Ibrutinib promotes atrial fibrillation by inducing structural remodeling and calcium dysregulation in the atrium

Impaired Cardiac AMPK (5'-Adenosine Monophosphate-Activated Protein Kinase) and Ca2+-Handling, and Action Potential Duration Heterogeneity in Ibrutinib-Induced Ventricular Arrhythmia Vulnerability

BACKGROUND

We recently demonstrated that acute administration of ibrutinib, a Bruton's tyrosine kinase inhibitor used in chemotherapy for blood malignancies, increases ventricular arrhythmia (VA) vulnerability. A pathway of ibrutinib-induced vulnerability to VA that can be modulated for cardioprotection remains unclear.

METHODS AND RESULTS

The effects of ibrutinib on cardiac electrical activity and Ca2+ dynamics were investigated in Langendorff-perfused hearts using optical mapping. We also conducted Western blotting analysis to evaluate the impact of ibrutinib on various regulatory and Ca2+-handling proteins in rat cardiac tissues. Treatment with ibrutinib (10 mg/kg per day) for 4 weeks was associated with an increased VA inducibility (72.2%±6.3% versus 38.9±7.0% in controls, P<0.002) and shorter action potential durations during pacing at various frequencies (P<0.05). Ibrutinib also decreased heart rate thresholds for beat-to-beat duration alternans of the cardiac action potential (P<0.05). Significant changes in myocardial Ca2+ transients included lower amplitude alternans ratios (P<0.05), longer times-to-peak (P<0.05), and greater spontaneous intracellular Ca2+ elevations (P<0.01). We also found lower abundance and phosphorylation of myocardial AMPK (5'-adenosine monophosphate-activated protein kinase), indicating reduced AMPK activity in hearts after ibrutinib treatment. An acute treatment with the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside ameliorated abnormalities in action potential and Ca2+ dynamics, and significantly reduced VA inducibility (37.1%±13.4% versus 72.2%±6.3% in the absence of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, P<0.05) in hearts from ibrutinib-treated rats.

CONCLUSIONS

VA vulnerability inflicted by ibrutinib may be mediated in part by an impairment of myocardial AMPK activity. Pharmacological activation of AMPK may be a protective strategy against ibrutinib-induced cardiotoxicity.

Atrial fibrillation in cancer, anticancer therapies, and underlying mechanisms

Atrial fibrillation (AF) is a common arrhythmic complication in cancer patients and can be exacerbated by traditional cytotoxic and targeted anticancer therapies. Increased incidence of AF in cancer patients is independent of confounding factors, including preexisting myocardial arrhythmogenic substrates, type of cancer, or cancer stage. Mechanistically, AF is characterized by fast unsynchronized atrial contractions with rapid ventricular response, which impairs ventricular filling and results in various symptoms such as fatigue, chest pain, and shortness of breath. Due to increased blood stasis, a consequence of both cancer and AF, concern for stroke increases in this patient population. To compound matters, cardiotoxic anticancer therapies themselves promote AF; thereby exacerbating AF morbidity and mortality in cancer patients. In this review, we examine the relationship between AF, cancer, and anticancer therapies with a focus on the shared molecular and electrophysiological mechanisms linking these disease processes. We also explore the potential role of sodium-glucose co-transporter 2 inhibitors (SGLT2i) in the management of anticancer-therapy induced AF.

Atrioventricular re-entrant tachycardia and atrioventricular node re-entrant tachycardia in a patient with cancer under chemotherapy: a case report and literature review

Cardio-oncology is a new field of interest in cardiology focusing on the detection and treatment of cardiovascular diseases, such as arrhythmias, myocarditis, and heart failure, as side-effects of chemotherapy and radiotherapy. The association between chemotherapeutic agents and arrhythmias has previously been established. Atrial tachyarrhythmias, particularly atrial fibrillation, are most common, but ventricular arrhythmias, including those related to treatment-induced QT prolongation, and bradyarrhythmias can also occur. However, the association between chemotherapeutic agents and atrioventricular re-entrant tachycardia (AVRT)/atrioventricular node re-entrant tachycardia (AVNRT) remains poorly understood. Here, we report a patient with new-onset AVRT/AVNRT and lung cancer who underwent chemotherapy. We considered that chemotherapy or cancer itself may have been a trigger for the initiation of paroxysmal AVRT/AVNRT, and that radiofrequency catheter ablation was effective in treating this type of tachycardia. Here, possible mechanisms and potential genes (mostly ion channels) involved in AVRT/AVNRT are summarized and the mechanisms underlying the possible regulatory patterns of cancer cells and chemotherapy on ion channels are reviewed. Finally, we considered that ion channel abnormalities may link cancer or chemotherapy to the onset of AVRT/AVNRT. The aim of the present study was to highlight the association between chemotherapeutic agents and AVRT/AVNRT and to provide new insights for future research. Understanding the intermediate mechanisms between chemotherapeutic agents and AVRT/AVNRT may be beneficial in preventing chemotherapy-evoked AVRT/AVNRT (and/or other arrhythmias) in future.

Arrhythmogenic Ventricular Remodeling by Next-Generation Bruton's Tyrosine Kinase Inhibitor Acalabrutinib

Cardiac arrhythmias remain a significant concern with Ibrutinib (IBR), a first-generation Bruton's tyrosine kinase inhibitor (BTKi). Acalabrutinib (ABR), a next-generation BTKi, is associated with reduced atrial arrhythmia events. However, the role of ABR in ventricular arrhythmia (VA) has not been adequately evaluated. Our study aimed to investigate VA vulnerability and ventricular electrophysiology following chronic ABR therapy in male Sprague-Dawley rats utilizing epicardial optical mapping for ventricular voltage and Ca2+ dynamics and VA induction by electrical stimulation in ex-vivo perfused hearts. Ventricular tissues were snap-frozen for protein analysis for sarcoplasmic Ca2+ and metabolic regulatory proteins. The results show that both ABR and IBR treatments increased VA vulnerability, with ABR showing higher VA regularity index (RI). IBR, but not ABR, is associated with the abbreviation of action potential duration (APD) and APD alternans. Both IBR and ABR increased diastolic Ca2+ leak and Ca2+ alternans, reduced conduction velocity (CV), and increased CV dispersion. Decreased SERCA2a expression and AMPK phosphorylation were observed with both treatments. Our results suggest that ABR treatment also increases the risk of VA by inducing proarrhythmic changes in Ca2+ signaling and membrane electrophysiology, as seen with IBR. However, the different impacts of these two BTKi on ventricular electrophysiology may contribute to differences in VA vulnerability and distinct VA characteristics.

Ibrutinib and atrial fibrillation: An in-depth review of clinical implications and management strategies

Ibrutinib, a targeted therapy for B-cell malignancies, has shown remarkable efficacy in treating various hematologic cancers. However, its clinical use has raised concerns regarding cardiovascular complications, notably atrial fibrillation (AF). This comprehensive review critically evaluates the association between ibrutinib and AF by examining incidence, risk factors, mechanistic links, and management strategies. Through an extensive analysis of original research articles, this review elucidates the complex interplay between ibrutinib's therapeutic benefits and cardiovascular risks. Moreover, it highlights the need for personalized treatment approaches, vigilant monitoring, and interdisciplinary collaboration to optimize patient outcomes and safety in the context of ibrutinib therapy. The review provides a valuable resource for healthcare professionals aiming to navigate the intricacies of ibrutinib's therapeutic landscape while prioritizing patient well-being.

Chronic Lymphocytic Leukemia: Management of Adverse Events in the Era of Targeted Agents

The treatment landscape for CLL has undergone a profound transformation with the advent of targeted agents (TAs) like Bruton's Tyrosine Kinase inhibitors (BTKis) and BCL-2 inhibitors (BCL-2is). These agents target crucial cellular pathways in CLL, offering superior efficacy over traditional chemo-immunotherapy, which has led to improved progression-free and overall survival rates. This advancement promises enhanced disease control and potentially normal life expectancy for many patients. However, the journey is not without challenges, as these TAs are associated with a range of adverse events (AEs) that can impact treatment efficacy and patient quality of life. This review focuses on detailing the various AEs related to TA management in CLL, evaluating their frequency and clinical impact. The aim is to present a comprehensive guide to the effective management of these AEs, ensuring optimal tolerability and efficacy of TAs. By reviewing the existing literature and consolidating findings, we provide insights into AE management, which is crucial for maximizing patient outcomes in CLL therapy.

