The effect of intravenous ondansetron on QT interval in the emergency department.

OBJECTIVE: Ondansetron, a 5HT3 receptor antagonist, is commonly used in emergency departments to treat nausea and vomiting. In 2011, the Food and Drug Administration (FDA) issued a warning that this medicine may cause QT prolongation, potentially leading to deadly arrhythmias. The objective of this study was to characterize the QT interval prolongation associated with ondansetron use in the Emergency Department. METHODS: This was a prospective, observational cohort study of adult patients who presented to the emergency department during a one-year period and were treated with intravenous ondansetron. We investigated the QT prolongation associated with dosages. ECGs were obtained before the medication and 5, 15, and 30 minutes after IV drug administration. Every QT measurement was recorded and compared to the zero point. The severity of drug-induced QT prolongation was determined according to the recommendations of the International Conference on Compliance (ICH). QTc prolongation was categorized as 'negligible' (<5 ms), 'significant' (>20 ms), 'potential concern' (>30 ms), or 'definitely worrying' (>60 ms). RESULTS: Of the 435 patients enrolled in the study, 60% (261 patients) were female and the mean age was 39 (±18). The QT prolongation peaked at the fifth minute and remained consistent at the fifteenth and thirty-first minutes. The maximum prolongation of the mean QT duration occured at the fifth minute (7.9 ± 18.1 ms). No patient revealed any problems with cardiac conduction. The prolonged QT interval was not related to the dose of ondansetron, but QT measurements were higher in the 30th minute in patients treated with 8 mg of ondansetron. The effect of ondansetron administration on QT prolongation was found to be above the 'negligible' but below the 'significant' value, according to the ICH recommendations. DISCUSSION: In this study, QT prolongation due to ondansetron administration was below the 'important' value according to the recommendations of the ICH. No cases of cardiac arrhythmia were reported in any of the partients. Thus, routine ECG monitoring in patients given ondansetron due to the risk of QTc prolongation does not seem cost-effective when evaluated together with additional factors such as its negative impact on emergency patient flow, waste of personnel and time, and increase in healthcare costs. In the absence of a known risk of cardiac arrhythmia, IV administration of 4 mg and 8 mg of ondansetron doses no risk of QT prolongation in the emergency population.

Right fascicular blocks: A case series and a comprehensive electrocardiographic analysis.

The main trunk of the right bundle branch divides into an anterior, middle (lateral) and posterior fascicle. This article describes the right anterior and posterior fascicular block. They present a diagnostic challenge and are often overlooked during diagnostic processes. The studied patients were young adults whose electrocardiographic tracings were registered at the Mexican Faculty of Medicine of La Salle University. The presence of delayed R-peak time in aVR and V1, along with the described ventricular complex morphologies, and a right or left deviation of the cardiac axis exceeding +60°, may be suggestive of right fascicular blocks.

Surgical Outcomes of Congenital Heart Disease in Down Syndrome: Tertiary Center Experience-Focus on the Electrical Conduction System.

To document outcomes of cardiac surgical repair in Down syndrome (DS) patients with specific focus on the associated electrical conduction morbidities, ultimately leading to a higher incidence of pacemaker implantation (PMI). A retrospective study conducted between 2011 and 2020. A total of 167 DS patients undergoing 204 surgeries were included. The mean gestational age (GA) and mean weight were 37.3 weeks and 5.5 kg, respectively. Complete atrioventricular septal defect (AVSD) was the most common diagnosis. Pre-operative ECG revealed superior axis deviation (SAD) in 92 and 32% of patients with AVSD and isolated perimembranous ventricular septal defect (VSD), respectively (p < 0.01). Postoperative right bundle branch block (RBBB) was observed in 83 and 55% of patients with AVSD and following perimembranous VSD repair, respectively (p = 0.04). Ten patients underwent post-operative pacemaker implantation (PMI). Reintervention rate was around 8.9%. Three mortalities were encountered throughout the study period, 2 of which were in-hospital deaths. Low mortality was observed, however, a higher rate of PMI requirements noted with risk factors including lower age and weight.

