ABNORMAL HEART RHYTHMS

Question 1

Heart rate in excess of 100 beats per minute (bpm)
Elevated body temperature, excessive sympathetic stimulation, toxic conditions

Answer 1

Tachycardia

Question 2

Heart rate less than 60 bpm Increased stroke volume in athletes, excessive vagus
nerve stimulation, nonfunctional SA node, carotid
sinus syndrome

Answer 2

Bradycardia

Question 3

Heart rate varies as much as 5% during respiratory cycle and
up to 30% during deep respiration
Cause not always known; occasionally caused by
ischemia, inflammation, or cardiac failure

Answer 3

Sinus arrhythmia

Question 4

Sudden increase in heart rate to 150–250 bpm for a few seconds or even for several hours; P waves precede every QRS complex; P wave is inverted and superimposed on T wave
Excessive sympathetic stimulation, abnormally
elevated permeability of cardiac muscle to Ca

Answer 4

Paroxysmal atrial tachycardia

Question 5

As many as 300 P waves/min and 125 QRS complexes/min;
resulting in two or three P waves (atrial contractions) for
every QRS complex (ventricular contraction)
Ectopic beats in atria

Answer 5

Atrial flutter

Question 6

No P waves, normal QRS and T waves, irregular timing;
ventricles are constantly stimulated by atria; reduced
ventricle filling; increased chance of fibrillation
Ectopic beats in atria

Answer 6

Atrial fibrillation

Question 7

Frequently causes fibrillation Often associated with damage to AV node or
ventricular muscle

Answer 7

Ventricular tachycardia