Artificial Intelligence Electrocardiography to Predict Atrial Fibrillation in Patients With Chronic Lymphocytic Leukemia

Background

The use of an artificial intelligence electrocardiography (AI-ECG) algorithm has demonstrated its reliability in predicting the risk of atrial fibrillation (AF) within the general population.

Objectives

This study aimed to determine the effectiveness of the AI-ECG score in identifying patients with chronic lymphocytic leukemia (CLL) who are at high risk of developing AF.

Methods

We estimated the probability of AF based on AI-ECG among patients with CLL extracted from the Mayo Clinic CLL database. Additionally, we computed the Mayo Clinic CLL AF risk score and determined its ability to predict AF.

Results

Among 754 newly diagnosed patients with CLL, 71.4% were male (median age = 69 years). The median baseline AI-ECG score was 0.02 (range = 0-0.93), with a value ≥0.1 indicating high risk. Over a median follow-up of 5.8 years, the estimated 10-year cumulative risk of AF was 26.1%. Patients with an AI-ECG score of ≥0.1 had a significantly higher risk of AF (HR: 3.9; 95% CI: 2.6-5.7; P < 0.001). This heightened risk remained significant (HR: 2.5; 95% CI: 1.6-3.9; P < 0.001) even after adjusting for the Mayo CLL AF risk score, heart failure, chronic kidney disease, and CLL therapy. In a second cohort of CLL patients treated with a Bruton tyrosine kinase inhibitor (n = 220), a pretreatment AI-ECG score ≥0.1 showed a nonsignificant increase in the risk of AF (HR: 1.7; 95% CI: 0.8-3.6; P = 0.19).

Conclusions

An AI-ECG algorithm, in conjunction with the Mayo CLL AF risk score, can predict the risk of AF in patients with newly diagnosed CLL. Additional studies are needed to determine the role of AI-ECG in predicting AF risk in CLL patients treated with a Bruton tyrosine kinase inhibitor.

Ibrutinib-induced pulmonary angiotensin-converting enzyme activation promotes atrial fibrillation in rats

The molecular mechanism of ibrutinib-induced atrial fibrillation (AF) remains unclear. We here demonstrate that treating rats with ibrutinib for 4 weeks resulted in the development of inducible AF, left atrial enlargement, atrial fibrosis, and downregulation of connexin expression, which were associated with C-terminal Src kinase (CSK) inhibition and Src activation. Ibrutinib upregulated angiotensin-converting enzyme (ACE) protein expression in human pulmonary microvascular endothelial cells (HPMECs) by inhibiting the PI3K-AKT pathway, subsequently increasing circulating angiotensin II (Ang II) levels. However, the expression of ACE and Ang II in the left atria was not affected. Importantly, we observed that perindopril significantly mitigated ibrutinib-induced left atrial remodeling and AF promotion by inhibiting the activation of the ACE and its downstream CSK-Src signaling pathway. These findings indicate that the Ibrutinib-induced activation of the ACE contributes to AF development and could serve as a novel target for potential prevention strategies.

Zbtb16 increases susceptibility of atrial fibrillation in type 2 diabetic mice via Txnip-Trx2 signaling

Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia, and recent epidemiological studies suggested type 2 diabetes mellitus (T2DM) is an independent risk factor for the development of AF. Zinc finger and BTB (broad-complex, tram-track and bric-a-brac) domain containing 16 (Zbtb16) serve as transcriptional factors to regulate many biological processes. However, the potential effects of Zbtb16 in AF under T2DM condition remain unclear. Here, we reported that db/db mice displayed higher AF vulnerability and Zbtb16 was identified as the most significantly enriched gene by RNA sequencing (RNA-seq) analysis in atrium. In addition, thioredoxin interacting protein (Txnip) was distinguished as the key downstream gene of Zbtb16 by Cleavage Under Targets and Tagmentation (CUT&Tag) assay. Mechanistically, increased Txnip combined with thioredoxin 2 (Trx2) in mitochondrion induced excess reactive oxygen species (ROS) release, calcium/calmodulin-dependent protein kinase II (CaMKII) overactivation, and spontaneous Ca2+ waves (SCWs) occurrence, which could be inhibited through atrial-specific knockdown (KD) of Zbtb16 or Txnip by adeno-associated virus 9 (AAV9) or Mito-TEMPO treatment. High glucose (HG)-treated HL-1 cells were used to mimic the setting of diabetic in vitro. Zbtb16-Txnip-Trx2 signaling-induced excess ROS release and CaMKII activation were also verified in HL-1 cells under HG condition. Furthermore, atrial-specific Zbtb16 or Txnip-KD reduced incidence and duration of AF in db/db mice. Altogether, we demonstrated that interrupting Zbtb16-Txnip-Trx2 signaling in atrium could decrease AF susceptibility via reducing ROS release and CaMKII activation in the setting of T2DM.

Drug-induced atrial fibrillation. A narrative review of a forgotten adverse effect

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with an increased morbidity and mortality. There is clinical evidence that an increasing number of cardiovascular and non-cardiovascular drugs, mainly anticancer drugs, can induce AF either in patients with or without pre-existing cardiac disorders, but drug-induced AF (DIAF) has not received the attention that it might deserve. In many cases DIAF is asymptomatic and paroxysmal and patients recover sinus rhythm spontaneously, but sometimes, DIAF persists, and it is necessary to perform a cardioversion. Furthermore, DIAF is not mentioned in clinical guidelines on the treatment of AF. The risk of DIAF increases in elderly and in patients treated with polypharmacy and with risk factors and comorbidities that commonly coexist with AF. This is the case of cancer patients. Under these circumstances ascribing causality of DIAF to a given drug often represents a clinical challenge. We review the incidence, the pathophysiological mechanisms, risk factors, clinical relevance, and treatment of DIAF. Because of the limited information presently available, further research is needed to obtain a deeper insight into DIAF. Meanwhile, it is important that clinicians are aware of the problem that DIAF represents, recognize which drugs may cause DIAF, and consider the possibility that a drug may be responsible for a new-onset AF episode.

Antineoplastic drugs inducing cardiac and vascular toxicity - An update

With the improvement in cancer prognosis due to advances in antitumor therapeutic protocols and new targeted and immunotherapies, we are witnessing a growing increase in survival, however, at the same timeincrease in morbidity among cancer survivors as a consequences of the increased cardiovascular adverse effects of antineoplastic drugs. Common cardiovascular complications of antineoplastic therapies may include cardiac complications such as arrhythmias, myocardial ischemia, left ventricular dysfunction culminating in heart failure as well as vascular complications including arterial hypertension, thromboembolic events, and accelerated atherosclerosis. The toxicity results from the fact that these drugs not only target cancer cells but also affect normal cells within the cardiovascular system. In this article, we review the clinical features and main mechanisms implicated in antineoplastic drug-induced cardiovascular toxicity, including oxidative stress, inflammation, immunothrombosis and growth factors-induced signaling pathways.

Mechanisms, prevalence and management of cardiac arrhythmias in cancer patients: a comprehensive review

Recently, prognosis and survival of cancer patients has improved due to progression and refinement of cancer therapies; however, cardiovascular sequelae in this population augmented and now represent the second cause of death in oncological patients. Initially, the main issue was represented by heart failure and coronary artery disease, but a growing body of evidence has now shed light on the increased arrhythmic risk of this population, atrial fibrillation being the most frequently encountered. Awareness of arrhythmic complications of cancer and its treatments may help oncologists and cardiologists to develop targeted approaches for the management of arrhythmias in this population. In this review, we provide an updated overview of the mechanisms triggering cardiac arrhythmias in cancer patients, their prevalence and management.

