Any disturbance that blocks the transmission of nerve impulse from SA node downwards is known as :

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2023

Explanation

Heart block is the specific medical term for a delay or blockage in the electrical pathway of the heart.
The question describes a problem with impulse transmission starting from the SA node and moving downwards, which is the exact definition of a heart block.
The heart's conduction system is an electrical system, and a block in it is distinct from a circulatory problem like a heart attack.
Sources like Sembulingam's Physiology define heart block as the blockage of impulses generated from the SA node as they pass through the heart's conductive system.

Option B: A heart attack (myocardial infarction) is the death of heart muscle tissue due to a lack of blood supply from a blocked coronary artery. It is a circulatory/vascular event, not primarily an electrical one.
Option C: This is a general term for blocking nerve signals, typically using local anesthetics for pain control or surgery. It is not specific to the heart's specialized conduction tissue.
Option D: This is not a standard or recognized clinical term. While a heart block is a type of cardiac arrhythmia, this phrasing is incorrect and redundant.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Cardiac Conduction System Disorders as background academic context rather than a clinical decision trigger.
Nurses must be able to recognize different types of heart blocks on an ECG, as the nursing interventions vary significantly. For example, a new third-degree block is a medical emergency requiring immediate intervention.
Patient education is crucial. A patient with a first-degree block may only need monitoring, while a patient receiving a pacemaker for a third-degree block needs extensive teaching on device function, activity restrictions, and signs of malfunction.
What if? If the patient's ECG showed a progressively lengthening PR interval until a QRS complex was dropped, the diagnosis would be a Second-Degree AV Block, Type I (Wenckebach). This is generally less dangerous than Type II and may not require immediate pacing.

How to Approach the Question

First, analyze the question stem to identify the core concept. The keywords are 'blocks transmission', 'nerve impulse', and 'SA node'.
Recognize that these terms describe the heart's electrical conduction system.
Evaluate the options in the context of cardiac electrophysiology.
Option A, 'Heart block', is the precise term for a disruption in this system.
Eliminate the other options by differentiating their meanings. 'Heart attack' is a blood flow issue. 'Nerve block' is a general anesthesia term. 'Nerve block cardiac arrhythmias' is not a standard medical term.
Select the most specific and accurate term that matches the pathophysiology described in the question.

Concept Tested & Keywords

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E6 Physiology Review Sembulingam 5e p. 116-118

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 557-559

E6 Pharmacology Katzung 16e p. 363-365

Practise the full RUHS, Jaipur, M.Sc Nursing Entrance Exam-2023

Attempt every question from this paper in a timed mock, then review the full solution for each one.