dyssynchrony and cause pacemaker induced cardiomyopathy (PiCM). Identifying which patients are at risk for PiCM is limited.Patients receiving RV-only permanent pacemakers (PPMs) at Duke University Medical Center between 2011 and 2017 who had normal baseline ejection fractions (EFs) were identified. Patients who developed a subsequent decrease in EF, died, or underwent cardiac resynchronization therapy, left ventricular assist device, or heart transplant without a competing cause were considered as the primary endpoint. Pre-PPM and post-PPM electrocardiograms (ECGs) were analyzed to extract scalar measurements including the lead one ratio (LOR) as well as advanced-ECG (A-ECG) features to identify predictors of PiCM. Traditional and penalized Cox regression were used to identify variables predictive of the primary endpoint.Pre-PPM ECGs were evaluated for 404 patients of whom 140 (35%) experienced the primary endpoint. Predictors included female sex (hazard ratio [HR] 1.14), a T' wave in V6 (HR 1.31), a P' wave in aVL (HR 0.88), and estimated glomerular filtration rate (HR 0.88). Post-PPM ECGs were evaluated for 228 patients for whom 94 (41%) experienced the primary endpoint. Predictors included female sex (HR 0.50), age (HR 1.06), and a history of congestive heart failure (HR 1.63). Neither LOR nor A-ECG parameters were strong predictors of the primary endpoint.Baseline and paced ECG data provide limited insight into which patients are at high risk for developing PiCM.

Introduction Data describing atrial fibrillation (AF) care in emergency centres (ECs) in sub-Saharan Africa is lacking. We sought to describe the prevalence and outcomes of AF in a Tanzanian EC. Methods In a prospective, observational study, adults presenting with chest pain or shortness of breath to a Tanzanian EC were enrolled from January through October 2019. Participants underwent electrocardiogram testing which were reviewed by two independent physician judges to determine presence of AF. Participants were asked about their medical history and medication use at enrollment, and a follow-up questionnaire was administered via telephone thirty days later to assess mortality, interim stroke, and medication use. Results Of 681 enrolled patients, 53 (7.8%) had AF. The mean age of participants with AF was 68.1, with a standard deviation (sd) of 21.1 years, and 23 of the 53 (43.4%) being male. On presentation, none of the participants found to have AF reported a previous history of AF. The median CHADS-VASC score among participants was 4 with an interquartile range (IQR) of 2-4. No participants were taking an anticoagulant at baseline. On index presentation, 49 (92.5%) participants with AF were hospitalised with 52 (98.1%) participants completing 30-day follow-up. 18 (34%) participants died, and 5 (9.6%) suffered a stroke. Of the surviving 31 participants with AF and a CHADS-VASC score ≥ 2, none were taking other anti-coagulants at 30 days. Compared to participants without AF, participants with AF were more likely to be hospitalised (OR 5.25, 95% CI 2.10-17.95, p, Highlights • In a Tanzanian emergency centre, atrial fibrillation was common but patient awareness of their condition was low • Use of anticoagulants among patients with atrial fibrillation was rare both before and after hospital presentation • Following hospital presentation, thirty-day mortality and stroke rates among patients with atrial fibrillation were high

Objective We designed an automatic, computationally efficient, and interpretable algorithm for detecting ventricular ectopic beats in long-term, single-lead electrocardiogram recordings. Methods We built five simple, interpretable, and computationally efficient features from each cardiac cycle, including a novel morphological feature which described the distance to the median beat in the recording. After an unsupervised subject-specific normalization procedure, we trained an ensemble binary classifier using the AdaBoost algorithm Results After our classifier was trained on subset DS1 of the Massachusetts Institute of Technology-Beth Israel Hospital (MIT-BIH) Arrhythmia database, our classifier obtained an F1 score of 94.35% on subset DS2 of the same database. The same classifier achieved F1 scores of 92.06% on the St. Petersburg Institute of Cardiological Technics (INCART) 12-lead Arrhythmia database and 91.40% on the MIT-BIH Long-term database. A phenotype-specific analysis of model performance was afforded by the annotations included in the St. Petersburg INCART Arrhythmia database Conclusion The five features this novel algorithm employed allowed our ventricular ectopy detector to obtain high precision on previously unseen subjects and databases Significance Our ventricular ectopy detector will be used to study the relationship between premature ventricular contractions and adverse patient outcomes such as congestive heart failure and death.

BACKGROUND Leadless pacemakers (LPs) provide ventricular pacing without the risks associated with transvenous leads and device pockets. LPs are appealing for patients who need pacing, but do not need defibrillator or cardiac resynchronization therapy. Most implanted LPs provide right ventricular pacing without atrioventricular synchrony (VVIR mode). The Mode Selection Trial in Sinus Node Dysfunction (MOST) showed similar outcomes in patients randomized to dual-chamber (DDDR) versus ventricular pacing (VVIR). We compared outcomes by pacing mode in LP-eligible patients from MOST. METHODS Patients enrolled in the MOST study with an left ventricular ejection fraction (LVEF) >35%, QRS duration (QRSd)

