EKG EXAM 3RD TIMES THE CHARM BABIES
What is considered an escape pacemaker? A) A pacemaker that speeds up the heart rate B) A pacemaker that slows down the heart rate C) A pacemaker that takes over when the normal pacemaker fails D) A pacemaker that causes abnormal heart rhythms
C) A pacemaker that takes over when the normal pacemaker fails is considered an escape pacemaker. The heart normally has its own pacemaker, known as the sinoatrial (SA) node, which sets the pace for the heart's contractions. However, if the SA node fails or is not functioning properly, another area of the heart can take over as a backup pacemaker. This is known as an escape pacemaker. It usually has a slower rate than the SA node, but it can maintain a stable heartbeat until the SA node resumes its normal function or a pacemaker is implanted.
When does the absolute refractory period begin and end? A) It begins at the start of the QRS complex and ends at the end of the T wave. B) It begins at the start of the P wave and ends at the end of the QRS complex. C) It begins at the peak of the action potential and ends when the cells have repolarized to their resting state. D) It begins when the cardiac cells are fully repolarized and ends at the start of the next action potential.
C) It begins at the peak of the action potential and ends when the cells have repolarized to their resting state. Rationale: The absolute refractory period is the period of time during which the cardiac cells are unresponsive to a new stimulus, no matter how strong it is. This period begins at the peak of the action potential, when the cells are fully depolarized, and ends when the cells have repolarized to their resting state.
Which leads are referred to as "limb leads" in an electrocardiogram (ECG)? A) V1-V6 B) Lead I, Lead II, and Lead III C) AVL, AVR, and AVF D) The precordial leads
Correct answer: B) Lead I, Lead II, and Lead III. Rationale: Limb leads refer to the electrodes that are placed on the arms and legs to record the electrical activity of the heart from different angles.
What does the QRS complex represent on an electrocardiogram (ECG) and the duration? A) The electrical activity generated when the atria contract B) The electrical activity generated when the ventricles contract C) The repolarization of the atria D) The repolarization of the ventricles
Correct answer: B) The electrical activity generated when the ventricles contract.The duration is 0.12 seconds or less. Rationale: The QRS represents the electrical activity generated when the ventricles contract and pump blood out of the heart. This depolarization wave is initiated by the bundle of His and spreads through the ventricles, causing them to contract in a synchronized manner.
What does the P wave represent on an electrocardiogram (ECG)? A) The electrical activity generated when the ventricles contract B) The electrical activity generated when the atria contract C) The repolarization of the ventricles D) The repolarization of the atria
Correct answer: B) The electrical activity generated when theterm-11 atria contract. Rationale: The P wave on an ECG represents the electrical activity generated when the atria contract and pump blood into the ventricles.
What is the PR interval on an electrocardiogram (ECG)? A) The time it takes for the ventricles to contract B) The time it takes for the atria to contract C) The time it takes for the electrical impulse to travel from the atria to the ventricles D) The time it takes for the electrical impulse to travel from the ventricles to the atria
Correct answer: C) The time it takes for the electrical impulse to travel from the atria to the ventricles. The duration is 0.12-0.20 seconds, 3 to five small boxes Rationale: The PR represents the time it takes for the impulse to travel from the atria to the ventricles. This interval includes the time it takes for the impulse to travel through the atrioventricular (AV) node, which acts as a gatekeeper to slow down the electrical signal before it reaches the ventricles.
What does the T wave represent on an electrocardiogram (ECG)? A) The depolarization of the atria B) The depolarization of the ventricles C) The repolarization of the atria D) The repolarization of the ventricles
Correct answer: D) The repolarization of the ventricles. Rationale: The T wave represents repolarization (or recovery) of the ventricles following contraction. It is the final wave of the cardiac cycle. The T wave can be used to help identify myocardial ischemia or electrolyte imbalances. A tall or peaked T wave indicates hyperkalemia (high potassium levels), while a flattened or inverted T wave can indicate hypokalemia (low potassium levels) or myocardial ischemia.
What value of time is associated with a small box? A) 0.04 seconds B) 0.1 seconds C) 0.2 seconds D) 0.5 seconds
Correct answer: A) 0.04 seconds Rationale: The small box represents 0.04 seconds. ECG paper is marked with small and large squares, with each small square representing 0.04 seconds and each large square representing 0.2 (0.04x5=0.2) seconds.