Recent Advances in Serum Biomarkers for Cardiological Risk Stratification and Insight into the Cardiac Management of the Patients With Hematological Malignancies Treated With Targeted Therapy

Cardiovascular diseases (CVD) have emerged as a common and serious complication of cancer treatment, particularly in patients undergoing cardiotoxic therapies. Over the last few years, the medical community has become increasingly aware of the potential for cardiotoxicity resulting from cancer treatments involving chemotherapy, targeted therapies, and radiation therapy. This recognition is due to the significant risk of morbidity and mortality in cancer patients and survivors resulting from such treatment-induced cardiovascular damage. While the cardiotoxic effects of chemotherapy and targeted therapy have been discussed in medical literature, only a limited number of studies have explored the role of serum biomarkers in cardiological risk stratification. In recent years, serum biomarkers have emerged as a valuable tool for assessing and managing cardiotoxicity in patients with hematological malignancies. This review article provides a summary of the current state of knowledge on the usefulness of biomarkers in managing cardiotoxicity resulting from different targeted therapies throughout the cancer care continuum. Although cardiac biomarkers have demonstrated potential in identifying subclinical cardiotoxicity and tracking the response to cardioprotective treatments, further research is necessary to determine optimal biomarkers and surveillance strategies. The incorporation of cardiac biomarkers into clinical practice in patients undergoing targeted therapies could potentially lead to improved long-term cardiovascular outcomes in cancer patients and survivors.

NADPH Oxidases and Oxidative Stress in the Pathogenesis of Atrial Fibrillation

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and its prevalence increases with age. The irregular and rapid contraction of the atria can lead to ineffective blood pumping, local blood stasis, blood clots, ischemic stroke, and heart failure. NADPH oxidases (NOX) and mitochondria are the main sources of reactive oxygen species in the heart, and dysregulated activation of NOX and mitochondrial dysfunction are associated with AF pathogenesis. NOX- and mitochondria-derived oxidative stress contribute to the onset of paroxysmal AF by inducing electrophysiological changes in atrial myocytes and structural remodeling in the atria. Because high atrial activity causes cardiac myocytes to expend extremely high energy to maintain excitation-contraction coupling during persistent AF, mitochondria, the primary energy source, undergo metabolic stress, affecting their morphology, Ca2+ handling, and ATP generation. In this review, we discuss the role of oxidative stress in activating AF-triggered activities, regulating intracellular Ca2+ handling, and functional and anatomical reentry mechanisms, all of which are associated with AF initiation, perpetuation, and progression. Changes in the extracellular matrix, inflammation, ion channel expression and function, myofibril structure, and mitochondrial function occur during the early transitional stages of AF, opening a window of opportunity to target NOX and mitochondria-derived oxidative stress using isoform-specific NOX inhibitors and mitochondrial ROS scavengers, as well as drugs that improve mitochondrial dynamics and metabolism to treat persistent AF and its transition to permanent AF.

Cardiac Arrhythmias in Oncological Patients-Epidemiology, Risk Factors, and Management within the Context of the New ESC 2022 Guidelines

PURPOSE OF REVIEW

To provide an update on epidemiology, risk factors, and management of cardiac arrhythmias in oncological patients within the context of the new European Society of Cardiology 2022 guidelines on cardio-oncology.

RECENT FINDINGS

One of the side effects of different chemotherapeutics is their pro-arrhythmic activity. Both atrial and ventricular arrhythmias may be induced by cancer itself or by anticancer treatment. Recent studies report on the cardiotoxic activity of such promising therapies as BRAF and MEK inhibitors, or CAR-T therapy. Risk factors of arrhythmias in oncological patients overlap with cardiovascular diseases risk factors, but there are some groups of anticancer drugs that increase the risk of cardiotoxicity. It is crucial to be aware of the risks associated with the oncological treatment and know how to act in case of cardiotoxicity.

Cardiovascular Toxicities of BTK Inhibitors in Chronic Lymphocytic Leukemia: JACC: CardioOncology State-of-the-Art Review

Over the past decade, the treatment landscape of chronic lymphocytic leukemia (CLL) has dramatically changed, shifting from cytotoxic chemotherapy to targeted therapies. Bruton's tyrosine kinase (BTK) inhibitors have revolutionized the treatment of CLL and are increasingly applied in many other malignancies. However, ibrutinib, the first BTK inhibitor approved, is associated with serious toxicities, including atrial fibrillation in up to 38% of patients, ventricular arrhythmias, and other cardiovascular toxicities. Emerging data suggest several newer BTK inhibitors (eg, acalabrutinib, zanubrutinib) are still associated with cardiotoxic risks. This review examines the current state of evidence, including incidence rates, risk factors, mechanisms, and management strategies of cardiovascular toxicities with BTK inhibitors and other CLL therapies. We specifically focus on atrial fibrillation, ventricular arrhythmias/sudden death, hypertension, heart failure, bleeding, and stroke. We also touch on other emerging BTK therapies (eg, pirtobrutinib). Finally, we highlight key unanswered questions and future directions of research.

Cardiotoxicity of anti-cancer drugs: cellular mechanisms and clinical implications

Cardio-oncology is an emerging field that seeks to enhance quality of life and longevity of cancer survivors. It is pertinent for clinicians to understand the cellular mechanisms of prescribed therapies, as this contributes to robust understanding of complex treatments and off-target effects, improved communication with patients, and guides long term care with the goal to minimise or prevent cardiovascular complications. Our aim is to review the cellular mechanisms of cardiotoxicity involved in commonly used anti-cancer treatments and identify gaps in literature and strategies to mitigate cardiotoxicity effects and guide future research endeavours.

5-Methoxytryptophan alleviates atrial structural remodeling in ibrutinib-associated atrial fibrillation

Background

Ibrutinib is an effective and well-tolerated treatment for B-cell lymphomas but is associated with an increased risk of atrial fibrillation (AF) by altering the structure of the atrium. 5-Methoxytryptophan (5-MTP) inhibits inflammatory and fibrotic processes. This study aimed to determine the effects and mechanisms of 5-MTP on the underlying mechanisms of AF caused by ibrutinib.

Methods

The effect of 5-MTP on ibrutinib-related AF was investigated in male Sprague Dawley rats using echocardiographic, electrophysiological, immunofluorescent, Masson staining, and molecular analyses.

Rusults

The ibrutinib+5-MTP group showed (1) a lower incidence and shorter duration of AF and accelerated atrial conduction; (2) a decreased left atrial mass and left atrial diameter; (3) decreased myocardial fibrosis in the left atrium; (4) lower atrial inflammation; (5) increased sarcoplasmic reticulum Ca2+-ATPase 2a protein expression, decreased phosphorylation of phospholamban at Thr17, and decreased sodium/calcium exchanger 1 protein expression and phosphorylation of ryanodine receptor 2 at S2814; and (6) decreased phosphorylation of CaMKII expression. 5-MTP treatment markedly activated the PI3K-Akt signaling. Inhibiting PI3K-Akt signaling significantly reversed the protective effect of 5-MTP on ibrutinib-related AF.

Conclusions

These findings suggest that 5-MTP administration decreases the vulnerability of ibrutinib-related AF mainly caused by ameliorated maladaptive left atrial remodeling and dysregulation of calcium handling proteins. Mechanistically, 5-MTP treatment markedly enhanced the activation of cardiac PI3K-Akt signaling.

Empagliflozin attenuates doxorubicin-impaired cardiac contractility by suppressing reactive oxygen species in isolated myocytes

In animal studies, sodium-glucose co-transporter-2 inhibitors-such as empagliflozin-have been shown to improve heart failure and impaired cardiac contractility induced by anthracyclines-including doxorubicin-although the therapeutic mechanism remains unclear. Moreover, abnormalities in Ca2+ handling within ventricular myocytes are the predominant feature of heart failure. Accordingly, this study aimed to investigate whether empagliflozin can alleviate Ca2+ handling disorders induced by acute doxorubicin exposure and elucidate the underlying mechanisms. To this end, ventricular myocytes were isolated from C57BL/6 mice. Contraction function, Ca2+ handling, and mitochondrial reactive oxygen species (ROS) generation were then evaluated using IonOptix or confocal microscopy. Ca2+ handling proteins were detected by western blotting. Results show that incubation with 1 μmol/L of doxorubicin for 120-min impaired cardiac contractility in isolated myocytes, which was significantly alleviated by pretreatment with 1 μmol/L of empagliflozin. Doxorubicin also markedly induced Ca2+ handling disorders, including decreased Ca2+ transients, prolonged Ca2+ transient decay time, enhanced frequency of Ca2+ sparks, and decreased Ca2+ content in the sarcoplasmic reticulum. These dysregulations were improved by pretreatment with empagliflozin. Moreover, empagliflozin effectively inhibited doxorubicin-induced mitochondrial ROS production in isolated myocytes and rescued doxorubicin-induced oxidation of Ca2+/calmodulin-dependent protein kinase II (ox-CaMKII) and CaMKII-dependent phosphorylation of RyR2. Similarly, preincubation with 10 μmol/L Mito-TEMPO mimicked the protective effects of empagliflozin. Collectively, Empagliflozin ameliorated the doxorubicin-induced contraction malfunction and Ca2+-handling disorders. These findings suggest that empagliflozin alleviates Ca2+-handling disorders by improving ROS production in the mitochondria and alleviating the enhanced oxidative CaMKII signaling pathway induced by doxorubicin.

