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ECG Certification
Notecards from NHA Certified EKG Tech Study Guide
| Question | Answer |
|---|---|
| Where is the heart located? | In the mediastenum |
| Where is the base of the heart located? | The level of the second intercostal |
| Where is the base of the heart located? | The level of 5th intercostal and mid-clavicular line on the left. |
| What is the endocardium? | The innermost layer of the heart |
| What is the chordae tendinae? | Strings of connective tissue that keep the av valves in place |
| What is the myocardium? | The middle and contractile layer of the heart |
| What makes up the heart skeleton? | Pericardum, parietal pericardum, viseral pericardium or epicardum and pericardial sac |
| What is the outside layer of the heart skeleton? | Parietal pericardium |
| What is the inner layer of the heart skeleton? | Visceral pericardium or epicardium |
| What are the layers and fluid between the two layers of pericardium that prevent friction? | Pericardial sac |
| What is the structure in the middle of the heart that divides the heart into two sides? | Septum |
| Which side pumps deoxygenated blood with low pressure from the veins to the lungs? | The right side |
| Which side of the heart is responsible for pulmonary circulation? | The right side |
| Which side pumps oxygenated blood with high pressure toward the tissue through the arteries? | The left side |
| Which side of the heart is responsible for systemic circulation? | The left side |
| How many chambers does the heart have? | Four |
| What are the right and left atria? | Smaller, thin-walled chambers that are situated on top of the ventricles and receive blood from the lungs and veins |
| What are the right and left ventricles? | Larger, more muscular chambers that eject blood out to the systemic circulation and the two lungs |
| What does the right atrium do? | Receives deoxygenated blood returning to the hart from the body via the superior vena cava which carries blood from the upper body and the inferior vena cava which carries blood from the lower body. |
| Where does the right atrium (RA) receive blood from? | The coronary sinus; the largest vein that drains the heart muscle's deoxygenated blood. |
| What does the right ventricle do? | Receives deoxygenated blood from the right atrium which it pumps to the lungs for oxygenation through the pulmonary trunk and then to the pulmonary arteries. |
| What are the pulmonary arteries? | The only arteries in the body that carry deoxygenated blood |
| What is the function of the left atrium? | Receives oxygenated blood returning from the lungs via the right and left pulmonary veins |
| What are the pulmonary veins? | The only veins in the body that carry oxygenated blood |
| What is the function of the left ventricle? | Receives oxygenated blood from the left atrium and pumps it to the body through the aorta, the largest artery of the body. |
| Do the heart chambers pump simultaneously? | Yes both atria contract and then the two ventricles |
| What is the flow of blood through the heart | Deoxygenated blood>superior vena cava>RA >tricuspid valve>RV>sl pulmonary valve>PA>pulmonary trunk>lungs>PV>LA>bicupsid or MV>LV>semiLV>systemic aortic valve |
| What is the purpose of the heart valves? | To prevent backflow of blood thereby assuring uni-directional flow through the heart |
| Where are atrioventricular (AV)valves located? | Between the atria and the ventricles |
| What are the characteristics of the av valves? | They have tough fibrous rings, long and strong leaflets (cuspids) they have accessory organs such as papillary muscles and chordae tendinae |
| Where is the tricuspid valve located? | Between the right atrium and the right ventricle. It has three cusps or leaflets |
| Where is the bicuspid/mitral valve located? | Between the left atrium and the left ventricle. It has two cusps or leaflets. |
| What are the characteristics of the semilunar valves? | Three leaflets, shallow in depth, they have no accessory organs |
| Where is the pulmonic valve located? | Between the right ventricle and the pulmonary trunk |
| Where is the aortic valve located? | Between the left ventricle and the aorta |
| Where are the coronary arteries located? | On the epicardium |
| What are the four vessels in coronary circulation? | Left Anterior Descending (LAD), Left Circumflex (LCX) artery, and the Left and Right Coronary Arteries |
| What is systole? | The period of contractions of both atrial and ventricles |
| What is diastole? | The period of relaxing and filling of all cardiac chambers. |
