Prolonged QRS Research Articles

QTc and QRS Abnormalities are Associated with Outcome in Pediatric Heart Failure.

Adult studies have shown that depolarization and repolarization abnormalities are associated with worsening heart failure; however, this relationship is not well understood in pediatric congenital heart disease. We evaluated the association between QTc and QRS duration to systolic function and outcome in children with heart failure and reduced ejection fraction (HFrEF). We performed a retrospective, single-center, 14-year cohort study of HFrEF children. Clinical records, echocardiograms, and electrocardiograms were reviewed for every clinical encounter. Diagnosis, interventions, outcomes, QRS and QTc duration, and systolic function were collected. Repeated-measure ANOVA evaluated the association between depolarization and repolarization to cardiac function. Cox regression analysisexamined the effects of age, time since diagnosis, and measured and change in QTc and QRS duration on time to transplant/death. We enrolled 136 cardiomyopathy (CM) and 47 structural heart disease (SHD) patients. Prolonged QRS (p = 0.0001) and QTc (p = 0.02) were associated with systolic dysfunction. This association was significant in SHD group (QRS p < 0.0001, QTc p = 0.048), but not CM group (QRS p = 0.5, QTc p = 0.3). Progressive lengthening of QTc was significantly associated with transplant or death in the overall cohort (HR 1.02, CI 1.011-1.028), SHD, (HR 1.020, CI 1.001-1.039), and CM (HR 1.017, CI 1.007-1.027). QTc and QRS prolongation are each associated with ventricular dysfunction in pediatric SHD with heart failure. QTc prolongation is an indication for poor outcomes in SHD and CM groups, leading to a higher risk of death or transplantation. Progressive lengthening of QTc over time in children with HFrEF may indicate increased risk in this population.

Association between complete right bundle branch block and atrial fibrillation development.

BackgroundComplete right bundle branch block (CRBBB) is an important predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation. However, the association between CRBBB and AF development remains unclear.MethodsWe performed a retrospective study of 2639 patients (male, n = 1549; female, n = 1090; mean age, 58 ± 13 years). CRBBB was defined as a late R (R′) wave in lead V1 or V2 with a slurred S wave in lead I and/or lead V6 with a prolonged QRS duration (≥120 ms).ResultsAmong the 2639 patients, CRBBB was detected in 40 patients (1.5%), and the prevalence of AF was 7.4% (196/2639). The proportion of patients with AF and CRBBB was higher than the proportion of patients with AF without CRBBB (22.5% vs. 7.2%; p = 0.001). In the forward multivariate logistic analysis, CRBBB (odds ratio [OR], 3.329; 95% confidence interval [CI], 1.350–8.211; p = 0.009), complete left bundle branch block (OR, 2.209; 95% CI, 1.238–3.940; p = 0.007), age (OR, 1.020; 95% CI, 1.005–1.035; p = 0.009), valvular heart disease (OR, 2.332; 95% CI, 1.531–3.552; p < 0.001), left atrial diameter (OR, 1.133; 95% CI, 1.104–1.163; p < 0.001), left ventricular ejection fraction (OR, 1.023; 95% CI, 1.006–1.041; p = 0.007), and class I or III anti‐arrhythmic drug use (OR, 10.534; 95% CI, 7.090–15.651; p < 0.001) were associated with AF.ConclusionComplete right bundle branch block was significantly associated with AF development in hospitalized patients with cardiovascular diseases.