Which is the top player for the cardiovascular safety? ibrutinib vs. obinutuzumab in CLL

Introduction: Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, is authorized for the treatment of chronic lymphocytic leukemia (CLL). This study aims to explore the cardiac safety profile of ibrutinib in comparison with obinutuzumab. Methods: A retrospective pharmacovigilance study was conducted on data retrieved from the European pharmacovigilance database (Eudravigilance) from 1 January 2014 to 30 September 2022. To compare the reporting frequency of cardiovascular events among ibrutinib, obinutuzumab, and the combination of both. Results: A total of 2 291 CV cases were retrieved, of which 1965 were related to ibrutinib, 312 to obinutuzumab, and 14 to the combination. Most cases referred to patients aged ≥65 years (N = 1,454; 63.47%) and male (N = 1,497; 65.34%). Most cases were serious (N = 2,131; 93.02%). The most reported events were: atrial fibrillation (N = 913; 31.31%) and haemorrhage (N = 201; 6.89%). A higher reporting frequency of CV events was found when ibrutinib was compared to obinutuzumab (ROR, 3.22; 95% CI, 2.89-3.60) or combination (ROR, 1.77; 95% CI, 1.11-2.83). A lower reporting was observed when obinutuzumab was compared to combination (ROR, 0.55; 95% CI, 0.34-0.88). Discussion: A higher reporting frequency of CV events in patients exposed to ibrutinib in comparison with obinutuzumab was found. Further studies are needed to better explore the safety of ibrutinib.

Ibrutinib impairs IGF-1-dependent activation of intracellular Ca handling in isolated mouse ventricular myocytes

Background

The Bruton tyrosine kinase (BTK) inhibitor Ibrutinib is associated with a higher incidence of cardiotoxic side effects including heart failure (HF).

Objectives

Ibrutinib is capable of inhibiting PI3K/Akt signaling in neonatal rat ventricular cardiomyocytes when stimulated with insulin-like growth factor 1 (IGF-1). We therefore hypothesized that Ibrutinib might disrupt IGF-1-mediated activation of intracellular Ca handling in adult mouse cardiomyocytes by inhibiting PI3K/Akt signaling.

Methods

Isolated ventricular myocytes (C57BL6/J) were exposed to IGF-1 at 10 nmol/L in the presence or absence of Ibrutinib (1 µmol/L) or Acalabrutinib (10 µmol/L; cell culture for 24 ± 2 h). Intracellular Ca handling was measured by epifluorescence (Fura-2 AM) and confocal microscopy (Fluo-4 AM). Ruptured-patch whole-cell voltage-clamp was used to measure ICa. Levels of key cardiac Ca handling proteins were investigated by immunoblots.

Results

IGF-1 significantly increased Ca transient amplitudes by ∼83% as compared to vehicle treated control cells. This was associated with unaffected diastolic Ca, enhanced SR Ca loading and increased ICa. Co-treatment with Ibrutinib attenuated both the IGF-1-mediated increase in SR Ca content and in ICa. IGF-1 treated cardiomyocytes had significantly increased levels of pS473Akt/Akt and SERCA2a expression as compared to cells concomitantly treated with IGF-1 and Ibrutinib. SR Ca release (as assessed by Ca spark frequency) was unaffected by either treatment. In order to test for potential off-target effects, second generation BTK inhibitor Acalabrutinib with greater BTK selectivity and lower cardiovascular toxicity was tested for IGF1-mediated activation of intracellular Ca handling. Acalabrutinib induced similar effects on Ca handling in IGF-1 treated cultured myocytes as Ibrutinib in regard to decreased Ca transient amplitude and slowed Ca transient decay, hence implying a functional class effect of BTK inhibitors in cardiac myocytes.

Conclusions

Inhibition of BTK by Ibrutinib impairs IGF-1-dependent activation of intracellular Ca handling in adult ventricular mouse myocytes in the face of disrupted Akt signaling and absent SERCA2a upregulation.

Predictors of ibrutinib-associated atrial fibrillation: 5-year follow-up of a prospective study

Ibrutinib-associated atrial fibrillation (IRAF) emerged among the adverse events of major interests in ibrutinib-treated patients as real-world studies showed a higher incidence compared to clinical trials. We prospectively analyzed predictors of IRAF in 43 single-center consecutive patients affected by chronic lymphocytic leukemia that started therapy with ibrutinib between 2015 and 2017. Key secondary endpoints were to describe the management of IRAF and survival outcomes. During a median follow-up period of 52 months, we registered 45 CV events, with a total of 23 AF events in 13 patients (CI 30.0% (95% CI: 16.5-43.9)). Pre-existent cardiovascular risk factors, in particular hypertension, a previous history of AF and a high Shanafelt risk score emerged as predictors of IRAF. Baseline echocardiographic evaluation of left atrial (LA) dimensions confirmed to predict IRAF occurrence and cut-off values were identified in our cohort: 32 mm for LA diameter and 18 cm2 for LA area. No difference in progression free survival and overall survival emerged in patients experiencing IRAF. Following AF, anticoagulation was started in all eligible patients, and cardioactive therapy was accordingly modified. Echocardiography represents a highly reproducible and widespread tool to be included in the work-up of ibrutinib candidates; the identification of IRAF predictors represents a useful guide to clinical practice.

Disordered gut microbiota promotes atrial fibrillation by aggravated conduction disturbance and unbalanced linoleic acid/SIRT1 signaling

Emerging evidence suggests an association of dysbiotic gut microbiota (GM) with atrial fibrillation (AF). The current study aimed to determine whether aberrant GM promotes AF development. A fecal microbiota transplantation (FMT) mouse model demonstrated that dysbiotic GM is sufficient to enhance AF susceptibility assessed by transesophageal burst pacing. Compared with recipients transplanted with GM obtained from healthy subjects (FMT-CH), the prolonged P wave duration and an enlarging tendency for the left atrium were detected in recipients transplanted with AF GM (FMT-AF). Meanwhile, the disrupted localizations of connexin 43 and N-cadherin and increased expression levels of phospho-CaMKII and phospho-RyR2, were observed in the atrium of FMT-AF, which indicated aggravated electrical remodeling caused by the altered gut flora. Specifically, exacerbated fibrosis disarray, collagen deposition, α-SMA expression, and inflammation in the atrium were also confirmed to be transmissible by the GM. Furthermore, deteriorated intestinal epithelial barrier and intestinal permeability, accompanied by disturbing metabolomic features in both feces and plasma, especially decreased linoleic acid (LA), were identified in FMT-AF mice. Subsequently, the anti-inflammatory role of LA among the imbalanced SIRT1 signaling discovered in the atrium of FMT-AF was confirmed in mouse HL-1 cells treated with LPS/nigericin, LA, and SIRT1 knockdown. This study provides preliminary insights into the causal role of aberrant GM in the pathophysiology of AF, suggesting the GM-intestinal barrier-atrium axis might participate in the vulnerable substrates for AF development, and the GM could be utilized as an environmental target in AF management.

Chemotherapy Induced Cardiotoxicity: A State of the Art Review on General Mechanisms, Prevention, Treatment and Recent Advances in Novel Therapeutics

As medicine advances to employ sophisticated anticancer agents to treat a vast array of oncological conditions, it is worth considering side effects associated with several chemotherapeutics. One adverse effect observed with several classes of chemotherapy agents is cardiotoxicity which leads to reduced ejection fraction (EF), cardiac arrhythmias, hypertension and Ischemia/myocardial infarction that can significantly impact the quality of life and patient outcomes. Research into possible mechanisms has elucidated several mechanisms, such as ROS generation, calcium overload and apoptosis. However, there is a relative scarcity of literature detailing the relationship between the exact mechanism of cardiotoxicity for each anticancer agent and observed clinical effects. This review comprehensively describes cardiotoxicity associated with various classes of anticancer agents and possible mechanisms. Further research exploring possible mechanisms for cardiotoxicity observed with anticancer agents could provide valuable insight into susceptibility for developing symptoms and management guidelines. Chemotherapeutics are associated with several side effects. Several classes of chemotherapy agents cause cardiotoxicity leading to a reduced ejection fraction (EF), cardiac arrhythmias, hypertension, and Ischemia/myocardial infarction. Research into possible mechanisms has elucidated several mechanisms, such as ROS generation, calcium overload, and apoptosis. However, there is a relative scarcity of literature detailing the relationship between the exact mechanism of cardiotoxicity for each anticancer agent and observed clinical effects. This review describes cardiotoxicity associated with various classes of anticancer agents and possible mechanisms. Further research exploring mechanisms for cardiotoxicity observed with anticancer agents could provide insight that will guide management.

