5-FU Cardiotoxicity: Vasospasm, Myocarditis, and Sudden Death

PURPOSE OF REVIEW

5-fluorouracil (5-FU) is one of the most common causes of cardiotoxicity associated with chemotherapy. The manifestations of 5-FU cardiotoxicity are diverse, and there are no established clinical guidelines addressing the diagnosis and management of this condition. Here we summarize the mechanistic and clinical data available to guide clinicians in caring for patients with suspected 5-FU cardiotoxicity.

RECENT FINDINGS

The decision to resume 5-FU treatment in patients with suspected cardiovascular toxicity remains challenging. Testing for predisposing genetic variants may be helpful, particularly in patients with other signs of 5-FU toxicity. Uridine triacetate is a recently approved antidote that can improve clinical outcomes in patients with life-threatening fluoropyrimidine cardiotoxicity. 5-FU cardiotoxicity remains poorly understood, with limited mechanistic or prospective clinical trial data available to define risk factors or effective management strategies. Risk stratification and therapeutic decisions should be individualized, based on the risk-benefit ratio of continuing 5-FU therapy for each patient.

Zebrafish Models of Cancer Therapy-Induced Cardiovascular Toxicity

Purpose of review: Both traditional and novel cancer therapies can cause cardiovascular toxicity in patients. In vivo models integrating both cardiovascular and cancer phenotypes allow for the study of on- and off-target mechanisms of toxicity arising from these agents. The zebrafish is the optimal whole organism model to screen for cardiotoxicity in a high throughput manner, while simultaneously assessing the role of cardiotoxicity pathways on the cancer therapy’s antitumor effect. Here we highlight established zebrafish models of human cardiovascular disease and cancer, the unique advantages of zebrafish to study mechanisms of cancer therapy-associated cardiovascular toxicity, and finally, important limitations to consider when using the zebrafish to study toxicity. Recent findings: Cancer therapy-associated cardiovascular toxicities range from cardiomyopathy with traditional agents to arrhythmias and thrombotic complications associated with newer targeted therapies. The zebrafish can be used to identify novel therapeutic strategies that selectively protect the heart from cancer therapy without affecting antitumor activity. Advances in genome editing technology have enabled the creation of several transgenic zebrafish lines valuable to the study of cardiovascular and cancer pathophysiology. Summary: The high degree of genetic conservation between zebrafish and humans, as well as the ability to recapitulate cardiotoxic phenotypes observed in patients with cancer, make the zebrafish an effective model to study cancer therapy-associated cardiovascular toxicity. Though this model provides several key benefits over existing in vitro and in vivo models, limitations of the zebrafish model include the early developmental stage required for most high-throughput applications.

Niacinamide May Be Associated with Improved Outcomes in COVID-19-Related Acute Kidney Injury: An Observational Study

Background

AKI is a significant complication of coronavirus disease 2019 (COVID-19), with no effective therapy. Niacinamide, a vitamin B3 analogue, has some evidence of efficacy in non-COVID-19-related AKI. The objective of this study is to evaluate the association between niacinamide therapy and outcomes in patients with COVID-19-related AKI.

Methods

We implemented a quasi-experimental design with nonrandom, prospective allocation of niacinamide in 201 hospitalized adult patients, excluding those with baseline eGFR <15 ml/min per 1.73 m² on or off dialysis, with COVID-19-related AKI by Kidney Disease Improving Global Outcomes (KDIGO) criteria, in two hospitals with identical COVID-19 care algorithms, one of which additionally implemented treatment with niacinamide for COVID-19-related AKI. Patients on the niacinamide protocol (B3 patients) were compared against patients at the same institution before protocol commencement and contemporaneous patients at the non-niacinamide hospital (collectively, non-B3 patients). The primary outcome was a composite of death or RRT.