Abstract 60: Mortality Following Heart Failure Hospitalization By QRS Duration In Patients With Preserved Ejection Fraction

Background: Heart failure with preserved ejection fraction (HFpEF) comprises almost half of all heart failure (HF) diagnoses. Similar to HF with reduced ejection fraction (HFrEF), HFpEF carries up to a 75% 5-year mortality following HF hospitalization. However, unlike its corollary, HFpEF has exceedingly limited therapeutic options to alter its natural history. While QRS prolongation (QRS &gt; 120 msec) carries prognostic significance in HFrEF, less is known about the implications of this conduction abnormality in HFpEF. Objective: To determine the association of QRS prolongation with survival among patients with HFpEF following HF hospitalization. Methods: A retrospective review of 1,454 patients with left ventricular EF ≥ 45% discharged from the Minneapolis VA Medical Center between 2015 and 2019 from a HF hospitalization. All patients’ electrocardiograms (ECG) were classified by QRS duration as either prolonged (QRS &gt;120 msec) or narrow complex (QRS ≤120 msec). Those with prolonged QRS were further subtyped as: left bundle branch block (LBBB), right bundle branch block (RBBB), intraventricular conduction delay (IVCD), or ventricular paced (VP) rhythm. Results: Of the 1,454 patients (mean age 75.1 ± 10.8 years, 97.7% male, and mean EF 58.5% ± 10.2%), 545 (37.5%) had QRS prolongation. Specifically, 61 (4.2%) had LBBB, 266 (18.3%) had RBBB, 77 (5.3%) had IVCD and 141 (9.7%) had VP. Over 4.09 ± 1.00 years of follow up, 769 (52.9%) of the patients died (Table). Patients with a narrow QRS had a similar survival relative to those with a QRS &gt;120 msec with an age and sex adjusted hazard ratio of 1.01 (95% CI: 0.87-1.17, p = 0.16) (Figure). Conclusions: The mortality rate is exceedingly high in patients with HFpEF discharged after a HF hospitalization. While the QRS interval was not significantly associated with near-term survival in this analysis, these data suggest that studies with greater statistical power and follow-up duration are warranted.

Determinants of Response to Cardiac Resynchronization Therapy.

Cardiac resynchronization therapy (CRT) is a well-established treatment modality for ambulatory patients with heart failure (HF) who have prolonged QRS, left bundle branch block, reduced left ventricular (LV) ejection fraction, and New York Heart Association class II–IV. CRT has been shown to induce reverse LV remodeling and improve HF symptoms and clinical outcomes. About one-third of CRT recipients are considered non-responders. Patient selection, LV lead location, LV lead selection, multipoint pacing, and optimization of the atrioventricular and ventriculo-ventricular intervals were all shown to be associated with a better CRT response rate. Herein, we review the determinants of CRT response.

Novel and Effective: ECG Utilization for MI Confirmation in Mouse Models

IntroductionElectrocardiography measures the electrical activity of the heart to generate an electrocardiogram (ECG) through a non‐invasive process that involves placing electrodes on strategic points on the body. When an MI occurs, the lack of contractility induces changes to the ECG, visualized by a prolonged QRS wave and amplification of the R wave. Previously, we identified the area under the QRS wave, 1 min after permanent ligation in a mouse model of myocardial infarction (MI) determined surgical success. The purpose of this study was to further demonstrate in a second cohort that the previous ECG parameters identified accurately confirmed that an MI has been administered by left anterior coronary artery ligation in real‐time.Methods and ResultsPermanent coronary artery ligation was performed on WT and CD8atmak1 (CD8‐/‐) mice (n=9/genotype); an ECG was recorded using a surgical monitoring platform and was analyzed on iWorkx LabScribe Data Acquisition and Analysis software. Previous analysis of the first dataset indicated no differences between sexes so both males and females were used in the second cohort. A receiver operating characteristic (ROC) curve was used to link changes in the QRS complex at the 1‐min mark with MI surgical success. By ROC analysis, the area under the QRS complex had an area under the curve (AUC) of 0.94 (p=0.01) indicating a strong association with MI success. To remove any potential effect of surgical platform variability, we normalized the 1 min data to pre‐MI values to determine fold‐change in the area under the QRS complex. ROC analysis of the normalized data also indicated a strong sensitivity and specificity for MI success with an AUC value of 0.90 (p=0.02). Mice in the second cohort were divided into two groups based on a cut‐off point for either the area under the QRS complex (≥0.003 mV/sec) or the normalized data (≥ 3.1 fold change in the QRS complex) to distinguish the two groups. Using the non‐normalized data alone, there was an 84% success rate with 2 false positives and 1 false negative. Analysis using the normalized data alone had an 74% success rate, with 2 false positives and 3 false negatives. None of these false positives or negatives were linked to genotype or sex.ConclusionOur data indicates that while changes in the QRS complex 1‐min after ligation may be useful for confirming MI surgical success, there are potential limitations that could skew the data. One possible explanation for the false positives could be variation between ECG boards. To remove this, we normalized post‐MI data to pre‐MI values but, this seemed to decrease effectiveness. It is also important to note that many of the false negatives were due to anomalies within the ECG such as the presence of R‐prime waves. For this reason, users must be consistent when analyzing the ECG data points to minimize variation. In summary, using the ECG data 1 min after ligation had a fairly strong prediction rate for MI surgical success.