Background: Biventricular (BiV) pacing increases transmural repolarization heterogeneity due to epicardial to endocardial conduction from the left ventricular (LV) lead. However, limited evidence is available on concomitant changes in ventricular depolarization and repolarization and long-term outcomes of BiV pacing. Therefore, we investigated associations of BiV pacing-induced concomitant changes in ventricular depolarization and repolarization with mortality (i.e., LV assist device, heart transplantation, or all-cause mortality) and sustained ventricular arrhythmia endpoints. Methods: Consecutive BiV-defibrillator recipients with digital preimplantation and postimplantation electrocardiograms recorded between 2006 and 2015 at Duke University Medical Center were included. We calculated changes in QRS duration and corrected JT (JTc) interval and split them by median values. For simplicity, these variables were named QRS decreased (≤ −12 ms), QRS increased (> –12 ms), JTc decreased (≤22 ms), and JTc increased (> 22 ms) and subsequently used to construct four mutually exclusive groups. Results: We included 528 patients (median age, 68 years; male, 69%). No correlation between changes in QRS duration and JTc interval was observed (P =.295). Compared to QRS decreased/JTc increased, increased risk of the composite mortality endpoint was associated with QRS decreased/JTc decreased (hazard ratio [HR] = 1.62; 95% confidence interval [CI] = 1.09-2.43), QRS increased/JTc decreased (HR = 1.86; 95% CI = 1.27-2.71), and QRS increased/JTc increased (HR = 2.25; 95% CI = 1.52-3.35). No QRS/JTc group was associated with excess sustained ventricular arrhythmia risk (P =.400). Conclusion: Among BiV-defibrillator recipients, QRS decreased/JTc increased was associated with the most favorable long-term survival free of LV assist device, heart transplantation, and sustained ventricular arrhythmias. Our findings suggest that improved electrical resynchronization may be achieved by assessing concomitant changes in ventricular depolarization and repolarization.

BACKGROUND: Some patients with ongoing heart failure symptoms after treatment with cardiac resynchronization therapy (CRT) demonstrate QRS prolongation during exercise. We investigated whether the optimal CRT pacing configuration changes during dobutamine stress. METHODS: Seven patients undergoing CRT implantation underwent invasive LV dP/dT(max) measurement during CRT pacing in 10 configurations to determine the optimal baseline pacing configuration (OPC). Measurements were repeated during dobutamine infusion. Differences in mean LV dP/dT(max) between pacing configurations were compared. RESULTS: Baseline OPC differed from stress OPC in 6/7 patients. The mean (SD) LV dP/dT(max) obtained during dobutamine infusion was 1140 (377) mmHg/sec in AAI pacing, 1458 (448) mmHg/sec in the baseline OPC, and 1656 (435) mmHg/sec in the dobutamine OPC (p 0.05). CONCLUSIONS: The optimal CRT pacing configuration changes during dobutamine infusion while LV and RV activation timing does not. Further studies investigating the usefulness of automated dynamic changes to CRT pacing configuration according to physiologic condition may be warranted.

Background: A low electrocardiogram (ECG) lead one ratio (LOR) of the maximum positive/negative QRS amplitudes is associated with lower left ventricular ejection fraction (LVEF) and worse outcomes in left bundle branch block (LBBB); however, the impact of LOR on cardiac resynchronization therapy (CRT) outcomes is unknown. We compared clinical outcomes and echocardiographic changes after CRT implantation by LOR. Methods: Consecutive CRT-defibrillator recipients with LBBB implanted between 2006 and 2015 at Duke University Medical Center were included (N = 496). Time to heart transplant, left ventricular assist device (LVAD) implantation, or death was compared among patients with LOR

Background Wait times for catheter ablation in patients with symptomatic atrial fibrillation (AF) may influence clinical outcomes. Objective This study examined the relationship between the duration from AF diagnosis to ablation, or diagnosis-to-ablation time (DAT), on the clinical response to catheter ablation in a large nationwide cohort of patients. Methods We identified patients with new atrial fibrillation (AF) who underwent catheter ablation between January 2014 and December 2017 using the IBM MarketScan databases. Cox proportional hazard models were used to estimate the strength of the association between DAT and the outcomes of AF recurrence and hospitalization at one year post-ablation. Results Among 11,143 AF patients who underwent ablation, the median age was 59 years, 31% were female and the median CHA2DS2-VASc score was 2. Median DAT was 5.5 (2.6, 13.1) months. At 1-year post-ablation, 10.0% (N=1,116) developed recurrent AF. For each year increase in DAT, the risk of AF recurrence increased by 20% after adjustment for baseline comorbidities and medications (hazard ratio (HR) 1.20, 95% CI 1.11-1.30). A longer DAT was associated with an increased risk of hospitalization (HR 1.08 per DAT year, 95% CI 1.02-1.15). DAT was a stronger predictor of AF recurrence post-ablation than traditional clinical risk factors, including age, prior heart failure, or renal failure. Conclusions Increasing duration between AF diagnosis and catheter ablation is associated with higher AF recurrence rates and all-cause hospitalization. Our findings are consistent with a growing body of evidence supporting the benefits of prioritizing early restoration of sinus rhythm.

