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Background: Type 2 long QT syndrome (LQT2) is an inherited arrhythmia syndrome caused by pathogenic variants in the KCNH2 gene which result in QT prolongation and confers susceptibility to arrhythmic syncope/seizures and sudden cardiac arrest/death. Oral progestin-based contraceptives increase the risk of cardiac events in women with LQT2 and we previously reported the case of a LQT2 woman with recurrent cardiac events attributed to the use of the progestin-based contraceptive, Medroxyprogesterone Acetate (“Depo-Provera”, Depo). Objective: To evaluate the arrhythmic-risk of Depo in a LQT2-specific, induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) model. Methods: An iPSC-CM line was generated from the previously reported woman (KCNH2-G1006A*fs) as well as a control line. Voltage-sensing dye was used to assess the optical action potential duration (APD) with 10 μM Depo. 3-D erratic beating patterns were then assessed using multiple electrode array (MEA) with Depo and isoproterenol (ISO) to mimic an adrenergic surge. Results: Addition of Depo to the G1006A*fs iPSC-CMs decreased the optical APD from baseline 438±14 ms (n=6) to 363±35 ms (n=12; p=0.0001). Despite the APD shortening at baseline, in the setting of ISO, Depo administration induced erratic beating patterns in MEA, characterized as alternating spike amplitudes, alternans, or early after depolarization-like phenomena. Combined Depo and ISO treatment increased the percent of electrodes displaying erratic beating in G1006A*fs [baseline 8%±13 vs. Depo + ISO 38%±40 (p=0.0097)] but not in controls [baseline 2%±5 vs. Depo + ISO 7%±11 (p=0.14)]. Neither Depo nor ISO alone changed beating patterns in G1006A*fs [baseline 8%±13, Depo 30%±41 (p=0.08), ISO 21%±30, (p=0.17)] and controls [baseline 2%±5, Depo 3%±7 (p=0.61), ISO 0%±0 (p=0.4)]. Conclusion: This patient-specific, re-engineered heart cell study provides a potential mechanism for the patient’s clinically documented, Depo-associated episodes of recurrent ventricular fibrillation. This in-vitro data should prompt a large-scale clinical assessment of Depo’s potential pro-arrhythmic effect in women with LQT2.

Introduction: Pathogenic variants in PKP2 -encoded plakophilin 2 cause arrhythmogenic right ventricular cardiomyopathy (ARVC). Electrocardiographically, PKP2 -mediated ARVC may mimic RYR2 -mediated catecholaminergic polymorphic ventricular tachycardia (CPVT). We compare the underlying mechanism of arrhythmia in ARVC and CPVT using induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Methods: iPSC-CMs were generated from 2 ARVC patients with different PKP2 variants [E149X (PKP2-1) and c.2146-1G>C (PKP2-2)], 1 patient with a CPVT variant [RyR2-R176Q (CPVT1)], and a wild-type (WT) control. Fluo-4 AM calcium dye was used to assess calcium kinetics in iPSC-CMs before and during treatment with 100 nM isoproterenol (ISO) at 8-10 min. Results: Compared to WT, PKP2 and RYR2 iPSC-CMs had a greater amplitude before (WT: 0.331±0.031, PKP2-1: 1.048±0.074, PKP2-2: 1.076±0.095, CPVT1: 0.966±0.061; P<0.0001) and during ISO (WT: 0.277±0.022, PKP2-1: 0.971±0.069, PKP2-2: 0.622±0.041, CPVT1: 0.756±0.051; P<0.0001). The Ca 2+ transient duration (CTD100) was longer in PKP2 and RYR2 iPSC-CMs compared to WT before (WT: 1.01±0.05 s, PKP2-1: 1.84±0.01 s, PKP2-2: 1.76±0.02 s, CPVT1: 1.81±0.02 s; P<0.0001) and during ISO (WT: 1.38±0.05 s, PKP2-1: 1.65±0.03 s, PKP2-2: 1.71±0.03 s, CPVT1: 1.61±0.05 s; P<0.001). Before (WT: 259±13 ms, PKP2-1: 538±23 ms, PKP2-2: 493±28 ms, CPVT1: 586±24 ms; P<0.0001) and during ISO (WT: 311±19 ms, PKP2-1: 406±21 ms, P=0.0172, PKP2-2: 487±28 ms, P<0.0001, CPVT1: 453±21 ms, P=0.0001), peak to 50% decay time was slower in PKP2 and RYR2 iPSC-CMs compared with WT. Upstroke time was longer in PKP2 and RYR2 iPSC-CMs compared to WT before (WT: 205±5 ms, PKP2-1: 539±13 ms, PKP2-2: 429±19 ms, CPVT1: 455±12 ms; P<0.0001) and during ISO (WT: 213±7 ms, PKP2-1: 375±16 ms, PKP2-2: 416±20 ms, CPVT1: 389±10 ms; P<0.0001). Conclusion: Here, iPSC-CMs, derived from patients with either PKP2 -mediated ARVC or RYR2 -mediated CPVT, display similar abnormal calcium handling properties such as greater amplitude, longer CTD100, and slower peak to 50% decay time and upstroke time compared to WT iPSC-CMs before and during ISO treatment. This may explain why patients with PKP2 -mediated ARVC often mimic the treadmill stress test seen in patients with CPVT1.

