Background Malignant ventricular arrhythmia (VA) is a major contributor to sudden cardiac death (SCD) in patients with pulmonary arterial hypertension (PAH)-induced right heart failure (RHF). Recently, dapagliflozin (DAPA), a sodium/glucose cotransporter-2 inhibitor (SGLT2i), has been found to exhibit cardioprotective effects in patients with left ventricular systolic dysfunction. In this study, we examined the effects of DAPA on VA vulnerability in a rat model of PAH-induced RHF. Methods Rats randomly received monocrotaline (MCT, 60 mg/kg) or vehicle via a single intraperitoneal injection. A day later, MCT-injected rats were randomly treated with placebo, low-dose DAPA (1 mg/kg/day), or high-dose (3 mg/kg/day) DAPA orally for 35 days. Echocardiographic analysis, haemodynamic experiments, and histological assessments were subsequently performed to confirm the presence of PAH-induced RHF. Right ventricle (RV) expression of calcium (Ca2+) handling proteins were detected via Western blotting. RV expression of connexin 43 (Cx43) was determined via immunohistochemical staining. An optical mapping study was performed to assess the electrophysiological characteristics in isolated hearts. Cellular Ca2+ imaging from RV cardiomyocytes (RVCMs) was recorded using Fura-2 AM or Fluo-4 AM. Results High-dose DAPA treatment attenuated RV structural remodelling, improved RV function, alleviated Cx43 remodelling, increased the conduction velocity, restored the expression of key Ca2+ handling proteins, increased the threshold for Ca2+ and action potential duration (APD) alternans, decreased susceptibility to spatially discordant APD alternans and spontaneous Ca2+ events, promoted cellular Ca2+ handling, and reduced VA vulnerability in PAH-induced RHF rats. Low-dose DAPA treatment also showed antiarrhythmic effects in hearts with PAH-induced RHF, although with a lower level of efficacy. Conclusion DAPA administration reduced VA vulnerability in rats with PAH-induced RHF by improving RVCM Ca2+ handling.

A majority of existing studies have focused on the efficacy of inhaled long-acting bronchodilators (ILABs), such as long-acting muscarinic antagonists (LAMAs) and long-acting β2–agonists (LABAs), and LABAs combined with LAMAs in treating chronic obstructive pulmonary disease (COPD). The current meta-analysis aimed to investigate the correlation of ILABs with specific cardiovascular adverse events (CAEs). Five electronic databases, including PubMed, Embase, Cochrane Library, Scopus, and Web of Science were systematically retrieved. Finally, 16 randomized controlled trials were enrolled into the current meta-analysis. Typically, the efficacy of 3 major classes of drugs (LABAs, LAMAs, and LABAs combined with LAMAs), and 7 specific drugs (including formoterol, glycopyrrolate, indacaterol, olodaterol, Salmeterol, tiotropium, and vilanterol) for 4 CAEs, including myocardial infarction, cardiac failure (CF), ischemic heart disease (IHD), and stroke in stable COPD patients, was examined. All the pooled results were analyzed through the odds ratios (ORs) with the corresponding 95% confidence intervals (CIs). The direct meta-analysis results suggested that LABAs could increase the risk of CF in patients with stable COPD compared with placebo controls (OR 1.70, 95% CI, 1.00–2.90). In addition, network meta-analysis results indicated that LAMAs combined with LABAs would result in an increased risk of CF in patients with stable COPD (OR 2.31, 95% CI, 1.10–5.09). According to the ILABs specific drug analysis, formoterol may potentially have protective effects on IHD compared with placebo controls (OR 0.45, 95% CI, 0.18–1.00). In conclusion, among these 3 kinds of ILABs, including LAMAs, LABAs, and LABAs/LAMAs, for stable COPD patients, LAMAs and LABAs are associated with the least possibility to induce myocardial infarction and stroke, respectively. However, the application of LABAs will probably increase the risk of CF; they should be used with caution for stable COPD patients with CF. In addition, in specific-drug analysis, the use of formoterol can reduce the risk of treatment-related IHD. Nevertheless, more studies on different drug doses are needed in the future to further validate this conclusion.

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