Background Comorbidities are common in patients with atrial fibrillation (AF) and affect prognosis, yet are often undertreated. However, contemporary rates of use of guideline-directed therapies (GDT) for non-AF comorbidities and their association with outcomes are not well described. Methods We used the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF) to test the association between GDT for non-AF comorbidities and major adverse cardiac or neurovascular events (MACNE; cardiovascular death, myocardial infarction, stroke/thromboembolism, or new-onset heart failure), all-cause mortality, new-onset heart failure, and AF progression. Adjustment was performed using Cox proportional hazards models and logistic regression. Results Only 6,782 (33%) of the 20,434 patients eligible for 1 or more GDT for non-AF comorbidities received all indicated therapies. Use of all comorbidity-specific GDT was highest for patients with hyperlipidemia (75.6%) and lowest for those with diabetes mellitus (43.1%). Use of “all eligible” GDT was associated with a nonsignificant trend toward lower rates of MACNE (HR 0.90 [0.79-1.02]) and all-cause mortality (HR 0.90 [0.80-1.01]). Use of GDT for heart failure was associated with a lower risk of all-cause mortality (HR 0.77 [0.67-0.89]), and treatment of obstructive sleep apnea was associated with a lower risk of AF progression (OR 0.75 [0.62-0.90]). Conclusions In AF patients, there is underuse of GDT for non-AF comorbidities. The association between GDT use and outcomes was strongest in heart failure and obstructive sleep apnea patients where use of GDT was associated with lower mortality and less AF progression.

BACKGROUND: Compared with medical therapy, catheter ablation of atrial fibrillation (AF) in patients with heart failure (HF) improves cardiovascular outcomes. Risk scores (CAAP-AF and APPLE) have been developed to predict the likelihood of AF recurrence after ablation, have not been validated specifically in patients with AF and HF. METHODS: We analyzed baseline characteristics, risk scores, and rates of AF recurrence 12 months post-ablation in a cohort of 230 consecutive patients with AF and HF undergoing PVI in the Duke Center for Atrial Fibrillation registry from 2009–2013. RESULTS: During a follow-up period of 12 months, 76 of 230 (33%) patients with HF experienced recurrent AF after ablation. The median APPLE and CAAP-AF scores were 1.5 [(Q1, Q3): (1.0, 2.0)] and 4.0 [(Q1, Q3): (3.0, 5.0)], respectively and were not different from those patients with and without recurrent AF. Freedom from AF was not different according to APPLE and CAAP-AF scores. Discrimination for recurrent AF with the CAAP-AF score was modest with a C-statistic of 0.60 (95% CI 0.52 – 0.67). Discrimination with the APPLE score was similarly modest, with a c-statistic of 0.54 (95% CI: 0.47 – 0.62). CONCLUSIONS: Validated predictive risk scores for recurrent AF after catheter ablation exhibit limited predictive ability in cohorts of AF and HF. Additional tools are needed to facilitate risk stratification and patient selection for AF ablation in patients with concomitant HF.

Atrial fibrillation (AF) and heart failure (HF) are associated with high morbidity and mortality, which is particularly detrimental when patients develop rapid ventricular rates (RVR). Atrioventricular junction (AVJ) ablation with pacemaker implantation has been used as a method of achieving rate control in patients with incessant AF with RVR. Right ventricular only pacing is known to be harmful in the setting of HF. His bundle pacing (HBP) and biventricular (BiV) pacing both offer durable pacing solutions that offer more physiologic activation. This review describes the benefits and drawbacks of HBP and BiV pacing in HF patients after AVJ ablation.

Background: Diabetes mellitus (DM) is an independent risk factor for atrial fibrillation (AF). Few studies have compared clinical outcomes after catheter ablation between patients with and those without DM. Objective: The purpose of this study was to compare AF ablation outcomes in patients with and those without DM. Methods: We performed a retrospective analysis of 351 consecutive patients who underwent first-time AF ablation. Clinical outcomes included freedom from recurrent atrial arrhythmia, symptom burden (Mayo AF Symptom Inventory score), cardiovascular and all-cause hospitalizations, and periprocedural complications. Results: Patients with DM (n = 65) were older, had a higher body mass index, more persistent AF, more hypertension, and larger left atrial diameter (P

Background: Randomized clinical trials have demonstrated that catheter ablation for atrial fibrillation in patients with heart failure with reduced ejection fraction may improve survival and other cardiovascular outcomes. Methods: We constructed a decision-analytic Markov model to estimate the costs and benefits of catheter ablation and medical management in patients with symptomatic heart failure with reduced ejection fraction (left ventricular ejection fraction ≤35%) and atrial fibrillation over a lifetime horizon. Evidence from the published literature informed the model inputs, including clinical effectiveness data from meta-analyses. Probabilistic and deterministic sensitivity analyses were performed. A 3% discount rate was applied to both future costs and benefits. The primary outcome was the incremental cost-effectiveness ratio assessed from the US health care sector perspective. Results: Catheter ablation was associated with 6.47 (95% CI, 5.89–6.93) quality-adjusted life years (QALYs) and a total cost of $105 657 (95% CI, $55 311–$191 934; 2018 US dollars), compared with 5.30 (95% CI, 5.20–5.39) QALYs and $63 040 (95% CI, $37 624–$102 260) for medical management. The incremental cost-effectiveness ratio for catheter ablation compared with medical management was $38 496 (95% CI, $5583–$117 510) per QALY gained. Model inputs with the greatest variation on incremental cost-effectiveness ratio estimates were the cost of ablation and the effect of catheter ablation on mortality reduction. When assuming a more conservative estimate of the treatment effect of catheter ablation on mortality (hazard ratio of 0.86), the estimated incremental cost-effectiveness ratio was $74 403 per QALY gained. At a willingness-to-pay threshold of $100 000 per QALY gained, atrial fibrillation ablation was found to be economically favorable compared with medical management in 95% of simulations. Conclusions: Catheter ablation in patients with heart failure with reduced ejection fraction patients and atrial fibrillation may be considered economically attractive at current benchmarks for societal willingness-to-pay in the United States.

