A nurse is teaching a client who is newly diagnosed with Alzheimer's disease and their family about newly prescribed medications for Alzheimer's disease. Which statement by the client indicates the teaching was effective?

A. Elevated erythrocyte sedimentation rate (ESR): Elevated ESR indicates inflammation in the body and is not typically associated with the cause of atrial fibrillation.

B. Elevated thyroid-stimulating hormone (TSH): This is the correct answer. A common cause of atrial fibrillation is hyperthyroidism, which is characterized by an overactive thyroid gland and often presents with elevated TSH levels. Thyroid hormones play a significant role in regulating heart rate and rhythm. Excess thyroid hormone can lead to increased heart rate and irregular heart rhythms, including atrial fibrillation.

C. Elevated brain natriuretic peptide (BNP): Elevated BNP levels are associated with heart failure and may indicate cardiac stress or dysfunction. While heart failure can predispose individuals to atrial fibrillation, elevated BNP levels themselves are not a direct cause of atrial fibrillation.

D. Elevated C-reactive protein (CRP): Elevated CRP levels indicate inflammation in the body and are associated with various cardiovascular diseases. While inflammation can contribute to atrial fibrillation, elevated CRP levels alone are not a direct cause of atrial fibrillation.

Pulseless electrical activity (PEA) refers to a situation in which an electrocardiogram (ECG) shows electrical activity in the heart, but there is no effective mechanical activity and no palpable pulse. PEA can result from various underlying conditions that impair cardiac function or compromise circulation.

A. Hypertension: Hypertension, or high blood pressure, is not typically a direct cause of PEA. While uncontrolled hypertension can contribute to cardiovascular disease and increase the risk of cardiac events such as myocardial infarction, it is not a direct cause of PEA.

B. Hypovolemia: Hypovolemia, or low blood volume, is a common cause of PEA. Reduced circulating blood volume leads to decreased preload and inadequate filling of the heart chambers, impairing cardiac output. This can result in ineffective cardiac contractions and the development of PEA.

C. Hypoxia: Hypoxia, or inadequate oxygenation of tissues, is a significant cause of PEA. Insufficient oxygen delivery to the myocardium impairs cardiac function and can lead to ineffective cardiac contractions. Without adequate oxygenation, the heart is unable to generate sufficient mechanical force to maintain circulation, resulting in PEA.

D. Hyperkalemia: Hyperkalemia, or elevated levels of potassium in the blood, can cause PEA by disrupting cardiac electrical activity. Excessive potassium ions in the extracellular fluid alter the normal myocardial action potential, leading to cardiac conduction abnormalities and potential arrhythmias, including PEA.

E. Hypernatremia: Hypernatremia, or elevated levels of sodium in the blood, is not typically a direct cause of PEA. While severe hypernatremia can lead to neurological symptoms and dehydration, it does not directly impair cardiac electrical activity or mechanical function to the extent that it causes PEA.

F. Hyperthermia: Hyperthermia, or elevated body temperature, is not typically a direct cause of PEA. While extreme hyperthermia can lead to cardiovascular complications such as heat stroke, it is not a common cause of PEA unless it is associated with severe systemic metabolic derangements.