Introduction: Physical activity is protective against cardiovascular (CV) disease and mortality, yet more than 25% of adults do not perform any regular exercise. Whole body electronic muscle stimulation (WB-EMS) is a novel FDA-approved device used for physical training that simultaneously stimulates all major muscle groups using percutaneous electrical impulse transmission during exercise. Preliminary studies demonstrated increased muscle mass, reduced fat mass, and improved functional capacity in elderly individuals who trained with WB-EMS. We evaluated the effects of training with WB-EMS on measures of CV health. Methods: Healthy adults were randomized to physical training with versus without WB-EMS for one 20-minute session each week for 16 weeks. Participants wore a specifically designed vest and arm and leg straps connected to the WB-EMS device (Miha Bodytec, Germany). Biphasic electrical stimulation was delivered through the vest and straps (4 sec on, 4 sec off) at a frequency that elicited a score of 5-6 on the Borg perceived exertion scale when each major muscle group was stimulated. Individuals randomized to no WB-EMS wore the same equipment but received no stimulation. Sessions were provided by trainers certified in WB-EMS training and consisted of a fixed protocol of simple exercises such as squats and lunges. Temporal changes in measures of CV health were compared between groups. Results: Forty-one individuals were recruited between 02/2021 and 02/2022 (n=24 WB-EMS, n=17 no WB-EMS; mean age 35.9±11.2 yrs; 61.3% females; median BMI 24.3 (21.8, 28.1) kg/m 2 . After 16 weeks there were significant and favorable differences in the intervention group compared to controls in waist: hip ratio (-1.2 cm vs. 0.9, p=0.05); total cholesterol (-1.1 mg/kg vs. 14.2 mg/kg, p=0.02); anaerobic threshold (68.2% vs. 30.8%, p=0.03); breathing efficiency (VE/VCO2: -10.36 vs -7.38, p=0.01); and peripheral endothelial function, measured with reactive hyperemia peripheral arterial tonometry (-0.009 vs. -0.29, p=0.06). Conclusions: Once weekly training with WB-EMS yielded more favorable changes in CV biomarkers compared to conventional training alone in healthy adults, and thus may offer an effective and time-efficient method of physical training.