Cardiovascular Toxicities Associated with Tyrosine Kinase Inhibitors

PURPOSE OF REVIEW

To provide a detailed overview of cardiovascular adverse events associated with the use of tyrosine kinase inhibitors across different tumor types.

RECENT FINDINGS

Despite an undeniable survival advantage of tyrosine kinase inhibitors (TKIs) in patients with hematologic or solid malignancies, the accompanying off-target cardiovascular adverse events can be life-threatening. In patients with B cell malignancies, the use of Bruton tyrosine kinase inhibitors has been associated with atrial and ventricular arrhythmias, as well as hypertension. Cardiovascular toxic profiles are heterogeneous among the several approved breakpoint cluster region (BCR)-ABL TKIS. Notably, imatinib might be cardioprotective. Vascular endothelial growth factor TKIs, constituting the central axis in the treatment of several solid tumors, including renal cell carcinoma and hepatocellular carcinoma, have strongly been associated with hypertension and arterial ischemic events. Epidermal growth factor TKIs as therapy for advanced non-small cell lung cancer (NSCLC) have been reported to be infrequently associated with heart failure and QT prolongation. While tyrosine kinase inhibitors have been demonstrated to increase overall survival across different types of cancers, special consideration should be given to cardiovascular toxicities. High-risk patients can be identified by undergoing a comprehensive workup at baseline.

Kinase Inhibitors and Atrial Fibrillation

Recent advances have significantly expanded the options of available therapeutics for cancer treatment, including novel targeted cancer therapies. Within this broad category of targeted therapies is the class of kinase inhibitors (KIs), which target kinases that have undergone aberrant activation in cancerous cells. Although KIs have shown a benefit in treating various forms of malignancy, they have also been shown to cause a wide array of cardiovascular toxicities, with cardiac arrhythmias, in particular atrial fibrillation (AF), being 1 of the predominant side effects. The occurrence of AF in patients undergoing cancer treatment can complicate the treatment approach and poses unique clinical challenges. The association of KIs and AF has led to new research aimed at trying to elucidate the underlying mechanisms. Furthermore, there are unique considerations to treating KI-induced AF because of the anticoagulant properties of some KIs as well as drug-drug interactions with KIs and some cardiovascular medications. Here, we review the current literature pertaining to KI-induced AF.

The Impact of Sleep Disturbance on Gut Microbiota, Atrial Substrate, and Atrial Fibrillation Inducibility in Mice: A Multi-Omics Analysis

This study examined the effect of sleep disturbance on gut microbiota (GM), atrial substrate, and atrial fibrillation (AF) inducibility. C57BL/6 mice were subjected to six weeks of sleep deprivation (SD) using the method of modified multiple-platform. Transesophageal burst pacing was performed to evaluate AF inducibility. Feces, plasma, and an atrium were collected and analyzed by 16s rRNA sequencing, liquid chromatography−mass spectrometry (LC-MS)-based metabolome, histological studies, and transcriptome. Higher AF inducibility (2/30 of control vs. 15/30 of SD, p = 0.001) and longer AF duration (p < 0.001), concomitant with aggravated fibrosis, collagen, and lipid accumulation, were seen in the SD mice compared to control mice. Meanwhile, elevated alpha diversity, higher abundance of Flavonifractor, Ruminococcus, and Alloprevotella, as well as imbalanced functional pathways, were observed in the gut of SD mice. Moreover, the global patterns for the plasma metabolome were altered, e.g., the decreased butanoate metabolism intermediates in SD mice. In addition, disrupted metabolic homeostasis in the SD atrium, such as fatty acid metabolism, was analyzed by the transcriptome. These results demonstrated that the crosstalk between GM and atrial metabolism might be a promising target for SD-mediated AF susceptibility.

Data mining and safety analysis of BTK inhibitors: A pharmacovigilance investigation based on the FAERS database

Objective: The introduction of Bruton's tyrosine kinase (BTK) inhibitors was a milestone in the treatment of B-cell malignancies in recent years owing to its desired efficacy against chronic lymphocytic leukaemia and small cell lymphocytic lymphoma. However, safety issues have hindered its application in clinical practice. The current study aimed to explore the safety warning signals of BTK inhibitors in a real-world setting using the FDA Adverse Event Reporting System (FAERS) to provide reference for clinical rational drug use. Methods: Owing to the short marketing time of other drugs (zanbrutinib and orelabrutinib), we only analysed ibrutinib and acalabrutinib in this study. All data were obtained from the FAERS database from January 2004 to December 2021. Disproportionality analysis and Bayesian analysis were utilised to detect and assess the adverse event (AE) signals of BTK inhibitors. Results: In total, 43,429 reports of ibrutinib were extracted and 1527 AEs were identified, whereas 1742 reports of acalabrutinib were extracted and 220 AEs were identified by disproportionality analysis and Bayesian analysis. Among reports, males were more prone to develop AEs (58.2% for males vs. 35.6% for females treated with ibrutinib, and 55.9% vs. 31.9%, respectively, for acalabrutinib), and more than 30% of patients that suffered from AEs were over 65 years of age. Subsequently, we investigated the top 20 preferred terms (PTs) associated with the signal strength of ibrutinib and acalabrutinib, and our results identified 25 (13 vs. 12, respectively) novel risk signals. Among the top 20 PTs related to death reports, the terms infectious, pneumonia, pleural effusion, fall, asthenia, diarrhoea, and fatigue were all ranked high for these two BTK inhibitors. Further, cardiac disorders were also an important cause of death with ibrutinib. Conclusion: Patients treated with ibrutinib were more prone to develop AEs than those treated with acalabrutinib. Importantly, infection-related adverse reactions, such as pneumonia and pleural effusion, were the most common risk signals related to high mortality associated with both BTK inhibitors, especially in elderly patients. Moreover, cardiovascular-related adverse reactions, such as atrial fibrillation and cardiac failure, were fatal AEs associated with ibrutinib. Our results provide a rationale for physicians to choose suitable BTK inhibitors for different patients and provide appropriate monitoring to achieve safer therapy and longer survival.

Atrial Fibrillation Induced by Anticancer Drugs and Underling Mechanisms

ABSTRACT

Cancer therapy has made major progress in the past several decades, but treatments are often accompanied by significant side effects. Arrhythmias are a widespread complication of some antineoplastic drugs, with atrial fibrillation (AF) being the most often encountered drug-associated arrhythmia. Preexisting AF risk factors are commonly present in cancer patients who develop drug-associated AF, and active cancer itself may cause or promote AF. Although anticancer drugs may induce AF in cancer patients without AF risk factors, it appears that most drug-associated AF develop when cancer drugs add or aggravate precancer-existing and/or cancer-related pro-AF factors/alterations, additively or synergistically producing AF. Abnormalities in intracellular calcium activity seem to be involved in the generation of anticancer drug-induced AF. In cancer survivors with cancer therapy-induced cardiomyopathy, AF often occurs, with most of the arrhythmias likely to develop secondary to the cardiomyopathy. AF may lead to modification or even cessation of cancer therapy. The management of AF in patients with cancer is currently conducted largely based on pragmatic assumptions. This review briefly discusses AF caused by anticancer drugs and the underlying mechanisms.

Ibrutinib-Associated Cardiotoxicity: From the Pharmaceutical to the Clinical

Ibrutinib is the first-in-class Bruton tyrosine kinase (BTK) inhibitor that has revolutionized the treatment of B cell malignancies. Unfortunately, increased incidences of cardiotoxicity have limited its use. Despite over a decade of research, the biological mechanisms underlying ibrutinib cardiotoxicity remain unclear. In this review, we discuss the pharmacological properties of ibrutinib, the incidence and mechanisms of ibrutinib-induced cardiotoxicity, and practical management to prevent and treat this condition. We also synopsize and discuss the cardiovascular adverse effects related to other more selective BTK inhibitors, which may guide the selection of appropriate BTK inhibitors.