PO-688-05 EVALUATION OF TRANSSEPTAL DELAY IN CARDIAC RESYNCHRONIZATION THERAPY PATIENTS WITH HEART FAILURE AND LEFT BUNDLE BRANCH BLOCK

Transseptal delay accounts for QRS prolongation in LBBB and may affect CRT programming. It is represented by the first notch of the QRS in Strauss-type LBBB indicating the depolarization of the LV endocardium after transiting the septum. However, little is known about the distribution of transseptal delay or the relationship with baseline electrical parameters common in CRT. To characterize transseptal delay in heart failure patients with LBBB. Heart failure patients with QRS> 120ms and Strauss-type LBBB receiving CRT, the transseptal delay (TSt) was estimated as the onset of the QRS to the peak of the first notch in at least two continuous leads (I, aVL, V1 or V6). Device-based measurements of RV and LV intrinsic activation delay (qRV/qLV) and paced inter-ventricular conduction times were evaluated for each patient. One hundred and forty-seven patients (65% Male, 32% ICM, 68 ± 10 yrs, EF 27±8%, qRV 21±11 ms, qLV 127 ± 24 ms, qLV/QRSd 0.76 ± 0.13 and QRSd 166 ± 17 ms) were evaluated. The TSt was 56 ± 14 ms (34% of QRSd; range 25 to 93 ms). There was no difference in TSt when gender (M/F) or type of cardiomyopathy (ICM/NICM) were compared. Further, correlation was poor between TSt and electrical measures during intrinsic conduction (qRV, r=0.11; qLV, r=0.08; and QRSd, r=0.22) or paced activation (RV pace to LV sense time, r=0.00 or LV pace to RV sense time, r=0.03). Transseptal delay, the basis for LV activation delay in LBBB, is widely distributed in CRT patients, not influenced by gender or type of cardiomyopathy, and unrelated to other baseline intrinsic or paced electrical parameters.

PO-663-07 IMPACT OF INTRINSIC AND PACED PARAMETERS ON BEST ELECTRICAL RESYNCHRONIZATION IN CARDIAC RESYNCHRONIZATION THERAPY IN PATIENTS WITH HEART FAILURE AND LBBB

Electrical factors that may influence efficacy of cardiac resynchronization therapy (CRT) are transseptal conduction time during intrinsic conduction (the source of QRS prolongation in LBBB), success of left ventricular (LV) preexcitation during LV pacing, and programmed AV interval. These have been tested separately, and whether they are co-dependent is unknown.

PO-688-07 IMPACT OF BASELINE PR INTERVAL ON RESPONSE TO CARDIAC RESYNCHRONIZATION THERAPY: AN INDIVIDUAL PATIENT DATA META-ANALYSIS OF FIVE RANDOMIZED TRIALS