Introduction: Hypertension (HTN) represents one of the greatest burdens in human health and is associated with increased morbidity and mortality. Despite the availability of several antihypertensive drugs, most patients have suboptimal blood pressure (BP) control, thus underscoring the need for new therapeutic drugs. The natriuretic peptide receptor A (NPRA) possesses potent vasodilating, natriuretic and diuretic actions via activation by ANP or BNP and generation of its second messenger, cGMP. Recently, we reported the discovery of a small molecule positive allosteric modulator (PAM) for NPRA, MCUF-651, which enhances the ANP/BNP/NPRA/cGMP pathway (PNAS,2021). To date, the in vivo actions of MCUF-651 remains unknown. Here we tested the hypothesis that MCUF-651 would have BP lowering and renal enhancing properties in experimental HTN. Methods: A single IV bolus of MCUF-651 (10mg/kg; n=4) or vehicle (V; n=5) was injected into anesthetized spontaneous hypertensive rats (SHRs). Plasma and urinary cGMP (PcGMP and UcGMP), mean arterial pressure (MAP) and urinary volume (UV) and sodium (UNa) excretion were assessed at baseline (BL) and over 60-mins post-bolus. Results: In SHRs, PcGMP and UcGMP were significantly elevated with MCUF-651 compared to the vehicle group (ΔPcGMP MCUF-651: 16±5, ΔPcGMP V: -2±3, pmol/mL; P =0.003; ΔUcGMP MCUF-651: 78±29, ΔUcGMP V: 30±8, pmol/min, P =0.01), thus supporting NPRA target engagement. Notably, the elevations in cGMP with MCUF-651 were associated with a significant reduction in MAP at 15-mins post bolus compared to vehicle (ΔMAP MCUF-651: -29±14, ΔMAP V: -6±2 mmHg; P =0.04) and this MAP reduction was sustained over 60 mins. Further, UV and UNa excretion were significantly increased, from BL, with MCUF-651 (BL UV: 6 ± 2, 60 mins post bolus UV: 56± 18 μL/min, P <0.001; BL UNa: 1±0.2, 60 mins post bolus UNa: 8±2 μmol/min, P <0.001). Conclusions: We report for the first time that MCUF-651, a novel NPRA small molecule PAM, engages NPRA, increases cGMP and reduces MAP while enhancing sodium and water excretion in experimental HTN. These findings support the development of MCUF-651 as a potential new therapeutic modality to optimize BP lowering goals and reduce adverse outcomes in human HTN.

Introduction: Genome-wide association studies have identified common genetic variants associated with hypertrophic (HCM) and dilated cardiomyopathy (DCM) and left ventricular (LV) characteristics. However, the association of these variants with myocardial fibrosis (MF), an important pathophysiological mediator of cardiomyopathy, is unknown. Hypothesis: We used the Multi-Ethnic Study of Atherosclerosis (MESA), to evaluate the association of these loci with interstitial MF measured by cardiac MRI (CMR). Methods: Unrelated MESA participants with T1-mapping CMR and no history of MI or heart failure were included (n=1,235). We used the extracellular volume (ECV) fraction as a well-established surrogate of interstitial MF. Genotyping was performed by Affymetrix Human SNP array 6.0, and imputation was performed using the TOPMED reference panel. Log ECV(%) was regressed on 50 candidate SNPs, in each ethnicity/race group, adjusting for age, sex, and population stratification principal component. The race-specific results were pooled by fixed-effect meta-analyses using METASOFT. Results: The SMARCB1 rs2186370 intronic variant, previously identified as a risk variant for DCM and HCM, was associated with ECV (p=0.0004). The rs2186370 A allele (frequency: 0.18 in Whites, and 0.50 in African Americans) was associated with a 1.6% increase in ECV. The rs2070458 A allele (another SMARCB1 intronic variant), in complete linkage disequilibrium with rs2186370, was known previously to be associated with increased LV wall thickness, mass, and concentricity. The direction of effect was similar in all four ancestry groups, but the effect was strongest in African Americans. These variants are strong expression quantitative loci (eQTLs) in human LV tissue and are associated with genotype-dependent expression of SMARCB1 ( p =7.3х10 -22 ) and MMP11 ( p =2.5х10 -24 ). Conclusions: In conclusion, variants in two linked SMARCB1 loci previously associated with HCM, DCM and LV traits, are associated with CMR-based interstitial MF. These loci are eQTL not only for SMARCB1 but also for MMP11 an important mediator of MF . These findings underscore the important link between MF and CM, and potentially provide novel mechanistic targets in understanding the development of CM.