Surgical creation of lymphocutaneous fistulas for the management of infants with central lymphatic obstruction.

PURPOSE: Central lymphatic obstructions are associated with anasarca and high mortality. We hypothesized that opening dilated cutaneous lymphatic channels by creating a lymphocutaneous fistula (LCF) would decompress the lymphatic circulation and improve anasarca. METHODS: We reviewed all patients that had at least one LCF created between 9/2019 and 12/2022. LCF efficacy was determined by changes in weight, urine/diuresis, ventilation, and clinical status. RESULTS: We created eleven LCFs in four infants. LCFs initially drained 108 cc/kg/d (IQR68-265 cc/kg/d). Weights significantly decreased after LCF creation (6.9 [IQR6.1-8.1] kg vs. 6.1 [IQR 4.9-7.6] kg, P = 0.042). Ventilatory support decreased significantly in all patients after at least one LCF was created, and 3/4 patients (75%) had significantly lower peak inspiratory pressures (28 [IQR 25-31] cmH2O vs. 22 [IQR 22-24] cmH2O, P = 0.005; 36 [IQR36-38] cmH2O vs. 33 [IQR 33-35] cmH2O, P = 0.002; 36 [IQR 34-47] cmH2O vs. 28 [28-31] cmH2O, P = 0.002). LCFs remained patent for 29d (IQR 16-49d). LCFs contracted over time, and 6/11 (54.5%) were eventually revised. There were no complications. Two patients died from overwhelming disease, one died from unrelated causes, and one remains alive 29 months after their initial LCF. CONCLUSION: LCFs provide safe and effective temporary lymphatic decompression in patients with central lymphatic obstruction. While LCFs are not a cure, they can serve as a bridge to more definitive therapies or spontaneous lymphatic remodeling. LEVEL OF EVIDENCE: IV.

Predictors of conduction disturbances after transcatheter aortic valve implantation with balloon-expandable valve for bicuspid aortic valve stenosis.

INTRODUCTION: Implantation depth and membranous septum (MS) length have been established as the predictors of new-onset conduction disturbance (CD) after transcatheter aortic valve replacement (TAVR) for tricuspid aortic valve (TAV) stenosis. However, little is known about the predictors with bicuspid aortic valve (BAV). This study investigated the role of MS length and implantation depth in predicting CD following TAVR with a balloon-expandable valve in patients with BAV. METHODS: This retrospective study analyzed 169 patients who underwent TAVR for BAV with balloon-expandable valve, and TAV cohort was established as a control group using propensity score (PS) matching. The primary endpoints were in-hospital new permanent pacemaker implantation (PPI) and new-onset CD (the composite outcome of new-onset left bundle branch block and new PPI). RESULTS: PPI developed in 14 patients (8.3%) and new-onset CD in 37 patients (21.9%) in the BAV cohort. Multivariate analysis revealed severe left ventricle outflow tract (LVOT) calcification (odds ratio [OR]: 5.83, 95% confidence interval [CI]: 1.08-31.5, p = .0407) and implantation depth-MS length (OR: 1.30, 95% CI: 1.12-1.51, p = .0005) as the predictors of new-onset CD within the BAV cohort. The matched comparison between BAV and TAV groups showed similar MS length (3.0 vs. 3.2 mm, p = .5307), but valves were implanted more deeply in the BAV group than in the TAV group (3.9 vs. 3.0 mm, p < .0001). New-onset CD was more frequent in patients who had BAV (22.3% vs. 13.9%, p = .0458). CONCLUSION: The implantation depth-MS length, and severe LVOT calcification predicted new-onset CD following TAVR in BAV with balloon-expandable valve. Among BAV patients, valves were implanted more deeply compared to TAV patients. High deployment technique could be considered to avoid new-onset CD in BAV anatomy.

Evaluation of oversizing in association with conduction disorder after implantation of a rapid deployment valve.

