Mixed Deck — All IBHRE Topics Flashcards

Ranolazine's antiarrhythmic properties are primarily due to inhibition of which sodium current?

Answer: Late INa

Ranolazine inhibits the late (persistent) sodium current, reducing intracellular sodium and calcium overload that can trigger arrhythmias.

In cardiac electrophysiology, what is an "ablation" procedure primarily used for?

Answer: To destroy or isolate areas of heart tissue that are causing abnormal electrical signals

Cardiac ablation is a therapeutic procedure used to treat various arrhythmias by targeting and neutralizing the specific heart tissue responsible for generating or sustaining abnormal electrical signals. Using heat (radiofrequency ablation) or cold (cryoablation), the procedure creates small scars that block the faulty electrical pathways. This effectively restores a normal heart rhythm and prevents future episodes of arrhythmia.

The standard tilt table test is typically performed at what upright angle?

Answer: 70 degrees

The Westminster protocol and most international guidelines recommend a tilt angle of 70 degrees as the standard for evaluating neurally mediated syncope.

In the VASIS (Vasovagal Syncope International Study) classification, Type 2B vasovagal syncope is characterized by:

Answer: Cardioinhibitory response with asystole ≥3 seconds

VASIS Type 2B is defined as a cardioinhibitory response with asystole of ≥3 seconds, which may favor pacemaker implantation in selected patients.

Standard 0.5 mm lead equivalent aprons typically attenuate scattered radiation by approximately?

Answer: 90–95%

Standard lead aprons attenuate approximately 90–95% of scattered radiation at diagnostic X-ray energies, substantially reducing operator dose.

A 58-year-old patient presents to the clinic for a follow-up visit. They mention having intermittent, crushing chest pain over the past week, but are currently pain-free. The ECG shows deeply inverted, symmetric T-waves in leads V2 and V3, with minimal (<1mm) ST-segment elevation and preserved R-wave progression. What is the most likely diagnosis?

Answer: Wellens' syndrome

The ECG findings described are characteristic of Wellens' syndrome (specifically Type B). This pattern, often seen when the patient is pain-free, is highly specific for a critical, proximal stenosis of the left anterior descending (LAD) artery and indicates a high risk of an impending large anterior wall myocardial infarction.

Which of the following is a key consideration when performing an electrophysiology study (EPS) on a pediatric patient?

Answer: The use of general anesthesia

Performing an electrophysiology study (EPS) on pediatric patients often requires the use of general anesthesia. Children, especially younger ones, may not be able to remain still or cooperate for the extended duration of the procedure, which involves inserting catheters and inducing arrhythmias. General anesthesia ensures patient comfort, safety, and the ability to obtain accurate diagnostic information.

A modern pacemaker's ventricular automatic capture feature confirms capture after each pacing stimulus by looking for an evoked response. To avoid misinterpreting the pacing artifact's afterpotential as a captured beat, the sensing amplifier is blanked for a short period. What is this afterpotential?

Answer: A residual electrical charge at the electrode-myocardium interface following the pacing stimulus

Following the delivery of a pacing stimulus, a residual electrical charge, known as the polarization artifact or afterpotential, develops at the electrode-tissue interface. This signal can be large enough to be sensed by the pacemaker's own amplifier. Automatic capture algorithms must differentiate this artifact from the true evoked response of depolarized myocardial tissue by using a short blanking period to allow the polarization artifact to dissipate.

In pediatric patients with Wolff-Parkinson-White (WPW) syndrome, which type of arrhythmia is most commonly observed?

Answer: Atrioventricular reentrant tachycardia (AVRT)

In pediatric patients with Wolff-Parkinson-White (WPW) syndrome, the most common arrhythmia observed is atrioventricular reentrant tachycardia (AVRT). This arrhythmia occurs due to a re-entry circuit involving the normal AV nodal pathway and the accessory pathway. The electrical impulse travels rapidly through this circuit, causing the heart to beat very fast.

