Caesar Says: This Post Makes No Sense

Carpe Diem

I don't know where I was going when I drew Julius Caesar (yes, the resemblance is a little questionable I suppose), but I still felt the need to share him with the world. As I'm currently cramming all the information I can about cardiology, I've decided to fill this post with a cardiology fact of the day!

The difference between eccentric and concentric hypertrophy:

Eccentric hypertrophy: increased preload, hypertrophic sarcomeres added in series.

Associated causes: mitral/aortic regurgitation, left to right shunt

Associated cardiomyopathy: dilated cardiomyopathy

Concentric hypertrophy: increased afterload, hypertrophic sarcomeres added in parallel.

Associated causes: Hypertension, aortic stenosis

Associated cardiomyopathies: hypertrophic and restrictive cardiomyopathies

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The difference between systolic and diastolic dysfunction:

Systolic dysfunction: volume overload, decreased ventricular contraction and decreased ejection fraction.

Associated causes: ischemia, myocardial infarction, dilated cardiomyopathy

Diastolic dysfunction: resistance to filling and normal ejection fraction.

Associated causes: hypertension, aortic stenosis, hypertrophic cardiomyopathy, restrictive cardiomyopathies

ECG: QT Interval

Another obscure pie reference unrelated to this post = the "pie in the sky" visual field defect

I know that this post is not directly related to pathology, but it's still medically-oriented so here we go!

Here's a poorly drawn electrocardiogram. From a 12 lead ECG, your reading from lead II should look somewhat like this, but not as bad. 

In layman's terms: each peak and valley represents different points of electrical activity of the heart. 

The QT interval covers the mechanical contraction of the heart's ventricles. It encompasses the period where the ventricles depolarize and then repolarize. 

The QT interval is of importance because anything that makes the QT any longer than it normally is can predispose the heart to Torsades de pointes --> ventricular arrhythmias. Also, arrhythmia is hard to spell. 

Class IA and Class III antiarrhythmics prolong the QT interval by blocking the potassium (K+) channels (makes phase 3 of the pacemaker action potential longer). 

Class IA: Na+ blockers: Quinidine, Procainamide, Disopyramide

Class III: K+ blockers: Sotalol, Dofetilide, Ibutilide, Amiodarone, Dronedarone

Anichkov Myocyte - Acute Rheumatic Fever

Needed an excuse to draw an AK47. Pew pew pew.

Some people describe these Anichkov myocytes to look like caterpillars, but I don't really see the resemblance. Anichkov (and probably any other Russian-ish name) does bring to mind the image of a Kalashnikov, so I threw that in for kicks!

Anichkov myocytes are found within fibrinoid/collagenous lesions caused by rheumatic fever. These lesions are known as Aschoff bodies. Acute rheumatic fever most often involves pancarditis or myocarditis resulting in mitral insufficiency. In chronic rheumatic fever, the mitral valve (causing either mitral stenosis or insufficiency) and aortic valve (causing either aortic stenosis or aortic regurgitation) can be involved.

Rheumatic fever occurs after an infection with Group A β-hemolytic streptococci. How can you tell if a certain strain of streptococci is β-hemolytic? Culture it on a blood agar plate and β-hemolytic cells should lyse the RBCs.