What is the first line of treatment of Torsade de pointes and why? A) Administration of magnesium sulfate B) Administration of amiodarone C) Electrical cardioversion D) Administration of beta-blockers
Correct answer: A) Administration of magnesium sulfate Rationale: Torsade de pointes is a type of ventricular tachycardia characterized by a twisting pattern on the electrocardiogram (ECG). It is usually associated with a prolonged QT interval, which can be congenital or acquired (due to certain medications or electrolyte imbalances). The treatment of Torsade de pointes primarily involves correcting the underlying cause and shortening the QT interval. Magnesium sulfate is the first-line treatment for Torsade de pointes because it is a natural calcium channel blocker that helps to stabilize the cell membrane and reduce the risk of arrhythmias. Magnesium sulfate can also help to shorten the QT interval and prevent the recurrence of Torsade de pointes. The recommended dose of magnesium sulfate is usually 1-2 g intravenously over 5-20 minutes. Amiodarone, a class III antiarrhythmic drug, can be used as an alternative to magnesium sulfate in cases where the patient does not respond to or cannot tolerate magnesium sulfate. However, amiodarone has a longer half-life and can cause serious side effects, such as pulmonary fibrosis, thyroid dysfunction, and liver toxicity. Electrical cardioversion is not usually recommended as a first-line treatment for Torsade de pointes, as it can sometimes exacerbate the arrhythmia and lead to ventricular fibrillation. Beta-blockers, such as propranolol and metoprolol, can help to reduce the risk of Torsade de pointes by slowing the heart rate and reducing myocardial oxygen demand. However, beta-blockers are not typically used as a first-line treatment for acute episodes of Torsade de pointes.
What is the function of magnesium and potassium in Torsade de pointes, what order are they administered and why? A) Magnesium and potassium increase the heart rate and are administered simultaneously B) Magnesium and potassium decrease the QT interval and are administered simultaneously C) Magnesium and potassium increase the QT interval and are administered simultaneously D) Magnesium and potassium have no effect on Torsade de pointes
Correct answer: B) Magnesium and potassium decrease the QT interval and are administered simultaneously Rationale: Torsade de pointes is a type of ventricular tachycardia that is often associated with a prolonged QT interval, which can be caused by electrolyte imbalances, medications, or genetic factors. The QT interval represents the time it takes for the heart to depolarize and repolarize, and a prolonged QT interval can lead to arrhythmias such as Torsade de pointes. Both magnesium and potassium can help to decrease the QT interval in patients with Torsade de pointes. Magnesium can help to restore normal intracellular concentrations of potassium and calcium, which can reduce the risk of arrhythmias. Potassium supplementation can also help to reduce the QT interval and prevent the recurrence of Torsade de pointes. Magnesium and potassium are typically administered simultaneously to treat Torsade de pointes, as both electrolytes work together to reduce the QT interval and prevent arrhythmias. The exact dosing and administration protocol may vary depending on the severity of the patient's condition and other individual factors. Answer A is incorrect because magnesium and potassium do not increase the heart rate. In fact, both electrolytes can have a negative chronotropic effect and slow down the heart rate. Answer C is incorrect because magnesium and potassium do not increase the QT interval. In fact, they have the opposite effect and can help to decrease the QT interval. Answer D is incorrect because magnesium and potassium do have an effect on Torsade de pointes and can be an effective treatment option when administered properly.
Which of the following statements best describes the primary function of the AV node and its importance? A) The primary function of the AV node is to initiate electrical impulses and stimulate the heart to contract, which is important for maintaining blood pressure. B) The primary function of the AV node is to delay electrical impulses from the atria and transmit them to the ventricles, which is important for coordinating atrial and ventricular contractions. C) The primary function of the AV node is to distribute electrical impulses throughout the ventricles, which is important for maintaining cardiac output. D) The primary function of the AV node is to regulate heart rate, which is important for maintaining blood flow to the brain and other vital organs.
Correct answer: B) The primary function of the AV node is to delay electrical impulses from the atria and transmit them to the ventricles; this delay is crucial because it allows the atria to contract and fill the ventricles with blood before the ventricles contract. Without this delay, the atria and ventricles would contract at the same time causing two pumps to work at the same time without any volume.