| What causes heart sounds? | The closure of the heart valves |
| S1 (Lubb) | Occurs during ventricular contraction and the closure of AV valves |
| S2 (Dubb) | Occurs during ventricular relaxation when SL valves close |
| What causes murmurs? | Diseases of the valves or other structural abnormalities |
| What is the heart rate | The number of heart contractions per minute |
| What is the normal heart rate? | 60-100 bpm |
| What controls the heart rate? | Chemo-receptors and baro receptors located in the aortic arch and carotid arteries |
| What is the autonomic nervous system (ANS)? | Sympathetic and parasympathetic |
| What does the parasympathetic nervous system (vagus nerve) do? | Via the neurotransmitter acetylcholine it slows SA pacemaker and HR, Slows the conduction of electricity in the AV node and decreases the strength of atrial and ventricular contraction |
| What does the sympathetic nervous system do? | Via the neurotransmitter norepinephrine(adrenaline) it increases the heart, increases the force of contraction, > the blood pressure and via dopaminergic receptors > the diameter of the visceral blood vessels and consequently the visceral blood flow |
| What is the stroke volume (preload)? | The blood volume ejected outside the ventricle after each contraction. |
| What does stroke volume depend on? | The volume of blood returning to the heart, The force of myocardium contraction, vascular resistance (afterload) |
| What is Starling Law? | The greater the volume of the blood inside the heart during diastole, the stronger the heart contraction force during the systole. |
| What is cardiac output? | The amount of blood ejected outside the heart per minute. |
| What is the cardiac output equation? | (Stroke volume)x(HR per min) |
| Peripheral Vascular Resistance | The force exerted against the blood flow and is determined by the diameter of the vessel. The lower the vascular resistance the less force is needed to eject the blood out of the heart during systole. |
| Blood Pressure | The force exerted by circulating blood volume on the walls of the artery during circulation |
| What is the BP calculation? | Cardiac Output x Vascular Resitance |
| EKG | Graphical presentation of heart electricity over time |
| What are cardiac cell properties? | Automaticity, Excitability, Conductivity, and Contractility |
| What is automaticity? | The ability to spontaneously trigger electrical impulses without being stimulated by another source |
| What is excitability? | The ability to respond and react to a stimulus |
| What is conductivity? | The ability to receive and transmit electrical impulses to adjacent cells. |
| What is contractility? | A myocardial cell's ability to shorten (or contract) in response to a stimulus |
| Depolarization | Occurs when positively charged ions (such as sodium and calcium) rapidly move from outside the myocardial cell membrane into the inside, changing the overall charge from negative to positive |
| What does depolarization result in? | Contraction |
| How does depolarization flow? | Endocardium>myocardium>epicardium or innermost to outermost |
| Repolarization | Occurs immediately after depolarization and is the movement of positively charged ions back to the outside of the cell, returning the cell back to its original polarized state |
| Absolute Refractory Period/Absolute Refusal | The 1st phase of repolarization in which a myocardial cell is unable to react to any electrical stimulus. |
| Relative Refractory Period | the 2nd phase of repolarization during which time a strong enough electrical stimulus might cause new depolarization and contraction. |
| Conduction system of the heart | SA node, AV node, Bundle of HIS, Bundle branches, Purkinje fibers |
| SA Node | Found in the upper posterior portion of the right atrial wall just below the opening of the superior vena cava. Primary pacemaker of the heart. 60-100bpm |
| AV Node | Located at posterior septal wall of the right atrium just above the tricuspid valve. 40-60bpm |
| Bundle of HIS | Found at the superior portion of the interventricular septum, it is the pathway that leads out of the AV node and connects to the Bundle branches |
| Bundle branches | Located at the interventricular septum, the Bundle of His divides into the right and left bundle branches, the function of which is to conduct the electrical impulse to the Purkinje fibers throughout the ventricles |
| Purkinje fibers | Found within the ventricular endocardium, it consists of a network of small conduction fibers that deliver the electrical impulses from the Bundle Branches to the ventricular myocardium. 20-40 bpm |