Background: Despite major scientific advances in contemporary resuscitation, survival outcome in both in-hospital and out-of-hospital cardiac arrest (CA) patients remain dismal. Objective: How do individuals’ demographic and socioeconomic status, insurance status, and hospital characteristics play a role in survival following CA in patients living with human immunodeficiency virus (PLWH)? Methods: Using the ICD10 codes B20-B24 for HIV and ICD10 code I46 for CA, we queried the national inpatient sample from 2016 to 2019 to identify admission cases of PLWH with CA. Weighted data was analyzed using logistic regression model. Results: Out of 475,910 admissions for PLWH from 2016 to 2019, 4,650 cases had CA. Of these, 3,065 patients died during the course of hospitalization (65.9%). Although mortality rate decreased for both genders over time, the decline was steeper for females (72% in 2016 to 62% in 2019) compared to the males (68% in 2016 to 64% in 2019). Female gender was however associated with an increased odds of death compared to male (OR: 1.2, 95%CI: 1-1.3, p=0.03). Asian or Pacific Islanders were associated with a lower odds ratio for mortality (OR: 0.6, 95%CI: 0.3-1, p=0.04). Additionally, beneficiaries of all the insurance types had higher odds of mortality compared to Medicare beneficiaries (OR between 1.8 and 3). The odds of death decreased with increasing household income (OR between 0.7 and 0.9). Patients admitted to the hospitals of West South Central (OR:1.6) and Pacific Regions (OR:1.7) had a higher mortality rate as had those residing in areas with less than 250,000 populaces (OR: 1.7). Conclusion: Despite declining trend in mortality from CA among hospitalized PLWH, more than 60% of the cases die during their hospital stay. Female gender, lower household income, non-Medicare beneficiaries, and being a resident of smaller size population areas were associated with higher mortality among PLWH hospitalized with CA.

A 41-year-old female with hyperlipidemia presented with typical exertional angina, dyspnea, and pre-syncope of 6 months duration. Physical examination was unremarkable. ECG showed low voltage QRS (Figure A), and Chest CTA was negative for obstructive-CAD, pulmonary emboli, aortic, and lung disease. Cardiac MRI was negative for myocarditis/pericarditis . Resting TTE was unremarkable with normal systolic and diastolic function. NT-Pro BNP, hs-CRP, serum/ urine protein electrophoresis, and free light chains ratio were normal. Regadenoson PET myocardial perfusion test showed a medium-sized area of stress-induced ischemia in mid/apical segments (Figure B) . Resting right heart Cath showed mean RA pressure (9mmHg) and RVEDP (10mmHg), mean PA pressure (19mmHg), and PCWP (15mmHg) with large v-waves, PCWP increased to 28mmHg with limited supine bike exercise, diagnostic of HFpEF (Figure C) . Angiography showed normal coronary arteries while coronary reactivity testing was diagnostic of severe epicardial and microvascular endothelial dysfunction (60% mid/distal LAD constriction and 19% decreased blood flow in response to intracoronary (IC) acetylcholine), and endothelial-independent microvascular dysfunction (coronary flow reserve 2.4 in response to IC adenosine), diagnostic of HFpEF due to coronary endothelial and microvascular disease (Figure D) . The patient’s symptoms improved at 2 weeks follow-up after initiation of furosemide, diltiazem, isosorbide mononitrate, and atorvastatin.

