Exam 2 - Cardiac Arrhythmias Flashcards
(9 cards)
Name and describe the two distinct components of the human heart and the types of cells that perform these functions.
the electrical impulse that tells the heart to beat via the conductive cells
the mechanical beating of the heart in response to the electrical stimulation resulting in pumping of the blood via the contracting cells
The unique property of the cells in the heart to discharge an electrical current without an external stimulus.
Automaticity
what roles do Ca++, K+, and Na+ ions play in the cardiac tissue?
Calcium (Ca++) ions cause myocyte contraction.
Potassium (K+) ions outflow causes repolarization of myocytes.
Sodium (Na+) ion movement produces cell to cell conduction of depolarization in the heart.
Electrical stimulus occurs in what three phases?
Polarization: “ready phase”
Depolarization: “discharge phase”
Repolarization: “recovery phase”
Innervations of the heart by the autonomic nervous system are divided into what two functions:
Sympathetic:
affects both atria & ventricles
INCREASES heart rate
conduction
irritability.
Parasympathetic:
affects only the atria
DECREASES heart rate
conduction
irritability
Describe the normal conduction pathway through the heart.
- SA node @ 0.5m/s (60 to 100bpm)
- AV node @ .05m/s (40 to 60bpm)
- Bundle of HIS
- Left and Right Bundle Branch
- Purkingie fibers @4m/s (20 to 40bpm)
Rhythm that presents as sinus, regular, P waves in front of every QRS complex, QRS complex normal, PR intervals elongated.
First Degree AV Heart Block
Rhythm that presents as sinus, regular, P waves in front of every QRS complex, more P waves than QRS complexes , PR intervals gradually increase until a QRS is skipped.
Second Degree AV Heart Block Type I
Rhythm that presents as sinus, regular, P waves in front of every QRS complex, more P waves than QRS complexes , PR intervals normal and consistent until a QRS is spontaneouslyskipped.
Second Degree AV Heart Block Type II
