Mechanism of Exertional Dyspnea in High Output States: is Diastolic Dysfunction a Culprit? Newer Insights from Doppler Echocardiography

Background: The underlying mechanism of cardiac failure in high output states has not been clearly understood. It is well known that left ventricular systolic functional indices are usually preserved. So, what causes the symptoms of cardiac failure?. We analysed the LV diastolic parameters in some of the common high output states Aim: The aim of this study was to evaluate Left Ventricular (LV) diastolic function in various high output states. Study population: Comprising 185 patients, mean age -25 (20-30) years, of various high output states such as pregnancy 2nd trimester (24-28 wks), 3rd trimester (32-36 wks), Chronic kidney disease patients with patent arterio-venous fistula, Hyperthyroidism, Anemia with hemoglobin levels of 6-8 gm%, patients with normal left ventricular systolic function (EF 58-65%),functional class II or III were included in our study.Patients with co-morbid states fused trans-mitral inflow E/A velocities and arrhythmias were excluded. Methods: Echocardiographic evaluation of all patients was done using Philips HD7XE machine in our Echo lab. Diastolic function was assessed using conventional trans-mitral inflow pattern, Pulmonary venous flow, and mitral annular tissue Doppler imaging. Results: Results are shown in Table 1. Table 1 Mean ±2SD. Conclusion: Diastolic LV function is relatively well preserved in most patients with physiologic high output states and it tends to get affected in pathologic high output states. It is likely that symptoms which suggest cardiac failure in some of these patients are not attributable to cardiac functional impairment as such. It is possible the symptoms of cardiac failure in high output states simply reflect hyper functioning heart due to increased metabolic demands.