Exercise Intolerance and Excessive Chronotropic Response Due to Possible Autonomic Dysfunction Post COVID-19 Infection

Introduction and Objectives: In patients with Post-Acute Sequelae of Coronavirus 2 infection (PASC), a post infectious autonomic dysfunction may be one of the underlying mechanisms. Patients often present with exercise intolerance and exaggerated heart rate response to exercise. We report a single centre experience of patients with PACS and suspected autonomic dysfunction. Methods: Forty-two patients evaluated in the Outpatient Cardiology Department with suspected PASC were included in the study. Patients complained of compromised exercise performance persisting >3 months after recovery from COVID-19 infection, compared to the pre-COVID-19 period. The patients were evaluated with 12-lead electrocardiogram, echocardiography, 24-hour ECG ambulatory monitoring and either exercise stress test or a 6-minute walk test. Results: All 42 patients demonstrated an exaggerated chronotropic response, defined as the inappropriate increase in heart rate before the 6th minute of exercise >100% of the age-predicted maximal heart rate value with reproduction of clinical symptoms. In addition, 24-hour ambulatory electrocardiography revealed an increased mean heart rate of 92 beats/minute and decreased mean standard deviation of sequential 5-minute N-N interval (SDNN) of 74.4 ms. Pharmaceutical treatment with b-blockers, ivabradine or both was administrated in 29 (69%) resulting in symptomatic improvement in 82.8% of those under treatment. However, residual symptoms persisted in 69% of patients after 3 months. Conclusions: In patients with “Post-acute COVID-19” syndrome, we found an excessive chronotropic response to exercise suggesting autonomic dysfunction as the underlying mechanism of symptoms. Treatment with beta blockers or ivabradine resulted in clinical improvement but a substantial proportion of patients remained symptomatic.

Takotsubo cardiomyopathy complicating transcatheter mitral valve-in-valve replacement

A 73-year-old female presented with symp-tomatic heart failure(NYHA class Ⅲ)due to a failed 29-mm Sorin(St.Jude Medical,St.Paul,MN)bioprosthetic heart valve surgically implanted 10-year before for severe primary mitral valve regurgitation(flail of the anterior mitral leaf-let at A2 scallop).Preprocedural echocardiography showed preserved left ventricular function with severe bioprosthetic valve stenosis and concomit-ant moderate regurgitation(Video 1 in Supplement).Because of prohibitive surgical risk,a transeptal mitral valve-in-valve(ViV)replacement was planned.

P Wave Analysis in Patients with Sarcoidosis

Introduction: Atrial arrhythmias in patients with sarcoidosis (Sar) are not unusual and can occur due to either atrial myocardial fibrosis and/or due to autonomic nervous system imbalance. Electrocardiographic markers (ECG), like maximum and minimum P wave duration and P wave dispersion {Pdis = Pmax?﹣Pmin} reflect atrial depolarization inhomogeneity and can indicate patients prone to develop atrial arrhythmias while standard deviation of RR interval (SDNN) is an index of heart rate variability, reflecting autonomic nervous system (ANS) activity. Methods: 90 patients with sarcoidosis (41 males/49 females) enrolled in this multicenter prospective study underwent digital electrocardiography, echocardiography and pulmonary function tests (PFTs). Diastolic and systolic indices of right and left ventricle were measured echocardiographically including Doppler parameters while Pmax, Pmin, Pdis and SDNN were measured in a 5-minute duration digital electrocardiogram. All consecutive patients were compared to 65 healthy volunteers (30 males/35 females). Results: Although heart rate and the echocardiographic indices were similar among the two groups, the electrocardiographic indices were significantly prolonged in the patient group compared to controls. Maximum P wave duration was correlated with SDNN (p dis was correlated with SDNN (p max and Pdis were independently correlated with SDNN. Conclusion: P wave dispersion is significantly increased in patients with systemic sarcoidosis compared to healthy persons while maximum P wave duration and P wave dispersion are negatively correlated with the standard deviation of RR, an index of heart rate variability implying imbalance of ANS function. Further studies are needed for the clarification of the significance of this correlation.