Longer QRS duration predicts greater benefit from cardiac resynchronization therapy (CRT). Many patients receiving CRT also have a prolonged PR interval, but it is unclear whether PR interval is also an important determinant of the effects of CRT. To investigate whether PR interval is an important determinant of the benefits of CRT. Individual patient data from five randomized trials (MIRACLE, MIRACLE-ICD, CARE-HF, RAFT and REVERSE) comparing CRT and control were pooled. The composite primary endpoint was heart failure hospitalization (HFH) and all-cause mortality. Multivariable analyses were performed including PR interval as well as variables associated with heart failure outcomes including age, gender, QRS duration and morphology, heart failure etiology, systolic blood pressure, beta-blocker use, left ventricular ejection fraction (LVEF) and New York Heart Failure Association class. Of 3872 patients, 1849 were assigned to control and 2023 to CRT. Follow-up ranged from six to 40 months. There are a number of independent predictors of clinical outcomes (Table 1). However, CRT benefit on HFH or death was only significantly influenced by baseline QRS duration (p<0.0001) and PR interval (p=0.0214) and not QRS morphology (p=0.1107). For patients with QRS duration at or above the median value (160ms), the effect of CRT was substantial and similar regardless of PR interval. For patients with QRS duration below the median, CRT was effective only for those with the shortest quartile of PR interval, with progressively less evidence of benefit as PR interval became more prolonged (Table 2). PR interval as well as QRS duration are important determinants of the response to CRT. Patients with marked QRS prolongation benefit from CRT regardless of PR interval. When QRS is not as prolonged, patients with longer PR intervals may obtain little or no benefit.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

False Negative ECG Device Results May Increase the Risk of Adverse Events in Clinical Oncology Trials

BackgroundSites participating in clinical trials may not have the expertise and infrastructure to accurately measure cardiac intervals on 12-lead ECGs and rely heavily on the automated ECG device generated results for clinical decision-making.MethodsUsing a dataset of over 260,000 ECGs collected in clinical oncology studies, we investigated the mean difference and the rate of false negative results between the digital ECG machine QTc and QRS measurements compared to those obtained by a centralized ECG core lab.ResultsThe mean differences between the core lab and the automated algorithm QTcF and QRS measurements were + 1.8 ± 16.0 ms and − 1.0 ± 8.8 ms, respectively. Among the ECGs with a centralized QTcF value > 450 or > 470 ms, 39.5% and 47.8% respectively had a device reported QTcF value ≤ 450 ms or ≤ 470 ms. Among the ECGs with a centrally measured QTcF > 500 ms, 55.8% had a device reported value ≤ 500 ms. Automated QTcF measurements failed to detect a QTcF increase > 60 ms for 53.9% of the ECGs identified by the core lab. Automated measurements also failed to detect QRS prolongation, though to a lesser extent than failures to detect QTc prolongation. Among the ECGs with a centrally measured QRS > 110 or 120 ms, 7.9% and 7.3% respectively had a device reported QRS value ≤ 110 ms or ≤ 120 ms.ConclusionRelying on automated measurements from ECG devices for patient inclusion and treatment (dis)continuation decisions poses a potential risk to patients participating in oncology studies.

Potential Impact of 3% Hypertonic Saline Infusion on Tramadol Poisoning-Induced Electrocardiogram Changes; a Randomized Clinical Trial

Introduction:Tramadol is a synthetic analgesic with weak mu-opioid receptor agonist activity. Tramadol overdose is associated with adverse cardiac effects due to inhibiting cardiac Na+ and K+ channels. This study aimed to investigate the potential ameliorative role of 3% hypertonic saline on the electrocardiogram (ECG) changes in patients presenting with tramadol poisoning.Methods:This was a single-center, controlled, randomized, single-blind clinical trial. Patients were randomized into the case (received hypertonic saline) and control (received placebo) groups. ECG was obtained twice in each group (upon arrival and following the intervention). Response to therapeutic interventions was evaluated using Wilcoxon Signed Ranks Test. Results:A total of 76 patients were included. The mean age of patients was 24.88 ± 4.29 years, and 62 (81.6%) were male. The mean ingested dose of tramadol was 1673.68 ± 608.85 (range: 550-2750) mg. The number needed to treat and the absolute risk reduction of 3% hypertonic saline in the treatment of wide QRS were 1 (95% CI: 1.00 – 1.00) and 100%, respectively. In the treatment of long QTc, these measures were 1.9 (95%CI: 1.2 – 4.5) and 53.85% (95%CI: 22.00 – 85.69), respectively.Conclusion:Given that hypertonic saline infusion can significantly ameliorate tramadol-mediated ECG changes, including QRS prolongation and QT lengthening, it can be regarded as a potential therapeutic strategy to prevent the development of life-threatening ventricular arrhythmias caused by tramadol toxicity.

