Arrythmias And Conduction Disorders

Front 1

Atrial Fibrillation

Back 1

Atrial fibrillation is a rapid, irregularly irregular atrial rhythm. Symptoms include palpitations and sometimes weakness, dyspnea, and presyncope. Atrial thrombi often form, causing a significant risk of embolic stroke. Diagnosis is by ECG. Treatment involves rate control with drugs, prevention of thromboembolism with anticoagulation, and sometimes conversion to sinus rhythm by drugs or cardioversion.

Front 2

Atrial Flutter

Back 2

Atrial flutter is a rapid regular atrial rhythm due to an atrial reentrant circuit. Symptoms are mainly palpitations. Atrial thrombi may form and embolize. Diagnosis is by ECG. Treatment involves rate control with drugs, prevention of thromboembolism with anticoagulants, and often conversion to sinus rhythm with drugs or cardioversion.

Front 3

Atrioventricular Block

Back 3

Atrioventricular (AV) block is partial or complete interruption of impulse transmission from the atria to the ventricles. The most common cause is idiopathic fibrosis and sclerosis of the conduction system. Diagnosis is by ECG; symptoms and treatment depend on degree of block, but treatment, when necessary, usually involves pacing.

Front 4

Bundle Branch and Fascicular Block

Back 4

Bundle branch block is partial or complete interruption of impulse conduction in a bundle branch; fascicular block is similar interruption in a hemifascicle of the bundle. The 2 disorders often coexist. There are usually no symptoms, but presence of either suggests a heart disorder. Diagnosis is by ECG. No specific treatment is indicated.

Front 5

Ectopic Supraventricular Rhythms

Back 5

Various rhythms result from supraventricular foci (usually in the atria); many are asymptomatic and require no treatment.

Front 6

Reentrant Supraventricular Tachycardias (SVT, PSVT)

Back 6

Reentrant supraventricular tachycardias involve reentrant pathways with a component above the bifurcation of the His bundle. Patients have sudden episodes of palpitations that begin and terminate abruptly; some have dyspnea or chest discomfort. Diagnosis is clinical and by ECG. Treatment is with vagotonic maneuvers and, if they are ineffective, with IV adenosine or nondihydropyridine Ca channel blockers for narrow QRS rhythms, procainamide or amiodarone for wide QRS rhythms, or synchronized cardioversion for all cases.

Front 7

Sinus Node Dysfunction
(Sick Sinus Syndrome)

Back 7

Sinus node dysfunction refers to a number of conditions producing physiologically inappropriate atrial rates. Symptoms may be minimal or include weakness, palpitations, and syncope. Diagnosis is by ECG. Symptomatic patients require a pacemaker.

Front 8

Ventricular Fibrillation

Back 8

Ventricular fibrillation produces uncoordinated quivering of the ventricle with no useful contractions. It causes immediate syncope and death within minutes. Treatment is with cardiopulmonary resuscitation, including immediate defibrillation.

Front 9

Ventricular Premature Beats

Back 9

Ventricular premature beats (VPBs) are single ventricular impulses caused by reentry within the ventricle or abnormal automaticity of ventricular cells. They are extremely common in healthy patients and in patients with a heart disorder. VPBs may be asymptomatic or cause palpitations. Diagnosis is by ECG. Treatment is usually not required.

Front 10

Ventricular Tachycardia

Back 10

Ventricular tachycardia is ≥ 3 consecutive ventricular beats at a rate ≥ 120 beats/min. Symptoms depend on duration and vary from none to palpitations to hemodynamic collapse and death. Diagnosis is by ECG. Treatment of more than brief episodes is with cardioversion or antiarrhythmics depending on symptoms. If necessary, long-term treatment is with an implantable cardioverter defibrillator.