Welcome to your THEME 4 — ⚡ Palpitations
1.
A patient with decreased myocardial contractility despite normal electrical conduction most likely has impaired:
2.
The physiological significance of AV nodal delay is to allow:
3.
Which feature of cardiac muscle allows atria to behave as a coordinated electrical unit?
4.
A standard ECG is recorded at 25 mm/sec. If R-R interval measures 5 large squares, the heart rate is approximately:
5.
An ECG shows a normal PR interval but widened QRS complex. Which site is most likely functionally affected?
6.
A person with diabetes, smoking, and hypertension has increased cardiovascular risk mainly due to:
7.
Disturbance in cardiac electrophysiology is most likely to produce:
8.
The right and left bundle branches are located mainly within the:
9.
Which statement best integrates ECG and cardiovascular risk prevention?
10.
Which feature of cardiac muscle is most important for synchronized ventricular contraction?
11.
During fear, a student develops tachycardia before an examination. Which autonomic change best explains this response?
12.
Which refractory period allows excitation only by a stronger-than-normal stimulus?
13.
A cardiac impulse reaches ventricular myocardium but spreads slowly and unevenly. Which system is most likely impaired?
14.
Which membrane channel is mainly responsible for slow inward current during cardiac plateau phase?
15.
A patient with delayed transmission from atria to ventricles develops reduced ventricular filling efficiency. Which part of the conduction system is most directly involved?
16.
A patient has slowed AV conduction after increased acetylcholine release. Which receptor-linked effect is most consistent?
17.
A lesion damages electrical communication between adjacent cardiac muscle cells. Which function will be impaired first?
18.
Which nerve provides the major parasympathetic supply to the heart?
19.
Gap junctions in cardiac muscle are important because they:
20.
An ectopic pacemaker refers to:
21.
The ability of cardiac tissue to transmit impulses from one cell to another is called:
22.
Rapid conduction of impulses through ventricular myocardium is mainly due to:
23.
A conduction defect in the interventricular septum most likely affects which structures?
24.
Which physiological effect is most directly associated with positive inotropic stimulation?
25.
The primary physiological role of the plateau phase in ventricular muscle is to:
26.
A public health clinic checks blood pressure and lipid profile in adults without symptoms. The main purpose is:
27.
Which structure normally initiates the heartbeat in the human heart?
28.
A positive chronotropic effect primarily produces:
29.
A patient develops ventricular fibrillation after severe myocardial ischemia. Which cellular event most directly promotes this arrhythmia?
30.
Which electrophysiological alteration is most likely in severe hyperkalemia?
31.
During excitation–contraction coupling in cardiac muscle, calcium binds directly to:
32.
Loss of AV nodal delay would most directly reduce cardiac efficiency by causing:
33.
In a 12-lead ECG, precordial leads are especially useful because they assess cardiac electrical activity in the:
34.
The major functional significance of calcium-induced calcium release in cardiac muscle is to:
35.
A reduction in extracellular calcium concentration would most directly decrease:
36.
During normal cardiac conduction, which event mainly explains the delay between atrial and ventricular electrical activity on ECG?
37.
Why does the fibrous skeleton make the AV conduction pathway clinically important?
38.
Which process directly initiates release of calcium from sarcoplasmic reticulum in cardiac muscle?
39.
The SA node acts as the normal pacemaker because it:
40.
A smoker with high LDL is counseled and treated before developing angina or infarction. This is mainly:
41.
Which conduction sequence best supports normal ventricular pumping?
42.
The major significance of prolonged refractory period in cardiac muscle is prevention of:
43.
The plateau phase of ventricular action potential is primarily maintained by simultaneous:
44.
A patient after myocardial infarction is advised supervised exercise, counseling, and long-term follow-up. This prevention level mainly aims to:
45.
During sympathetic stimulation, increased heart rate occurs mainly because of enhanced:
46.
Which event best explains why atrial contraction normally precedes ventricular contraction?
47.
The rapid depolarization phase of ventricular muscle action potential occurs mainly due to influx of:
48.
Which conduction tissue normally has the slowest conduction velocity?
49.
The prolonged action potential of ventricular muscle is mainly advantageous because it:
50.
Which phase of ventricular action potential corresponds to rapid repolarization?
