Sinus Tachycardia: a Multidisciplinary Expert Focused Review.

Sinus tachycardia (ST) is ubiquitous, but its presence outside of normal physiological triggers in otherwise healthy individuals remains a commonly encountered phenomenon in medical practice. In many cases, ST can be readily explained by a current medical condition that precipitates an increase in the sinus rate, but ST at rest without physiological triggers may also represent a spectrum of normal. In other cases, ST may not have an easily explainable cause but may represent serious underlying pathology and can be associated with intolerable symptoms.

COVID-19 and postural tachycardia syndrome: a case series.

Background: Postural tachycardia syndrome (PTS) is a novel identified sequela of COVID-19 infection. This observational study describes clinical presentation, testing, and treatment response in seven patients diagnosed with PTS following COVID-19 infection.

Case Summary: A total of seven active patients (three collegiate athletes, one recreational athlete, two registered nurses, one hospitality employee), age 24 ± 6 years, and six females were followed for a mean of 152 ± 105 days after contracting COVID-19.

Dyspnea in Chronic Low Ventricular Preload States.

Dyspnea in low-preload states is an underrecognized but growing diagnosis in patients with unexplained dyspnea. Patients can often experience debilitating symptoms at rest and with exertion, as low measured preload often leads to decreased cardiac output and ultimately dyspnea. In the present article, we performed a review of the literature and a multidisciplinary evaluation to understand the pathophysiology, diagnosis, and treatment of dyspnea in low-preload states.

Functional capacity and quality of life in the postural tachycardia syndrome: A retrospective cross-sectional study.

Background: Postural tachycardia syndrome (POTS) is a complex syndrome of orthostatic intolerance that significantly affects quality of life. The relationship between functional capacity, quality of life, and age remains poorly understood in this patient population. The purpose of this cross-sectional study was to assess the clinical and exercise characteristics of patients with POTS who underwent exercise stress testing as part of cardiac rehabilitation, and to evaluate the relationships between functional capacity with age and sex, as well as the relationship between functional capacity and quality of life.

High Submaximal Exercise Heart Rate Impacts Exercise Intolerance in the Postural Orthostatic Tachycardia Syndrome.

Purpose: Exercise intolerance is a hallmark of the postural orthostatic tachycardia syndrome (POTS). However, no data are available on the implications of an exaggerated submaximal heart rate (HR) on exercise intolerance in patients. We investigated whether exaggerated HR responses occurring early on during incremental stress testing relate with increased odds of POTS and exercise intolerance.

Correction to: ST‑segment changes during tilt table testing for postural tachycardia syndrome: correlation with exercise stress test results.

Unfortunately, the 3rd author name was incorrectly published in the original publication. The complete correct name is given below.

ST-segment changes during tilt table testing for postural tachycardia syndrome: correlation with exercise stress test results.

Background: Prior studies have reported ECG (Electrocardiogram) changes during tilt table testing (TTT), specifically during repolarization with ST-segment and T-wave changes. The correlation with ischemic evaluation remains unclear. The purpose of this study was to analyze the prevalence of ST-segment changes during TTT in a young, otherwise healthy population of patients with postural tachycardia syndrome (POTS), and correlate them with exercise stress test results.

Postural Tachycardia Syndrome and Vasovagal Syncope: A Hidden Case of Obstructive Cardiomyopathy without Severe Septal Hypertrophy.

A 36-year-old female with symptoms of orthostatic intolerance and syncope was diagnosed with vasovagal syncope on a tilt table test and with postural tachycardia syndrome (POTS) after a repeat tilt table test. However, an echocardiogram at our institution revealed obstructive cardiomyopathy without severe septal hypertrophy, with a striking increase in left ventricular outflow tract gradient from 7 mmHg at rest to 75 mmHg during Valsalva, with a septal thickness of only 1.3 cm.

Compound heterozygous mutations in the SCN5A-encoded Nav1.5 cardiac sodium channel resulting in atrial standstill and His-Purkinje system disease.

An 11-year-old girl on evaluation for syncope was found to have progressive sinus node dysfunction and His-Purkinje system disease with atrial standstill. Genetic analysis revealed compound heterozygous mutations of the SCN5A gene in a novel combination.

Characteristics of heart rate reduction with resumption of supine position in the postural tachycardia syndrome: factors influencing recovery.

Objectives: Postural orthostatic tachycardia syndrome (POTS), a heart rate (HR) rise with upright positioning, is dependent on autonomic influences. HR recovery (HR decrease after exercise cessation) is a measure of autonomic function. Characteristics of HR reduction during supine Recovery after head-up Tilt in POTS patients have not been elucidated.

POTS due to excessive venous pooling in an enlarged inferior vena cava.

Postural tachycardia syndrome (POTS) is a form of orthostatic intolerance characterized by a marked increase in heart rate within the first 10 min of head-up tilt (HUT). We present a patient whose enlarged inferior vena cava that appears to be a contributing mechanism to her POTS and presyncopal symptoms.

Circadian and gender effects on repolarization in healthy adults: a study using harmonic regression analysis.

Background: Sudden cardiac death and myocardial infarction have a circadian variation with a peak incidence in the early morning hours. Increased dispersion of repolarization facilitates the development of conduction delay necessary to induce sustained arrhythmia. Both QT-dispersion and T-wave peak to T-wave end (TpTe) have been proposed as markers of dispersion of myocardial repolarization.

Early versus late postural tachycardia: a re-evaluation of a syndrome.

Postural tachycardia syndrome (POTS) involves an HR-rise within 10 minutes of head-up tilt. Hypokinetic circulation, older age, and ACE-inhibitor or Angiotensin-Receptor Blockers were associated with "Late" POTS (after 10 minutes of tilt) versus "Early" POTS (within 10 minutes of tilt).

Dynamic changes in T-wave amplitude during tilt table testing: correlation with outcomes.

Background: Changes in autonomic tone may play a role in syncope. Autonomic tone has been shown to affect cardiac repolarization in the ECG. Changes in the T wave can be seen during head-up tilt table (HUT) testing with unknown significance or relationship to outcomes.

Age and gender difference in ST height at rest and after double autonomic blockade in normal adults.

Background: ST elevation is commonly seen in young, healthy men. The exact mechanisms that cause ST height to be greater in young men are not yet completely understood. The purpose of the present study was to determine whether autonomic tone is responsible for age and gender differences in ST height.

Quality of anastomosis in conventional on-pump coronary artery bypass graft surgery: influence of the interrupted technique using u-clips and correlation with intraoperative graft flow patterns.

Background: The interrupted suture technique in creating graft-coronary artery anastomoses in coronary artery bypass graft (CABG) surgery is hypothesized to be superior to the standard continuous technique. However, because of the increased time and knot tying involved with the interrupted technique, the continuous suture became standard. In 2000, the U-clip (a self-closing metal clip) was introduced to help in creating an interrupted anastomosis, although data regarding its clinical use are still somewhat limited.

Menstrual cycle and ST height.

Background: Sex hormones and menstrual cycle effects on ST height have not yet been clearly identified.

Methods: Twenty-two young, healthy women (aged 22-32 years) were included in this study. Twelve-lead ECGs were registered during menses, follicular and luteal phase of the menstrual cycle at baseline, and after double autonomic blockade (DAB).