Rapid deployment valve has expanded surgical indication for high-risk patients with aortic stenosis despite its accommodated risk for conduction disorder (CD). The purpose of this study was to evaluate the degree of oversizing in association with postoperative CD. During June 2019 to September 2021, 25 patients underwent aortic valve replacement with Edwards INTUITY. Device size selection was evaluated intraoperatively using provided sizers. Oversizing was evaluated retrospectively by measuring the difference of the dimension of the annulus and left ventricular outflow tract (LVOT) compared to the dimensions of the device used by preoperative-computed tomography. Although there was no incidence of pacemaker implantation, seven patients (28.0%) experienced CD after surgery. There was no difference in device area and annulus area (CD: - 37 ± 22.7 mm2 vs. no CD: - 56 ± 63.6 mm2, p = 0.47), and device circumference and annulus circumference (CD: - 4.4 ± 2.77 mm vs. no CD: - 6.9 ± 5.60 mm, p = 0.26) in patients with and without CD. However, there was a significant difference in area of the device skirt and sub-annular area at the LVOT (CD: 114 ± 28.4 mm2 vs. no CD: - 8 ± 80.0 mm2, p < 0.001), and circumference of device skirt and the LVOT (CD: 3.9 ± 2.08 mm vs. no CD: - 4.6 ± 5.24 mm, p < 0.001) between the two groups. Receiver operating characteristic curve analysis showed that an area difference of 77.7 mm2 and circumference difference of 0.91 mm at LVOT were associated with postoperative CD with specificities of 0.83, 0.78 and sensitivity of 1.0, 1.0, respectively. Preoperative measurement of the LVOT may be useful in evaluating the risk of postoperative CD in patients receiving rapid deployment valve.

Beta-Blocker-Related Atrioventricular Conduction Disorders-A Single Tertiary Referral Center Experience.

Background and Objectives: Drug-related bradyarrhythmia is a well-documented major adverse event among beta-blocker users and a potential cause for hospitalization or additional interventions. Whether beta-blocker use is associated with specific bradyarrhythmia presentations, and how this relates to other predisposing factors, is not well known. We aim to evaluate the association between beta-blocker use and the type of atrioventricular (AV) conduction disorder in patients with symptomatic bradycardia. Materials and Methods: We conducted a retrospective cohort study on 596 patients with a primary diagnosis of symptomatic bradyarrhythmia admitted to a single tertiary referral center. Of the cases analyzed, 253 patients were on beta-blocker treatment at presentation and 343 had no bradycardic treatment. We analyzed demographics, clinical and paraclinical parameters in relation to the identified AV conduction disorder. A multivariate regression analysis was performed to explore factors associated with beta-blocker use. Results: Of the 596 patients (mean age 73.9 ± 8.8 years, 49.2% male), 261 (43.8%) had a third-degree AV block, 92 (15.4%) had a second-degree AV block, 128 (21.5%) had slow atrial fibrillation, 93 (15.6%) had sick sinus syndrome and 21 (3.5%) had sinus bradycardia/sinus pauses. Beta-blocker use was associated with the female gender (p < 0.001), emergency admission (p < 0.001), dilated cardiomyopathy (p = 0.003), the lower left ventricular ejection fraction (p = 0.02), mitral stenosis (p = 0.009), chronic kidney disease (p = 0.02), higher potassium levels (p = 0.04) and QRS duration > 120 ms (p = 0.02). Slow atrial fibrillation (OR = 4.2, p < 0.001), sick sinus syndrome (OR = 2.8, p = 0.001) and sinus bradycardia/pauses (OR = 32.9, p < 0.001) were more likely to be associated with beta-blocker use compared to the most common presentation (third-degree AV block), after adjusting for other patient characteristics. Conclusions: Beta-blocker use is more likely to be associated with slow atrial fibrillation, sick sinus syndrome and sinus bradycardia/pauses, compared to a second- or third-degree AV block, after adjusting for other patient factors such as gender, admission type, ECG, comorbidities, cardiac function and lab testing.

Prophylactic permanent pacemaker strategy in patients with right bundle branch block undergoing transcatheter aortic valve replacement.

