A nurse is caring for a client who has had a myocardial infarction. Upon his first visit to cardiac rehabilitation, he tells the nurse that he doesn't understand why he needs to be there because there is nothing more to do, as the damage is done. Which of the following is the correct nursing response?

Swallowing the capsules whole is the correct way to take nitroglycerin oral, sustained-release capsules, as they are designed to release the medication slowly and steadily over time. The client should not crush, chew, or open the capsules, as this can alter the absorption and effectiveness of the medication.

Taking 1 capsule at the onset of anginal pain is not appropriate, as nitroglycerin oral, sustained-release capsules are not meant for acute episodes of angina, but for long-term prevention and management. The client should use a fast-acting form of nitroglycerin, such as sublingual tablets or spray, to relieve anginal pain.

Taking the medication with meals is not necessary, as nitroglycerin oral, sustained-release capsules can be taken with or without food. However, the client should take the medication at regular intervals and around the same time each day.

Stopping taking the medication if side effects are troublesome is not advisable, as nitroglycerin oral, sustained-release capsules can cause withdrawal symptoms and rebound angina if discontinued abruptly. The client should consult with the provider before stopping or changing the dose of the medication. The client should also report any severe or persistent side effects, such as headache, dizziness, hypotension, or tachycardia.

The P wave is the first wave on the ECG strip and represents the electrical activity of the atria. It reflects the depolarization of the atrial myocardium, which is the process of changing the electrical charge of the cardiac cells from negative to positive, triggering a contraction. The P wave precedes the QRS complex, which represents ventricular depolarization, and the T wave, which represents ventricular repolarization.

The other options are not correct because:

a. Slow repolarization of ventricular Purkinje fibers. This statement is incorrect because it describes the U wave, which is a small and sometimes invisible wave that follows the T wave on the ECG strip. It reflects the repolarization of the ventricular Purkinje fibers, which are specialized cardiac cells that conduct electrical impulses to the ventricles. The U wave is more prominent in conditions that cause hypokalemia, such as diuretic use or vomiting.

c. Early ventricular repolarization. This statement is incorrect because it describes the ST segment, which is the flat line between the QRS complex and the T wave on the ECG strip. It reflects the early phase of ventricular repolarization, which is the process of restoring the electrical charge of the cardiac cells to negative after a contraction. The ST segment can be elevated or depressed in conditions that cause myocardial ischemia or injury, such as angina or myocardial infarction.

d. Ventricular depolarization. This statement is incorrect because it describes the QRS complex, which is the largest and most visible wave on the ECG strip. It reflects the depolarization of the ventricular myocardium, which triggers a ventricular contraction. The QRS complex follows the P wave and precedes the T wave on the ECG strip.