A nurse is providing teaching to a client who has atrial fibrillation and reports dizziness and palpitations. Which of the following should the nurse understand is the cause of these manifestations?

A. "Your heart condition is caused by thickening of the ventricular walls and septum." Thickening of the ventricular walls and septum is characteristic of conditions like hypertrophic cardiomyopathy, not pericarditis. This statement does not accurately describe the cause of pericarditis.

B. "Your heart condition is caused by excessive stretching of the ventricles." Excessive stretching of the ventricles is not a typical cause of pericarditis. While stretching of the heart muscle may occur in certain conditions, it is not directly related to pericarditis.

C. "Your heart condition is caused when the ventricular tissue becomes fibrous and fatty." Fibrous and fatty changes in ventricular tissue are features of conditions such as ischemic cardiomyopathy, not pericarditis. This statement does not accurately explain the cause of pericarditis.

D. "Your heart condition is caused from stiffening of the walls of the ventricles." Pericarditis is inflammation of the pericardium, the sac-like membrane surrounding the heart. When the pericardium becomes inflamed, it can stiffen, restricting the heart's movement and leading to chest pain. Therefore, option D accurately explains the cause of pericarditis, attributing it to the stiffening of the pericardium.

A. A decrease in systolic blood pressure greater than 10 mm Hg during inspiration: Pulsus paradoxus is an exaggerated decrease in systolic blood pressure during inspiration. Normally, there is a slight decrease in systolic blood pressure during inspiration due to increased intrathoracic pressure and decreased venous return to the heart. However, in conditions such as cardiac tamponade or severe asthma exacerbations, the decrease in systolic blood pressure during inspiration is more pronounced (>10 mm Hg), indicating impaired cardiac output and decreased left ventricular filling during inspiration.

B. A decrease in heart rate greater than 10/min when lying down: This finding is not indicative of pulsus paradoxus. Pulsus paradoxus primarily refers to changes in systolic blood pressure during inspiration rather than alterations in heart rate when lying down.

C. An increase in diastolic blood pressure greater than 10 mm Hg during inspiration: This finding is not indicative of pulsus paradoxus. Pulsus paradoxus is characterized by an exaggerated decrease in systolic blood pressure during inspiration, not changes in diastolic blood pressure.

D. An increase in heart rate greater than 20/min when standing: This finding is not indicative of pulsus paradoxus. Pulsus paradoxus primarily refers to changes in systolic blood pressure during inspiration rather than alterations in heart rate when standing.