Relationship between QRS duration on Admission ECG and Angiographic Severity of Coronary Artery Disease in Patients with Acute Anterior Myocardial Infarction

Background: Early risk stratification of patients with myocardial infarction is critical to determine optimum treatment strategies and improve outcomes. This study was designed to determine the relation between QRS duration on admission ECG and severity of coronary artery disease (CAD) in patients with acute anterior myocardial infarction (AMI). Methods: This observational study was carried out from November 2019 to October 2020 with total of 100 patients with first attack of anterior MI who were treated with thrombolytic therapy. Based on the cut-off value of QRS duration 100, the patients were divided into two groups – one group with QRS duration £100 msec (normal QRS) and another group with QRS duration &gt; 100 msec (prolonged QRS). Severity of CAD was assessed using Gensini score derived from coronary angiographic data. Gensini score &lt; 36 points was regarded as mild coronary artery disease and Gensini score ³36 points as moderate to severe coronary artery disease. Then patients with prolonged and normal QRS durations were compared with severity of CAD to find their association. Results: Acute AMI patients with prolonged QRS duration (&gt; 100 msec) more often tend to be associated with severe CAD. Risk of having severe CAD in patients with prolonged QRS duration were almost 8 (95% of CI = 3.2– 19.3) times higher than those with normal QRS duration (£100 msec) (p &lt; 0.001). Conclusion: The study concluded that three out of four patients of acute anterior MI with prolonged QRS duration are likely to have severe CAD. QRS duration more than 100 msec can be used as a cheap, easily available prognostic factor in patients with acute anterior MI. Cardiovasc j 2022; 14(2): 143-149

Protein Kinase C-Mediated Hyperphosphorylation and Lateralization of Connexin 43 Are Involved in Autoimmune Myocarditis-Induced Prolongation of QRS Complex.

Myocarditis is a serious and potentially life-threatening disease, which leads to cardiac dysfunction and sudden cardiac death. An increasing number of evidence suggests that myocarditis is also a malignant complication of coronavirus pneumonia, associated with heart failure and sudden cardiac death. Prolonged QRS complexes that are related to malignant arrhythmias caused by myocarditis significantly increase the risk of sudden cardiac death in patients. However, the molecular mechanisms are not fully known at present. In this study, we identify protein kinase C (PKC) as a new regulator of the QRS complex. In isolated hearts of normal rats, the PKC agonist, phorbol-12-myristate-13-acetate (PMA), induced prolongation of the QRS complex. Mechanistically, hyperphosphorylation and lateralization of connexin 43 (Cx43) by PKC induced depolymerization and internalization of Cx43 gap junction channels and prolongation of the QRS duration. Conversely, administration of the PKC inhibitor, Ro-32-0432, in experimental autoimmune myocarditis (EAM) rats after the most severe inflammation period still significantly rescued the stability of the Cx43 gap junction and alleviated prolongation of the QRS complex. Ro-32-0432 reduced phosphorylation and blocked translocation of Cx43 in EAM rat heart but did not regulate the mRNA expression level of ventricular ion channels and the other regulatory proteins, which indicates that the inhibition of PKC might have no protective effect on ion channels that generate ventricular action potential in EAM rats. These results suggest that the pharmacological inhibition of PKC ameliorates the prolongation of the QRS complex via suppression of Cx43 hyperphosphorylation, lateralization, and depolymerization of Cx43 gap junction channels in EAM rats, which provides a potential therapeutic strategy for myocarditis-induced arrhythmias.