Results

A total of 38 out of 90 B3 patients and 62 out of 111 non-B3 patients died or received RRT. Using multivariable Cox proportional hazard modeling, niacinamide was associated with a lower risk of RRT or death (HR, 0.64; 95% CI, 0.40 to 1.00; P=0.05), an association driven by patients with KDIGO stage-2/3 AKI (HR, 0.29; 95% CI, 0.13 to 0.65; P=0.03; P interaction with KDIGO stage=0.03). Total mortality also followed this pattern (HR, 0.17; 95% CI, 0.05 to 0.52; in patients with KDIGO stage-2/3 AKI, P=0.002). Serum creatinine after AKI increased by 0.20 (SEM, 0.08) mg/dl per day among non-B3 patients with KDIGO stage-2/3 AKI, but was stable among comparable B3 patients (+0.01 [SEM, 0.06] mg/dl per day; P interaction=0.03).

Conclusions

Niacinamide was associated with lower risk of RRT/death and improved creatinine trajectory among patients with severe COVID-19-related AKI. Larger randomized studies are necessary to establish a causal relationship.

Outcomes of COVID-19 in Patients With a History of Cancer and Comorbid Cardiovascular Disease

BACKGROUND

Cancer and cardiovascular disease (CVD) are independently associated with adverse outcomes in patients with COVID-19. However, outcomes in patients with COVID-19 with both cancer and comorbid CVD are unknown.

METHODS

This retrospective study included 2,476 patients who tested positive for SARS-CoV-2 at 4 Massachusetts hospitals between March 11 and May 21, 2020. Patients were stratified by a history of either cancer (n=195) or CVD (n=414) and subsequently by the presence of both cancer and CVD (n=82). We compared outcomes between patients with and without cancer and patients with both cancer and CVD compared with patients with either condition alone. The primary endpoint was COVID-19-associated severe disease, defined as a composite of the need for mechanical ventilation, shock, or death. Secondary endpoints included death, shock, need for mechanical ventilation, need for supplemental oxygen, arrhythmia, venous thromboembolism, encephalopathy, abnormal troponin level, and length of stay.

RESULTS

Multivariable analysis identified cancer as an independent predictor of COVID-19-associated severe disease among all infected patients. Patients with cancer were more likely to develop COVID-19-associated severe disease than were those without cancer (hazard ratio [HR], 2.02; 95% CI, 1.53-2.68; P<.001). Furthermore, patients with both cancer and CVD had a higher likelihood of COVID-19-associated severe disease compared with those with either cancer (HR, 1.86; 95% CI, 1.11-3.10; P=.02) or CVD (HR, 1.79; 95% CI, 1.21-2.66; P=.004) alone. Patients died more frequently if they had both cancer and CVD compared with either cancer (35% vs 17%; P=.004) or CVD (35% vs 21%; P=.009) alone. Arrhythmias and encephalopathy were also more frequent in patients with both cancer and CVD compared with those with cancer alone.

CONCLUSIONS

Patients with a history of both cancer and CVD are at significantly higher risk of experiencing COVID-19-associated adverse outcomes. Aggressive public health measures are needed to mitigate the risks of COVID-19 infection in this vulnerable patient population.

Predictors of steroid-refractory immune checkpoint inhibitor associated myocarditis

Background/Introduction

Immune checkpoint inhibitor (ICI)-associated myocarditis has a high mortality rate of approximately 50%. Clinical decompensation often occurs despite first-line treatment with corticosteroids. Factors associated with steroid failure are currently unknown.

Purpose

To identify predictors of steroid failure in patients with ICI-associated myocarditis.

Methods

We developed a web-based registry to collect and study 157 cases with clinical manifestations of ICI-associated myocarditis across 16 countries. Steroid failure was defined as patients who were escalated to immunomodulators after ≥1mg/kg daily dose of prednisone or had in-hospital death due to myocarditis despite ≥1mg/kg daily dose of prednisone. Steroid response was defined as all other patients treated with steroids without escalation to immunomodulators and without death due to myocarditis. A multivariate logistic model accounting for age and sex was used to predict association with steroid failure.