Anisotropy in cardiac tissue refers to the property where conduction velocity is dependent on the direction of wavefront propagation relative to the myocardial fiber orientation. In healthy ventricular tissue, conduction velocity is typically:

Answer: Fastest in the direction longitudinal (parallel) to the fiber orientation.

Anisotropy is the directional dependence of conduction velocity. Conduction is fastest along the longitudinal axis of cardiac muscle fibers due to the elongated shape of the myocytes and the preferential alignment of gap junctions at the intercalated discs. This facilitates rapid and coordinated ventricular activation.

Which of the following is an example of situational reflex syncope?

Answer: Micturition syncope

Micturition syncope is a form of situational reflex syncope triggered by specific physiological acts such as urination, defecation, coughing, or swallowing.

Which direct oral anticoagulant (DOAC) acts as a direct thrombin inhibitor rather than a factor Xa inhibitor?

Answer: Dabigatran

Dabigatran directly inhibits thrombin (factor IIa), whereas rivaroxaban, apixaban, and edoxaban are all factor Xa inhibitors.

Pulmonary vein isolation is the cornerstone ablation strategy for which arrhythmia?

Answer: Atrial fibrillation

Pulmonary vein isolation electrically disconnects the pulmonary veins from the left atrium, eliminating the primary triggers of atrial fibrillation originating from these structures.

Which component of a pacemaker or ICD is responsible for detecting the heart's intrinsic electrical activity?

Answer: The lead(s)

The leads are crucial components of pacemakers and ICDs, serving as the communication link between the pulse generator and the heart. They are responsible for both delivering electrical impulses to the heart (pacing) and sensing the heart's own intrinsic electrical activity. This sensing capability allows the device to respond appropriately, pacing only when needed and inhibiting pacing when the heart's natural rhythm is sufficient.

What constitutes the endpoint of successful accessory pathway catheter ablation?

Answer: Loss of pre-excitation on ECG and non-inducibility of AVRT

Successful accessory pathway ablation eliminates the delta wave (pre-excitation) on surface ECG and renders AVRT non-inducible during programmed stimulation.

On an implantable loop recorder (ILR) in a patient with recurrent syncope, which finding best supports a neurally mediated (vasovagal) mechanism?

Answer: Gradual progressive bradycardia leading to asystole coinciding with syncope

A gradual progressive sinus bradycardia followed by asystole during spontaneous syncope on ILR is the hallmark ILR pattern of neurally mediated syncope.

Informed consent for EP ablation procedures must include discussion of?

Answer: Risks, benefits, alternatives, and expected outcomes

Informed consent requires complete disclosure of procedure risks, benefits, reasonable alternatives, and expected outcomes to allow autonomous patient decision-making.

Which serious complication is uniquely associated with transseptal puncture for left-sided EP procedures?

Answer: Cardiac tamponade from aortic or atrial perforation

Transseptal puncture to access the left atrium carries risk of cardiac tamponade if the needle inadvertently perforates the aorta, atrial free wall, or pericardium.

A remote transmission from an asymptomatic 65-year-old patient with an ICD for primary prevention (ischemic cardiomyopathy, EF 30%) is flagged for a 12-beat run of non-sustained ventricular tachycardia (NSVT) at 155 bpm. The device functioned appropriately and did not deliver therapy. What is the most appropriate next step for the reviewing clinician?

Answer: Contact the patient to assess for symptoms and schedule a routine in-person follow-up.

Brief, asymptomatic, non-sustained VT is a common finding on device interrogations and does not typically warrant immediate or emergent action in a stable patient. The appropriate response is to correlate the arrhythmia with any potential symptoms, ensure the patient is otherwise stable, and schedule a routine follow-up to review device settings and overall clinical status. Urgent intervention is not indicated for this isolated finding.

Vascular closure devices (VCDs) after EP procedures are primarily used to?

Answer: Achieve hemostasis with reduced manual compression time

Vascular closure devices seal the arterial or venous puncture site using collagen plugs, sutures, or clips, significantly reducing manual compression time and patient discomfort.