HESI (Health and Environmental Sciences Institute) Health Assessment Practice Test

Tachycardia, characterized by an elevated heart rate, can occur in various conditions, but hyperthyroidism is particularly known for this effect. In hyperthyroidism, the thyroid gland is overactive, producing excessive amounts of thyroid hormones. These hormones, especially thyroxine (T4) and triiodothyronine (T3), increase the metabolic rate of almost all tissues in the body, leading to various symptoms, including an increased heart rate. The elevated levels of thyroid hormones result in heightened cardiovascular stimulation, which manifests as tachycardia.

The other conditions mentioned do not typically lead to an increase in heart rate to the same extent as hyperthyroidism. For instance, while rapid dyspnea may suggest respiratory distress that could elevate heart rate, it is not a direct cause like hyperthyroidism. Constipation generally does not have a significant impact on heart rate, nor does an atrophied nodular thyroid, which can actually lead to lower hormone levels and possibly a slower heart rate rather than tachycardia. Thus, hyperthyroidism is the most clear-cut condition among the options to cause a consistent increase in heart rate.