Results

Compared to steroid responsive cases, steroid failure was more likely to result in fulminant myocarditis (56.7% vs 19.6%, OR=5.37 [2.62–10.98] p&lt;0.001) and all-cause in-hospital mortality (49.1% vs 12.9%, OR=6.50 [2.86–14.73] p&lt;0.001) with shorter time from presentation to death (27.5 vs 43.0 days HR: 2.56 [1.45–4.50] p=0.001). When adjusting for age and sex, cases were more likely to be steroid-refractory if they were female (46.7% vs 30.1%, OR=2.77 [1.31–5.85] p=0.007), higher body mass index (27.2 vs 22.0, OR=1.09 [1.01–1.18] p=0.012), had higher intake creatine kinase (2800.5 vs 528.0 U/L, OR=1.48 [1.14–1.90] p=0.003) had higher intake troponin T (1.40 vs 0.25 ng/mL OR=1.63 [1.00–2.64] p=0.049), or had one or more concomitant non-cardiac immune-related adverse event (90.0% vs 74.2%, OR=3.10 [1.14–8.25] p&lt;0.026). The only immune-related adverse events independently associated with steroid failure in myocarditis were myasthenia gravis-like syndrome (26.7% vs 8.2%, OR=3.84 [1.47–10.10] p=0.006) and myositis (45.0% vs 24.7%, OR=2.38 [1.16–4.92] p=0.018). Steroid failure was not significantly associated with cardiovascular or autoimmune history but was associated with a history of thymoma (12.0% vs 2.6%, OR=18.86 [0.10–356.7] p=0.05)

Conclusion(s)

Features such as female sex, high body mass index, and pre-existing thymoma as well as findings of elevated cardiac biomarkers and other non-cardiac immune-related adverse events – particularly myositis and myasthenia gravis-like syndrome – may represent a steroid-refractory phenotype of ICI-associated myocarditis. These results suggest that a multidisciplinary approach to diagnosing concomitant non-cardiac immune related adverse events is key to risk-stratifying ICI-associated myocarditis.

Forrest Plot

Funding Acknowledgement

Type of funding source: Private hospital(s). Main funding source(s): National Institutes of Health

Management of Cardiovascular Disease During Coronavirus Disease (COVID-19) Pandemic

Patients with pre-existing cardiovascular disease and risk factors are more likely to experience adverse outcomes associated with the novel coronavirus disease-2019 (COVID-19). Additionally, consistent reports of cardiac injury and de novo cardiac complications, including possible myocarditis, arrhythmia, and heart failure in patients without prior cardiovascular disease or significant risk factors, are emerging, possibly due to an accentuated host immune response and cytokine release syndrome. As the spread of the virus increases exponentially, many patients will require medical care either for COVID-19 related or traditional cardiovascular issues. While the COVID-19 pandemic is dominating the attention of the healthcare system, there is an unmet need for a standardized approach to deal with COVID-19 associated and other traditional cardiovascular issues during this period. We provide consensus guidance for the management of various cardiovascular conditions during the ongoing COVID-19 pandemic with the goal of providing the best care to all patients and minimizing the risk of exposure to frontline healthcare workers.

Changes in Citric Acid Cycle and Nucleoside Metabolism Are Associated with Anthracycline Cardiotoxicity in Patients with Breast Cancer

Anthracyclines and HER2-targeted antibodies are very effective for the treatment of breast cancer, but their use is limited by cardiotoxicity. In this nested case-control study, we assessed the role of intermediary metabolism in 38 women with breast cancer treated with anthracyclines and trastuzumab. Using targeted mass spectrometry to measure 71 metabolites in the plasma, we identified changes in citric acid and aconitic acid that differentiated patients who developed cardiotoxicity from those who did not. In patients with cardiotoxicity, the magnitude of change in citric acid at three months correlated with the change in left ventricular ejection fraction (LVEF) and absolute LVEF at nine months. Patients with cardiotoxicity also demonstrated more pronounced changes in purine and pyrimidine metabolism. Early metabolic changes may therefore provide insight into the mechanisms associated with the development of chemotherapy-associated cardiotoxicity.