Febuxostat increases ventricular arrhythmogenesis through calcium handling dysregulation in human induced pluripotent stem cell-derived cardiomyocytes

Febuxostat is a xanthine oxidase inhibitor used to reduce the formation of uric acid and prevent gout attacks. Previous studies have suggested that febuxostat was associated with a higher risk of cardiovascular events, including atrial fibrillation, compared with allopurinol, another anti-hyperuricemia drug. Whereas in our clinical practice, we identified two cases of febuxostat-associated ventricular tachycardia events. The proarrhythmogenic effects of febuxostat on human cardiomyocytes and underlined mechanisms remain poorly understood. In this study, we employed real time cell analysis (RTCA) and calcium transient to investigate the effects of febuxostat on the cytotoxicity and electrophysiology properties of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Up to 10 μM febuxostat treatment did not show toxicity to cell viability. However, 48-hour febuxostat exposure generated dose-dependent increased irregular calcium transients and decreased calcium transient amplitude. Furthermore, RNA-seq analysis indicated that the MAPK signaling pathway was enriched in the febuxostat-treated group, especially the protein kinases JNK. Western blotting of three main protein kinases demonstrated that JNK activation is related to febuxostat-induced arrythmia rather than ERK or p38. The dysfunctional calcium dynamics of febuxostat-treated hiPSC-CMs could be ameliorated by SP600125, the inhibitor of JNK. In conclusion, our study demonstrated that febuxostat increases the predisposition to ventricular arrythmia by dysregulating calcium dynamics.

Commensal microbe-derived SCFA alleviates atrial fibrillation via GPR43/NLRP3 signaling

Rationale: Dysbiotic gut microbiota (GM) and NLRP3 inflammasome are proarrhythmic factors in atrial fibrillation (AF). Herein, whether short-chain fatty acid (SCFA) produced from GM fermentation of dietary fiber serving as invisible mediators is yet unclear. Thus, the current study aimed to determine whether SCFA alleviated from NLRP3 signaling-mediated atrial remodeling protects AF development. Methods: First, a cross-sectional study based on the GC-MS metabolomics was performed to explore the association between fecal SCFA levels and AF traits in a cohort consisted of 48 individuals. Then, a well-established mice model fed diet deficient or enriched in dietary fiber was established to elucidate the pathophysiological role of SCFA involved in AF susceptibility, atrial remodeling, and G-protein-coupled receptor 43 (GPR43)/NLRP3 signaling. Finally, the effects of SCFA were verified on HL-1 cells. Results: Fecal SCFA levels were remarkably reduced in AF patients with a declining trend from paroxysmal to persistent AF. Prolonged P wave duration based on surface ECG and increased left atrial diameter gained from echocardiography was identified in low-fiber diet mice but lost in SCFA-supplemented group. Lack of dietary fiber enhanced susceptibility to AF under burst pacing, whereas SCFA might exert a protective effect. The supplementation of SCFA prevented dietary fiber deficiency-upregulated phosphorylation of calmodulin-dependent protein kinase II and ryanodine receptor 2, the disarray fibrosis, collagen expression, and NLRP3 inflammasome activation in atrial tissue. Finally, the AF protective roles of SCFA were identified through GPR43 mediated deactivation of NLRP3 by GPR43 knockdown in HL-1 cells. Conclusions: SCFA derived from dietary fiber fermentation by gut commensals alleviates AF development via GPR43/NLRP3 signaling.

Cardiotoxicity of BTK inhibitors: ibrutinib and beyond

INTRODUCTION

The development of Bruton<apos;>s Tyrosine Kinase (BTK) inhibitors has transformed the treatment of B-cell malignancies and other non-malignant conditions. Management of the unique cardiotoxic profile of these agents requires prompt recognition and a multi-disciplinary approach.

AREAS COVERED

The increasing indications and addition of newer agents to clinical practice and emergence of BTK inhibitor-related cardiac adverse events have complicated the management decisions for utilization of this class of therapy. We review the incidence, mechanisms, and management approaches for BTK inhibitor-related atrial fibrillation, hypertension, and ventricular arrhythmias.

EXPERT OPINION

The newer BTK inhibitor acalabrutinib represents a new standard of care in front-line chronic lymphocytic leukemia (CLL) given the results of the ELEVATE-RR trial demonstrating comparable efficacy and a more favorable toxicity profile especially with regard to cardiac adverse events as compared to ibrutinib. Often not recognized by clinicians, BTK inhibitor-induced hypertension is common and can be severe, requiring prompt recognition and initiation or adjustment of anti-hypertensive medications to prevent major adverse cardiac outcomes. Novel BTK inhibitors in development are being designed to overcome the patterns of resistance from first-generation agents and to minimize off-target kinase activity, with promising toxicity profiles in early trials.

Empagliflozin Ameliorates Ouabain-Induced Na+ and Ca2+ Dysregulations in Ventricular Myocytes in an Na+-Dependent Manner

PURPOSE

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a novel class of glucose-lowering agents that have improved clinical outcomes in patients with heart failure; however, their therapeutic mechanisms remain elusive. Although contradictory results have been reported, it has been proposed that improving Na⁺ homeostasis may be the underlying mechanism of action of SGLT2 inhibitors in heart failure treatment. This study explored whether empagliflozin ameliorates Na⁺ and Ca²⁺ handling disorders induced by ouabain in an Na⁺-dependent manner.

METHODS

Isolated ventricular myocytes of mice were incubated with ouabain to establish a cellular model of Na⁺ overload. Effects of empagliflozin on Na⁺ and Ca²⁺ handling were evaluated using an ionOptix system and a confocal microscope. Distinct cytosolic Na⁺ levels were established by incubating different ouabain concentrations (10, 50, and 100 μmol/L).

RESULTS

In the absence of ouabain, 1 μmol/L empagliflozin had a negligible impact on Na⁺ and Ca²⁺ handling in ventricular myocytes. Ouabain (50 μmol/L) significantly enhanced cytosolic Na⁺ levels and dysregulated Ca²⁺ handling, including an increased Ca²⁺ transient amplitude, elevated Ca²⁺ content in the sarcoplasmic reticulum, and enhanced spontaneous Ca²⁺ release normalized by treatment with 1 μmol/L empagliflozin within 10 min. All Na⁺ and Ca²⁺ handling abnormalities induced by ouabain were reversed by 1 μmol/L empagliflozin. The efficacy of empagliflozin was more potent at higher cytosolic Na⁺ levels. Pretreatment with the Na⁺/H⁺ exchanger (NHE) inhibitor (1 μmol/L cariporide) abolished the effects of empagliflozin.

CONCLUSION

Empagliflozin ameliorates ouabain-induced Na⁺ and Ca²⁺ handling disorders in a cytosolic Na⁺-dependent manner, potentially by inhibiting the NHE.

Tyrosine Kinase Inhibitors-Induced Arrhythmias: From Molecular Mechanisms, Pharmacokinetics to Therapeutic Strategies

With the development of anti-tumor drugs, tyrosine kinase inhibitors (TKIs) are an indispensable part of targeted therapy. They can be superior to traditional chemotherapeutic drugs in selectivity, safety, and efficacy. However, they have been found to be associated with serious adverse effects in use, such as myocardial infarction, fluid retention, hypertension, and rash. Although TKIs induced arrhythmia with a lower incidence than other cardiovascular diseases, much clinical evidence indicated that adequate attention and management should be provided to patients. This review focuses on QT interval prolongation and atrial fibrillation (AF) which are conveniently monitored in clinical practice. We collected data about TKIs, and analyzed the molecule mechanism, discussed the actual clinical evidence and drug-drug interaction, and provided countermeasures to QT interval prolongation and AF. We also pooled data to show that both QT prolongation and AF are related to their multi-target effects. Furthermore, more than 30 TKIs were approved by the FDA, but most of the novel drugs had a small sample size in the preclinical trial and risk/benefit assessments were not perfect, which led to a suspension after listing, like nilotinib. Similarly, vandetanib exhibits the most significant QT prolongation and ibrutinib exhibits the highest incidence in AF, but does not receive enough attention during treatment.