OBJECTIVES: To report on the experience with a selective prophylactic permanent pacemaker (PPx-PPM) implantation strategy in patients with pre-existing right bundle branch block (RBBB) undergoing transcatheter aortic valve replacement (TAVR). BACKGROUND: Pre-existing RBBB is an independent predictor for PPM after TAVR and has been linked to increased mortality. METHODS: Hospital patient flow and longer-term clinical endpoints were compared for TAVR patients with pre-existing RBBB treated in a period with and without selective PPx-PPM strategy (2013-2020). RESULTS: A total of 260 patients were included: 170 in the early period without PPx-PPM strategy and 90 patients in the late period with selective PPx-PPM strategy. A PPx-PPM was implanted in 44% of patients in the late period. Overall, 69% versus 80% of all patients in the early versus late period ended up with a PPM (p = .06). Streamlined transfemoral TAVR was routinely used from 2017-in this series of patients, both TAVR procedural time and hospital length of stay (LoS) were significantly shorter in the late versus early period (mean procedural time: 70 vs. 83 min and LoS ≥5 days: 15% vs. 40%; p < .05). No difference in all-cause/cardiovascular mortality was observed between both strategies, whereas cardiac rehospitalization was significantly higher for patients treated in the early versus late period (hazard ratio 2.33 [1.04-5.26]; p = .042)-this mainly due to (sub)acute PPM-implantation early after discharge. CONCLUSIONS: Selective prophylactic PPM implantation in TAVR candidates with pre-existing RBBB results in shorter TAVR procedural time and hospital LoS and prevents early cardiac rehospitalization related to complete heart block.

Computed tomography derived predictors of permanent pacemaker implantation after transcatheter aortic valve replacement: A meta-analysis.

OBJECTIVES: This meta-analysis sought to assess predictors of permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR) with focus on preprocedural multi-slice computed tomography (MSCT) derived data. BACKGROUND: Transcatheter aortic valve replacement (TAVR) has expanded to a well-established treatment for severe symptomatic aortic stenosis at high and intermediate surgical risk. PPI after TAVR remains one of the most frequent procedure-related complications and appears to be influenced by several factors. METHODS: The authors conducted a literature search in PubMed/MEDLINE and EMBASE databases to identify studies that investigated preprocedural MSCT data and the rate of PPI following TAVR with new-generation devices. RESULTS: Ten observational studies (n = 2707) met inclusion criteria for the final analysis. PPI was performed in 387 patients (14.3%) after TAVR. Patients requiring PPI had a larger annulus perimeter (MD: 1.66 mm; p < .001) and a shorter membranous septum length (MD: -1.1 mm; p < .05). Concerning calcification distribution, patients with requirement for new pacemaker implantation showed increased calcification of the left coronary cusp (MD: 47.6 mm3 ; p < .001), and the total left ventricular outflow tract (MD: 24.42 mm3 ; p < .01). Lower implantation depth (MD: 0.95 mm; p < .05) and oversizing (MD: 1.52%; p < .05) were procedural predictors of PPI following TAVR. CONCLUSIONS: Besides the well-known impact of electrocardiographic and procedure-related factors on conduction disturbances, MSCT derived distribution of the aortic valve and left ventricular outflow tract calcification, as well as membranous septum length, are associated with an increased risk of PPI following TAVR.

Deletion of Trpm4 Alters the Function of the Nav1.5 Channel in Murine Cardiac Myocytes.