Cardioprotection in cancer therapy: novel insights with anthracyclines

Anthracyclines are a class of antineoplastic agents that remain critical to modern-day cancer treatment. However, their propensity to cause cardiotoxic effects limits their use and can cause increased morbidity and mortality among patients with cancer. Currently available methods to minimize the impact of anthracycline cardiotoxicity have not been widely successful. While it is largely accepted that the generation of oxygen radicals contributes to the development of anthracycline cardiotoxicity, the exact mechanisms of cardiomyocyte injury remain unclear. In this review, we discuss the current state of basic and translational research on the cardiotoxic mechanisms of anthracyclines that have led to the discovery of new therapeutic targets. Pending validation in patient populations, these recent advances have the potential to be translated into clinical approaches that will minimize anthracycline cardiotoxicity and improve outcomes in cancer survivors.

Gender differences in industry payments among cardiologists

BACKGROUND

There is a wage gap among men and women practicing cardiology. Differences in industry funding can be both a consequence of and a contributor to gender differences in salaries. We sought to determine whether gender differences exist in the distribution, types, and amounts of industry payments among men and women in cardiology.

METHODS

In this cross-sectional analysis, we used the Centers for Medicare & Medicaid Services Open Payment program database to obtain 2016 industry payment data for US cardiologists. We also used UK Disclosure data to obtain 2016 industry payments to UK cardiologists. Outcomes included the proportions of male and female cardiologists receiving industry funding and the mean industry payment amounts received by male and female cardiologists. Where possible, we also assessed 2014 and 2015 data in both locations.

RESULTS

Of the 22,848 practicing Centers for Medicare & Medicaid Services US cardiologists in 2016, 20,037 (88%) were men and 2,811 (12%) were women. Proportionally more men than women received industry payments in 2016 (78.0% vs 68.5%, respectively; P < .001). Men received higher overall mean industry payments than women ($6,193.25 vs. $2,501.55, P < .001). Results were similar in 2014 and 2015. Among UK cardiologists, more men (24.4%) than women (13.5%) received industry payments in 2016 (P < .001). However, although the difference in overall industry payments was numerically larger among men compared to women, this did not achieve statistical significance (£2,348.31 vs £1,501.37, respectively, P = .35).

CONCLUSIONS

Industry payments to cardiologists are common, and there are gender differences in these payments on both sides of the Atlantic.

Cyp1 Inhibition Prevents Doxorubicin-Induced Cardiomyopathy in a Zebrafish Heart-Failure Model

Doxorubicin is a highly effective chemotherapy agent used to treat many common malignancies. However, its use is limited by cardiotoxicity, and cumulative doses exponentially increase the risk of heart failure. To identify novel heart failure treatment targets, a zebrafish model of doxorubicin-induced cardiomyopathy was previously established for small-molecule screening. Using this model, several small molecules that prevent doxorubicin-induced cardiotoxicity both in zebrafish and in mouse models have previously been identified. In this study, exploration of doxorubicin cardiotoxicity is expanded by screening 2271 small molecules from a proprietary, target-annotated tool compound collection. It is found that 120 small molecules can prevent doxorubicin-induced cardiotoxicity, including 7 highly effective compounds. Of these, all seven exhibited inhibitory activity towards cytochrome P450 family 1 (CYP1). These results are consistent with previous findings, in which visnagin, a CYP1 inhibitor, also prevents doxorubicin-induced cardiotoxicity. Importantly, genetic mutation of cyp1a protected zebrafish against doxorubicin-induced cardiotoxicity phenotypes. Together, these results provide strong evidence that CYP1 is an important contributor to doxorubicin-induced cardiotoxicity and highlight the CYP1 pathway as a candidate therapeutic target for clinical cardioprotection.