Pre-existing cardiovascular disease increases risk of atrial arrhythmia and mortality in cancer patients treated with Ibrutinib

Background

Ibrutinib is a Bruton’s tyrosine kinase inhibitor used in the treatment of hematological malignancies. The most common cardiotoxicity associated with ibrutinib is atrial arrhythmia (atrial fibrillation and flutter). It is known that patients with cardiovascular disease (CVD) are at an increased risk for developing atrial arrhythmia. However, the rate of atrial arrhythmia in patients with pre-existing CVD treated with ibrutinib is unknown.

Objective

This study examined whether patients with pre-existing CVD are at a higher risk for developing atrial arrhythmias compared to those without prior CVD.

Methods

A single-institution retrospective chart review of patients with no prior history of atrial arrhythmia treated with ibrutinib from 2012 to 2020 was performed. Patients were grouped into two cohorts: those with CVD (known history of coronary artery disease, heart failure, pulmonary hypertension, at least moderate valvular heart disease, or device implantation) and those without CVD. The primary outcome was incidence of atrial arrhythmia, and the secondary outcomes were all-cause mortality, risk of bleeding, and discontinuation of ibrutinib. The predictors of atrial arrhythmia (namely atrial fibrillation) were assessed using logistic regression. A Cox-Proportional Hazard model was created for mortality.

Results

Patients were followed for a median of 1.1 years. Among 217 patients treated with ibrutinib, the rate of new-onset atrial arrhythmia was nearly threefold higher in the cohort with CVD compared to the cohort without CVD (17% vs 7%, p = 0.02). Patients with CVD also demonstrated increased adjusted all-cause mortality (OR 1.9, 95% CI 1.06-3.41, p = 0.01) and decreased survival probability (43% vs 54%, p = 0.04) compared to those without CVD over the follow-up period. There were no differences in risk of bleeding or discontinuation between the two cohorts.

Conclusions

Pre-existing cardiovascular disease was associated with significantly higher rates of atrial arrhythmia and mortality in patients with hematological malignancies managed with ibrutinib.

Distinct Effects of Ibrutinib and Acalabrutinib on Mouse Atrial and Sinoatrial Node Electrophysiology and Arrhythmogenesis

Background

Ibrutinib and acalabrutinib are Bruton tyrosine kinase inhibitors used in the treatment of B‐cell lymphoproliferative disorders. Ibrutinib is associated with new‐onset atrial fibrillation. Cases of sinus bradycardia and sinus arrest have also been reported following ibrutinib treatment. Conversely, acalabrutinib is less arrhythmogenic. The basis for these different effects is unclear.

Methods and Results

The effects of ibrutinib and acalabrutinib on atrial electrophysiology were investigated in anesthetized mice using intracardiac electrophysiology, in isolated atrial preparations using high‐resolution optical mapping, and in isolated atrial and sinoatrial node (SAN) myocytes using patch‐clamping. Acute delivery of acalabrutinib did not affect atrial fibrillation susceptibility or other measures of atrial electrophysiology in mice in vivo. Optical mapping demonstrates that ibrutinib dose‐dependently impaired atrial and SAN conduction and slowed beating rate. Acalabrutinib had no effect on atrial and SAN conduction or beating rate. In isolated atrial myocytes, ibrutinib reduced action potential upstroke velocity and Na⁺ current. In contrast, acalabrutinib had no effects on atrial myocyte upstroke velocity or Na⁺ current. Both drugs increased action potential duration, but these effects were smaller for acalabrutinib compared with ibrutinib and occurred by different mechanisms. In SAN myocytes, ibrutinib impaired spontaneous action potential firing by inhibiting the delayed rectifier K⁺ current, while acalabrutinib had no effects on SAN myocyte action potential firing.

Conclusions

Ibrutinib and acalabrutinib have distinct effects on atrial electrophysiology and ion channel function that provide insight into the basis for increased atrial fibrillation susceptibility and SAN dysfunction with ibrutinib, but not with acalabrutinib.

Safety Profile of Ibrutinib: An Analysis of the WHO Pharmacovigilance Database

As ibrutinib has become a standard of care in B-cell malignancies in monotherapy or in combination with other agents, definition of its safety profile appears essential. The aim of this study was to further characterize the safety profile of ibrutinib through the identification of potential safety signals in a large-scale pharmacovigilance database. All serious individual case safety reports (ICSRs) in patients aged ≥18 years involving ibrutinib suspected in the occurrence of serious adverse drug reactions or drug interacting from November 13th, 2013 to December 31st, 2020 were extracted from VigiBase, the World Health Organization global safety database. Disproportionality reporting was assessed using the information component (IC) and the proportional reporting ratio (PRR), with all other anticancer drugs used as the reference group. To mitigate the confounding of age, two subgroups were considered: patients aged<75 years and ≥75 years. A signal of disproportionate reporting (SDR) was defined if both IC and PRR were significant. A total of 16,196 ICSRs were included. The median age of patients was 72.9 years, 42.6% of ICSRs concerned patients aged ≥75 years, and 64.2% male patients. More than half (56.2%) of ICSRs resulted in hospitalization or prolonged hospitalization. Among 713 SDRs, 36 potential safety signals emerged in ibrutinib-treated patients, mainly ischemic heart diseases, pericarditis, uveitis, retinal disorders and fractures. All potential safety signals having arisen in this analysis may support patient care and monitoring of ongoing clinical trials. However, owing to the mandatory limitations of this study, our results need further confirmation using population-based studies.

Cardiovascular Risk Associated With Ibrutinib Use in Chronic Lymphocytic Leukemia: A Population-Based Cohort Study

PURPOSE

Ibrutinib reduces mortality in chronic lymphocytic leukemia (CLL). It increases the risk of atrial fibrillation (AF) and bleeding and there are concerns about heart failure (HF) and central nervous system ischemic events. The magnitude of these risks remains poorly quantified.

METHODS

Using linked administrative databases, we conducted a population-based cohort study of Ontario patients who were treated for CLL diagnosed between 2007 and 2019. We matched ibrutinib-treated patients with controls treated with chemotherapy but unexposed to ibrutinib on prior AF, age ≥ 66 years, anticoagulant exposure, and propensity for receiving ibrutinib. Study outcomes were AF-related health care contact, hospital-diagnosed bleeding, new diagnoses of HF, and hospitalizations for stroke and acute myocardial infarction (AMI). The cumulative incidence function was used to estimate absolute risks. We used cause-specific regression to study the association of ibrutinib with bleeding rates, while adjusting for anticoagulation as a time-varying covariate.

RESULTS

We matched 778 pairs of ibrutinib-treated and unexposed patients with CLL (N = 1,556). The 3-year incidence of AF-related health care contact was 22.7% (95% CI, 19.0 to 26.6) in ibrutinib-treated patients and 11.7% (95% CI, 9.0 to 14.8) in controls. The 3-year risk of hospital-diagnosed bleeding was 8.8% (95% CI, 6.5 to 11.7) in ibrutinib-treated patients and 3.1% (95% CI, 1.9 to 4.6) in controls. Ibrutinib-treated patients were more likely to start anticoagulation after the index date. After adjusting for anticoagulation as a time-varying covariate, ibrutinib remained positively associated with bleeding (HR, 2.58; 95% CI, 1.76 to 3.78). The 3-year risk of HF was 7.7% (95% CI, 5.4 to 10.6%) in ibrutinib-treated patients and 3.6% (95% CI, 2.2 to 5.4) in controls. There was no significant difference in the risk of ischemic stroke or AMI.

CONCLUSION

Ibrutinib is associated with higher risk of AF, bleeding, and HF, but not AMI or stroke.

Ibrutinib in patients with atrial fibrillation - the challenge of thromboembolic prophylaxis

Ibrutinib is a novel drug used in haematological malignancies. Its use is associated with an increased risk of atrial fibrillation (AF), which, in turn, exposes patients to embolic risk, including stroke. Reducing this risk requires anticoagulant therapy which is a matter of concern in the context of the increased bleeding risk of patients with haematological malignancies. In this context the presence of thrombocytopenia related to haematological disorder, ibrutinib-anticoagulants and ibrutinib-platelets interactions contribute to the amplification of the problem. The correct assessment of the thrombosis vs. haemorrhage balance represents a significant challenge for the clinician. In this paper we discuss practical issues related to anticoagulation in patients treated with ibrutinib and incident AF.

