Lin, Guan‐Ling

Abstract Background Graves' disease (GD) is associated with atrial fibrillation (AF) with a prevalence ranging between 16% and 60%, but its risk factors are not well-defined. We aimed to describe the incidence, risk factors and outcomes of GD-related AF. Methods Patients diagnosed with GD between 2009 and 2019 were included retrospectively. We defined GD-related AF as AF diagnosed within 30 days before or any time after diagnosis of GD. Late onset AF was defined as GD-related AF diagnosed more than 90 days after GD diagnosis. Observed AF events were compared to the expected events in the general population utilizing published data of age and sex-specific rates of AF. Results Of 1371 patients with GD, AF occurred in 139 (10.1%) patients. Late onset AF occurred in 32 (23%), of which 50% had attained euthyroidism. The observed incidence of AF was higher in GD than that expected in the general population (p<0.001), Figure 1. When comparing the incidence of only late AF to that in the general population, late AF still happened more frequently in GD although not achieving statistical significance (p=0.06), Figure 1. Independent risk factors were age [HR 1.05 (1.03–1.06) per year], overt hyperthyroidism [HR 2.71 (1.35–5.44)], and male gender [HR 2.42 (1.57–3.71)] for early AF and age [HR 1.06 (1.02–1.09) per year], BMI [1.07 (1.01–1.12) per unit], COPD [3.33 (1.08–10.27)), heart failure [HR 4.19 (1.39–17.42)], and treatment with thionamide [vs. radioiodine ablation HR 2.94 (1.38–6.27)] for late AF. AF was associated with higher rates of mortality [HR 16.32 (4.66–56.58)], acute coronary syndrome/stable angina events [HR 3.89 (1.23–12.31)], and cardiac hospitalizations [HR 15.39 (8.17–29.00)] when adjusted to age, sex, and previous AF. Conclusion AF occurred in 10.1% of GD patients. Late onset AF is an important entity comprising a quarter of GD-related AF cases and requires surveillance even after restoring euthyroidism. Risk factors for AF in GD are similar to those in general population, although overt hyperthyroidism conferred the highest risk, especially for early AF. Treatment with thionamide was associated with late AF. Funding Acknowledgement Type of funding sources: None.

Abstract Introduction Coronary artery calcification (CAC) is associated with and identifies patients at higher risk of major adverse cardiovascular events (MACE). However, the prevalence, characteristics, and outcomes of cancer patients with CAC on CT before or after chest radiation therapy (RT) are not well addressed. Methods Retrospective cohort study of all breast cancer patients who underwent chest RT at Mayo Clinic Rochester in 2010. All pre-RT CTs were reviewed and the extent of CAC was recorded in addition to history of pre-RT atherosclerotic risk factors (hypertension (HTN), diabetes mellitus (DM), dyslipidemia, and smoking), history of pre-RT cardiovascular disease (CVD), and RT dosage. MACE (sudden cardiac death (SCD), acute coronary syndrome (ACS), and stroke), and CAC progression in follow-up were recorded. CAC extent was quantified before and on 5-year follow-up CT scan in all patients, and a positive change was considered progression. Patients were divided into 2 groups based on the presence of CAC before RT: present (group 1) or absent (group 2). Results Our cohort was comprised of 244 breast cancer patients who received chest RT. A total of 39 patients (16.9%) had evidence of CAC on CT prior to RT. Compared with patients without CAC before RT (n=205), those with CAC before RT were found to be older (71.8±7.7 vs 58.9±11.3, p<0.01), had higher pre-RT history of HTN (84.6% vs 47.8%); p<0.01), DM (20.5% vs 4.4%; p<0.01), dyslipidemia (74.2% vs 40%; p<0.01), CAD (23.1% vs 3.9%; p<0.01), and stroke (7.69% vs 1.45%; p=0.04). Following RT, patients in group 1 were more likely to exhibit ACS (33.3% vs 2.9%; p<0.01), and stroke (22.6% vs 5.2%; p<0.01). Multinomial logistic regression identified pre-RT CAD pre-RT CAC (β=1.01 (0.33–1.69), OR=7.60 (1.93–29.93); p=0.02) pre-RT CAD (β=0.78 (0.06–1.49), OR=4.74 (1.14–19.74); p=0.03) as independent predictors for the development of MACE after RT. Progression in CAC after RT was found in 61.9% of all patients (13/21) who developed MACE. Conclusion MACE in breast cancer patients undergoing RT can be predicted before RT based on the CV risk factor and disease profile. The strongest predictor for MACE, however, is evidence of CAC before RT. These data provide a unique window for the identification and follow-up of breast cancer RT patients who have a risk of MACE. Funding Acknowledgement Type of funding source: None