Left bundle branch block (LBBB) increases the likelihood of developing reduced left ventricular (LV) ejection fraction (EF) but predicting which patients with LBBB and normal LVEF will develop decreased LVEF remains challenging. Fifty patients with LBBB and normal LVEF were retrospectively identified. Clinical, electrocardiographic, and echocardiographic variables were compared between patients who developed a decreased LVEF and those who did not. A total of 16 of 50 patients developed reduced LVEF after 4.3 (SD = 2.8) years of follow-up. Baseline patient and electrocardiographic variables were similar between patients who did and did not develop decreased LVEF. Baseline LVEF was lower in patients who developed decreased LVEF than in those who did not (51.9% [SD = 2.2%] vs 54.9% [SD = 4.4%], p

Aims Prediction models for outcomes in atrial fibrillation (AF) are used to guide treatment. While regression models have been the analytic standard for prediction modelling, machine learning (ML) has been promoted as a potentially superior methodology. We compared the performance of ML and regression models in predicting outcomes in AF patients. Methods and results The Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) and Global Anticoagulant Registry in the FIELD (GARFIELD-AF) are population-based registries that include 74 792 AF patients. Models were generated from potential predictors using stepwise logistic regression (STEP), random forests (RF), gradient boosting (GB), and two neural networks (NNs). Discriminatory power was highest for death [STEP area under the curve (AUC) = 0.80 in ORBIT-AF, 0.75 in GARFIELD-AF] and lowest for stroke in all models (STEP AUC = 0.67 in ORBIT-AF, 0.66 in GARFIELD-AF). The discriminatory power of the ML models was similar or lower than the STEP models for most outcomes. The GB model had a higher AUC than STEP for death in GARFIELD-AF (0.76 vs. 0.75), but only nominally, and both performed similarly in ORBIT-AF. The multilayer NN had the lowest discriminatory power for all outcomes. The calibration of the STEP modelswere more aligned with the observed events for all outcomes. In the cross-registry models, the discriminatory power of the ML models was similar or lower than the STEP for most cases. Conclusion When developed from two large, community-based AF registries, ML techniques did not improve prediction modelling of death, major bleeding, or stroke.

Background: Catheter ablation is an increasingly used treatment for symptomatic atrial fibrillation (AF). However, there are limited prospective, nationwide data on patient selection and procedural characteristics. This study describes patient characteristics, techniques, treatment patterns, and safety outcomes of patients undergoing AF ablation. Methods: A total of 3139 patients undergoing AF ablation between 2016 and 2018 in the Get With The Guidelines-Atrial Fibrillation registry from 24 US centers were included. Patient demographics, medical history, procedural details, and complications were abstracted. Differences between paroxysmal and patients with persistent AF were compared using Pearson χ 2 and Wilcoxon rank-sum tests. Results: Patients undergoing AF ablation were predominantly male (63.9%) and White (93.2%) with a median age of 65. Hypertension was the most common comorbidity (67.6%), and patients with persistent AF had more comorbidities than patients with paroxysmal AF. Drug refractory, paroxysmal AF was the most common ablation indication (class I, 53.6%) followed by drug refractory, persistent AF (class I, 41.8%). Radiofrequency ablation with contact force sensing was the most common ablation modality (70.5%); 23.7% of patients underwent cryoballoon ablation. Pulmonary vein isolation was performed in 94.6% of de novo ablations; the most common adjunctive lesions included left atrial roof or posterior/inferior lines, and cavotricuspid isthmus ablation. Complications were uncommon (5.1%) and were life-threatening in 0.7% of cases. Conclusions: More than 98% of AF ablations among participating sites are performed for class I or class IIA indications. Contact force-guided radiofrequency ablation is the dominant technique and pulmonary vein isolation the principal lesion set. In-hospital complications are uncommon and rarely life-threatening.