A small-molecule allosteric inhibitor of BAX protects against doxorubicin-induced cardiomyopathy

Doxorubicin remains an essential component of many cancer regimens, but its use is limited by lethal cardiomyopathy, which has been difficult to target, owing to pleiotropic mechanisms leading to apoptotic and necrotic cardiac cell death. Here we show that BAX is rate-limiting in doxorubicin-induced cardiomyopathy and identify a small-molecule BAX inhibitor that blocks both apoptosis and necrosis to prevent this syndrome. By allosterically inhibiting BAX conformational activation, this compound blocks BAX translocation to mitochondria, thereby abrogating both forms of cell death. When co-administered with doxorubicin, this BAX inhibitor prevents cardiomyopathy in zebrafish and mice. Notably, cardioprotection does not compromise the efficacy of doxorubicin in reducing leukemia or breast cancer burden in vivo, primarily due to increased priming of mitochondrial death mechanisms and higher BAX levels in cancer cells. This study identifies BAX as an actionable target for doxorubicin-induced cardiomyopathy and provides a prototype small-molecule therapeutic.

Abstract P5-14-06: Statins to mitigate cardiotoxicity in breast cancer patients treated with anthracyclines and/or trastuzumab: A systematic review and meta-analysis

Background: Due to advances in treatment and early detection, nearly 90% of women with breast cancer are living at least 5 years following their diagnosis. Yet, there is a risk for cardiotoxicity as a result of cancer treatments such as anthracyclines and/or trastuzumab. Recent evidence has demonstrated the potential for statins to mitigate the risk of cardiotoxicity. This systematic review and meta-analysis was aimed to address the research question of: Does statin use lower the risk of cardiotoxicity among breast cancer patients who receive treatment with anthracyclines and/or trastuzumab? Methods: A systematic review of the literature was conducted using the databases PubMed, Embase, Web of Science, ClinicalTrials.gov, and Cochrane Central. Two reviewers independently performed study selection and data extraction. Five studies were identified, of which only one was a prospective randomized controlled trial; all examined statin use among breast cancer patients treated with anthracyclines and/or trastuzumab; four studies examined the primary outcome of cardiotoxicity defined as 1) incidence of heart failure or 2) having a reduction in left ventricular ejection fraction of &gt;10% from baseline to an absolute value of &lt;50%; and three studies included the secondary outcome of mean change in left ventricular ejection fraction from baseline (before statin use) to the time of collected outcome. Pooled relative risks and weighted mean differences using study-specific estimates were calculated, and a random-effects model using inverse variance weighting was applied. Results: Data were available on 890 patients (two studies also included gastric cancer, leukemia, and lymphoma), all treated with anthracyclines and/or trastuzumab. For the primary outcome of cardiotoxicity, there was a decreased risk of cardiotoxicity in patients treated with statins versus control (6.85% vs 13.89%, relative risk of 0.49 (95% CI 0.31 to 0.79), p = 0.003). For the secondary outcome, there was a smaller decline in left ventricular ejection fraction from baseline among statin users compared to controls with risk difference of 5.35% (95% CI 2.48 to 8.21), p &lt; 0.001. Sensitivity analyses in studies restricted to breast cancer patients showed consistent results. Conclusions: Statins are associated with decreased overall risk of cardiotoxicity and mitigate changes in left ventricular ejection fraction among cancer patients treated with anthracyclines and/or trastuzumab. While small sample sizes and retrospective design for most studies are a limitation of this meta-analyses and further research is warranted, statin use is a potential solution to mitigate cardiotoxicity from breast cancer treatment.

Citation Format: Jacqueline B Vo, Arielle Abovich, Mary Obasi, Yawen Gao, Anju Nohria, Aarti Asnani, Ann H Partridge. Statins to mitigate cardiotoxicity in breast cancer patients treated with anthracyclines and/or trastuzumab: A systematic review and meta-analysis [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-14-06.

