Left Ventricular end Diastolic Diameter in Patients of Mild and Severe Postural Orthostatic Tachycardia Syndrome

Abstract

Introduction Postural orthostatic tachycardia syndrome (POTS) is a form of dysautonomia presenting with palpitations, lightheadedness, brain fog, headaches, nausea and fainting¹. Several tests are used in POTS workup. Most important is the Tilt Table Test. POTS is diagnosed as change of 30 beats per minute(bpm) or more in adults and 40 bpm in people less than 18 or heart rate greater than 120 bpm within 10 minutes of head-up tilt table test. Left ventricular end diastolic diameter(LVEDD) shows the amount of blood in the left ventricle at the end of the diastole². If this diameter is less than normal then it may be the one reason contributing to the large increase in heart rate in severe POTS patients.The aim of the study is to indicate the role of LVEDD in increase of heart rate in patients of severe POTS as compared to mild POTS. Methods We analysed the POTS patients retrospectively. Inclusion Criteria POTS patients who underwent tilt table test during their workup, were analysed. Experimental Group Those having a change of 50 bpm or greater in heart rate during tilt table test were included in this group and termed as severe POTS patients. Total 132 patients meet this criteria. Control Group It comprises 144 patients having heart rate changes between 30 to 50 during tilt table test and termed as patients with mild POTS. LVEDD of these patients were measured through their echocardiograms. Females having LVEDD < 3.8 cm and Males having LVEDD < 4.2 cm were considered abnormally low diameter. Results Out of 132 patients of the experimental group (severe POTS), 32 patients (24%) had below normal LVEDD i.e. below 3.8 cm in females and below 4.2 cm in males. While in the control group, 36 patients (25%) out of 144 had abnormal LVEDD. Remaining patients have their LVEDD within the normal range. Postural orthostatic tachycardia syndrome (POTS) is a form of dysautonomia presenting with palpitations, lightheadedness, brain fog, headaches, nausea and fainting¹. Several tests are used in POTS workup. Most important is the Tilt Table Test. POTS is diagnosed as change of 30 beats per minute(bpm) or more in adults and 40 bpm in people less than 18 or heart rate greater than 120 bpm within 10 minutes of head-up tilt table test. Left ventricular end diastolic diameter(LVEDD) shows the amount of blood in the left ventricle at the end of the diastole². If this diameter is less than normal then it may be the one reason contributing to the large increase in heart rate in severe POTS patients.The aim of the study is to indicate the role of LVEDD in increase of heart rate in patients of severe POTS as compared to mild POTS. We analysed the POTS patients retrospectively. POTS patients who underwent tilt table test during their workup, were analysed. Those having a change of 50 bpm or greater in heart rate during tilt table test were included in this group and termed as severe POTS patients. Total 132 patients meet this criteria. It comprises 144 patients having heart rate changes between 30 to 50 during tilt table test and termed as patients with mild POTS. LVEDD of these patients were measured through their echocardiograms. Females having LVEDD < 3.8 cm and Males having LVEDD < 4.2 cm were considered abnormally low diameter. Out of 132 patients of the experimental group (severe POTS), 32 patients (24%) had below normal LVEDD i.e. below 3.8 cm in females and below 4.2 cm in males. While in the control group, 36 patients (25%) out of 144 had abnormal LVEDD. Remaining patients have their LVEDD within the normal range.