Background Left ventricular assist devices (LVADs) generate electromagnetic interference that causes high‐frequency noise artifacts on 12‐lead ECGs. We describe the causes of this interference and potential solutions to aid ECG interpretation in patients with LVAD. Methods and Results Waveform data from ECGs performed before and after LVAD implantation were passed through a fast Fourier transform to identify LVAD‐related changes in the spectral profile. ECGs recorded in 9 patients with HeartMate II, HeartMate 3, and HeartWare LVADs were analyzed to identify the LVAD model‐specific spectral patterns. Waveform data were then passed through digital low‐pass and bandstop filters and redisplayed to evaluate the effect of filtering on LVAD‐related electromagnetic interference. The spectral profile of patients with HeartMate II and HeartMate 3 LVADs demonstrated a prominent signal at the device‐specific frequency of impeller rotation. In patients with the HeartMate 3 LVAD, 2 additional peaks were observed at the frequencies equivalent to the LVAD's artificial pulsatility rotational speeds. Patients with HeartWare devices demonstrated a prominent signal peak at a frequency equal to double their LVAD's set rotational speed. Applying a low‐pass filter to a value below the observed frequency peak from the LVAD significantly improved the waveform tracing and quality of the ECG. Applying a speed‐specific bandstop filter to remove the observed LVAD frequency peak also improved the clarity of the ECG without compromising physiological high‐frequency signal components. Conclusions LVADs create impeller rotational speed‐specific electromagnetic interference that can be ameliorated by application of low‐pass or bandstop filters to improve ECG clarity.

No abstract available Keywords: Biventricular pacing; Cardiac resynchronization therapy; Electrophysiology; Exercise testing; QRS interval.

Background: The optimal timing of catheter ablation for atrial fibrillation (AF) in reference to the time of diagnosis is unknown. We sought to assess the impact of the duration between first diagnosis of AF and ablation, or diagnosis-to-ablation time (DAT), on AF recurrence following catheter ablation. Methods: We conducted a systematic electronic search for observational studies reporting the outcomes associated with catheter ablation for atrial fibrillation stratified by diagnosis-to-ablation time. The primary meta-analysis using a random effects model assessed AF recurrence stratified by DAT ≤1 year versus >1 year. A secondary analysis assessed outcomes stratified by DAT ≤3 years versus >3 years. Results: Of the 632 screened studies, 6 studies met inclusion criteria for a total of 4950 participants undergoing AF ablation for symptomatic AF. A shorter DAT ≤1 year was associated with a lower relative risk of AF recurrence compared with DAT >1 year (relative risk, 0.73 [95% CI, 0.65–0.82]; P 2 =51%). When excluding the one study consisting of only patients with persistent AF, the heterogeneity improved substantially (I 2 =0%, Cochran’s Q P =0.55) with a similar estimate of effect (relative risk, 0.78 [95% CI, 0.71–0.85]; P Conclusions: Shorter duration between time of first AF diagnosis and AF ablation is associated with an increased likelihood of ablation procedural success. Additional study is required to confirm these results and to explore implementation of earlier catheter AF ablation and patient outcomes within the current AF care pathway. Visual Overview A visual overview is available for this article.

“New tools provide, for the first time, a mechanism for informal, self-directed just-in-time learning.”—Eugene Stead [(1)][1] The doubling time of medical knowledge has shortened dramatically—in 1950, it was 50 years; in 2010, 3.5 years; and by 2020, it is projected to be a mere 73

Background Patients with left bundle branch block (LBBB) often respond to cardiac resynchronization therapy (CRT) with left ventricular ejection fraction (LVEF) improvement. Guideline-directed medical therapy (GDMT), not CRT, is first-line therapy for patients with reduced LVEF with LBBB. However, there are little data on how patients with reduced LVEF and LBBB respond to GDMT. Objectives This study examined patients with cardiomyopathy and sought to assess rates of LVEF improvement for patients with LBBB compared to other QRS morphologies. Methods Using data from the Duke Echocardiography Laboratory Database, the study identified patients with baseline electrocardiography and LVEF ≤35% who had a follow-up LVEF 3 to 6 months later. The study excluded patients with severe valve disease, a cardiac device, left ventricular assist device, or heart transplant. QRS morphology was classified as LBBB, QRS duration Results There were 659 patients that met the criteria: 111 LBBB (17%), 59 wide QRS duration ≥120 ms but not LBBB (9%), and 489 narrow QRS duration (74%). Adjusted mean increase in LVEF over 3 to 6 months in the 3 groups was 2.03%, 5.28%, and 8.00%, respectively (p Conclusions LBBB is associated with a smaller degree of LVEF improvement compared with other QRS morphologies, even with GDMT. Some patients with LBBB may benefit from CRT earlier than guidelines currently recommend.

Background: Changes in left ventricular (LV) activation after cardiac resynchronization therapy (CRT) influence survival but are difficult to quantify noninvasively. Methods and Results: We studied 527 CRT patients to assess whether noninvasive quantification of changes in LV activation, defined by change (Δ) in QRS area (QRSA), can predict outcomes after CRT. The study outcome was time until LV assist device(LVAD), cardiac transplant, or death. The three-dimensional QRSA was measured from clinical 12 lead ECGs which were transformed into vectorcardiograms using the Kors method. QRSA was calculated as (QRSx 2 + QRSy 2 + QRSz 2) 1/2; ΔQRSA was calculated as post-QRSA minus pre-QRSA, where a negative value represents a reduction in LV activation delay. Kaplan–Meier plots and multivariable Cox proportional hazards models were used to relate ΔQRSA area with outcomes after stratifying the population into quartiles of ΔQRSA. The median baseline QRSA of 93.6 µVs decreased to 59.7 µVs after CRT. Progressive reductions in QRSA with CRT were associated with a lower rate of LVAD, transplant, or death across patient quartiles (P

