Question

A 35-year-old male presented to clinic with dyspnea. Examination and Investigations revealed that the patient has low cardiac output. Treatment involved drugs that increase the heart contractility. Which of the following reasons can be involved in decreasing the cardiac contractility in this patient? Digitalis intake Increase thyroxine level Increase glucagon level Rising extracellular levels of K+

Answer 1

Dyspnea also known as shortness of breath is a feeling of not able to breath well enough. It is an uncomfortable abnormal awareness of breathing. It is a sign of serious disease of airways, lungs or heart. Heart failure is a very common cause of external dyspnea resulting in both impaired lungs and systemic organ perfusion. This is due to reduced cardiac output. Heart failure is often accompained by elevations in pulmonary capillary pressure which leads to pulmonary edema and impaired gas exchange in the lungs. The major form of thyroid hormone is thyroxine which acts mainly as a prohormone. Excess thyroxine hormone increases the force of contraction of the heart muscle and increases the amount of oxygen demand by the heart. Thyroxine increases resting heart rate and left ventricular contractility. It causes decreased systemic vascular resistance (SVR) by a direct effect on the arteriolar smooth muscles. Thus increase thyroxine levels causes decreased cardiac contractility in dyspnea patient.