What is the primary pacemaker site of the heart and what is its intrinsic rate? A) The primary pacemaker site is the atrioventricular (AV) node, with an intrinsic rate of 40-60 beats per minute. B) The primary pacemaker site is the sinoatrial (SA) node, with an intrinsic rate of 60-100 beats per minute. C) The primary pacemaker site is the bundle of His, with an intrinsic rate of 40-60 beats per minute. D) The primary pacemaker site is the Purkinje fibers, with an intrinsic rate of 20-40 beats per minute.
Correct answer: B) The primary pacemaker site is the sinoatrial (SA) node, with an intrinsic rate of 60-100 beats per minute. Rationale: The SA node is the primary pacemaker; it initiates impulses that stimulate contraction. The SA node is in the right atrium, near the opening of the superior vena cava with an intrinsic rate of 60-100 beats per minute.
Which of the following statements best describes how medical interventions such as pacemakers or medications target the different pacemaker sites to regulate heart rate? A) Pacemakers deliver electrical impulses to the SA node to increase heart rate B) Medications increase the activity of the Purkinje fibers to regulate heart rate C) Pacemakers deliver electrical impulses to the AV node to regulate heart rate D) Medications block the activity of the SA node to slow down heart rate
Correct answer: C) Pacemakers deliver electrical impulses to the AV node to regulate heart rate. Rationale: Pacemakers implanted internally to chest to regulate heart rate. They deliver impulses to the heart to make it contract and have different types depending on the target/type of pacemaker; ie a pacemaker that targets the AV node is called an AV sequential pacemaker, which help coordinate the timing of the electrical impulses between the atria and ventricles. Meds can be used to regulate heart rate by targeting different receptors in the heart, but they do not target or affect pacemaker sites.
Question: Where in the EKG can you detect a bundle branch block (BBB)? A) P wave B) QRS complex C) T wave D) U wave
Rationale: A bundle branch block (BBB) can be detected on an electrocardiogram (EKG) by examining the QRS complex, which represents the depolarization of the ventricles. A BBB causes a delay or blockage in the conduction of electrical impulses through the ventricles, which can result in a widened QRS complex with a characteristic shape depending on which bundle branch is affected. The delay in depolarization causes the ventricles to contract later than usual, which results in a widening of the QRS complex. Therefore, the correct answer is (B) QRS complex.
Which of the following is a common cause of AIVR (Accelerated Idioventricular Rhythm)? A) Blocked or damaged electrical pathways in the heart B) High levels of caffeine in the bloodstream C) Excessive alcohol consumption D) Low potassium levels in the blood
Rationale: AIVR is a type of abnormal heart rhythm that originates in the ventricles and is characterized by a heart rate of 60 to 120 beats per minute. It can occur in people with or without underlying heart disease. Option A is a common cause of many types of arrhythmias, including AIVR. If the electrical pathways in the heart are blocked or damaged, it can disrupt the normal heart rhythm and cause AIVR to occur. Options B and C are not known to be direct causes of AIVR, although they can contribute to the development of other types of arrhythmias. Option D can also cause AIVR. Potassium is an important electrolyte that helps regulate the heart's rhythm. Low levels of potassium in the blood can disrupt the heart's normal electrical activity and cause arrhythmias like AIVR to occur.
Which of the following is the mechanism of action of an implantable cardioverter-defibrillator (ICD)? A) Increases heart rate B) Prevents clot formation C) Delivers an electric shock to the heart D) Dilates blood vessels
Rationale: An implantable cardioverter-defibrillator (ICD) is a small device that is implanted under the skin of the chest to monitor and treat abnormal heart rhythms. Option C is correct. An ICD works by delivering an electric shock to the heart when it detects a life-threatening arrhythmia, such as ventricular fibrillation (VF) or ventricular tachycardia (VT). The shock is intended to reset the heart's electrical activity and restore a normal heart rhythm. Option A is incorrect. An ICD does not increase heart rate. In fact, it can be programmed to pace the heart at a specific rate if the heart rate is too slow. Option B is also incorrect. An ICD does not prevent clot formation. It is designed to monitor and treat abnormal heart rhythms, not prevent blood clots. Option D is also incorrect. An ICD does not dilate blood vessels. Its primary function is to monitor and treat abnormal heart rhythms.