Transient receptor potential melastatin member 4 (TRPM4) encodes a Ca2+-activated, non-selective cation channel that is functionally expressed in several tissues, including the heart. Pathogenic mutants in TRPM4 have been reported in patients with inherited cardiac diseases, including conduction blockage and Brugada syndrome. Heterologous expression of mutant channels in cell lines indicates that these mutations can lead to an increase or decrease in TRPM4 expression and function at the cell surface. While the expression and clinical variant studies further stress the importance of TRPM4 in cardiac function, the cardiac electrophysiological phenotypes in Trpm4 knockdown mouse models remain incompletely characterized. To study the functional consequences of Trpm4 deletion on cardiac electrical activity in mice, we performed perforated-patch clamp and immunoblotting studies on isolated atrial and ventricular cardiac myocytes and surfaces, as well as on pseudo- and intracardiac ECGs, either in vivo or in Langendorff-perfused explanted mouse hearts. We observed that TRPM4 is expressed in atrial and ventricular cardiac myocytes and that deletion of Trpm4 unexpectedly reduces the peak Na+ currents in myocytes. Hearts from Trpm4-/- mice presented increased sensitivity towards mexiletine, a Na+ channel blocker, and slower intraventricular conduction, consistent with the reduction of the peak Na+ current observed in the isolated cardiac myocytes. This study suggests that TRPM4 expression impacts the Na+ current in murine cardiac myocytes and points towards a novel function of TRPM4 regulating the Nav1.5 function in murine cardiac myocytes.

[Heart arrhythmias and conduction disorders in patients with acromegaly: the role of cardiac magnetic resonance imaging].

Cardiovascular complications including arrhythmias and cardiac conduction disorders are one of the main reasons of high mortality rate in acromegaly, while they have not been well explored. AIM: To estimate arrhythmias frequency in acromegaly, identify risk factors leading to the development of arrhythmia and cardiac conduction disorder, to determine the role of cardiac MRI in detecting structural and functional changes. MATERIALS AND METHODS: A single-center prospective cohort study, which included 461 patients (151 men and 310 women) with acromegaly, was conducted. All the patients underwent a standard medical examination, including hormonal blood test, electrocardiogram, echocardiography, electrocardiogram daily monitoring. 18 patients with arrhythmias (11 men and 7 women) had cardiac MRI with gadolinium-based contrast. RESULTS: The results of our research show high frequency of arrhythmias and cardiac conduction disorders in patients with acromegaly 42%. Most frequent kinds of arrhythmias and cardiac conduction disorders were sinus bradycardia 19.1% of the cases and conduction disorders of bundle branch blocks 14.5%. Men were more likely to suffer from arrhythmias and cardiac conduction disorders than women (54.2% and 37.4%, respectively,p=0.0005). Not acromegaly activity but duration of the disease was a main risk factor of arrhythmias and cardiac conduction disorders. Patients with arrhythmias had a long anamnesis of acromegaly (10 and 7 years, respectively, p=0.04). Meanwhile, cardiac conduction disorders were commonly observed in the patients who were treated with somatostatin analogs comparing to the patients who didnt undergo this therapy (50% and 38.6% respectively,p=0.004). We showed that 61% of patients with acromegaly and cardiac conduction disorders who underwent magnetic resonance imaging (MRI) had the signs of myocardial fibrosis. The value of the ejection fraction of the left ventricle according to MRI was higher than with echocardiography (p=0.04). CONCLUSION: Arrhythmias and cardiac conduction disorders are often observed in patients with acromegaly even with remission of the disease. High risk group need careful diagnostic and monitoring approaches. Cardiac MRI is the gold standard for visualization of structural and morphological changes in the heart. Use of cardiac MRI in acromegalic patients expands our understanding of arrhythmias and cardiac conduction disorders in this disease. There are no specific laboratory markers of diffuse myocardial fibrosis, and the role of myocardial fibrosis in the occurrence of cardiac arrhythmias and conduction disorders needs further studying.

[Vitamin D deficiency study in railway drivers.]

Heart rhythm disturbances are significant pathology and one of the reason of sudden cardiac arrest. Locomotive crew drivers are at high risk for cardiovascular diseases, including heart rhythm disturbances. Multiple factors as a professional stress, frequent night shifts, lack of insolation, diet disbalance, low physical activity, exposure to vibration and noise, and an unfavorable industrial climate. In this study it was found that railway-men are predisposed to vitamin D deficiency. This condition reduces resistance to stress and increases risk of unfavorable heart rhythm disturbances.

Incidence of Positive Ventricular Late Potentials Differs in Postural Changes among Supine, Left, and Right Lateral Decubitus, and Prone and Sitting Positions in Brugada Syndrome.

