Postural orthostatic tachycardia syndrome: pathophysiology, management, and experimental therapies.

INTRODUCTION: Postural orthostatic tachycardia syndrome (POTS) is an increasingly well-recognized condition encountered in clinical practice. Diagnosis and treatment remain extremely challenging. The limited success of currently available therapies has laid the foundation for a number of experimental therapies. AREAS COVERED: In this review, we will briefly outline the pathophysiology and clinical features of this syndrome, before moving on to its management, with a specific focus on experimental pharmacological therapies. Finally, we briefly discuss POTS related to the SARS CoV-2 (COVID-19) pandemic. EXPERT OPINION: Despite tremendous advances, the diagnosis and management of POTS remains extremely challenging. The multitude of contributory mechanisms, which predominate to varying degrees in different patients further complicates management. Improved characterization of pathophysiological phenotypes is essential to individualize management. Lifestyle measures form the first line of therapy, followed by beta-blockers, ivabradine, fludrocortisone, and midodrine. Supplemental therapies such as iron, vitamin D and α lipoic acid are quite safe and a trial of their use is reasonable. The use of erythropoietin, IVIG, desmopressin, etc., are more specialized and nuanced alternatives. In recent years, interest has grown in the use of cardiac neuromodulation. Though preliminary, some of these therapies are quite promising.

Cardiac Arrhythmias and COVID-19: Correlation With Disease Severity.

Background Cardiac arrhythmia is one of the life-threatening cardiovascular complications commonly reported in patients hospitalized with coronavirus disease 2019 (COVID-19). We aimed to evaluate the association between cardiac arrhythmias and disease severity based on oxygen requirement. Methods In this retrospective observational chart review-based study we recruited 396 patients hospitalized with COVID-19 from March 2020 to May 2020 from two regional medical centers in New Jersey, USA. Patients' baseline characteristics, secondary diagnoses, and laboratory findings were manually extracted and compared among two groups: patients with cardiac arrhythmias and those without. Poisson regression analysis was used to evaluate the correlation of cardiac arrhythmias and increased oxygen requirement, which are: room air (RA), nasal cannula (NC), high flow nasal cannula (HFNC), and bi-level positive airway pressure ventilation or invasive mechanical ventilation (BIPAP/MV). Results The demographic characteristics of the patients were: aged 61 +/- 18.7 years (mean +/- standard deviation); with 56% being male, and 44.9% of African American race. There were 16% patients on RA, 40% on NC, 15% on HFNC, and 29% on BIPAP/MV. The incidence of cardiac arrhythmias was 36.7% (20% pulseless electrical activity (PEA), 13.5% atrial fibrillation (AF). 56% of AF was new-onset arrhythmia. Compared to the RA group, the risk of cardiac arrhythmias was significantly higher in BIPAP/MV (OR 3.3; 95% CI 1.8 - 6.2, p <0.001) and HFNC (OR 2.9; 95% CI 1.5-5.7, p0.001), but not in NC group (OR 0.95; 95% CI 0.4-1.8, p0.89). Compared to patients without arrhythmias, patients with arrhythmias were older (mean age 71 vs. 56 years, p <0.001) and had more comorbidities (Charlson comorbidity index (CCI), 4.7 vs. 2.9, p <0.001). The continued therapy of angiotensin-converting enzyme inhibitors or angiotensin-II receptor blockers did not seem to be associated with increased or decreased risk of cardiac arrhythmias. Conclusion The incidence of cardiac arrhythmias among hospitalized COVID-19 patients was 36.7% with PEA being common in patients who succumbed to death, and AF in those patients who survived. The incidence of cardiac arrhythmias positively correlated with disease severity based on oxygen requirement and was higher among patients requiring HFNC or BIPAP/MV.

Outpatient initiation of dofetilide: insights from the complexities of atrial fibrillation management during the COVID-19 lockdown.

BACKGROUND: At peak COVID-19 lockdown, patients with symptomatic atrial fibrillation (AF) were faced with an equipoise between a palliative rate-control versus cautious rhythm-control strategy, including hospitalization for initiation of antiarrhythmic drug/s (AADs) and cardiac procedures which was impossible due to hospitalization restrictions. OBJECTIVES: We aimed to evaluate the efficacy and safety of outpatient initiation of dofetilide in patients with AF using cardiac implantable electronic devices (CIEDs) for rhythm and QTc interval monitoring. METHODS: Adult patients with symptomatic AF with prior failure or intolerance to other AADs were enrolled if they were willing to in-office insertion of implantable loop recorders or already implanted with pacemakers or defibrillators capable of remote monitoring. Exclusion criteria were known medical contraindications of dofetilide and unable to provide consent. After making a shared management decision, dofetilide was initiated in a physician office, and rhythm and QTc intervals were monitored by ECGs and CIEDs. Patients were followed to assess the efficacy and safety of the treatment. RESULTS: The study cohort comprised of 30 patients, age 76 ± 7 years (mean ± standard deviation), 10 female (33%), CHA2DS2-VASc score 3.25 ± 1.3, ejection fraction 63.45% ± 8.52, and QTc interval 431.68 ± 45.09 ms. From 22 (73%) patients in AF at presentation, SR was restored in 14 (64%) patients after 4 doses of dofetilide. At 46 ± 59 days of follow-up, maintenance of SR in total 22 (73%) patients without cardiac adverse effects was accomplished. CONCLUSION: Effective and safe outpatient initiation of dofetilide during the extenuating circumstance of COVID-19 lockdown was possible in patients with AF who had CIEDs.