How can atrial fibrillation (AFib) and bundle branch block (BBB) exist at the same time? A) AFib can cause BBB B) BBB can cause AFib C) They are unrelated conditions that can coexist D) They cannot exist at the same time
Rationale: Atrial fibrillation (AFib) is a type of arrhythmia where the atria of the heart fibrillate or quiver instead of contracting properly. This can cause irregular heartbeats and a decrease in cardiac output. Bundle branch block (BBB) is a condition where there is a delay or blockage in the conduction of electrical impulses through the bundle branches of the heart. It can cause a widened QRS complex on an electrocardiogram (EKG). AFib and BBB can coexist in the same patient, but they are usually unrelated conditions. However, in some cases, AFib can cause BBB by affecting the conduction of electrical impulses through the bundle branches. This is known as a high-grade AV block or complete heart block. Similarly, BBB can rarely cause AFib by disrupting the normal electrical activity of the atria. Therefore, the correct answer is (A) AFib can cause BBB.
Where do bundle branch blocks originate? A) From the atria B) From the ventricles C) From the sinoatrial node D) From the atrioventricular node
Rationale: Bundle branch blocks occur when there is a delay or blockage in the electrical signals through the bundle branches, which are specialized fibers that conduct impulses through the ventricles . These bundle branches originate from the bundle of His, which is located in the ventricular septum of the heart. Therefore, the correct answer is (B) From the ventricles.
Why do bundle branch blocks appear flipped on an EKG? A) Due to the orientation of the heart in the chest B) Due to the positioning of the EKG leads C) Due to the delay or blockage of electrical signals in the heart D) Due to interference from surrounding muscles
Rationale: Bundle branch blocks occur when there is a delay or blockage in the transmission of electrical signals through the bundle branches of the heart. This can cause the ventricles to depolarize in an abnormal pattern, leading to changes in the electrical activity of the heart that are detected by an EKG. These changes can cause the QRS complex to appear widened and flipped in direction, depending on which bundle branch is affected. Therefore, the correct answer is (C) Due to the delay or blockage of electrical signals in the heart.
How do ventricular rhythms affect cardiac output? A) Ventricular rhythms have no effect on cardiac output B) Ventricular rhythms can decrease cardiac output C) Ventricular rhythms can increase cardiac output D) Ventricular rhythms can cause the heart to stop beating
Rationale: Cardiac output refers to the amount of blood that the heart pumps per minute and is determined by the heart rate and stroke volume. Ventricular rhythms are abnormal heart rhythms that originate in the ventricles and can have a significant impact on cardiac output. In normal sinus rhythm, the atria and ventricles work together to efficiently pump blood throughout the body. However, in ventricular rhythms, the coordination between the atria and ventricles is disrupted, leading to inefficient pumping and decreased cardiac output. Some ventricular rhythms, such as ventricular tachycardia, can cause the heart to beat too fast and reduce the amount of time the ventricles have to fill with blood, leading to decreased stroke volume and cardiac output. Ventricular fibrillation, a life-threatening arrhythmia, causes the ventricles to quiver rather than contract, resulting in a complete loss of cardiac output. Therefore, the correct answer is (B) Ventricular rhythms can decrease cardiac output.
Which of the following is the mechanism of action of amiodarone in treating monomorphic VT? A) Increases heart rate B) Prolongs cardiac action potential C) Decreases blood pressure D) Constricts blood vessels
Rationale: Monomorphic ventricular tachycardia (VT) is a type of arrhythmia characterized by a fast heart rate originating in the ventricles. Amiodarone is an antiarrhythmic drug commonly used to treat monomorphic VT. Option B is correct. Amiodarone prolongs the cardiac action potential, which means it slows down the electrical activity in the heart. This effect can help prevent the fast, abnormal heart rhythm of monomorphic VT from occurring. Option A is incorrect. Amiodarone does not increase heart rate. In fact, it has a negative chronotropic effect, meaning it slows down the heart rate. Option C is incorrect. Amiodarone does not decrease blood pressure. It has some vasodilator properties, which means it can cause blood vessels to relax and widen, but this effect is not significant enough to cause a decrease in blood pressure. Option D is incorrect. Amiodarone does not constrict blood vessels. As mentioned above, it has some vasodilator properties, meaning it can cause blood vessels to relax and widen, but it does not have any significant vasoconstrictor effects.