Fluoropyrimidine-Associated Cardiotoxicity: A Retrospective Case-Control Study

BACKGROUND

The fluoropyrimidines, 5-fluorouracil (5-FU) and capecitabine, are commonly used chemotherapeutic agents that have been associated with coronary vasospasm.

METHODS

In this retrospective case-control study, we identified patients at our institution who received 5-FU or capecitabine in 2018. We compared characteristics of patients who experienced cardiotoxicity with controls. We described phenotypes and outcomes of cardiotoxic cases.

RESULTS

We identified 177 patients who received fluoropyrimidines. After adjudication, 4.5% of the cohort met the criteria for cardiovascular toxicity. Coronary artery disease was more common among cases than controls (38% vs. 7%, p < .05). There was also a trend toward increased prevalence of cardiovascular risk factors in cases compared with controls. Most cardiotoxic cases had chest pain, although a minority of cases presented with nonischemic cardiomyopathy.

CONCLUSION

Cardiotoxicity phenotypes associated with fluoropyrimidine use are not limited to coronary vasospasm. Cardiac risk factors and ischemic heart disease were highly prevalent among patients with cardiotoxicity.

Fluoropyrimidine-Associated Cardiotoxicity

Fluoropyrimidines are chemotherapeutic agents that confer great benefit to many patients with solid tumors, but their use is often limited by cardiotoxicity. The incidence and precise mechanisms of cardiotoxicity remain uncertain. Clinical presentations of fluoropyrimidine toxicity are varied and include chest pain, myocardial infarction, acute cardiomyopathy, arrhythmia, cardiogenic shock, and sudden cardiac death. Proposed mechanisms include coronary vasospasm, coronary endothelial dysfunction, direct myocardial toxicity, myocarditis, and Takotsubo cardiomyopathy. Therapeutic and prophylactic interventions primarily target coronary vasospasm as the underlying cause. Prospective studies are needed to develop evidence-based approaches to cardioprotection in patients receiving fluoropyrimidines.

A novel network-based approach for discovering dynamic metabolic biomarkers in cardiovascular disease

Metabolic biomarkers may play an important role in the diagnosis, prognostication and assessment of response to pharmacological therapy in complex diseases. The process of discovering new metabolic biomarkers is a non-trivial task which involves a number of bioanalytical processing steps coupled with a computational approach for the search, prioritization and verification of new biomarker candidates. Kinetic analysis provides an additional dimension of complexity in time-series data, allowing for a more precise interpretation of biomarker dynamics in terms of molecular interaction and pathway modulation. A novel network-based computational strategy for the discovery of putative dynamic biomarker candidates is presented, enabling the identification and verification of unexpected metabolic signatures in complex diseases such as myocardial infarction. The novelty of the proposed method lies in combining metabolic time-series data into a superimposed graph representation, highlighting the strength of the underlying kinetic interaction of preselected analytes. Using this approach, we were able to confirm known metabolic signatures and also identify new candidates such as carnosine and glycocholic acid, and pathways that have been previously associated with cardiovascular or related diseases. This computational strategy may serve as a complementary tool for the discovery of dynamic metabolic or proteomic biomarkers in the field of clinical medicine.

