A nurse is measuring a waveform of the ECG strip and determines it is normally around 06 to 1 the waveform s/he is measuring is the

Correct Answer: A

Rationale: The correct answer is A: P wave. The P wave represents atrial depolarization in an ECG waveform, typically lasting around 0.06 to 0.1 seconds. A nurse measuring this waveform within this time range indicates the measurement aligns with the characteristics of a P wave. The PRI (choice B) represents the time from the beginning of the P wave to the beginning of the QRS complex, usually around 0.12 to 0.2 seconds. The QRS complex (choice C) represents ventricular depolarization, typically lasting around 0.06 to 0.1 seconds. The QT interval (choice D) represents the time from the start of the Q wave to the end of the T wave, which varies but is generally around 0.36 to 0.44 seconds. Therefore, choices B, C, and D are incorrect as they do not match the description provided in the question.

Correct Answer: C

Rationale: Rationale: 1. Dobutamine is a beta-1 adrenergic agonist, leading to increased heart rate (tachycardia). 2. Bradycardia and heart failure are not common adverse effects of dobutamine. 3. Respiratory distress is not a typical adverse effect of dobutamine. 4. Therefore, choice C (Tachycardia) is the correct answer as it aligns with dobutamine's pharmacological effects.

Correct Answer: B

Rationale: The correct answer is B: They decrease the velocity of electrical activity on the AV node. Calcium channel blockers specifically target calcium channels in the heart muscle, which slows down the influx of calcium ions responsible for electrical conduction in the heart. By reducing the velocity of electrical activity on the AV node, calcium channel blockers help to decrease heart rate and improve myocardial oxygen supply. Incorrect choices: A: They increase the preload on the heart - This is incorrect because calcium channel blockers do not directly affect preload, which is the volume of blood in the heart at the end of diastole. C: They block the sodium channels in the heart muscle - This is incorrect because calcium channel blockers do not target sodium channels; they specifically inhibit calcium channels. D: They cause vasoconstriction of coronary arteries - This is incorrect because calcium channel blockers actually have a vasodilatory effect on coronary arteries, which can help improve blood flow to the heart muscle.

Correct Answer: D

Rationale: The correct answer is D: Adenosine. Adenosine is the drug of choice for treating paroxysmal supraventricular tachycardia (PSVT) due to its ability to rapidly terminate the arrhythmia by blocking the AV node temporarily. It works by slowing down the conduction of electrical impulses in the heart. Flecainide (A) and Lidocaine (B) are antiarrhythmic drugs used for ventricular arrhythmias, not PSVT. Metoprolol (C) is a beta-blocker that can be used for long-term management of PSVT but is not the first-line choice for acute treatment.

Correct Answer: C

Rationale: The correct answer is C: It relaxes vascular smooth muscle. Nitroprusside is a vasodilator that works by directly relaxing the smooth muscle in blood vessels, leading to vasodilation and subsequently lowering blood pressure. This mechanism of action is essential in treating hypertension. Incorrect choices: A: It blocks conversion of angiotensin I to angiotensin II - This is not the mechanism of action of nitroprusside. Angiotensin-converting enzyme (ACE) inhibitors work by inhibiting this conversion. B: It blocks the calcium channels in the blood vessels - This is the mechanism of action of calcium channel blockers, not nitroprusside. D: It blocks the sodium channels in the heart - This is not the mechanism of action of nitroprusside. Sodium channel blockers are used in antiarrhythmic medications.