When are PVCs considered serious, and how are they treated? A) PVCs are always considered serious and require immediate treatment B) PVCs are generally not considered serious unless they occur frequently or are associated with other heart conditions C) PVCs are only considered serious if they cause symptoms such as chest pain or fainting D) PVCs are never considered serious and do not require treatment
Rationale: Premature ventricular contractions (PVCs) are extra heartbeats that occur earlier than normal in the ventricles. While PVCs can be a normal variation in heart rhythm, they can also be a sign of an underlying heart condition. PVCs are generally not considered serious unless they occur frequently (more than 5 per minute) or are associated with other heart conditions, such as heart disease or heart failure. In some cases, PVCs can cause symptoms such as chest pain, shortness of breath, or fainting, which may require further evaluation and treatment. Treatment for PVCs depends on the underlying cause and severity of symptoms. In some cases, no treatment is necessary, and the PVCs may go away on their own. However, if PVCs are frequent or causing symptoms, treatment options may include medications such as beta-blockers or anti-arrhythmic drugs, or procedures such as catheter ablation to target and eliminate the source of the PVCs. Therefore, the correct answer is (B) PVCs are generally not considered serious unless they occur frequently or are associated with other heart conditions.
In an EKG, why would the Q and S fuse together? What is the S wave? A) Due to an enlarged heart B) Due to a bundle branch block C) Due to normal conduction D) Due to interference from surrounding muscles
Rationale: The S wave is a downward deflection that immediately follows the QRS complex on an EKG. In some cases, the Q wave and S wave can fuse together, creating a single wave called the QS wave. This can occur due to a variety of reasons, including a prior heart attack, a ventricular conduction defect, or normal variation in cardiac conduction. The S wave represents the final depolarization of the ventricles and the beginning of their repolarization. It is typically small in amplitude but can be increased in amplitude in conditions such as left ventricular hypertrophy or a bundle branch block. Therefore, the correct answer for the first part of the question is not provided as both (B) and (C) could be correct. The correct answer for the second part of the question is (D) Due to interference from surrounding muscles.
What is the formula for cardiac output? A) Stroke volume x heart rate B) Heart rate x blood pressure C) Stroke volume / blood pressure D) Blood pressure / heart rate
Rationale: The correct answer is A) Stroke volume x heart rate.
Why does the AV node need to delay impulses in the heart? A) To allow the ventricles to contract before the atria B) To regulate blood pressure C) To receive oxygen from the lungs D) To transmit electrical impulses to the SA node
Rationale: The correct answer is A) The AV node delays impulse to ensure the atria have enough time to contract and fill the ventricles with blood before the ventricles contract and pump blood out of the heart.
What is preload in the cardiac cycle and what is its role? A) The amount of blood in the ventricles before each contraction; it determines the initial stretch on the cardiac muscle fibers. B) The amount of blood in the atria after each contraction; it determines heart rate. C) The amount of blood ejected from the ventricles with each contraction; it determines cardiac output. D) The amount of blood remaining in the heart after each contraction; it determines blood pressure.
Rationale: The correct answer is A) The amount of blood in the ventricles before contraction; it determines the stretch on the muscle. Preload is the amount of blood in the ventricles at the end of diastole, just before the heart contracts. The greater the preload, the greater the force of contraction.
What is stroke volume and what is its role in cardiac output? A) The amount of blood pumped out of the heart with each contraction; it determines cardiac output. B) The amount of blood remaining in the heart after each contraction; it has no role in cardiac output. C) The amount of blood in the ventricles before each contraction; it determines heart rate. D) The amount of blood in the atria before each contraction; it determines stroke volume.
Rationale: The correct answer is A) The amount of blood pumped out of the heart with each contraction; it determines cardiac output. Stroke volume is the amount of blood ejected from the ventricles with each contraction of the heart.
