University:
West Coast University
Course:
PHAR 740 | IPC Cardiopulmonary and Renal III
Academic year:

2024
Views:

471

Pages:

14
Author:

Asal A.

Lara Avanesian 1 CES Complex P Ware T Wave SUPRAVENTRICULAR SA node Sinus bradycardia Less K and Caf less negative inside o Takes longer to depolarize. P and QRS is normal Longer RR (HR<60bmp) Sick sinus syndrome (bradyarrhythmia) Sinus arrest o SA node not firing. o Flat line in ECG (if nothing takes over) AV node takes over. o Inverted P waves (junctional escape rhythm) Sinoatrial Block • SA node is working but its blocked. • Sinoatrial block refers to the failure of depolarization to be transmitted out of the sinus node to the atria. This can result in a pause or skipped beat on the ECG. Bradycardia-tachycardia syndrome o SA node fires really fast, then slows down. Bradycardia Lara Avanesian 2 Sinus Tachycardia: Enhanced Automaticity (more calcium) Enhanced Automaticity o SA node cells have enhanced automaticity, meaning they have a heightened ability to generate electrical impulses and initiate the heart's contractions. Sympathetic o sympathetic opening of "funny channels" in the pacemaker cells, less time to reach phase 0 faster depolarization. As a result, the heart rate increases. o Opening of Ca channels Steeper phase 0 (less time to get to phase 0) faster depolarization EKG o Normal P and QRS Shorter RR Tachycardia Re for SA and AV node its enhanced because they are supposed to beat on their own, but for ventricles and atria, they are not supposed to beat on their own, I triggered it to beat. Atria Triggered automaticity generation of abnormal impulses from myocardial cells, rather than the usual pacemaker cells they beat with the SA node (two of them beating at the same time) not following the same pathway. Late phase 3 o Early Afterdepolarization (EAD): Triggered automaticity Premature Ventricular Contractions (PVCs) (Tachyarrhythmias) (PVCs) are the most common type of ventricular arrhythmias. They are characterized by abnormal electrical impulses that are generated in the ventricles and occur earlier than the next expected normal heartbeat. They are triggered by factors such as sympathetic activation, alcohol, and certain medications (B adrenergic receptor inducers such as inhalers and cocaine On an ECG, PVCs are identified by a wide and bizarre QRS complex, with the absence or close proximity of the P wave. After a PVC, there is usually a compensatory pause before the next normal heartbeat. PVCs can occur randomly or in a regular pattern. While occasional PVCs are typically harmless, frequent or sustained PVCs may require further evaluation and management. Reentry mechanism (ventricular tachycardia) Ventricular Tachycardia (VT) is a condition where there is a rapid heartbeat originating from the ventricles, the lower chambers of the heart. It occurs when there are three or more consecutive Premature Ventricular Contractions (PVCs), which are abnormal electrical impulses. The heart rate during VT is typically between 120 to 200 beats per minute, and it may be slightly irregular. VT is considered an emergency and can be a sign of cardiac arrest, a life-threatening condition. It's important to seek immediate medical attention if VT is suspected. After a heart attack (myocardial infarction or MI), approximately 3.5% of patients may develop VT within the first 48 hours. There is a risk of developing sustained VT within the first 6 weeks post-infarction. Sustained VT refers to VT that lasts for an extended period of time. This post-infarction VT is associated with a high mortality rate within one year.. WAL The morphology, or shape, of the waveform in Ventricular Tachycardia (VT) can vary and provide important clues about the underlying cause. There are two main types of waveform morphology seen in VT: o Uniform Uniform waveform morphology refers to a consistent appearance of the QRS complexes during the tachycardia. This type of morphology is often seen in VT caused by healed infarctions, where there has been previous damage to the heart muscle due to a heart attack. o Polymorphic polymorphic waveform morphology refers to a changing or varying appearance of the QRS complexes. This type of morphology is commonly associated with acute coronary ischemia or infarction, where there is a sudden blockage or reduced blood flow to the heart muscle. QT interval prolongation, which is an abnormal delay in the repolarization of the ventricles, can also lead to polymorphic VT.