| EKG basic concepts | Electrode, cable, lead |
| Electrode | a paper, plastic or metal sensor placed on the patient's skin on a specific location and transmits it to a cable |
| Cable | a wire that connects the electrode to the EKG machine |
| Lead | a recorded tracing of the heart electricity from one or two electrodes that provides a specific view of the heart |
| EKG lead types | Standard Bipolar Limb Leads, Augmented Unipolar and Precordial Chest Unipolar Leads |
| Standard Bipolar Limb Leads | Record electrical activity in the frontal plane. Lead I=the L arm is + and the R arm is -. Lead II= the L leg is + and the R arm is - Lead III= the L leg is + and the L arm is -. |
| Augmented Unipolar | Also records electrical activity in the frontal plane. Records the heart electricity from one limb and compare it with a zero voltage lead in the center of the heart. |
| AV | Augmented voltage |
| R | Right Arm |
| L | Left Arm |
| F | Left Leg |
| Lead aVR | the right arm is positive and the other limbs are negative |
| Lead aVL | the left arm is positive and the other limbs are negative |
| Lead aVF | the left leg (or foot) is positive and the other limbs are negative |
| Precordial Chest Unipolar Leads | All these electrodes are positive and record the heart electricity in the horizontal plane. They include leads: V1, V2, V3, V4, V5 and V6 |
| V1 | Fourth intercostal space, right sternal border |
| V2 | Fourth intercostal space, left sternal border |
| V3 | Equidistant between V2 and V4 |
| V4 | Fifth intercostal space, left midclavicular line |
| V5 | Fifth intercostal space, anterior axillary line |
| V6 | Fifth intercostal space, midaxillary line |
| 1 small EKG square | 1 mm or .04 sec |
| 1 large EKG square | 5mm or .2 sec |
| 2 large EKG squares | 1 mV |
| 5 large EKG squares | 1 second |
| Waveform | refers to movement away from the isoelectric line with either upward (positive) deflection or downward (negative) deflection |
| Segment | line between two waveforms |
| Interval | Waveform plus a segment |
| Complex | several waveforms |
| Atrial Depolarization | P wave=the first deflection after the diastole, produced by atrial depolarization |
| Ventricular depolarization | QRS complex=represents ventricular depolarization (activation) |
| Q wave | the initial negative deflection produced by ventricular depolarization |
| R wave | the first positive deflection produced by ventricular depolarization |
| S wave | the first negative deflection produced by the ventricular depolarization that follows the first positive deflection, (R) wave |
| Ventricular Repolarization | T wave= the first wave after the QRS complex |
| U wave | the deflection seen following the T wave but preceding the diastole |
| PR segment | measured from the end of the P wave to the beginning of the QRS complex |
| ST segment | represents the time of ventricular contraction and the beginning of repolarization of both ventricles. |
| Normal interval and junctions | a segment plus a waveform |
| PR interval | P wave and PR segment and is measured from the beginning of P wave to the beginning of QRS complex. Normal interval 0.12-0.2 |
| QT interval | represents the total ventricular activity (ventricular depolarization PLUS ventricular repolarization), and it is measure from the beginning of QRS to the end of T wave. The normal duration of this interval depends on the age and the HR. |
| RR interval | important to determine the HR and its regularity. The interval between two R waves |
| J (RST) junction | point at which QRS complex ends and ST segment |
| ST segment | from J point to the onset of the T wave. This segment is compared to the PR segment to help identify myocardial ischemia or injury |
| Analyzing the EKG strip | Assess the HR 6 second method Assess Rhythm Identify and examine Pwaves Assess intervals (PR, QRS, QT) Evaluate ST segments and T waves General Evaluation and conclusion |
| Exercise Stress Test | performed until at least 85% of the target heart rate is reached or symptoms or EKG changes that develop which requires the test to be terminated. |
| What is the most common indication for a stress test? | Chest pain during exercise or physical effort (angina pectoris) |
| Target Heart Rate | 220 minus patient's age |
| Pharmacologic stress test | For patients with physical limitation. Adenosine, dipyridamole, dobutamine are given intraveneously through an IV line |
Created by:
kristinajoy
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