BACKGROUND: High-risk patients with Brugada syndrome (BrS) have inherent late potential (LP) fluctuations that might be explained by autonomic activity, electrolyte abnormality, and body temperature changes. However, the correlation between postural changes and LP determinates remains unknown. METHODS: Forty patients with BrS (38 men, 43.9 ± 13.5 years) and 15 controls (15 men, 42.4 ± 11.2 years) were enrolled. LP variations were investigated at five body positions using high-resolution ambulatory monitoring electrocardiography (HR-ambulatory ECG). The HR-ambulatory ECG was recorded for 3 hours and LP parameters (fQRSd, LAS40, and RMS40) were obtained for at least 15 minutes in each at the supine, left and right lateral decubitus, and prone and sitting positions. RESULTS: Determinate LP in the BrS group was significantly abnormal in all positions. Among the five body positions, positive LP were much more frequent in the supine and left and right lateral decubitus positions than in the prone and sitting positions and normalized in the last two positions in patients with BrS. RMS40 variance by postural change was significantly larger in the coved group than in the saddle back group. Determinate LP improved in the sitting position compared to the supine position in the coved group. CONCLUSIONS: Positive LP findings normalized in the sitting position in patients in the coved BrS group with a resuscitation history, suggesting that depolarization instability might be related to the risk of fatal ventricular arrhythmia. Posture-induced LP variance should be examined using HR-ambulatory ECG analysis in patients with BrS.

Bradycardia risk stratification with implantable loop recorder after unexplained syncope.

BACKGROUND: An implantable loop recorder is an effective tool for diagnosing unexplained syncope. However, after a first episode in non-high-risk patients, the usefulness of implantable loop recorder implantation remains unclear. AIMS: To analyse relevant risk factors for significant bradycardia in order to identify patients who do or do not benefit from implantable loop recorder implantation. Also, to study whether implantable loop recorder implantation with remote monitoring is associated with less recurrence of traumatic syncope. METHODS: This was a retrospective monocentric study including patients with implantable loop recorder implantation after unexplained syncope, using remote monitoring and iterative consultations. RESULTS: Two hundred and thirty-seven patients were implanted for unexplained syncope. Significant bradycardia occurred in 53 patients (22.4%): 23 (43.4%) caused by paroxysmal atrioventricular block and 30 (56.6%) caused by sinus node dysfunction, leading to permanent pacemaker implantation in 48 patients. Compared with younger patients, there was a 3.46-fold increase (95% confidence interval 1.92-6.23; P<0.0001) in the risk of significant bradycardia in patients aged≥60 years. Based on multivariable analysis, only "typical syncope" was associated with significant bradycardia occurrence (hazard ratio 3.14, 95% confidence interval 1.75-5.65; P=0.0001). There was no recurrence of significant bradycardia with traumatic complications among patients implanted for traumatic syncope. CONCLUSIONS: This study shows that: (1) implantable loop recorders identify more significant bradycardia in patients aged≥60 presenting with a first non-high-risk typical syncope, suggesting that an implantable loop recorder should be implanted after a first episode of unexplained syncope in such conditions; and (2) after traumatic syncope, implantable loop recorder implantation is safe, and is associated with little or no recurrence of traumatic syncope.

Physical Activity Modifies the Risk of Incident Cardiac Conduction Disorders Upon Inflammation: A Population-Based Cohort Study.