Severe bradycardia from severe hyperkalemia: Patient characteristics, outcomes and factors associated with hemodynamic support

ObjectiveBradycardia is an under-studied manifestation of hyperkalemia potentially associated with adverse outcomes. We sought to systematically describe emergency department (ED) patients that present with severe bradycardia (heart rate < 50) associated with severe hyperkalemia (potassium ≥6.0 mEQ/L) and identify factors associated with the receipt of hemodynamic support. MethodsRetrospective, single-center, case series performed at an urban, tertiary-care hospital from 1/1/2014 to 6/30/2020. We included consecutive adult ED patients presenting simultaneously with severe bradycardia and severe hyperkalemia. Patients with prehospital cardiac arrest, hemolyzed potassium specimens, or only point-of-care lab results were excluded. Detailed information, including chronic medications, electrocardiogram (ECG) features, and potassium/heart rate-directed treatments, was abstracted from the ED medical record. Intensive care utilization and in-hospital outcomes were also recorded. Factors associated with receipt of bradycardia-targeted treatment in the ED were determined with univariate comparisons. ResultsWe screened 319 records and included 87 patients [mean age 72.5 (95% CI 53–92), 55% female, median heart rate 43 (38–47) beats/min, mean potassium 7.1 (95% CI 5.6–8.7) mEQ/L]. Cardiovascular (hypertension 82%, congestive heart failure 28%) and renal (dialysis dependence 30%) comorbidities were common. Many patients were prescribed negative chronotropic agents (84%) or potassium-retaining (52%) chronic medications. Common presenting scenarios were missed hemodialysis, isolated acute renal failure, or acute renal failure in the setting of concomitant critical illness. ECG revealed: junctional rhythm (39%), peaked T waves (27%), and QRS prolongation (30%). Twenty-eight (32%) patients exhibited hypotension and 34 (40%) altered mentation. Thirty-three (38%) patients received hemodynamic support, including 12 (14%) requiring temporary cardiac pacing. Forty-two (48%) patients received emergent renal replacement therapy and 57 (66%) were admitted to the intensive care unit. Hospital mortality was 10%. Factors associated with receipt of hemodynamic-targeted treatment included a lack of dialysis dependence, junctional rhythm, and concomitant presentation with hypothermia, acidemia, or sepsis. ConclusionsPatients presenting with severe bradycardia represent a unique phenotype of ED patients with hyperkalemia that may require significant resuscitation and critical care resources. Further research on the treatment of this uncommon, but potentially life-threatening condition is needed.

Abstract P067: Elite Female Athlete’S Heart Of Asians: The Chief Heart Study

Background: Women have been reported with smaller cardiac size and blood volume in response to intensive physical training compared to men. However, adaptive cardiac characteristics to exercises have been rarely compared between elite and non-elite female athletes particularly among Asian athletes. Methods: This study included 177 women, aged 18-34 years, under a standard 6-month military training course in Taiwan. In 2020, all attended a 3000-meter run to assess endurance capacity, and 89 were randomly selected to complete a 2-minute push-up test to assess muscular strength. Elite athletes were those whose performance fell one standard deviation above the mean (16%) of each exercise modality. Cardiac characteristics evaluated by a 12-lead electro-cardiography (ECG) and transthoracic echocardiography were compared between elite and non-elite female athletes. Multiple logistic regression analysis was used to determine the predictors of elite female athletes’s cardiac adaptation to endurance versus strength exercise. Results: Compared to non-elite controls, elite female endurance athletes had greater QRS duration (92.12±10.35 ms vs. 87.26±9.89 ms, p =0.01) and higher prevalence of right axis deviation (34.9% vs. 11.1%, p &lt;0.001). There were no differences in any echocardiographic variables, i.e. left ventricular mass index and diastolic function. Greater QRS duration, right axis deviation and lower systolic blood pressure levels were independent predictors of elite endurance athletes [odds ratios (OR) and 95% confidence intervals: 1.05 (1.01-1.09), 2.91 (1.12-7.59) and 0.93 (0.88-0.98), respectively]. In contrast, elite female strength athletes had greater right ventricular outflow tract (RVOT) (28.06±3.57 mm vs. 25.38± 3.61 mm, p =0.007), while demonstrated no differences in ECG variables. Greater RVOT was the only predictor of elite strength athletes [OR: 1.26 (1.05-1.50)]. Conclusions: In physically active Asian women, QRS prolongation and right axis deviation in ECG rather than the heart structure and functional changes characterize the elite endurance athletes. However, the right ventricular outflow enlargement documented in elite strength athletes requires further investigations.