BACKGROUND: PR interval prolongation is associated with poor outcome after cardiac resynchronization therapy (CRT) among patients with left bundle branch block (LBBB) but the mechanisms are unknown. We investigated clinical outcomes, electrocardiogram (ECG), and echocardiogram changes after CRT by PR interval.METHODS: This is a retrospective study of CRT recipients with a baseline ejection fraction ≤35% and ECG showing sinus rhythm and LBBB. Patients were stratified by baseline PR interval quartile and the primary combined endpoint was time to heart transplantation, left ventricular assist device (LVAD) implantation, or death. ECG, echocardiogram, and clinical variables were compared to identify mechanisms for observed differences in outcomes.RESULTS: Of 291 eligible patients, the mean age was 65 years, 60% were male, and 19% had prior atrial fibrillation. Patients with PR prolongation (quartile 4, PR > 200 ms) more frequently had a history of atrial fibrillation, coronary artery bypass graft surgery, prior implantable cardioverter defibrillator implantation, and use of amiodarone than patients in PR quartiles 1-3. A PR > 200ms was associated with an adjusted hazard ratio of 1.7 (95% CI: 1.1-2.5) for the primary endpoint. Patients with PR > 200 ms had less reduction in QRS duration and QRS area after CRT while having more increase in QT and QTc intervals than patients with PR ≤ 200 ms. No major differences were observed in echocardiography by baseline PR interval quartiles.CONCLUSIONS: PR prolongation predicts shorter survival free of heart transplantation or LVAD implantation in patients with LBBB. This may be due to inadequate ventricular resynchronization.

Background Reports on the subcutaneous implantable cardioverter-defibrillator (S-ICD) cumulatively demonstrate a low rate of complications, but clinical experience with this technology is limited compared with transvenous devices. Objective The purpose of this study was to describe and analyze S-ICD complications reported to the Food and Drug Administration's Manufacturer and User Facility Device Experience database. Methods We reviewed all S-ICD events reported to the Manufacturer and User Facility Device Experience submitted over 24 months (from February 2016 through February 2018) through a prospective and standardized approach at a time when an estimated 15,000 S-ICDs were in service. Results After removing duplicate entries and nonclinical events (n = 493), 1604 events remained. A total of 542 instances of infection were reported with system removal in 414/542 (77.5%). Inappropriate shocks occurred in 550 patients, and 382 (69%) were attributed to oversensing; in response, 254 (56%), 147 (33%), and 80 (18%) patients underwent system reprogramming, removal, or revision, respectively. There were 15 deaths, and causes included defibrillation failure during follow-up (n = 2), ventricular fibrillation induced by the device (n = 4), device-device interaction resulting in undersensing (n = 1), procedure-related complications (n = 4), and uncertain etiology (n = 4). There were 137 reports of system migration, and in 57 (42%) of these, there were associated inappropriate shocks. System migration events were managed with a combination of system revision (69 [51%]), reprogramming (25 [18%]), and system removal (44 [32%]). Conclusion Several S-ICD complications have been reported that appear to be related to the ICD's design and function over time. A better understanding of these complications may help inform patient selection, implant technique, and postimplantation management.

Background Little is known about healthcare-seeking behaviour and barriers to care for cardiovascular disease (CVD) in sub-Saharan Africa. Methods Emergency department patients in Tanzania with acute CVD were prospectively enrolled. Questionnaires were administered at enrollment and 30 d later. Results Of 241 patients, 186 (77.2%) had visited another facility for the same illness episode (median symptom duration prior to presentation was 7 d) and 82 (34.0%) reported that they were initially unaware of the potential seriousness of their symptoms. Of the 208 (86.3%) patients completing follow-up, 16 (7.7%) had died, 38 (18.3%) had visited another facility for persistent symptoms, 99 (47.6%) felt they understood their diagnosis, 87 (41.8%) felt they understood their treatment and 11 (7.8%) could identify any of their medications. Predictors of 30 d survival with symptom improvement included medication compliance (p Conclusions Patients with CVD in Tanzania usually visit multiple facilities for the same illness episode, typically after prolonged delays. Only a minority understand their diagnosis and treatment, and such understanding is correlated with survival with symptom improvement. Patient-centred interventions are needed to improve the quality of cardiovascular care in Tanzania.

Item does not contain fulltext INTRODUCTION: We evaluated the association between a novel electrocardiographic (ECG) marker of late, rightward electrocardiographic forces (termed the lead one ratio [LOR]), and left ventricular ejection fraction (LVEF), myocardial scar, and clinical outcomes in patients with left bundle branch block (LBBB). METHODS AND RESULTS: LOR was calculated in patients with LBBB from a derivation cohort (n = 240) and receiver operator characteristic curves identified optimal threshold values for predicting myocardial scar and LVEF less than 35%. An independent validation cohort of patients with LBBB (n = 196) was used to test the association of LOR with the myocardial scar, LVEF, and the likelihood of death, heart transplant or left ventricular assist device (LVAD) implantation. The optimal thresholds in the derivation cohort were LOR less than 13.7 for identification of scar (sensitivity 55%, specificity 80%), and LOR less than 12.1 for LVEF less than 35% (sensitivity 49%, specificity 80%). In the validation cohort, LOR less than 13.7 was not associated with scar size or presence (P > 0.05 for both). LOR less than 12.1 was associated with lower LVEF (30 [20-40] versus 40 [25-55]%; P = 0.002) and predicted LVEF less than 35% in univariable (odds ratio [OR], 2.2 [1.2-4.1]; P = 0.01) and multivariable analysis (OR, 2.2 [1.2-4.3]; P = 0.02). LOR less than 12.1 was associated with scar presence when patients with nonischemic cardiomyopathy were excluded (OR = 7.2 [1.5-33.2]; P = 0.002). LOR less than 12.1 had an adjusted hazard ratio of 1.53 ([1.05-2.21]; P = 0.03) for death, transplant or LVAD implantation. CONCLUSIONS: In conclusion, ECG LOR less than 12.1 predicts reduced-LV systolic function and poorer prognosis in patients with LBBB.

