ACCSAP Arrhythmias Flashcards
What CHADSVASc score in patients with HCM requires anticoagulation?
Any afib/flutter necessitates AC regardless of chadsvasc score due to high rate of thromboembolism.
What is classical manifestation and cause of long QT syndrome type 1?
Sudden cardiac death while swimming, this is a loss of function mutation in the Inward K+ channels that are responsible for membrane repolarization, and therefore produce long QT
What is the most common cause of VF or polymorphic VT?
Ischemia
What are the EKG appearances of type I and type II Brugada pattern? How do you prove someone has this syndrom?
Type 1 ST-segment changes, “coved,” are diagnostic of the syndrome whereas type 2 “saddle back” ST changes are equivocal, as seen in this ECG (Figure 2). To make a definitive diagnosis, type 1 ST-segment elevations must be observed following superior placement of precordial leads (V1 and V2) in the second intercostal space or after administration of sodium channel blocking drugs.
There is no clear role for genetic testing in Brugada syndrome.
What are diagnostic criteria for Long QT syndrome?
Long QT syndrome (LQTS) is diagnosed in the presence of corrected QT interval (QTc) = 500 msec or LQTS risk score = 3.5 when secondary causes have been excluded or in the presence of a pathogenic mutation in one of the LQTS genes. It can also be diagnosed when the QTc is 480-499 msec in a patient presenting with syncope.
What is the mechanism of Na channel blockers in treating rapid arrhythmias?
“Use dependence” Class I antiarrhythmics block inward sodium channels and slow conduction velocity in the myocardium. Class I drugs exhibit a phenomenon called “use dependence” in which the extent of channel block is increased at a higher heart rate. These drugs therefore block the sodium channels to a greater degree at faster heart rates.
How do you diagnose sinus node dysfunction with chronotropic incompetence?
SND with chronotropic incompetence as evidenced by her heart rate response during exercise, with a peak heart rate <100 bpm and <70% age-predicted maximum heart rate.
Which beta blocker can accumulate in patients with renal dysfunction?
Atenolol.
Where is the typical location of Mobitz 1 vs mobitz 2 block?
Mobitz 1 is usually AV nodal and mobitz 2 is typically in the His-Purkinje system. If there is 2:1 block you can use noninvasive vagal and sympathetic maneuvers to distinguish one from the other. Carotid sinus massage typically slows AV conduction and will worsen AV clock. Can also use exercise to improve AV nodal conduction and worsen HIS-Purkinje conduction.
What is QTC cutoff felt to be most predictive of a a positive genetic screen for LQTS?
The probability of a positive genetic test for LQTS is greatest when the QTc is >480 msec, especially in the setting of a positive family history
What are the class I indications for ICD and for BiV pacing?
Class I indication for defibrillator includes an EF of 35% or less with NYHA class II or III symptoms. Class I indication for biventricular pacing with class II, III, or ambulatory IV heart failure, LBBB, and QRS duration of 150 ms or greater
Define paroxysmal, persistent, and permanent afib
Persistent if the episode is >7 days. Longstanding persistent if >12 months. Permanent AFib is defined by cessation of attempts to control rhythm (decision with pt/provider)
CPVT - Catecholaminergic polymorphic VT.
What is the mutation most commonly involved?
Ryanodine receptor
Characterized by VT induced by exercise or emotional stress
Familial thoracic aortic aneurysm diseases.
What is the mutation most commonly involved?
TGF-beta (transforming growth factor-beta) mutations
Marfan syndrome.
What is the mutation most commonly involved?
Fibrillin mutations
