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Re-entry ventricular arrhythmia is a type of paroxysmal tachycardia occurring in the ventricle where the cause of the arrhythmia is due to the electric signal not completing the normal circuit, but rather an alternative circuit looping back upon itself. [1] There develops a self-perpetuating rapid and abnormal activation.
Lown–Ganong–Levine syndrome (LGL) is a pre-excitation syndrome of the heart. Those with LGL syndrome have episodes of abnormal heart racing with a short PR interval and normal QRS complexes seen on their electrocardiogram when in a normal sinus rhythm.
The main symptom of AVNRT is the sudden development of rapid regular palpitations. [1] These palpitations may be associated with a fluttering sensation in the neck, caused by near-simultaneous contraction of the atria and ventricles against a closed tricuspid valve leading to the pressure or atrial contraction being transmitted backwards into the venous system. [2]
Cardiac stress testing is used to determine to assess cardiac function and to disclose evidence of exertion-related cardiac hypoxia. Radionuclide testing using thallium or technetium can be used to demonstrate areas of perfusion abnormalities. With a maximal stress test the level of exercise is increased until the person's heart rate will not ...
In clinical practice, therefore, factors that would lead to the right conditions to favour such re-entry mechanisms include increased heart size through hypertrophy or dilatation, drugs which alter the length of the refractory period and areas of cardiac disease. Therefore, the substrate of ventricular fibrillation is transient or permanent ...
They are generally due to one of two mechanisms: re-entry or increased automaticity. [3] Diagnosis is typically by electrocardiogram (ECG), Holter monitor, or event monitor. [4] Blood tests may be done to rule out specific underlying causes such as hyperthyroidism, pheochromocytomas, or electrolyte abnormalities. [4]
Cardiology Atrioventricular reentrant tachycardia ( AVRT ), or atrioventricular reciprocating tachycardia , is a type of heart arrhythmia with an abnormally fast rhythm ( tachycardia ); it is classified as a type of supraventricular tachycardia (SVT).
The underlying mechanism typically involves an accessory pathway that results in re-entry. [3] Diagnosis is typically by an electrocardiogram (ECG) which shows narrow QRS complexes and a fast heart rhythm typically between 150 and 240 beats per minute. [3] Vagal maneuvers, such as the Valsalva maneuver, are often used as the initial treatment. [4]