Background There is a need for improved selection criteria for cardiac resynchronization therapy (CRT). High myocardial scar burden has been associated with worse outcome in CRT patients. However, it is unclear whether high scar burden prevents CRT clinical benefit or is merely predictive of prognosis in heart failure (HF) patients regardless of CRT implantation. We aimed to study the predictive value of scar burden estimated by electrocardiographic Selvester QRS scoring in determining CRT benefit in the multicenter automatic defibrillator implantation trial-cardiac resynchronization therapy (MADIT-CRT) population. Methods Selvester QRS scoring was performed on all 1820 ECGs of the MADIT-CRT population by a single observer. In both arms and in their respective LBBB subgroups, QRS score was analyzed in comparison to echocardiographic volumes and in relation to time to HF event or death using Cox proportional hazard ratios. To determine effect on CRT clinical benefit, we tested for interaction between the effects of CRT assignment and QRS score on time to HF event or death. Results In the CRT-D arm, a significant correlation was found between higher continuous QRS score and less increase of left ventricular ejection fraction (LVEF) as well as less decrease of left ventricular end-systolic volume (LVESV) (multivariate -p-values

BACKGROUND Frequent premature ventricular contractions (PVCs) can cause a reversible reduction in systolic function. Most studies use 24-hour ambulatory electrocardiograms (AECGs) to assess PVC burden; however, PVC counts vary across 24-hour periods. We hypothesized that extended AECG monitoring would better identify clinically significant ectopy. METHODS All 14-day AECGs performed at the San Francisco Veterans Affairs Medical Center between 2012 and 2015 (N = 694) were reviewed, and individuals with PVC counts ≥1.0% of total heartbeats were included (N = 101). Daily PVC counts and the range of these values across 24-hour periods were assessed. Median time for these ranges to cross clinically significant thresholds (PVCs ≥ 10%, 15%, or 20% of total heartbeats) was determined. RESULTS Median PVC burden was 2.6% of total heartbeats (interquartile range [IQR]: 1.6-5.4%) and the median range across 24-hour periods was 3.6% (IQR: 2.0-9.1%). Individual ranges of daily PVC burden crossed thresholds of 10%, 15%, and 20% of total heartbeats in 26.7%, 16.8%, and 6.9% of patients, respectively. Median time to detecting an individual's maximum PVC burden was 6 days (IQR: 2-11 days). While 75% of those who reached the 20% threshold did so on day one of monitoring, only 53% of those reaching the 10% threshold did similarly, with a continually increasing yield throughout the 14-day monitoring period. CONCLUSIONS PVC burden varies widely from day-to-day. While most patients with PVC burdens ≥20% were detected with 24 hours of monitoring, extended monitoring nearly doubled the identification of those reaching the 10% threshold.

To prevent death, necrotizing soft-tissue infections should be diagnosed quickly and treated with broad-spectrum antibiotics and surgical debridement.

We compared the incidence of left ventricular systolic dysfunction (LVSD) among patients with left bundle branch block (LBBB) to a matched cohort of patients with a narrow QRS duration120 ms (NQRS). We hypothesized patients with preserved ejection fraction (EF) ≥50% and LBBB would have higher incidence of LVSD compared with a matched population of NQRS patients. Patients with LBBB on electrocardiogram within 30 days of a baseline echocardiogram with EF ≥50%, who had at least 1 follow-up echocardiogram ≥6 months later, were matched 1:1 on risk factors for cardiomyopathy to patients with NQRS. Incident LVSD was defined as a decline in EF to ≤45% on follow-up echocardiogram, or heart transplant, receipt of a cardiac device for LVSD (defibrillator or biventricular pacemaker), or implantation of a left ventricular assist device ≥6 months post baseline echocardiogram. Relative risk was calculated using conditional Poisson regression techniques. The final study cohort consisted of 188 patients, 94 with LBBB and 94 with NQRS. On follow-up, progression to LVSD was noted in 36% of LBBB patients and 10% of NQRS patients. The relative risk for LVSD in patients with LBBB was 3.78 (95% confidence interval = 1.98 to 7.19). In conclusion, there is a strong association between LBBB and the subsequent development of LVSD independent of common risk factors for cardiomyopathy.