Abstract Introduction Cardiopulmonary exercise testing (CPET) has an established role in the clinical evaluation of exercise intolerance and in the risk stratification of patients with heart failure. There is limited data assessing its prognostic utility in the evaluation of patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). The predisposition of patients with ARVC for ventricular arrhythmias and sudden cardiac death has led to recommendations for exercise restrictions and limits our understanding of how the impairment in oxygen extraction and cardiac output impact disease progression and outcomes in these patients. Purpose We examined the association between CPET indices and event free survival (time to mortality or cardiac transplantation) in patients with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC). Methods Patients with definite ARVC based on 2010 task force criteria and genetically positive were enrolled into our institutional ARVC registry. 43 patients underwent CPET and have been included in our analyses. Indications for testing included: Evaluation of exercise-induced palpitations/arrhythmias or syncope (37%), pharmacotherapy optimization (28%), heart failure evaluation (19%), and ARVC management decisions (16%). CPET data (peak oxygen consumption (pVO2), respiratory exchange ratio (RER), and ventilatory efficiency (VE/VCO2) were assessed in patients at time of initial evaluation. Median follow-up time was 4.9 years (IQR 9 years). Results 126 patients were studied (age 43.7+ 15 yrs; 41% women; LVEF 57+ 11%; 15% with LVEF <50%) and 43 underwent CPET evaluation. 41 patients (95%) performed at near maximal effort (RER >1) and no fatal events were reported during testing. During the follow up period, the outcome (death or cardiac transplantation) occurred in 31 patients. On Kaplan Meier analysis, pVO2 ≤14 mL/kg/min was associated with worse outcomes (unadjusted p<0.001). Peak oxygen consumption (pVO2) ≤14 mL/kg/min and ventilatory efficiency (VE/VCO2) >34 were associated with shorter event free survival (HR 5.58, p=0.002 and HR 5.56 p=0.005, respectively). After adjusting for age, sex, and right ventricular function, the association between peak oxygen consumption (pVO2) and event free survival remained significant (p=0.02). Conclusions In patients with ARVC, peak oxygen consumption (pVO2) was a prognostic indicator of worse outcomes. Our findings suggest a potential role for pVO2 in disease surveillance and early assessment for advanced heart failure therapies. Figure 1. KM plot pVO2 & event free survival Funding Acknowledgement Type of funding source: Other. Main funding source(s): Mayo Clinic

Abstract Objective QTc interval prolongation can lead to life-threatening complications such as torsade de pointes (TdP), ventricular tachycardia (VT), and sudden cardiac death (SCD). It can occur with various tyrosine kinase inhibitors (TKIs) but comparative analyses on the incidence and complication rates are scarce. We thus conducted a comprehensive analysis of TKI use and QTc prolongation in clinical practice. Methods We retrospectively reviewed the electronic medical records of all cancer patients who were treated with TKI between 01/2005 and 12/2018 at our institution. QTc prolongation was defined as a QTc ≥450 ms or 460 ms among male or female patients, respectively. For each type of TKIs, we determined the administration rate and incidence of QTc interval prolongation. We also studied the frequency of QTc prolongation ≥500 ms, the rate of increase of the QTc interval by ≥60 ms, and the development of complications (VT, TdP, and SCD). Results In the present study, we analyzed the data of 685 cancer patients (431 male and 254 female), including 299 patients with RCC, 188 with chronic leukemia, 55 with acute leukemia, 65 with thyroid cancer, 48 with lung cancer and 39 with GIST. These patients received 902 TKI administrations and QTc prolongation was reported in 1/3 of these (289 administrations). The highest frequency was seen with imatinib, nilotinib, and dasatinib (30, 40 and 50%). Among cases of QTc prolongation, a QTc interval ≥500 ms was documented in 53 (18.3%) and QTc progression ≥60 ms in 72 (25%). Complications were found in 14 cases (5%) including VT in 9, TdP in 2 and SCD in 3 administrations. Table 1 demonstrates the findings for each TKI. Findings for TKIs in all patients Total Prolonged QTc QTc ≥500 QTc progression ≥60 VT SCD TdP Imatinib 165 54 13 10 2 Nilotinib 75 33 8 19 Dasatinib 115 58 10 16 2 1 Sunitinib 134 31 1 2 1 1 Pazopanib 165 36 5 6 2 1 Others 248 77 16 18 2 1 1 Conclusion The current findings suggest that TKI therapy leads to QTc prolongation in 1/3 of patients on average and most commonly with the Bcr-Abl TKIs, imatinib, nilotinib, and dasatinib. While SCD is rare (1%) it can still evolve and in 5% of all QTc prolongations with TKIs are potentially life-threatening. These data support recommendations for serial ECGs in cancer patients undergoing TKI therapy. Acknowledgement/Funding None