内科学英文课件：Cardiac Arrhythmia

• When episodes are infrequent, use of an
Arrhythmia
What is Cardiac Arrthythmia?
• Cardiac arrhythmia is an abnormality in the heart's rhythm, or heartbeat pattern. The heartbeat can be too slow, too fast, have extra beats, skip a beat, or otherwise beat irregularly.
Clinical manifestations
•Whether slow heart rates produces symptoms at rest or on exertion depends upon whether cerebral perfusion can be maintained, which is generally a function of whether the patient is upright or supine and whether left ventricular function is adequate to maintain stroke volume.
• Ventricular tachycardia in the prolonged QT syndrome and in some of digitalis toxicity
Diagnosis
Clinical manifestations
– History – Symptoms: can be • lethal (sudden cardiac death) • symptomatic (chest distress, palpitations, dizziness,
• Unfortunately, this is not always easy because symptoms are usually sporadic.
• Continuous ECG monitor
• Patients with aborted sudden death and recent or recurrent syncope are often monitored in the hospital.
Clinical manifestations
•If the heart rate abruptly slow, as with the onset of complete heart block or sinus arrest, syncope or convulsions may result.
Techniques for evaluating rhythm disturbances
• Electrocardiographic monitoring • Electrophysiologic testing • Autonomic testing(tilt-table testing)
• Routine ECG
Definition of Arrhythmia
• The Origin, Rate, Rhythm, Conduct velocity and sequence of heart activation are abnormal
Mechanisms
Most arrhythmias can be classified as
• Disorders of impulse FOR • Sinus node arrest, premature
Formation
beats, automatic rhythms
• Abnormalities of impulse conduction
• Re-entry
• Triggered activity
fatigue, near syncope, syncope and shock）
• asymptomatic – Signs: slow, fast and irregular heart beats or pulses.
Clinical manifestations
•Stable SVT is generally well tolerated in patients without underlying heart disease but may lead to myocardial ischemia or congestive heart failure in patients with coronary disease, valvular abnormalities, and systolic or diastolic myocardial dysfunction.
Clinical manifestations
•VT, if prolonged(lasting more than 1030 seconds), often results in hemodynamic compromise and is more likely to deteriorate into ventricular fibrillation.
• Sino-atrial exit block, atrioventricular block, establishing reentry circuit
• premature beats, paroxysmal supraventricular tachycardias, atrial flutter
• The ideal way of establishing a causal relationship between a symptom and a rhythm disturbance is to demonstrate the presence of the rhythm during the symptom.