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2 types of cardiac cells - CORRECT ANSWER: Electrical
-specialized cells which conduct electrical impulses
-these cells start and transmit electrical activity in the heart
Mechanical
-cells which make up bulk musculature in the heart
-these cells contract in response to stimuli from the electrical cells
2 types of cardiac cells - CORRECT ANSWER: Electrical
-specialized cells which conduct electrical impulses
-these cells start and transmit electrical activity in the heart
Mechanical
-cells which make up bulk musculature in the heart
-these cells contract in response to stimuli from the electrical cells
a cardiac arrhythmia is - CORRECT ANSWER: is any deviation from the normal pattern
of
the heartbeat (normal sinus rhythm)
a cardiac arrhythmia is - CORRECT ANSWER: is any deviation from the normal pattern
of
the heartbeat (normal sinus rhythm)
,a cardiac cycle on ecg is - CORRECT ANSWER: PQRST
a prolonged QT interval - CORRECT ANSWER: more prone to arrhythmia
a prolonged QT interval - CORRECT ANSWER: more prone to arrhythmia
Absolute refractory period - CORRECT ANSWER: Cardiac cells have not repolarized to
their threshold potential and are unable to respond to a stimulus
Period extends from onset of QRS complex to peak of T wave
Absolute refractory period - CORRECT ANSWER: Cardiac cells have not repolarized to
their threshold potential and are unable to respond to a stimulus
Period extends from onset of QRS complex to peak of T wave
Accelerated junctional rhythm - CORRECT ANSWER: originates in an ectopic
pacemaker site in the AV junction at a rate of 60 to 100 beats/minute. The term
accelerated denotes a rhythm that occurs at a rate faster than the inherent junctional
rate of 40 to 60 beats/minute, but that isn't fast enough to be junctional tachycardia.
Accelerated junctional rhythm is a regular, continuous rhythm characterized by an
inverted P wave that may occur before the QRS, after the QRS, or be hidden within the
QRS complex; a short PR interval of 0.10 second or less; and a normal QRS complex.
afterload - CORRECT ANSWER: the amount of resistance to ejection of blood from the
(left) ventricle - amount of resistance to overcome
Altered automaticity - CORRECT ANSWER: firing rate of the sinus node decreases,
resulting in a slower sinus rate and allowing a faster ectopic site the opportunity to take
control as pacemaker of the heart.
,•Automaticity of the ectopic site increases, resulting in a faster ectopic rate which takes
control of the heart from the slower-firing SA node.
Amount of pressure against which the left ventricle must work during systole to open the
aortic valve
Clinically measure by systolic blood pressure - CORRECT ANSWER: afterload
Amount of pressure against which the left ventricle must work during systole to open the
aortic valve
Clinically measure by systolic blood pressure - CORRECT ANSWER: afterload
An atrial ectopic beat that occurs late instead of early is called an - CORRECT
ANSWER: atrial escape beat. The morphologic characteristics of the late beat are the
same as with the PAC. Atrial escape beats usually occur during a pause in the
underlying rhythm. Escape beats act as an electrical backup to maintain the heart rate
and require no treatment.
An ECG tracing provides a view of the heart's electrical activity between two poles (a
positive and a negative pole). - CORRECT ANSWER: • Current flowing toward a
positive pole produces a positive deflection
• Current flowing toward a negative pole produces a negative deflection
• Current flowing away from both poles will produce a biphasic deflection; biphasic
deflections may be equally positive and negative, more positive than negative, or more
negative than positive.
, An ECG tracing provides a view of the heart's electrical activity between two poles (a
positive and a negative pole). - CORRECT ANSWER: • Current flowing toward a
positive pole produces a positive deflection
• Current flowing toward a negative pole produces a negative deflection
• Current flowing away from both poles will produce a biphasic deflection; biphasic
deflections may be equally positive and negative, more positive than negative, or more
negative than positive.
Anatomy of the heart - CORRECT ANSWER: Large, muscular organ consisting of
mostly cardiac tissue called the myocardium
Surrounded by a sac called the pericardium
Consists of 2 sides, right and left, separated by a septum
Consists of 4 chambers: 2 atria and 2 ventricles
2 sets of valves: semilunar valves and atrioventricular valves (AV valves)
Valves produce the "lub" and "dub" sounds of the heartbeat
Atrial arrhythmias originate from - CORRECT ANSWER: ectopic sites in the atria
Atrial fibrillation - CORRECT ANSWER: is a rapid and highly irregular heart rhythm
originating in an ectopic site in the atria, depolarizing at a rate greater than 400
beats/minute. As in atrial flutter, the AV node blocks most of the impulses from entering
the ventricles, thus protecting the ventricles from excessive rates. The AV node
conducts impulses irregularly, resulting in an irregular ventricular rhythm. When the
ventricular rate is less than 100 beats/minute, the rhythm is called controlled atrial
fibrillation.When the ventricular rate is greater than 100 beats/minute, the rhythm is
called uncontrolled atrial fibrillation. The ventricular rhythm is more irregular with slower
rates and less irregular with faster rates.
The atrial impulses are so rapid in atrial fibrillation that they cause the atria to quiver
instead of contract regularly, producing irregular, wavy deflections called fibrillatory