AV Conduction Disorders
3.2 AV Conduction Disorders 1st Degree AV Block Mechanism: Delay in impulse conduction at the AV node without interruption of this impulse ECG characteristics: No pause Prolongation of the PQ…
Sinus Arrythmias
3.1 Sinus Arrythmias Sinus Bradycardia Mechanism: Slow diastolic depolarization of the sinus node ECG characteristics: Sinus rhythm with a frequency of less than 60 per minute Etiology: Sinus node syndrome,…
Acute Myocardial Infarction
4.4 Acute Myocardial Infarction Acute Myocardial Infarction Anatomical pathology: Necrosis zone: Electrically inactive zone (infarction Q) Lesion zone: Cells markedly damaged by ischemia form abnormal potentials without participating in excitation,…
Reentry Tachycardia
3.11 Reentry Tachycardia AV Nodal Reentry Tachycardia (Slow–Fast Type) Termination mechanism: After establishing the reentry circuit, sudden blockade of retrograde conduction in the fast pathway, hence no excitation of the…
Right Bundle Branch Block
3.3 Right Bundle Branch Block Isolated Complete Right Bundle Branch Block Mechanism: Delayed conduction in the right bundle branch, secondary (delayed) excitation of the right ventricle via the left ventricular…
Left Bundle Branch Block
3.4 Left Bundle Branch Block Isolated Complete Left Bundle Branch Block Mechanism: Block in the left bundle branch resulting in secondary (delayed) excitation of the left ventricle via the right…
Medication-Related ECG Changes
5.11 Medication-Related ECG Changes Class IA Antiarrhythmics (E.g., Quinidine) ECG characteristics: Class IA: Quinidine, disopyramide, procainamide Mechanism of action: Blockade of the voltage-dependent sodium channels raising the threshold potential (phase…
Stress-Induced Ischemia in Coronary Heart Disease
4.2 Stress-Induced Ischemia in Coronary Heart Disease Stress-Induced Ischemia in Coronary Heart Disease Mechanism: In the affected area the inner myocardial layer (endocardium) is particularly susceptible to ischemia (so-called last…
Atrial Fibrillation
3.10 Atrial Fibrillation Comparison of Isthmus-Dependent “Typical” Atrial Flutter (Counter-Clockwise vs. Clockwise) Atrial Fibrillation—In General Mechanism: Mostly left atrial micro-reentry with changing circuits of excitation Left atrial dilatation has a…
Further Explanations
2.6 Further Explanations (I) Blockade of conduction arises between the sinus node and the atrium or in the region of the AV node (between the atrium and the ventricle). A…