Young adults after arterial switch operation for transposition of the great arteries in Switzerland: a growing population.

Adults with transposition of the great arteries (d-TGA) after the arterial switch operation (ASO) are an evolving cohort in adult cardiology. We aimed to analyze cardiac function and cardiac events after transition to the adult clinic in Switzerland. Adults with prior ASO enrolled in the Swiss Adult Congenital HEart disease Registry (SACHER) were included. We analyzed initial cardiac anatomy, surgical history, residual lesions and cardiac function at the time of inclusion, as well as cardiac events during follow-up. Patients were classified as complex (with ventricular septal defect) or simple (with intact interventricular septum) d-TGA. The cohort included 149 patients (99 simple d-TGA, 50 complex d-TGA; age 21±3 years; 71% male, follow-up 27 [15-46] months). Prior to inclusion, patients with complex d-TGA had undergone more interventions related to the left ventricular outflow tract (16% vs. 3%, p = 0.01). Functional and cardiovascular status were similar between the groups. Eleven patients (7%) had a total of 19 cardiac events (5 complications and 14 re-interventions) during follow-up. Patients with complex d-TGA had more cardiac-related complications compared to those with simple d-TGA (8% vs. 1%, p = 0.03). The frequency of re-interventions was not statistically different between the two groups (12% vs. 4%, p = 0.07). During follow-up, an increase in QRS duration was observed. Other parameters of cardiac function remained unchanged. The majority of adult ASO patients have normal functional class and cardiac function. Complex anatomy and residual lesions play a key role when regarding the occurrence of cardiac-related complications during follow-up. The role of QRS prolongation over time needs to be investigated further.

Disposition, outcomes, and lengths of stay due to bupropion overdose at a tertiary care center with a medical toxicology service

IntroductionBupropion is an antidepressant with unique mechanisms of action leading to a narrow therapeutic window. Parallel to increasing indications, there is an increasing number of overdoses and fatalities attributable to bupropion overdose. Due to the serious effects of a bupropion overdose including arrhythmias and early or delayed seizures, these patients necessitate prolonged monitoring with high levels of medical care. In the setting of a tertiary care center with a medical toxicology consult service, our institution is heavily relied upon to manage these patients. This study was performed to provide clarity on the resources used, lengths-of-stay, and treatments provided for these patients. MethodsAll patients at a tertiary care center with an oral bupropion overdose and a medical toxicology consult less than 24 h after the ingestion were included between July 15, 2017 and October 14, 2021. Chart review was performed to determine lengths-of-stay, the unit of disposition, treatments provided, and outcomes. ResultsA total of 73 cases were identified with 36 bupropion-only ingestions. Most cases were transferred from outside facilities, developed seizures, had QRS prolongation; and almost a third required intubation. The vast majority were admitted to an ICU and received GABA-A agonists. A median of 1.47 days per case was spent in the ED or ICU. There was an average of 41.9 ED or ICU bed-days per year and 68.5 non-psychiatric bed-days per year occupied by a patient after a bupropion overdose at a single center. ConclusionsBupropion overdose necessitates high resource utilization which we believe will increase with the expanding indications for its use.

Prevalence and predictors of bradyarrhythmias requiring permanent pacing in patients with Anderson-Fabry disease.