Introduction: Rilonacept reduced pericarditis recurrence in the phase 3 trial RHAPSODY. The long-term extension (LTE) enabled further insights into efficacy, safety, and clinical decision making. Methods: The RHAPSODY run-in (RI) and randomized-withdrawal periods were followed by an LTE that enabled open-label rilonacept treatment up to 24 additional months. A decision at 18 months after the most recent recurrence was based on clinical status at investigator discretion: 1) continue rilonacept on-study, 2) suspend rilonacept for observation or 3) discontinue from the LTE without observation. Endpoints included recurrence and quality of life. Results: In May 2020, 74 of 75 eligible subjects continued to LTE; US subjects (n=45) switched to commercial therapy or discontinued in April 2021 (treatment duration from RI baseline [median; maximum] 18; 27 months). Non-US subjects (n=29) completed the LTE in June 2022 (treatment duration from RI baseline [median; maximum] 27; 33 months). Concomitant oral medications during LTE: 22% NSAIDS, 20% colchicine, 0% corticosteroids, 43% none. Inflammation signs (CRP), RP symptoms (PGIPS), and recurrences were low on-treatment. Before the 18-month decision (n=74), there were 3 investigator-assessed recurrences (0.04 per patient-year). At the 18-month decision (n=52), 64% (n=33) continued rilonacept on-study, 15% (n=8) suspended rilonacept for observation, and 21% (n=11) discontinued the study without observation, of whom 7 switched to commercial rilonacept. There was a 75% recurrence rate (n=6/8) in the off-treatment observation group (median time to event 11.8 [3.7, Not-Estimable (NE)] weeks) but only 1 recurrence in subjects on rilonacept (time to event NE [too few events]) associated with a 4-week interruption; HR 0.018, p<0.0001; Fig 1. Conclusions: Continued rilonacept treatment resulted in continued treatment response, whereas treatment suspension at 18 months may be associated with pericarditis recurrence.

Introduction: Wearable cardiac defibrillators (WCD) have been shown to be effective for detection and treatment of ventricular tachyarrhythmias. However, their efficacy in improving survival or decreasing mortality in patients with newly diagnosed cardiomyopathy (CM) is uncertain. This study reviews the current available evidence. Method: We searched databases since inception to April 2022, without language and year of publication restriction for randomized trials and cohort studies that examined the difference between WCD use and non-use in mortality and survival among patients with ischemic and non-ischemic CM. Two independent investigators screened the abstracts and full texts and extracted the data. Data was analyzed using random effect model. Results: From 603 records identified by a librarian, only 4 randomized trials on WCD use in ischemic CM met the inclusion criteria. One of them was an abstract without any full text published. The total participants were 18,779 of which 2,408 were in the WCD group (mean age 65.12±11.5, 20.7% female) and the rest in control group (mean age 65.45±11.36, 28% female). The adjusted all-cause mortality at 3 months follow up was significantly lower in WCD group (RR 0.32, CI [0.11-0.97], including three studies, 2,360 patients in WCD group and 4,954 in control group) (heterogeneity score I 2 =86%)(figure). Adjusted all-cause mortality at 12 months was also significantly lower in WCD group (RR 0.43, CI [0.25-0.71], two studies, 857 patients in WCD group and 15,566 in control group) (heterogeneity score, I 2 =49%). Only one study reported adjusted risk for arrhythmic death, myocardial infarction, arrhythmia (atrial or ventricular), stroke and hospitalization. In addition, one study reported the difference in cost and healthcare use between the two groups. Conclusion: Our meta-analysis confirms significant reduction in all-cause mortality associated with WCD use in patients with newly diagnosed ischemic cardiomyopathy.

Background: Cardiac proton beam ablation therapy has emerged as a promising tool for catheter-free arrhythmia ablation. The time course of the lesion change was demonstrated in MRI 8 weeks following the ablation; however, the pericardial effusion after the ablation has not been fully analyzed. Objective: The purpose of this study was to evaluate the pericardial effusion after pencil-beam scanned proton therapy on normal myocardium in swine in MRI. Methods: 32 domestic swine were irradiated with pencil-beam scanned proton therapy using irradiation doses of 30/40Gy to the left ventricle (LV) anterior wall, posterior wall, and apex. Each swine was subjected to monthly contrast-enhanced cardiac MRI to evaluate the post-irradiation effects. Results: Moderate to significant pericardial effusion (PE) was observed in 10 swine (31%), starting at 4 weeks, and increasing from 8-16 weeks until 24 weeks. With the exception of one case,, improvement was observed in all animals within a month from when the PE first became moderate or significant. . In the case where the significant PE did not improve, the PE was non-septic and transudate. Clinically, the PE did not cause cardiac tamponade and did not correlate to sudden death. Also, there was no correlation between animals with larger tissue volumes receiving higher dose (more than 20Gy) and the grade of PE . Conclusion: Proton beam radiation caused various grades of pericardial effusion, but in 90% of the animals, it resolved without intervention within a month with no major adverse events.