What is contractility in the cardiac cycle and what is its role? A) The force of the heart's contraction; it determines stroke volume. B) The amount of blood in the ventricles before each contraction; it determines the initial stretch on the cardiac muscle fibers. C) The amount of resistance to blood flow in the arteries; it determines afterload. D) The amount of blood in the atria before each contraction; it determines heart rate.
Rationale: The correct answer is A) The force of the heart's contraction; it determines stroke volume. Contractility is the ability of the muscles to contract with force, independent of changes in preload or afterload. It is determined by the availability of calcium ions in the muscle cells, the sensitivity of the muscle fibers to calcium, and the energy available for contraction. The greater the contractility, the greater the force of contraction and the greater the stroke volume.
What is the atrial kick and what percentage of ventricular filling does it account for? A) It is the contraction of the ventricles that pumps blood out of the heart, 20% B) It is the relaxation of the ventricles that allows blood to flow into them, 30% C) It is the contraction of the atria that pushes blood into the ventricles, 20-30% D) It is the relaxation of the atria that allows blood to flow into the ventricles, 50%
Rationale: The correct answer is C) It is the contraction of the atria that pushes blood into the ventricles, accounting for 20-30% of ventricular filling. The atrial kick refers to the additional volume of blood that is pushed into the ventricles during atrial contraction.
Why are electrical signals from the Purkinje fibers unable to produce a P wave on an electrocardiogram (ECG)? A) The Purkinje fibers do not generate electrical signals B) The electrical signals from the Purkinje fibers are too weak to produce a P wave C) The P wave is generated by electrical activity in the atria, not the ventricles D) The Purkinje fibers are too deep within the ventricular muscle to produce a P wave
Rationale: The electrocardiogram (ECG) is a graphical representation of the electrical activity of the heart. The P wave represents the depolarization (contraction) of the atria, which is followed by the QRS complex, representing the depolarization of the ventricles. The electrical signals that generate the P wave are initiated by the sinoatrial (SA) node in the right atrium and spread through the atrial muscle. The Purkinje fibers, on the other hand, are specialized conducting fibers that distribute electrical impulses throughout the ventricular muscle, causing it to contract. Since the Purkinje fibers are located deep within the ventricular muscle, they do not generate electrical signals that are strong enough to be detected on the surface of the body and produce a P wave on an ECG. Therefore, the correct answer is (C) The P wave is generated by electrical activity in the atria, not the ventricles.
What structure in the heart is responsible for generating ventricular rhythms? A) SA node B) AV node C) Purkinje fibers D) Bundle of His
Rationale: The heart is a complex organ that relies on the coordinated activity of multiple structures to function properly. The sinoatrial (SA) node is a small group of specialized cells located in the right atrium that acts as the natural pacemaker of the heart. The SA node generates electrical impulses that cause the atria to contract and helps determine the normal heart rate. After the electrical impulses generated by the SA node travel through the atria, they are conducted to the atrioventricular (AV) node, which is located in the lower portion of the interatrial septum. The AV node delays the impulses slightly before passing them on to the ventricles, allowing time for the atria to contract and fill the ventricles with blood. From the AV node, the impulses are conducted to the bundle of His and then to the Purkinje fibers, which are specialized conducting fibers that distribute the impulses throughout the ventricles. The Purkinje fibers are responsible for generating ventricular rhythms, which are slower than atrial rhythms due to their larger size and greater electrical resistance. Therefore, the correct answer is (C) Purkinje fibers.
What are we trying to prevent in prolonged QT in Torsades de Pointes? A) Hypertension B) Bradycardia C) Ventricular fibrillation D) Atrial fibrillation
Rationale: Torsades de Pointes is a type of ventricular tachycardia that is associated with a prolonged QT interval on an electrocardiogram (EKG). A prolonged QT interval can be caused by a variety of factors, including certain medications, electrolyte imbalances, and inherited conditions. In Torsades de Pointes, the abnormal electrical activity of the ventricles can cause them to contract in a twisting or "twisting of points" pattern, leading to a sudden loss of cardiac output and potentially leading to cardiac arrest. Therefore, the primary goal in treating Torsades de Pointes is to prevent the development of ventricular fibrillation and cardiac arrest. Therefore, the correct answer is (C) Ventricular fibrillation.