QRS duration (QRSd) is used to diagnose left bundle branch block (LBBB) and is important to determine cardiac resynchronization therapy eligibility. The same QRSd thresholds established decades ago are used for all patients. However, significant interpatient variability of normal QRSd exists, and individualized QRSd thresholds might improve diagnosis and intervention strategies. Previous work reported left ventricular (LV) mass and papillary muscle location predicted QRSd in healthy subjects, but the relation in diseased ventricles is unknown. The aim of the present study was to determine the association between LV anatomy and QRSd in patients with cardiomyopathy. Patients referred for primary prevention implantable defibrillators (n = 166) received cardiac magnetic resonance imaging, and those with normal conduction (without bundle branch or fascicular block) and LBBB were studied. The LV mass, length, internal diameter, LV end-diastolic volume, septal and lateral wall thicknesses, and papillary muscle location were measured. In patients with normal conduction, LV length (r = 0.35, p0.001), mass (r = 0.32, p0.001), diameter (r = 0.20, p = 0.03), and septal wall thickness (r = 0.20, p = 0.03) had positive correlations with QRSd. In patients with LBBB, LV length (r = 0.32, p = 0.03), mass (r = 0.39, p = 0.01), diameter (r = 0.34, p = 0.02), and LV end-diastolic volume (r = 0.32, p = 0.04) had positive correlations with QRSd. Contrary to previous studies in healthy subjects, papillary muscle angle (location) was not associated with QRSd in cardiomyopathy patients with normal conduction or LBBB. In conclusion, increasing LV anatomical measurements were associated with increasing QRSd in patients with cardiomyopathy. Future work should investigate the use of LV anatomical measurements in developing individualized QRSd thresholds for diagnosing conduction abnormalities such as LBBB and identifying candidates for cardiac resynchronization therapy.

Comorbidities are common in AF and are often under-treated. We evaluated the association of guideline-directed medical therapy (GDMT) for comorbidities and outcomes in AF patients. Patients from the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF) with any GDMT eligible condition

Fourteen drugs have been removed from the market worldwide because they cause torsade de pointes. Most drugs that cause torsade can be identified by assessing whether they block the human ether à gogo related gene (hERG) potassium channel and prolong the QT interval on the electrocardiogram. In response, regulatory agencies require new drugs to undergo "thorough QT" studies. However, some drugs block hERG potassium channels and prolong QT with minimal torsade risk because they also block calcium and/or sodium channels. Through analysis of clinical and preclinical data from 34 studies submitted to the US Food and Drug Administration and by computer simulations, we demonstrate that by dividing the QT interval into its components of depolarization (QRS), early repolarization (J-Tpeak), and late repolarization (Tpeak-Tend), along with atrioventricular conduction delay (PR), it may be possible to determine which hERG potassium channel blockers also have calcium and/or sodium channel blocking activity. This translational regulatory science approach may enable innovative drugs that otherwise would have been labeled unsafe to come to market.

ObjectivesThis study sought to test the hypothesis that right bundle branch block (RBBB) patients have larger scar size than left bundle branch block (LBBB) patients do.BackgroundA proximal septal perforating branch of the left anterior descending (LAD) coronary artery most commonly perfuses the right bundle branch and left anterior fascicle, but not the left posterior fascicle. Thus, proximal LAD occlusions should cause RBBB, not LBBB.MethodsWe performed electrocardiograms and magnetic resonance imaging for scar quantification in 233 patients with left ventricular (LV) ejection fraction ≤35% who were receiving primary prevention implantable cardioverter-defibrillators (ICD cohort). Scar size and location were compared among patients with RBBB, LBBB, nonspecific LV conduction delay, and QRS

The mortality benefit of implantable cardioverter defibrillators (ICD) in patients with prior myocardial infarction (MI) and reduced left ventricular ejection fraction (LVEF) demonstrated in Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II) and Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) has resulted in recommendation for broad use of these devices and dramatically increased implantation rates in recent years.1–4 The high incremental cost-effectiveness ratio and relatively low rate of appropriate ICD discharge illustrates the need for better risk-stratification techniques to identify patients for ICD implantation.5, 6 The mortality reduction in MADIT-II was due to a reduction in sudden cardiac death (SCD) with no effect on heart failure (HF) deaths.7 Prior studies have shown that as HF progresses, the relative risk of total mortality and HF death (non-SCD) increases while the relative risk of SCD decreases.8–10 This may explain the U-shaped pattern in ICD efficacy observed where ICD efficacy was greatest in patients with an intermediate risk of death, but lower in patients at highest risk for death.11 Distinguishing individuals at high risk for non-SCD from those primarily at risk for SCD may allow for identification of who will benefit most from ICDs. Analysis of the SCD-HeFT trial found that quantifying infarct size using the Selvester QRS score was predictive of ventricular tachycardia or ventricular fibrillation (VT/VF) and, when combined with LVEF, was able to separate subgroups of low, medium and high risk of VT/VF.12 Additionally, several studies have implicated infarct size as a predictor of both heart failure development and worse outcomes.13–15 The value of the QRS score in predicting SCD vs. non-SCD risk in ICD eligible subjects has not yet been examined. This study evaluated whether QRS score is useful for risk stratification of ICD eligible patients. We hypothesized that (1) subjects with moderate/large infarcts would have the highest rate of SCD; (2) as MI size increases, the rates of non-SCD would approach that of VT/VF and/or SCD; and (3) ICDs would confer the greatest mortality benefit in patients with large MIs.