Heart blocks: Pathology review
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Heart blocks: Pathology review
Pathology
Cardiac arrhythmias
Atrioventricular block
Bundle branch block
Pulseless electrical activity
Atrial fibrillation
Atrial flutter
Atrioventricular nodal reentrant tachycardia (AVNRT)
Premature atrial contraction
Wolff-Parkinson-White syndrome
Brugada syndrome
Long QT syndrome and Torsade de pointes
Premature ventricular contraction
Ventricular fibrillation
Ventricular tachycardia
Cardiac tumors
Cardiac tumors
Shock
Shock
Vascular disorders
Arterial disease
Aneurysms
Aortic dissection
Angina pectoris
Coronary steal syndrome
Myocardial infarction
Prinzmetal angina
Stable angina
Unstable angina
Abetalipoproteinemia
Familial hypercholesterolemia
Hyperlipidemia
Hypertriglyceridemia
Coarctation of the aorta
Conn syndrome
Cushing syndrome
Hypertension
Hypertensive emergency
Pheochromocytoma
Polycystic kidney disease
Renal artery stenosis
Hypotension
Orthostatic hypotension
Lymphangioma
Lymphedema
Peripheral artery disease
Subclavian steal syndrome
Nutcracker syndrome
Superior mesenteric artery syndrome
Angiosarcomas
Human herpesvirus 8 (Kaposi sarcoma)
Vascular tumors
Behcet's disease
Kawasaki disease
Vasculitis
Chronic venous insufficiency
Deep vein thrombosis
Thrombophlebitis
Cardiovascular system pathology review
Acyanotic congenital heart defects: Pathology review
Aortic dissections and aneurysms: Pathology review
Atherosclerosis and arteriosclerosis: Pathology review
Cardiac and vascular tumors: Pathology review
Cardiomyopathies: Pathology review
Coronary artery disease: Pathology review
Cyanotic congenital heart defects: Pathology review
Dyslipidemias: Pathology review
Endocarditis: Pathology review
Heart blocks: Pathology review
Heart failure: Pathology review
Hypertension: Pathology review
Pericardial disease: Pathology review
Peripheral artery disease: Pathology review
Shock: Pathology review
Supraventricular arrhythmias: Pathology review
Valvular heart disease: Pathology review
Vasculitis: Pathology review
Ventricular arrhythmias: Pathology review
Assessments
Heart blocks: Pathology review
USMLE® Step 1 questions
0 / 3 complete
Questions
USMLE® Step 1 style questions USMLE
of complete
Reproduced from: Wikimedia Commons
Which of the following is the most likely cause of this patient’s symptoms?
Transcript
Content Reviewers
Mikey is a 22 year old male college student from Vermont who was sent to the emergency department after passing out.
His vital signs show a heart rate of 40 beats per minute and a blood pressure of 90/50. On examination, there is an erythematous circular rash with central clearing.
His friends mention they recently went on a hiking trip. His ECG is as follows.
Natasha is a 60 year old female with chronic hypertension, diabetes, and peripheral vascular disease who comes to the emergency room complaining of sudden-onset, squeezing retrosternal chest pain accompanied by shortness of breath and sweating.
Her ECG is as follows. On laboratory evaluation, her troponin levels are significantly elevated.
Alright, so the normal electrical activity of the heart starts in the sinoatrial or SA node located near the opening of the superior vena cava into the right atrium.
Electrical activity is then conducted through the atrium to the atrioventricular, or AV node, after which it goes through the Bundle of His, then the right and left branches of the Bundle, and finally through the Purkinje fibers which deliver the current to the right and left ventricles.
Now, normally there is delay in conduction at the AV node and the Bundle of His, which gives some time for ventricular filling before the ventricle contracts.
A “heart block”, or AV block, occurs when conduction is delayed for too long at the AV node or the bundle of His. Also, electrical activity may be blocked at the level of the bundle branches, which are called bundle branch blocks.
Sources
- "Pathophysiology of Heart Disease" Wolters Kluwer Health (2015)
- "Chou's Electrocardiography in Clinical Practice" Saunders (2008)
- "Clinical electrophysiology of atrioventricular block" Cardiol Clin (1983)
- "Left Bundle Branch Block: Current and Future Perspectives" Circ Arrhythm Electrophysiol (2020)
- "2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society" J Am Coll Cardiol (2019)
- "Bradycardias and atrioventricular conduction block" BMJ. 2002 (2002)
- "Observations on second degree atrioventricular block, including new criteria for the differential diagnosis between type I and type II block" The American Journal of Cardiology (1972)
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