Arrhythmia

ARRHYTHMIA
Edited by Yingmin Chen

* Definition of Arrhythmia:
The Origin, Rate, Rhythm, Conduct velocity and sequence of heart activation are abnormally.

Anatomy of the conducting system
Pathogenesis and Inducement of Arrhythmia
* Some physical condition
* Pathological heart disease
* Other system disease
* Electrolyte disturbance and acid-base imbalance
* Physical and chemical factors or toxicosis


Mechanism of Arrhythmia
* Abnormal heart pulse formation
* Sinus pulse
* Ectopic pulse
* Triggered activity
* Abnormal heart pulse conduction
* Reentry
* Conduct block

Classification of Arrhythmia
* Abnormal heart pulse formation
* Sinus arrhythmia
* Atrial arrhythmia
* Atrioventricular junctional arrhythmia
* Ventricular arrhythmia
* Abnormal heart pulse conduction
* Sinus-atrial block
* Intra-atrial block
* Atrio-ventricular block
* Intra-ventricular block
* Abnormal heart pulse formation and conduction

Diagnosis of Arrhythmia
* Medical history
* Physical examination
* Laboratory test

Therapy Principal
* Pathogenesis therapy
* Stop the arrhythmia immediately if the hemodynamic was unstable
* Individual therapy

Anti-arrhythmia Agents
* Anti-tachycardia agents
* Anti-bradycardia agents
Anti-tachycardia agents
* Modified Vaugham Williams classification
* I class: Natrium channel blocker
* II class: ß-receptor blocker
* III class: Potassium channel blocker
* IV class: Calcium channel blocker
* Others: Adenosine, Digital

Anti-bradycardia agents
* ß-adrenic receptor activator
* M-cholinergic receptor blocker
* Non-specific activator

Clinical usage
Anti-tachycardia agents:
* Ia class: Less use in clinic
* Guinidine
* Procainamide
* Disopyramide: Side effect: like M-cholinergic receptor blocker

Anti-tachycardia agents:
* Ib class: Perfect to ventricular tachyarrhythmia
1. Lidocaine
2. Mexiletine
Anti-tachycardia agents:
* Ic class: Can be used in ventricular and/or supra-ventricular tachycardia and extrasystole.

1. Moricizine
2. Propafenone

Anti-tachycardia agents:
* II class: ß-receptor blocker
* Propranolol: Non-selective
* Metoprolol: Selective ß1-receptor blocker, Perfect to hypertension and coronary artery disease patients associated with tachyarrhythmia.
* III class: Potassium channel blocker, extend-spectrum anti-arrhythmia agent.
* Amioarone: Perfect to coronary artery disease and heart failure patients
* Sotalol: Has ß-blocker effect
* Bretylium
* IV class: be used in supraventricular tachycardia
* Verapamil
* Diltiazem
* Others:
Adenosine: be used in supraventricular tachycardia

Anti-bradycardia agents
* Isoprenaline
* Epinephrine
* Atropine
* Aminophylline
Proarrhythmia effect of antiarrhythmia agents
* Ia, Ic class: Prolong QT interval, will cause VT or VF in coronary artery disease and heart failure patients
* III class: Like Ia, Ic class agents
* II, IV class: Bradycardia

Non-drug therapy
* Cardioversion: For tachycardia especially hemodynamic unstable patient
* Radiofrequency catheter ablation (RFCA): For those tachycardia patients (SVT, VT, AF, AFL)
* Artificial cardiac pacing: For bradycardia, heart failure and malignant ventricular arrhythmia patients.

Sinus Arrhythmia

Sinus tachycardia
* Sinus rate > 100 beats/min (100-180)
* Causes:
* Some physical condition: exercise, anxiety, exciting, alcohol, coffee
* Some disease: fever, hyperthyroidism, anemia, myocarditis
* Some drugs: Atropine, Isoprenaline
* Needn’t therapy
Sinus Bradycardia
* Sinus rate < 60 beats/min
* Normal variant in many normal and older people
* Causes: Trained athletes, during sleep, drugs (ß-blocker) , Hypothyriodism, CAD or SSS
* Symptoms:
* Most patients have no symptoms.
* Severe bradycardia may cause dizziness, fatigue, palpitation, even syncope.
* Needn’t specific therapy, If the patient has severe symptoms, planted an pacemaker may be needed.
Sinus Arrest or Sinus Standstill
* Sinus arrest or standstill is recognized by a pause in the sinus rhythm.
* Causes: myocardial ischemia, hypoxia, hyperkalemia, higher intracranial pressure, sinus node degeneration and some drugs (digitalis, ß-blocks).
* Symptoms: dizziness, amaurosis, syncope
* Therapy is same to SSS
Sinoatrial exit block (SAB)
* SAB: Sinus pulse was blocked so it couldn’t active the atrium.
* Causes: CAD, Myopathy, Myocarditis, digitalis toxicity, et al.
* Symptoms: dizziness, fatigue, syncope
* Therapy is same to SSS

Sinoatrial exit block (SAB)
* Divided into three types: Type I, II, III
* Only type II SAB can be recognized by EKG.

Sick Sinus Syndrome (SSS)
* SSS: The function of sinus node was degenerated. SSS encompasses both disordered SA node automaticity and SA conduction.
* Causes: CAD, SAN degeneration, myopathy, connective tissue disease, metabolic disease, tumor, trauma and congenital disease.
* With marked sinus bradycardia, sinus arrest, sinus exit block or junctional escape rhythms
* Bradycardia-tachycardia syndrome

Sick Sinus Syndrome (SSS)
* EKG Recognition:
* Sinus bradycardia, ≤40 bpm;
* Sinus arrest > 3s
* Type II SAB
* Nonsinus tachyarrhythmia ( SVT, AF or Af).
* SNRT > 1530ms, SNRTc > 525ms
* Instinct heart rate < 80bmp

Sick Sinus Syndrome (SSS)
* Therapy:
* Treat the etiology
* Treat with drugs: anti-bradycardia agents, the effect of drug therapy is not good.
* Artificial cardiac pacing.

Atrial arrhythmia
Premature contractions
* The term “premature contractions” are used to describe non sinus beats.
* Common arrhythmia
* The morbidity rate is 3-5%
Atrial premature contractions (APCs)
* APCs arising from somewhere in either the left or the right atrium.
* Causes: rheumatic heart disease, CAD, hypertension, hyperthyroidism, hypokalemia
* Symptoms: many patients have no symptom, some have palpitation, chest incomfortable.
* Therapy: Needn’t therapy in the patients without heart disease. Can be treated with ß-blocker, propafenone, moricizine or verapamil.

Atrial tachycardia
* Classify by automatic atrial tachycardia (AAT); intra-atrial reentrant atrial tachycardia (IART); chaotic atrial tachycardia (CAT).
* Etiology: atrial enlargement, MI; chronic obstructive pulmonary disease; drinking; metabolic disturbance; digitalis toxicity; electrolytic disturbance.........

ARRHYTHMIA.ppt