Cardiotoxicities associated with immune checkpoint inhibitors

This review provides an overview of clinical manifestations, diagnostic approaches, and management strategies for cardiotoxicities associated with the use of immune checkpoint inhibitors (ICI). ICI therapy represents a novel treatment modality for advanced-stage malignancies, including melanoma, metastatic renal cell cancer, and non-small cell lung cancers. ICIs have been shown to provide significant mortality benefit and are generally well-tolerated. The major adverse effects associated with ICIs are immune-mediated toxicities, which can affect multiple different organ systems. Immune-mediated cardiotoxicity is quickly gaining recognition as a rare but devastating consequence of ICI therapy. ICI-associated cardiotoxicity can manifest in a variety of ways, including fulminant lymphocytic myocarditis, supraventricular and ventricular arrhythmias, pericardial disease, and even Takotsubo-like cardiomyopathy. While not entirely clear, the primary mechanism of injury has been hypothesized to involve hyperactivation and infiltration of cytotoxic T-cells into cardiovascular tissue. The diagnosis is typically made using cardiac biomarkers and imaging, in conjunction with endomyocardial biopsy when necessary. Treatment options remain limited and generally focus on immunosuppression.

Chest Pain During Chemotherapy: A Case of Severe Myocardial Bridging

A cancer patient presented with acute chest pain at rest 40 hours after IV fluorouracil infusion. Angiography showed evidence of myocardial bridging.

Highly potent visnagin derivatives inhibit Cyp1 and prevent doxorubicin cardiotoxicity

Anthracyclines such as doxorubicin are highly effective chemotherapy agents used to treat many common malignancies. However, their use is limited by cardiotoxicity. We previously identified visnagin as protecting against doxorubicin toxicity in cardiac but not tumor cells. In this study, we sought to develop more potent visnagin analogs in order to use these analogs as tools to clarify the mechanisms of visnagin-mediated cardioprotection. Structure-activity relationship studies were performed in a zebrafish model of doxorubicin cardiomyopathy. Movement of the 5-carbonyl to the 7 position and addition of short ester side chains led to development of visnagin analogs with 1,000-fold increased potency in zebrafish and 250-fold increased potency in mice. Using proteomics, we discovered that doxorubicin caused robust induction of Cytochrome P450 family 1 (CYP1) that was mitigated by visnagin and its potent analog 23. Treatment with structurally divergent CYP1 inhibitors, as well as knockdown of CYP1A, prevented doxorubicin cardiomyopathy in zebrafish. The identification of potent cardioprotective agents may facilitate the development of new therapeutic strategies for patients receiving cardiotoxic chemotherapy. Moreover, these studies support the idea that CYP1 is an important contributor to doxorubicin cardiotoxicity and suggest that modulation of this pathway could be beneficial in the clinical setting.

Management of atrial fibrillation in patients taking targeted cancer therapies

Atrial fibrillation (AF) is frequently observed in patients being treated for cancer and can lead to increased morbidity and mortality in this population. With the use of newer, targeted cancer therapies, several drug-drug interactions have emerged that complicate the use of antiarrhythmic drugs (AADs) in patients with active malignancy. Moreover, specific targeted therapies such as ibrutinib may contribute directly to the development of AF. The decision to pursue systemic anticoagulation can be challenging in patients with malignancy due to a number of factors, including the need for frequent procedures, the presence of malignancy-related risk factors for bleeding, and limited data regarding the safety of the novel oral anticoagulants (NOACs) in cancer patients. This review describes the challenges associated with AF management in patients with cancer and highlights a number of important drug-drug interactions that can impact patient management.

Cardiac Toxicity of Cancer Chemotherapy

With the aging of the population, the number of patients diagnosed with cancer has grown significantly over the past few decades. In parallel, survival rates have improved due to the increased efficacy and tolerability of cancer treatments. As such, the acute and long-term toxicities of cancer therapies have become increasingly prominent as contributors to morbidity and mortality in cancer survivors. Cardiac toxicity can occur with a broad range of cancer treatments, from conventional cytotoxic agents to newer targeted and immune-based therapies. Common manifestations of chemotherapy-associated cardiotoxicity include asymptomatic left ventricular dysfunction, congestive heart failure, myocardial ischemia, myocarditis, QT prolongation, and arrhythmia. In this review, we will describe antitumor agents that have commonly been associated with an increased risk of cardiac toxicity, with an emphasis on clinical manifestations, underlying mechanisms, and cardioprotective strategies that can be implemented in this setting.