Advances in the application of nanotechnology in reducing cardiotoxicity induced by cancer chemotherapy

Advances in the development of anti-tumour drugs and related technologies have resulted in a significant increase in the number of cancer survivors. However, the incidence of chemotherapy-induced cardiotoxicity (CIC) has been rising continuously, threatening their long-term survival. The integration of nanotechnology and biomedicine has brought about an unprecedented technological revolution and has promoted the progress of anti-tumour therapy. In this review, we summarised the possible mechanisms of CIC, evaluated the role of nanoparticles (including liposomes, polymeric micelles, dendrimers, and hydrogels) as drug carriers in preventing cardiotoxicity and proposed five advantages of nanotechnology in reducing cardiotoxicity: Liposomes cannot easily penetrate the heart's endothelial barrier; optimized delivery strategies reduce distribution in important organs, such as the heart; targeting the tumour microenvironment and niche; stimulus-responsive polymer nano-drug carriers rapidly iterate; better economic benefits were obtained. Nanoparticles can effectively deliver chemotherapeutic drugs to tumour tissues, while reducing the toxicity to heart tissues, and break through the dilemma of existing chemotherapy to a certain extent. It is important to explore the interactions between the physicochemical properties of nanoparticles and optimize the highly specific tumour targeting strategy in the future.

Modulated Calcium Homeostasis and Release Events Under Atrial Fibrillation and Its Risk Factors: A Meta-Analysis

Background: Atrial fibrillation (AF) is associated with calcium (Ca²⁺) handling remodeling and increased spontaneous calcium release events (SCaEs). Nevertheless, its exact mechanism remains unclear, resulting in suboptimal primary and secondary preventative strategies.

Methods: We searched the PubMed database for studies that investigated the relationship between SCaEs and AF and/or its risk factors. Meta-analysis was used to examine the Ca²⁺ mechanisms involved in the primary and secondary AF preventative groups.

Results: We included a total of 74 studies, out of the identified 446 publications from inception (1982) until March 31, 2020. Forty-five were primary and 29 were secondary prevention studies for AF. The main Ca²⁺ release events, calcium transient (standardized mean difference (SMD) = 0.49; I² = 35%; confidence interval (CI) = 0.33–0.66; p < 0.0001), and spark amplitude (SMD = 0.48; I² = 0%; CI = −0.98–1.93; p = 0.054) were enhanced in the primary diseased group, while calcium transient frequency was increased in the secondary group. Calcium spark frequency was elevated in both the primary diseased and secondary AF groups. One of the key cardiac currents, the L-type calcium current (I_CaL) was significantly downregulated in primary diseased (SMD = −1.07; I² = 88%; CI = −1.94 to −0.20; p < 0.0001) and secondary AF groups (SMD = −1.28; I² = 91%; CI = −2.04 to −0.52; p < 0.0001). Furthermore, the sodium–calcium exchanger (I_NCX) and NCX1 protein expression were significantly enhanced in the primary diseased group, while only NCX1 protein expression was shown to increase in the secondary AF studies. The phosphorylation of the ryanodine receptor at S2808 (pRyR-S2808) was significantly elevated in both the primary and secondary groups. It was increased in the primary diseased and proarrhythmic subgroups (SMD = 0.95; I² = 64%; CI = 0.12–1.79; p = 0.074) and secondary AF group (SMD = 0.66; I² = 63%; CI = 0.01–1.31; p < 0.0001). Sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA) expression was elevated in the primary diseased and proarrhythmic drug subgroups but substantially reduced in the secondary paroxysmal AF subgroup.

Conclusions: Our study identified that I_CaL is reduced in both the primary and secondary diseased groups. Furthermore, pRyR-S2808 and NCX1 protein expression are enhanced. The remodeling leads to elevated Ca²⁺ functional activities, such as increased frequencies or amplitude of Ca²⁺ spark and Ca²⁺ transient. The main difference identified between the primary and secondary diseased groups is SERCA expression, which is elevated in the primary diseased group and substantially reduced in the secondary paroxysmal AF subgroup. We believe our study will add new evidence to AF mechanisms and treatment targets.

Quercetin prevents isoprenaline-induced myocardial fibrosis by promoting autophagy via regulating miR-223-3p/FOXO3

Atrial fibrillation (AF) is the common arrhythmias. Myocardial fibrosis (MF) is closely related to atrial remodeling and leads to AF. MF is the main cause of cardiovascular diseases and a pathological basis of AF. Thus, the underlying mechanism in MF and AF development should be fully elucidated for AF therapeutic innovation. Autophagy is a highly conserved lysosomal degradation pathway, and the relationship between autophagy and MF has been previously shown. Moreover, research reported that quercetin (Que) could ameliorate MF. The current study aimed to explore the mechanism of Que in MF. The results in this study showed that in clinical AF patients and in aged rats, miR-223-3p was high-expressed, while FOXO3 and autophagy pathway related proteins, such as ATG7, p62/SQSTM1 and the ratio of LC3B-II/LC3B-I were significantly inhibited. In vivo and in vitro studies, we found that Que can effectively inhibit the expression of miR-223-3p in AF model cells and rats myocardial tissues, and meanwhile enhance the expression of FOXO3 and activate the autophagy pathway, and significantly inhibit myocardial fibrosis, and improve myocardial remodeling in atrial fibrillation. All in all, in this study, we found that Que prevents isoprenaline-induced MF by increasing autophagy via regulating miR-223-3p/FOXO3.

Recognition, Prevention, and Management of Arrhythmias and Autonomic Disorders in Cardio-Oncology: A Scientific Statement From the American Heart Association

With the advent of novel cancer therapeutics and improved screening, more patients are surviving a cancer diagnosis or living longer with advanced disease. Many of these treatments have associated cardiovascular toxicities that can manifest in both an acute and a delayed fashion. Arrhythmias are an increasingly identified complication with unique management challenges in the cancer population. The purpose of this scientific statement is to summarize the current state of knowledge regarding arrhythmia identification and treatment in patients with cancer. Atrial tachyarrhythmias, particularly atrial fibrillation, are most common, but ventricular arrhythmias, including those related to treatment-induced QT prolongation, and bradyarrhythmias can also occur. Despite increased recognition, dedicated prospective studies evaluating true incidence are lacking. Moreover, few studies have addressed appropriate prevention and treatment strategies. As such, this scientific statement serves to mobilize the cardio-oncology, electrophysiology, and oncology communities to develop clinical and scientific collaborations that will improve the care of patients with cancer who have arrhythmias.

RIPK3-Mediated Necroptosis in Diabetic Cardiomyopathy Requires CaMKII Activation

Activation of Ca²⁺/calmodulin-dependent protein kinase (CaMKII) has been proved to play a vital role in cardiovascular diseases. Receptor-interaction protein kinase 3- (RIPK3-) mediated necroptosis has crucially participated in cardiac dysfunction. The study is aimed at investigating the effect as well as the mechanism of CaMKII activation and necroptosis on diabetic cardiomyopathy (DCM). Wild-type (WT) and the RIPK3 gene knockout (RIPK3^−/−) mice were intraperitoneally injected with 60 mg/kg/d streptozotocin (STZ) for 5 consecutive days. After 12 w of feeding, 100 μL recombinant adenovirus solution carrying inhibitor 1 of protein phosphatase 1 (I1PP1) gene was injected into the caudal vein of mice. Echocardiography, myocardial injury, CaMKII activity, necroptosis, RIPK1 expression, mixed lineage kinase domain-like protein (MLKL) phosphorylation, and mitochondrial ultrastructure were measured. The results showed that cardiac dysfunction, CaMKII activation, and necroptosis were aggravated in streptozotocin- (STZ-) stimulated mice, as well as in (Lepr) KO/KO (db/db) mice. RIPK3 deficiency alleviated cardiac dysfunction, CaMKII activation, and necroptosis in DCM. Furthermore, I1PP1 overexpression reversed cardiac dysfunction, myocardial injury and necroptosis augment, and CaMKII activity enhancement in WT mice with DCM but not in RIPK3^−/− mice with DCM. The present study demonstrated that CaMKII activation and necroptosis augment in DCM via a RIPK3-dependent manner, which may provide therapeutic strategies for DCM.