CRAT TEST PREP (Anatomy)Correct 100% The heart receives its blood supply through the two main coronary arteries its branches - ANSWER Left Coronary Artery Right Coronary Artery The left coronary artery begins as a main stem called the - ANSWER Left Ma

CRAT TEST PREP (Anatomy)Correct 100% The heart receives its blood supply through the two main coronary arteries its branches - ANSWER Left Coronary Artery Right Coronary Artery The left coronary artery begins as a main stem called the - ANSWER Left Main Coronary Artery (LMCA) • varies in length • Divides into 2 major branches ~ Left anterior descending artery (LAD) ~ Circumflex Artery (CX) Left anterior descending artery (LAD) - ANSWER Location: Front anterior surface of the left ventricle Supplies the anterior wall of the left ventricle, lateral wall and inter ventricular septum. Obstruction if this artery causes infarction of large muscular area in the left ventricle and may be fatal Circumflex artery (CX) [back] - ANSWER Runs along the groove between the left atrium and ventricle then winds around to the back (posterior) portion of the heart Obtuse marginal - ANSWER Supplies the lateral and posterior wall of the left ventricle and left atrium The right coronary artery (RCA) - ANSWER • Main coronary artery that runs in the groove between the right atrium and ventricle. • Supplies right atrium and right ventricle inferior wall of left ventricle and posterior portion of the interventricular septum Automaticity - ANSWER Ability of the cardiac cell to initiate an impulse Excitability - ANSWER Ability of the car excel to respond to an impulse Conductivity - ANSWER Ability of the card excel to conduct or transmit an impulse Contractility - ANSWER Ability of the cardiac so it's a contract/pump in response to an electrical impulse Absolute refractory period - ANSWER • cardiac cells cannot respond to any electrical stimulus • From onset of the QRS to peak of T wave Relative refractory period - ANSWER • A portion of the cardiac cells have repolarizing are able to respond to strong electrical stimulus • Downslope of T wave (Peak of T wave to end of T wave) St Depression - ANSWER • 0.5mm or more below baseline • Due to ischemia or Digoxin Toxicity ischemia - reduced blood flow ST Elevation - ANSWER • 1mm or more above the baseline • Hallmark sign of AMI (Acute Myocardial Infarction) Sinus Arrest (Sinus Pause) - ANSWER • Regular Rhythm • Rate of 60- 99.9 • P-Waves - Present, Uniform, Upright (Rhythm does not return on time) Sinus Exit block - ANSWER • Regular, but irregular during pause • Rate depends on underlying rhythm • Present, Upright, Uniform (Rhythm returns on time) Atrial Tachycardia w/block - ANSWER • Irregular Rhythm • Rate: Atrial Rate 140-250 BPM ventricular Rate slower • P-waves: present/uniform • PRI: unmeasurable QRS: 0.06- 0.11 Paroxysmal Atrial Tachycardia Paroxysmal = Sudden onset/offset - ANSWER • Irregular Rhythm • Rate: Depends on underlying rhythm at least 140-250 BPM at time of event • P-Waves: Hidden • PRI: Normal with underlying rhythm QRS: 0.06-0.11 Ventricular pre-excitation - ANSWER (Wolf Parkinson-White Syndrome • Regular Rhythm • Rate: Usually tachy rates • P-Waves- Present, upright, uniform • PRI: Shorten .12 • QRS Complex: Maybe .12 sec or greater due to the delta wave Atrial Flutter - ANSWER •Regular or Irregular • Atrial Rate 250-400 BPM