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Background: A wide range of cardiac arrhythmias were reported in the setting of active infection or as a complication of COVID-19. The main pathophysiology can be attributed to dysautonomia or autonomic nervous system dysfunction. Postural orthostatic tachycardia syndrome (POTS) is a complex, multisystemic disorder affecting usually younger age with tachycardia at rest or with minimal effort being the main symptom. Data regarding the safety and efficacy of ivabradine in POTS treatment is limited to small studies and case reports., Methods: This prospective observational study included a total of 55 COVID-19-associated POTS patients after the exclusion of other causes of tachycardia. Ivabradine 5 mg twice daily was initiated. Re-assessment of patients' symptoms, heart rate, and heart rate variability (HRV) parameters' changes after 3 days of ivabradine therapy was done., Results: The mean age of the included patients was 30.5±6.9 years with 32 patients being males (58.2%). 43 of 55 (78%) of the included patients reported significant improvement of the symptoms within 7 days of ivabradine therapy. 24-hour heart rate (minimum, average, and maximum) was significantly lower ( p -value < 0.0001*, = 0.001*, < 0.0001* consecutively) with a significant difference in HRV time-domain parameters (SDNN, rMSSD) ( p -value < 0.0001*) after ivabradine therapy., Conclusion: In a prospective study that evaluated the effects of ivabradine in post-COVID-19 POTS, patients treated with ivabradine reported improvement of their symptoms within 7 days of ivabradine treatment with a significant reduction of 24-hour average, minimum, and maximum heart rate, and improvement of HRV time domains parameters. Ivabradine might be a useful option to relieve symptoms of tachycardia in COVID-19 POTS. Further research is required to confirm the safety and efficacy of ivabradine in POTS treatment., Competing Interests: None., (AJCD Copyright © 2023.)

Background: An increased heart rate (HR) is deleterious in patients with decompensated heart failure. Ivabradine, an HR lowering agent which acts by inhibiting the I f current in the sinoatrial node, is indicated for chronic heart failure with reduced ejection fraction. However, data regarding the safety and efficacy of ivabradine in acute decompensated heart failure is limited. This retrospective observational study aimed to investigate the effects of ivabradine on morbidity and short-term mortality of hospitalized patients with acute decompensated heart failure., Methods: A total of 998 patients with acute decompensated heart failure on top of a chronic status from 1/5/2014 to 1/5/2019 who were already on guideline-directed treatment including a beta-blocker were included. Patients were divided into two groups, the first group (No-ivabradine) where patients continued the same dose of beta-blocker alone while the second group (ivabradine group) ivabradine 5 mg BID was added in addition to the same dose of beta-blocker. Patients with hemodynamic instabilities were excluded from the study. Propensity matching was performed to exclude confounding factors., Results: There was no significant difference between groups regarding baseline patient characteristics, laboratory, and echocardiographic data. There were significant differences between groups regarding average HR (87 ± 15 and 90 ± 12 bpm in ivabradine and control groups, consecutively, P = 0.0006*) and length of hospital stay (5.3 ± 2.3 and 7.7 ± 5.6 days in ivabradine and control groups, consecutively, P < 0.0001*). However, there were no differences in rehospitalization and mortality rates at 1 month and 6 months., Conclusion: In a retrospective cohort study aimed to investigate the effects of ivabradine on morbidity and short-term mortality of hospitalized patients with acute decompensated heart failure. Ivabradine was associated with significantly lower average HR and length of hospital stay. However, there was no benefit in the reduction of rehospitalization and mortality rates at 1- and 6-month follow-ups., Competing Interests: None., (AJCD Copyright © 2023.)

Background: Autonomic malfunction is linked to elevated cardiovascular morbidity and mortality. Various patient characteristics can alter the cardiac autonomic function therefore, using a prospective observational study, we aimed to assess the effects of different clinical and angiographic factors of coronary artery disease (CAD) patients on the cardiac autonomic function evaluated by heart rate variability (HRV) measurement., Methods and Patients: 100 patients undergoing coronary angiography when clinically indicated were enrolled. A short-term 5-minute HRV measurement was performed by CheckMyheart™ handheld HRV device manufactured by DailyCare BioMedical Inc, Taiwan. HRV data were fed to CheckMyheart™ 5-min HRV analysis software and interpreted based on the standard methods for HRV measurement as discussed in the Task Force of the European Society of Cardiology (ESC) and The North American Society of Pacing and Electrophysiology (NAPSE). Coronary angiography was done with an emphasis on SYNTAX (SX) score calculation., Results: The mean age of the recruited patients was 56.89±10.75 years with 85% of them were males and the mean SX score 13.11±8.52. Multivariate regression analysis of the different patient clinical and angiographic characteristics affecting HRV showed that CAD type either single or multi-vessel and SX score were the major independent variables affecting HRV in patients with CAD., Conclusion: The complexity of CAD measured by SX score was the main independent predictor affecting the cardiac autonomic function estimated by HRV measurement., Competing Interests: None., (AJCD Copyright © 2021.)

Objective: To study the effects of coronary revascularization using elective percutaneous coronary intervention (PCI) on autonomic modulation assessed by heart rate variability measurement (HRV) in coronary artery disease (CAD) patients., Methods: A single-center prospective cohort study included 100 patients were included undergoing elective PCI excluding those with contraindication to contrast or dual antiplatelet therapy, atrial fibrillation or multiple premature beats, receiving anti-arrhythmic drugs and those who underwent previous PCI or coronary artery bypass graft (CABG). Short-term measurement of time domain parameters (mean, SDNN, RMSSD) and frequency domain parameters (LF component, HF component, LF/HF ratio) of HRV was performed at the same time of the day, pre-PCI, 24 hours and 6 months post-PCI by CheckMyheart™ handheld HRV device. 5-min HRV analysis software was used to interpret the data using standard methods of HRV measurement of the Task Force of The European Society of Cardiology (ESC) and The North American Society of Pacing and Electrophysiology. SYNTAX (SX) score was calculated before PCI and residual SYNTAX (rSS) score was calculated after PCI using SYNTAX score calculator software., Results: The mean age of the studied population was 56.89±10.75 years with 85% males. HRV time and frequency domain parameters showed a statistically significant improvement at different time intervals (before PCI, 24 hours and 6 months after PCI) ( p -value <0.001). HRV time and frequency domain measures showed a statistically significant difference between time and frequency domain HRV parameters 24 hours and 6 months after PCI in patients who had complete revascularization (CR) with those who had incomplete revascularization (IR). ( p -value <0.001)., Conclusion: Autonomic modulation in CAD patients was improved by coronary revascularization using PCI assessed by serial HRV measurement. Patients with CR had better autonomic modulation than those with IR assessed by HRV 24 and 6 months after PCI., Competing Interests: None., (AJCD Copyright © 2021.)