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Abstract Different rat strains are used in various animal models of pulmonary hypertension and right ventricular (RV) failure. No systematic assessment has been made to test differences in RV response to pressure overload between rat strains. We compared RV adaptation to pulmonary trunk banding (PTB) in Wistar (W), Sprague Dawley (SD), and Fischer344 (F) rats by hemodynamic profiling focusing on diastolic function. Age‐matched male rat weanlings were randomized to sham surgery (W‐sham, n = 5; SD‐sham, n = 4; F‐sham, n = 4) or PTB (W‐PTB, n = 8; SD‐PTB, n = 8; F‐PTB, n = 8). RV function was evaluated after 5 weeks by echocardiography, cardiac MRI, and invasive pressure‐volume measurements. PTB caused RV failure and increased RV systolic pressures four‐fold in all three PTB groups compared with sham. W‐ and SD‐PTB had a 2.4‐fold increase in RV end‐systolic volume index compared with sham, while F‐PTB rats were less affected. Diastolic and right atrial impairment were evident by increased RV end‐diastolic elastance, filling pressure, and E/e' in PTB rats compared with sham, again F‐PTB the least affected. In conclusions, PTB caused RV failure with signs of diastolic dysfunction. Despite a similar increase in RV systolic pressure, F‐PTB rats showed less RV dilatation and a more preserved diastolic function compared with W‐ and SD‐PTB.

Abstract Aims Impaired myocardial energy homeostasis plays an import role in the pathophysiology of heart failure with preserved ejection fraction (HFpEF). Left ventricular relaxation has a high energy demand, and left ventricular diastolic dysfunction has been related to impaired energy homeostasis. This study investigated whether trimetazidine, a fatty acid oxidation inhibitor, could improve myocardial energy homeostasis and consequently improve exercise haemodynamics in patients with HFpEF. Methods and results The DoPING‐HFpEF trial was a phase II single‐centre, double‐blind, placebo‐controlled, randomized cross‐over trial. Patients were randomized to trimetazidine treatment or placebo for 3 months and switched after a 2‐week wash‐out period. The primary endpoint was change in pulmonary capillary wedge pressure, measured with right heart catheterization at multiple stages of bicycling exercise. Secondary endpoint was change in myocardial phosphocreatine/adenosine triphosphate, an index of the myocardial energy status, measured with phosphorus‐31 magnetic resonance spectroscopy. The study included 25 patients (10/15 males/females; mean (standard deviation) age, 66 (10) years; body mass index, 29.8 (4.5) kg/m2); with the diagnosis of HFpEF confirmed with (exercise) right heart catheterization either before or during the trial. There was no effect of trimetazidine on the primary outcome pulmonary capillary wedge pressure at multiple levels of exercise (mean change 0 [95% confidence interval, 95% CI −2, 2] mmHg over multiple levels of exercise, P = 0.60). Myocardial phosphocreatine/adenosine triphosphate in the trimetazidine arm was similar to placebo (1.08 [0.76, 1.76] vs. 1.30 [0.95, 1.86], P = 0.08). There was no change by trimetazidine compared with placebo in the exploratory parameters: 6‐min walking distance (mean change of −6 [95% CI −18, 7] m vs. −5 [95% CI −22, 22] m, respectively, P = 0.93), N‐terminal pro‐B‐type natriuretic peptide (5 (−156, 166) ng/L vs. −13 (−172, 147) ng/L, P = 0.70), overall quality‐of‐life (KCCQ and EQ‐5D‐5L, P = 0.78 and P = 0.51, respectively), parameters for diastolic function measured with echocardiography and cardiac magnetic resonance, or metabolic parameters. Conclusions Trimetazidine did not improve myocardial energy homeostasis and did not improve exercise haemodynamics in patients with HFpEF.

Abstract This article examines technical use of Fitbit during an intervention for pulmonary hypertension (PAH)‐patients. Technical issues with the device led to data being unavailable(37.5%). During intervention objective daily physical activity (DPA) decreased and subjective DPA increased. This emphasizes that an assessment of DPA in PAH requires incorporating both objective and subjective measurements.

Abstract Titin‐dependent stiffening of cardiomyocytes is a significant contributor to left ventricular (LV) diastolic dysfunction in heart failure with preserved LV ejection fraction (HFpEF). Small heat shock proteins (HSPs), such as HSPB5 and HSPB1, protect titin and administration of HSPB5 in vitro lowers cardiomyocyte stiffness in pressure‐overload hypertrophy. In humans, oral treatment with geranylgeranylacetone (GGA) increases myocardial HSP expression, but the functional implications are unknown. Our objective was to investigate whether oral GGA treatment lowers cardiomyocyte stiffness and attenuates LV diastolic dysfunction in a rat model of the cardiometabolic syndrome. Twenty‐one‐week‐old male lean (n = 10) and obese (n = 20) ZSF1 rats were studied, and obese rats were randomized to receive GGA (200 mg/kg/day) or vehicle by oral gavage for 4 weeks. Echocardiography and cardiac catheterization were performed before sacrifice at 25 weeks of age. Titin‐based stiffness (Fpassive) was determined by force measurements in relaxing solution with 100 nM [Ca2+] in permeabilized cardiomyocytes at sarcomere lengths (SL) ranging from 1.8 to 2.4 μm. In obese ZSF1 rats, GGA reduced isovolumic relaxation time of the LV without affecting blood pressure, EF or LV weight. In cardiomyocytes, GGA increased myofilament‐bound HSPB5 and HSPB1 expression. Vehicle‐treated obese rats exhibited higher cardiomyocyte stiffness at all SLs compared to lean rats, while GGA reduced stiffness at SL 2.0 μm. In obese ZSF1 rats, oral GGA treatment improves cardiomyocyte stiffness by increasing myofilament‐bound HSPB1 and HSPB5. GGA could represent a potential novel therapy for the early stage of diastolic dysfunction in the cardiometabolic syndrome.

Hyperventilation is common in pulmonary arterial hypertension and may be related to autonomic imbalance. Patients underwent exercise testing and hyperoxic breathing before and after bisoprolol treatment. We found that neither beta blocker treatment nor hyperoxic breathing in patients reduced hyperventilation at rest and during exercise, although it reduced heart rate.

Abstract Nutritional deficiencies have been described in patients with pulmonary arterial hypertension (PAH), such as in iron and vitamin D. However, an extensive description of vitamin and mineral status is lacking and until now there is no data on dietary intake in PAH patients. We analyzed blood samples and determined nutritional intake using a food frequency questionnaire (HELIUS) in a cohort of prevalent PAH patients at a single center in Amsterdam, the Netherlands. Quality of life (QoL) was assessed by the SF‐36 questionnaire. In total, 37 patients were included (6 males, 31 females; 48 ± 16 years). The dietary intake of sugar was above 25 g in 87% of the patients and fluid intake was above 1500 ml in 78% of the patients. Sodium intake was below 1800 mg in the majority (56%) of the patients. Sugar and fluid intake were linear related. We confirm previously observed deficiencies of iron and vitamin D in our study population. In addition, we observed a functional vitamin B12 deficiency in 29% of patients, which coincided with an increased expression of methylmalonic acid. 60% of patients had a low vitamin K1 status (