Provided is an ECG image of sinus tachycardia.
Identify the wave pattern and describe its characteristics.
The wave pattern shows a regular sinus rhythm with a heart rate greater than 100 beats per minute.
The wave pattern shows a regular rhythm with a heart rate between 60 and 100 beats per minute.
The wave pattern shows an irregular rhythm with P waves that change in morphology.
The wave pattern shows a rapid rate with no visible P waves and narrow QRS complexes.
The Correct Answer is A
Choice A rationale
Sinus tachycardia is defined by a heart rate exceeding 100 beats per minute, originating from the sinoatrial node. The rhythm remains regular because the electrical impulses follow the normal conduction pathway through the atria and ventricles. Each QRS complex is preceded by a visible P wave, and the PR interval remains within the normal range of 0.12 to 0.20 seconds. This rhythm is often a physiological response to stress, fever, exercise, or pain.
Choice B rationale
A heart rate between 60 and 100 beats per minute with a regular rhythm defines normal sinus rhythm. In this state, the sinoatrial node fires at a standard physiological pace, and the electrical conduction through the heart is unimpeded. Because sinus tachycardia specifically refers to a rate that is faster than this normal range, this choice does not accurately describe the wave pattern in question. It represents a healthy cardiac electrical state rather than a tachycardic one.
Choice C rationale
An irregular rhythm with changing P wave morphology is characteristic of rhythms like wandering atrial pacemaker or multifocal atrial tachycardia. These conditions involve multiple ectopic foci within the atria competing for dominance, rather than a single impulse from the sinoatrial node. In true sinus tachycardia, the P waves should look identical to one another because they are all generated from the same location. Therefore, this description is inconsistent with the diagnostic criteria for sinus tachycardia.
Choice D rationale
A rapid rate without visible P waves and narrow QRS complexes is typical of supraventricular tachycardia or atrial fibrillation, depending on the regularity of the rhythm. In sinus tachycardia, the P wave must be present and clearly associated with the QRS complex because the rhythm originates from the sinus node. The absence of P waves suggests that the rhythm is originating from a different part of the atrium or the atrioventricular junction, which is incorrect.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A rationale
Powerlessness refers to the perception that one's own actions will not significantly affect an outcome. While a critical care environment can certainly contribute to a lack of control, the specific physiological and psychological response to constant auditory stimuli like alarms and pumps is more directly related to sensory processing. Powerlessness is a broader psychosocial response to the loss of autonomy in the hospital setting, whereas constant noise specifically targets the patient's neurological and sensory thresholds.
Choice B rationale
Frustration is an emotional response to being hindered or blocked from reaching a goal. While a patient may feel frustrated by the noise and the inability to rest, this is a secondary emotional consequence. The primary clinical phenomenon occurring when the environment is filled with constant, competing auditory stimuli is the saturation of the brain's ability to process information. Frustration describes the feeling, but it does not capture the physiological state of sensory system exhaustion and overstimulation.
Choice C rationale
Physical pain is a localized or generalized unpleasant sensory and emotional experience associated with actual or potential tissue damage. While the stress of a noisy environment can lower a patient's pain tolerance or increase the perception of existing pain due to lack of rest, the noise itself is not the source of physical pain. Pain management requires different interventions, such as analgesics, whereas managing environmental noise requires a reduction in stimuli to prevent the exhaustion of the patient's sensory receptors.
Choice D rationale
Sensory overload occurs when an individual receives more sensory stimuli than their nervous system can navigate or process simultaneously. In an intensive care unit, the repetitive and unpredictable nature of monitor alarms, ventilator hissing, and pump humming keeps the reticular activating system in a state of constant arousal. This prevents the patient from entering deep sleep and leads to cognitive impairment, anxiety, and disorientation. Normal environmental processing becomes impossible as the brain is bombarded by excessive auditory inputs.
Correct Answer is B
Explanation
Choice A rationale
Administering nitroglycerin is a standard treatment for chest pain because it induces vasodilation of the coronary arteries. However, prioritizing it over oxygen in a patient with an oxygen saturation of 89 percent is incorrect. Nitroglycerin can significantly lower blood pressure, and it should only be administered after assessing hemodynamic stability. In this clinical scenario, addressing the documented hypoxemia takes precedence to ensure myocardial tissue receives adequate oxygenation to prevent further ischemic damage.
Choice B rationale
Supplemental oxygen is the priority because the patient is hypoxemic, with a saturation below the normal range of 95 to 100 percent. Oxygen therapy increases the partial pressure of oxygen in the blood, enhancing delivery to the myocardium. Correcting hypoxemia reduces the workload on the heart and limits the size of the infarction. Current guidelines emphasize maintaining oxygen saturation at or above 94 percent to optimize cellular respiration and prevent systemic metabolic acidosis.
Choice C rationale
The supine position is not ideal for a patient experiencing chest pain and respiratory distress because it increases venous return and cardiac preload, potentially worsening pulmonary congestion. Positioning the patient in semi-Fowler or high-Fowler position is usually preferred to facilitate lung expansion. While morphine is used for pain that is unresponsive to nitrates, it is not the first priority. Oxygenation must be addressed immediately to mitigate the underlying cause of the myocardial hypoxia.
Choice D rationale
Thrombolytic therapy is a critical intervention for ST-segment elevation myocardial infarction when percutaneous intervention is unavailable, but it is never initiated before establishing vascular access and confirming the diagnosis via a 12-lead ECG. Furthermore, safety screening for contraindications like recent surgery or bleeding disorders is mandatory. Starting this treatment without basic stabilization, such as oxygen administration for a desaturating patient, violates the primary assessment sequence of airway, breathing, and circulation.
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