Quiz #3 - Electrophysiology

Tachycardia is a condition characterized by a heart rate above 100 beats per minute (BPM). This increased heart rate can occur due to various reasons such as stress, exercise, or certain medical conditions. Tachycardia can cause symptoms like palpitations, shortness of breath, dizziness, and chest pain. It is important to identify and treat the underlying cause of tachycardia to prevent any complications and manage the symptoms effectively.

The QRS complex corresponds to ventricular depolarization. Depolarization is the process by which the electrical activity of the heart muscle cells changes from a resting state to a state of contraction. The QRS complex represents the depolarization of the ventricles, which are the lower chambers of the heart responsible for pumping blood to the rest of the body. This electrical activity is detected and recorded by an electrocardiogram (ECG) as a series of waves and complexes. Therefore, the correct answer is ventricular depolarization.

The P wave on an ECG corresponds to atrial depolarization. This is the electrical activation of the atria, which causes them to contract and pump blood into the ventricles. Depolarization refers to the change in electrical charge that occurs when the heart muscle cells are stimulated. Therefore, the P wave represents the beginning of the electrical activity in the atria, leading to their contraction.

The SA Node, also known as the sinoatrial node, is responsible for setting the natural pace of the heart. It is often referred to as the "natural pacemaker" of the heart. The SA Node generates electrical impulses that initiate each heartbeat, causing the atria to contract. The normal rate of the SA Node is between 60-100 beats per minute (BPM), which is considered the normal resting heart rate for adults.

AV Block - 3rd Degree is the correct answer because it is a condition in which the electrical signals between the atria and ventricles are completely blocked, resulting in an independent rhythm of the atria and ventricles. In this condition, the ventricles beat at a slower rate than the average resting heart rate of 60bpm, leading to a slower heart rate overall. Tachycardia, AVRT, and Premature Ventricular Contractions all result in a faster heart rate, so they are not the correct answer.

AVRT (WPW) is the correct answer because it is the only supraventricular tachycardia (SVT) associated with a delta wave on an ECG. A delta wave is a slurred upstroke at the beginning of the QRS complex, and it is characteristic of Wolff-Parkinson-White (WPW) syndrome. AVNRT, AFlutter, and AFib are other types of SVT, but they do not exhibit a delta wave on an ECG.

Calcium plays a crucial role in muscle contraction. It binds to the protein troponin, causing a change in its shape and allowing the myosin heads to bind with actin, leading to muscle contraction. Additionally, calcium also delays repolarization by prolonging the plateau phase of the action potential in cardiac muscle cells. This delay allows for adequate contraction and relaxation of the heart muscles, ensuring proper pumping of blood. Therefore, the statement "Calcium initiates contraction and also delays repolarization" is true.

The impulses are delayed at the AV node to allow for ventricular filling. This delay ensures that the atria have enough time to contract and fully empty their blood into the ventricles before the ventricles contract. This synchronized contraction allows for efficient filling of the ventricles and proper blood flow through the heart.

Atrial flutter (Aflutter) is a supraventricular tachycardia characterized by a sawtooth pattern on an ECG. During Aflutter, the atria contract rapidly and regularly, resulting in a rapid heart rate. This sawtooth pattern is caused by the rapid firing of electrical impulses in the atria, which leads to a coordinated but abnormal contraction of the atrial muscles. Aflutter can cause symptoms such as palpitations, shortness of breath, and dizziness. Treatment options for Aflutter may include medications to control heart rate and rhythm, cardioversion, or catheter ablation.

The correct answer is T Wave. Ventricular repolarization refers to the recovery phase of the ventricles after contraction. This is represented by the T wave on an ECG. The T wave represents the electrical activity as the ventricles reset and prepare for the next contraction. The ST segment represents the early phase of ventricular repolarization, the U wave represents repolarization of the papillary muscles, and the QRS complex represents ventricular depolarization.

During depolarization, the cell's inner electric charge actually becomes less negative or more positive. This is because depolarization is the process in which the cell's membrane potential becomes less negative, moving towards a more positive charge. This occurs when positive ions, such as sodium ions, enter the cell, causing the cell to become less negative and closer to reaching its threshold for an action potential. Therefore, the correct answer is False.

AFib, or atrial fibrillation, is actually characterized by rapid and irregular contractions of the atria, not regular contractions. This condition causes the atria to quiver instead of contracting properly, which can lead to an irregular heartbeat and other complications. Therefore, the statement "AFib is characterized by rapid, regular contractions of the Atria" is false.

In a normal healthy individual, the sinoatrial (SA) node is responsible for setting the pace of the heartbeat. It initiates the electrical signals that cause the heart to contract and beats at a rate of 60-100 beats per minute (BPM). However, in the given scenario where the patient has a heartbeat of 40-60 BPM, it indicates bradycardia, which means the heart rate is slower than normal. In this case, the SA node is not setting the pace as it should, and the heartbeat is likely being regulated by another part of the heart, such as the atrioventricular (AV) node, which is depolarizing spontaneously.

The action potential travels from the AV node to the right and left bundle branches via the bundle of His and atrioventricular bundle.

blood coagulation in LAA causes clot formation which can be sent through systemic circulation to the brain (LA-->LV-->Aorta-->carotid artery-->brain)

Congenital health conditions are present at birth

Intermittent failure of the AV Node is referred to as Second Degree AV Block. In this condition, some of the electrical signals from the atria fail to reach the ventricles, leading to an irregular heartbeat. This can result in symptoms such as dizziness, fainting, and fatigue. Second Degree AV Block is further classified into two types: Type 1, also known as Mobitz Type 1 or Wenckebach, where there is a progressive delay in the electrical signals, and Type 2, where some signals are completely blocked from reaching the ventricles.

The correct answer is "Paroxysmal, Persistent, permanent, recurrent." These are the four categories of AFib. Paroxysmal AFib refers to episodes that come and go on their own. Persistent AFib is when the irregular heartbeat lasts for more than 7 days and doesn't go away on its own. Permanent AFib is when the irregular heartbeat is ongoing and long-term. Recurrent AFib refers to multiple episodes of AFib that occur over time.

Ventricular Fibrillation is dangerous because it can result in asystole, also known as cardiac arrest. During ventricular fibrillation, the heart's electrical signals become chaotic, causing the ventricles to quiver instead of pumping blood effectively. If left untreated, this can lead to the heart stopping completely, resulting in asystole or cardiac arrest. Asystole is a state of no electrical activity in the heart, leading to a complete cessation of blood flow and the absence of a pulse. Immediate medical intervention, such as CPR and defibrillation, is crucial to restore normal heart rhythm and prevent irreversible damage or death.