Bradyarrhythmias are an established red flag for storage cardiac conditions including Anderson-Fabry disease (AFD). The prevalence of bradyarrhythmias requiring a pacemaker (PM) and their timing in AFD is unresolved. We evaluated the prevalence and predictors of PM requirement in a large AFD cohort, investigating the occurrence of bradyarrhythmias as initial versus late manifestation. We retrospectively evaluated 82 consecutive AFD patients referred to our multidisciplinary referral center from 1994 to 2020 with a median follow-up of 6.9 years, identifying those requiring pacing. Univariable analysis was performed to identify cardiac features associated with PM implantation. Five of 82 (6%) AFD patients required PM implantation (5/39, i.e., 13% of those with cardiac involvement), always in the context of advanced cardiomyopathy. In none, bradyarrhythmias were the presenting feature. Indications included sick sinus syndrome in three patients, advanced atrioventricular block in two patients. QRS prolongation during follow-up strongly correlated with the onset of bradyarrhythmias. Severe bradyarrhythmias are relatively frequent in patients with AFD cardiomyopathy, but do not represent a mode of presentation, occurring late in the disease course and always in the context of advanced cardiac involvement. Monitoring QRS variations over time may help to identify patients requiring pacing.

Prevalence and long-term prognostic implications of prolonged QRS duration in left ventricular hypertrophy: a population-based observational cohort study

ObjectivesECG left ventricular hypertrophy (ECG-LVH) has been associated with left ventricular dysfunction and adverse prognosis, but little is known about the prevalence and prognostic significance of different levels of QRS...

Long-term outcomes of left bundle branch area pacing versus biventricular pacing in patients with heart failure and complete left bundle branch block

Left bundle branch area pacing (LBBAP) has developed in an effort to improve cardiac resynchronization therapy (CRT). We aimed to compare the long-term clinical outcomes between LBBAP and biventricular pacing (BIVP) in patients with heart failure (HF) and complete left bundle branch block (CLBBB). Consecutive patients with HF and CLBBB requiring CRT received either LBBAP or BIVP were recruited at the Second Affiliated Hospital of Nanchang University from February 2018 to May 2019. We assessed their implant parameters, electrocardiogram (ECG), clinical outcomes at implant and during follow-up at 1, 3, 6, 12, and 24 months. Forty-one patients recruited including 21 for LBBAP and 20 for BIVP. Mean follow-up duration was 23.71 ± 4.44 months. LBBAP produced lower pacing thresholds, shorter procedure time and fluoroscopy duration compared to BIVP. The QRS duration was significantly narrower after LBBAP than BIVP (129.29 ± 31.46 vs. 156.85 ± 26.37 ms, p = 0.005). Notably, both LBBAP and BIVP significantly improved LVEF, LVEDD, NYHA class, and BNP compared with baseline. However, LBBAP significantly lowered BNP compared with BIVP (416.69 ± 411.39 vs. 96.07 ± 788.71 pg/ml, p = 0.007) from baseline to 24-month follow-up. Moreover, patients who received LBBAP exhibited lower number of hospitalizations than those in the BIVP group (p = 0.019). In addition, we found that patients with moderately prolonged left ventricular activation time (LVAT) and QRS notching in limb leads in baseline ECG respond better to LBBAP for CLBBB correction. LBBAP might be a relative safe and effective resynchronization therapy and as a supplement to BIVP for patients with HF and CLBBB.

Conduction System Pacing: Basis and Scope

Long-term right ventricular pacing (RVP) is associated with more cardiovascular death, atrial fibrillation (AF), thromboembolic complications and heart failure(HF). RVP often results in prolonged QRS duration(QRSd) and ventricular desynchronization. The ventricular desynchronization as a result of RVP leads to an increased risk of heart failure hospitalization (HFH) and AF, and this effect is dependent on cumulative percent ventricular paced ( % VP). In the sub-study from the MOST trial, it was evident that % VP &gt;40% was associated with a 2.6-fold increased risk of HFH compared with pacing &lt; 40% of the time despite preserved atrioventricular synchrony. Moreover this adverse effect of RVP induced ventricular desynchrony was more pronounced in patients with left ventricular ejection fraction( LVEF) of 40% or less resulting in increased death or HFH.