What is the cause of ventricular arrhythmias? A) Abnormal electrical signals generated by the sinoatrial (SA) node B) Blockage or narrowing of the coronary arteries C) Changes in the structure or function of the heart's electrical system D) Anxiety or stress
Rationale: Ventricular arrhythmias are abnormal heart rhythms that originate in the ventricles, the lower chambers of the heart. These arrhythmias can range from mild to life-threatening, depending on their frequency and severity. The normal heartbeat is regulated by the heart's electrical system, which coordinates the contraction of the atria and ventricles. Ventricular arrhythmias occur when there are changes in the structure or function of the heart's electrical system, leading to abnormal electrical signals in the ventricles. These changes can be caused by a variety of factors, including heart disease, such as coronary artery disease, heart attack, or heart failure, as well as genetic conditions, electrolyte imbalances, and drug interactions. Certain lifestyle factors, such as smoking, excessive alcohol consumption, and drug abuse, can also increase the risk of developing ventricular arrhythmias. Therefore, the correct answer is (C) Changes in the structure or function of the heart's electrical system.
Which of the following describes what happens in the heart during ventricular flutter? A) The heart beats too slowly B) The heart's electrical signals are disorganized and chaotic C) The heart's ventricles quiver rather than contract effectively D) The heart's chambers are not able to fill with enough blood
Rationale: Ventricular flutter is a type of arrhythmia that occurs in the ventricles, or the lower chambers of the heart. It is characterized by a rapid heart rate of 250-350 beats per minute. Option C is correct. During ventricular flutter, the heart's ventricles do not contract effectively. Instead, they quiver or flutter, which means they are not able to effectively pump blood out to the rest of the body. This can lead to a decrease in blood pressure and cause symptoms like dizziness, fainting, or chest pain. Option A is incorrect. Ventricular flutter is not characterized by a slow heart rate, but rather a rapid one. Option B is also incorrect. While the electrical signals in the heart are disorganized and chaotic during some types of arrhythmias, this is not the case in ventricular flutter. Option D is also incorrect. While a decrease in blood volume or other factors can cause the heart's chambers to not fill with enough blood, this is not the primary mechanism underlying ventricular flutter.
Which of the following best describes contractility in the cardiac cycle and its role? A) Contractility refers to the ability of the heart to generate an electrical impulse that triggers each heartbeat, ensuring a coordinated contraction of all cardiac muscle fibers. B) Contractility refers to the ability of the heart muscle to stretch and recoil during each cardiac cycle, allowing for the efficient ejection of blood from the ventricles. C) Contractility refers to the strength of the cardiac muscle fibers and their ability to contract with greater force, enabling the heart to pump more blood with each beat. D) Contractility refers to the relaxation phase of the cardiac cycle, during which the heart muscle fibers rest and recover before the next contraction.
The correct answer is C. Contractility refers to the strength of the cardiac muscle fibers and their ability to contract with greater force, enabling the heart to pump more blood with each beat. This mechanism helps the heart compensate for changes in demand for blood.
Which of the following best describes afterload in the cardiac cycle and its role? A) Afterload refers to the resistance that the heart has to overcome in order to eject blood from the ventricles, and its role is to ensure that blood flows in the correct direction through the heart. B) Afterload refers to the amount of blood that is left in the ventricles after each contraction, and its role is to maintain a steady flow of blood through the circulatory system. C) Afterload refers to the amount of pressure that the heart generates during each contraction, and its role is to regulate blood pressure and flow throughout the body. D) Afterload refers to the pressure that the heart has to generate to overcome the resistance of the systemic circulation, and its role is to ensure that blood is delivered to the body's tissues and organs.
The correct answer is D. Afterload refers to the pressure that the heart has to generate to overcome the resistance of the systemic circulation, and its role is to ensure that blood is delivered to the body's tissues and organs.
Which of the following is most likely to happen to heart rate when the SA node is damaged or not functioning properly? A) Heart rate will increase B) Heart rate will decrease C) Heart rate will remain the same D) Heart rate will become irregular
The correct answer: B) HR will slow because the SA node generates electrical impulses to coordinate heart muscles. If the SA node is damaged or not functioning properly, the heart may still be able to make impulses from other areas, but they will be slow and less coordinated than the SA node leading to decreased HR.