BACKGROUND: Emerging evidence suggests a central role for inflammation in cardiac conduction disorder (CCD). It is unknown whether habitual physical activity could modulate the inflammation-associated risks of incident CCD in the general population. METHODS AND RESULTS: This population-based cohort was derived from the China Kailuan study, including a total of 97 192 participants without prior CCD. The end points included incident CCD and its subcategories (atrioventricular block and bundle-branch block). Systemic inflammation was indicated by the monocyte-to-lymphocyte ratio (MLR). Over a median 10.91-year follow-up, 3747 cases of CCD occurred, with 1062 cases of atrioventricular block and 2697 cases of bundle-branch block. An overall linear dose-dependent relationship was observed between MLR and each study end point (all P-nonlinearity≥0.05). Both higher MLR and physical inactivity were significantly associated with higher risks of conduction block. The MLR-associated risks of developing study end points were higher in the physically inactive individuals than in those being physically active, with significant interactions between MLR levels and physical activity for developing CCD (P-interaction=0.07) and bundle-branch block (P-interaction<0.05) found. Compared with those in MLR quartile 2 and being physically active, those in the highest MLR quartile and being physically inactive had significantly higher risks for all study end points (1.42 [95% CI, 1.24-1.63], 1.62 [95% CI, 1.25-2.10], and 1.33 [95% CI, 1.13-1.56], respectively, for incident CCD, atrioventricular block, and bundle-branch block). CONCLUSIONS: MLR should be a biomarker for the risk assessment of incident CCD. Adherence to habitual physical activity is favorable for reducing the MLR-associated risks of CCD.

Impact of the Aortomitral Positional Anatomy on Atrioventricular Conduction Disorder Following Mitral Valve Surgery.

BACKGROUND: Variations in the aortomitral positional anatomy, including aortic root rotation appear to be related to variations in the location of the conduction system, including the bundle of His. However, little is known about their clinical significance. METHODS AND RESULTS: This study included 147 patients with normal ECGs who underwent mitral valve surgery. The aortomitral anatomy was classified using preoperative 3-dimensional transesophageal echocardiography, and postoperative conduction disorders, including atrioventricular block and bundle branch block, were analyzed. Variations classified as aortomitral appearance were designated as having a center appearance (85.7%, n=126/147) or lateral appearance (14.3%, n=21/147) on the basis of whether the aortic root was located at the center or was shifted to the left fibrous trigone side. Subsequently, those with a center appearance, aortic root rotation was classified as having a center rotation (83.3% [n=105/126]), in which the commissure of the left and noncoronary aortic leaflet was located at the center, lateral rotation (14.3% [n=18/126]), rotated to the left trigone side, or medial rotation (2.4% [n=3/126]), rotated to the right. The incidence of 3-month persistent new-onset conduction disorder was higher in the lateral appearance than the center appearance group (21.1% versus 5.0%; P=0.031) and higher in the lateral rotation than in the center or medial rotation groups (29.4% versus 1.0% versus 0.0%, respectively; P<0.001). CONCLUSIONS: Aortomitral variations can be classified using 3-dimensional transesophageal echocardiography. Lateral appearance and lateral rotation are risk factors for conduction disorders in mitral valve surgery.

Long QT Syndrome With Drugs Used in the Management of Arrhythmias: A Systematic Review.

Long QT syndrome (LQTS) is a severe cardiac disorder characterized by an abnormally prolonged QTc interval on an electrocardiogram (ECG), which can result in life-threatening irregular heart rhythms. The use of certain medications, particularly anti-arrhythmic drugs such as quinidine, sotalol, and amiodarone, can lead to acquired LQTS by prolonging the QT interval through the inhibition of specific ion channels responsible for heart repolarization, which may present symptoms like fainting, seizures, and sudden cardiac arrest. This systematic review, conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, focused on analyzing the association between Long QT syndrome and drugs utilized for managing arrhythmias, involving a thorough examination of six selected studies from an initial pool of 68 articles. It was found that antiarrhythmic drugs such as amiodarone, sotalol, dofetilide, procainamide, quinidine, and flecainide have the potential to cause QT prolongation as a side effect, which is often influenced by factors including dosage, coexisting medical conditions, electrolyte imbalances, and other risk factors. Prolonged QT interval significantly elevates the risk of a life-threatening arrhythmia called torsade de pointes. The management of this side effect typically involves reducing the medication dosage or discontinuing it altogether and, in some cases, employing selective beta blockers. However, further research is essential to improve the understanding and implementation of strategies to prevent and manage QT prolongation caused by antiarrhythmic drugs. Additional clinical studies are warranted to enhance knowledge and provide comprehensive guidelines to healthcare practitioners regarding the appropriate use of these medications. Close monitoring of the QT interval is recommended for patients receiving anti-arrhythmic therapy, and consideration should be given to patient-specific risk factors for LQTS, including age, sex, and electrolyte imbalances.