51.
Failure of SERCA pump activity in cardiac muscle would most directly increase:
52.
A patient with chronic hypertension develops increased left ventricular workload. Which complication is most logically expected over time?
53.
A patient with recurrent tachyarrhythmia is given a drug that prolongs ventricular action potential duration. The major therapeutic benefit is:
54.
Palpitations associated with abnormal impulse generation are most commonly related to:
55.
A patient receiving calcium channel blockers develops reduced AV nodal conduction because nodal depolarization depends mainly on:
56.
Which ECG feature best reflects rapid spread of impulse through the His-Purkinje system?
57.
The SA node is located in which chamber of the heart?
58.
Which structural feature explains why impulse conduction through ventricles is faster than ordinary myocardial spread alone?
59.
Which risk factor combination includes only non-modifiable cardiovascular risk factors?
60.
Which structure allows direct electrical communication between adjacent cardiac muscle cells?
61.
A drug that reduces sympathetic influence on the SA node would most likely cause:
62.
A positive dromotropic effect would most likely produce:
63.
Which property allows cardiac muscle cells to generate impulses spontaneously?
64.
Which feature differentiates excitation–contraction coupling in cardiac muscle from skeletal muscle?
65.
Compared with skeletal muscle, cardiac muscle action potential is characterized by:
66.
A patient has prolonged QT interval. Which cardiac electrical activity is being prolonged?
67.
Compared with skeletal muscle fibers, cardiac muscle fibers require extracellular calcium because cardiac sarcoplasmic reticulum is:
68.
If an ECG has regular rhythm and each large square equals 0.20 second, four large squares between R waves indicate:
69.
During ventricular activation, which structural arrangement helps both ventricles contract in a coordinated manner?
70.
A student explains that the heart can beat without direct nervous stimulation. Which concept best supports this statement?
71.
The relative refractory period differs from the absolute refractory period because it permits excitation by:
72.
Which phase of ventricular action potential corresponds to opening of fast voltage-gated sodium channels?
73.
Which component of the conduction system is responsible for delaying the cardiac impulse before ventricular contraction?
74.
Which ion movement is mainly responsible for repolarization of ventricular muscle cells?
75.
Failure of conduction through the AV node may result in:
76.
Which ECG abnormality is most expected when ventricular activation is delayed but atrial activation remains normal?
77.
A sudden increase in vagal activity slows the heart rate. Which nodal effect is most responsible?
78.
The resting membrane potential of ventricular cardiac muscle is closest to:
79.
A patient has palpitations due to abnormal impulse formation outside the normal leading pacemaker. Which mechanism best explains this?
80.
A cardiac cell group reaches threshold earlier than all other conducting tissues. Which property explains its dominance?
81.
The effective refractory period of cardiac muscle mainly overlaps with:
82.
Which ECG wave is broad because recovery of ventricular muscle occurs more slowly than activation?
83.
Which structural feature permits myocardium to function as a functional syncytium?
84.
A drug that blocks L-type calcium channels would most likely reduce:
85.
A community program promotes exercise and healthy diet among school children before obesity and hypertension develop. This is best classified as:
86.
Which intracellular event directly initiates cross-bridge cycling in cardiac muscle?
87.
The Bundle of His normally conducts impulses between which structures?
88.
Which ECG measurement is most directly affected if paper speed is changed from standard setting?
89.
Which ion is primarily responsible for the plateau phase of ventricular cardiac muscle action potential?
90.
In complete interruption of impulse passage from atria to ventricles, ventricular rhythm may continue slowly because of:
91.
A positive dromotropic effect mainly influences:
92.
The term functional syncytium refers to:
93.
A patient with recurrent palpitations has increased automaticity in ischemic ventricular tissue. Which abnormal rhythm source is likely present?
94.
Which autonomic stimulation increases heart rate and conduction velocity?
95.
Which finding best indicates correct standard voltage calibration before ECG interpretation?
96.
Which physiological property is most directly responsible for prevention of summation in cardiac muscle?
97.
Parasympathetic stimulation of the heart primarily causes:
98.
Which structure electrically separates atria from ventricles?
99.
A positive inotropic effect directly causes:
100.
A tracing shows ST segment deviation after chest pain. Which physiological process is most directly disturbed?