Brugada Syndrome: A Comprehensive Review of Fundamental and Electrophysiological New Findings.

Brugada syndrome is characterized by pronounced J-ST segment elevation in the right precordial leads on surface electrocardiograms. The etiological underpinnings of these distinctive features have been the subject of extensive debate, encompassing various theories related to repolarization anomalies and conduction irregularities. Genetic investigations have unveiled SCN5A, the gene encoding NaV1.5, a critical sodium channel, as the most frequently implicated causative gene, with mutations typically manifesting as loss of function. Nonetheless, the detection rate of SCN5A mutations remains below 20%, underscoring the intricate genetic landscape of the syndrome. Histological analyses have divulged localized structural irregularities, primarily marked by fibrotic alterations, within the right ventricular outflow tract. Electrophysiological inquiries employing direct epicardial mapping techniques have uncovered localized conduction impediments concomitant with modifications in unipolar morphologies within the J-ST segment. Thus, the theory positing conduction abnormalities emerges as a compelling mechanism accounting for J-ST segment elevation. However, the precise mechanisms governing the onset of life-threatening tachyarrhythmias remain shrouded in uncertainty. Recent clinical case reports have proffered evidence supporting the notion that phase 2 reentry, arising from the marked heterogeneity in action potentials within the epicardial domain, may serve as the instigator of premature ventricular contractions, ultimately culminating in ventricular fibrillation. In light of these developments, it becomes increasingly evident that comprehending the mechanisms underlying the electrocardiographic manifestations and lethal arrhythmias in Brugada syndrome necessitates the consideration of a multifaceted perspective, transcending the binary discourse of repolarization versus depolarization anomalies.

Durvalumab-Associated Myocarditis Initially Presenting With Sinus Bradycardia Progressing Into Complete Heart Block.

Durvalumab is a monoclonal antibody that blocks programmed cell death ligand-1 (PD-L1). It has been recently approved for the treatment of advanced urothelial and non-small cell lung cancer (NSCLC) with a more favorable side effect profile compared to traditional chemotherapy agents. We present a case of durvalumab-induced myocarditis complicated by complete heart block (CHB). A 71-year-old male with a history of atrial flutter status post ablation, type 2 diabetes mellitus, hypertension, and non-small cell lung carcinoma (NSCLC) recently started on durvalumab, presented with new sinus bradycardia on electrocardiogram (EKG). His initial labs were notable for a troponin T of 207 ng/L (normal range ≤50). Transthoracic echo (TTE) and computed tomography angiography (CTA) of the coronaries were unremarkable. The hospital course was complicated by CHB on telemetry for 15 minutes. Given hemodynamic instability, cardiac magnetic resonance imaging (MRI) could not be obtained. The patient received transvenous pacing. Electrophysiology and cardiology-oncology were consulted to evaluate for pacemaker implantation as well as management for durvalumab-induced myocarditis. Methylprednisolone 1000 mg intravenous (IV) was started with an improvement in troponin levels but without improvement in CHB. His course was further complicated by polymorphic ventricular tachycardia prompting the placement of a permanent dual-chamber pacemaker. The patient was discharged on a prednisone taper, and durvalumab was discontinued. A diagnosis of durvalumab-induced myocarditis was made based on elevated troponin levels, with the exclusion of coronary artery disease with CTA of the coronaries. The persistence of conduction abnormalities despite treatment with steroids leads to the placement of a permanent pacemaker. Durvalumab falls under the category of immune checkpoint inhibitor (ICI) therapy which are novel agents that have more favorable side effect profiles compared to traditional chemotherapeutic agents. A review of the literature shows myocarditis with arrhythmias as a potentially rare side effect of ICI therapy. Corticosteroid therapy seems to be promising as a potential therapy.