Monthly Archives: April 2015

One MCQ a day – 12.04.2015

Answer to the question on 11.04.2015

Answer : D

localizing the AP

1. Left free-wall APs are associated with positive delta waves in lead V1 and negative delta
waves in leads I and aVL

2. The ECG in a patient with a manifest right-sided AP shows a negative delta wave in lead V1 and positive delta waves in leads I and aVL.

3. The polarity of the delta waves in leads III and aVF is helpful in localizing the AP on the AV annulus. Positive delta waves in these leads point to an insertion at the anterior, anterolateral, or lateral aspect of the tricuspid or mitral annulus. Negative delta waves in these leads are consistent with an insertion at the inferior aspect of the AV valves (e.g., posterior, posterolateral, or posteroseptal aspect of the tricuspid or mitral annulus)

4. For anteroseptal and midseptal accessory pathways, a few additional observations are helpful. Typically, a negative delta wave is present in lead V1 in patients with anteroseptal and midseptal accessory pathways. Septal accessory pathways may be distinguished
from right free-wall pathways if the precordial QRS transition (negative to positive) occurs at or before lead V3. If the transition occurs between V3 and V4, the amplitude of the delta
wave in lead II is examined. An amplitude of 1.0 mV or greater is consistent with a septal AP, whereas amplitude less than 1.0 mV suggests a right free wall connection. In a patient whose ECG is consistent with a posteroseptal AP, a steeply negative delta wave in lead II is suggestive of an epicardial connection.

(Ref: Cardiac Electrophysiology: From Cell to Bedside: 6th edition, Page : 758)

MCQ 12.04.2015

A 32 years old male patient presented to emergency with complains of palpitation for 30 mins. He has history of recurrent episodes of palpitation for last one year. On examination his pulse was variable, blood pressure was 100/70 mmHg. The ECG is shown below. Which is the initial drug of choice for this patient

WPW-AF

A. Intravenous procainamide

B. Intravenous adenosine

C. Intravenous diltiazem

D. Intravenous Verapamil

Keywords: Cardiology, Multiple choice questions, medical students, Electrophysiology

One MCQ a day – 11.04.2015

Answer to the question on 10.04.2015

Answer: B

Accessory pathways are anomalous bypass tracts composed of working myocardial cells. Most APs insert along the mitral or tricuspid valve and are referred to as AV accessory pathways. Approximately 60% of APs insert along the mitral valve and are referred to as left free-wall pathways. About 25% insert along the septal aspect of the tricuspid or mitral valve and are classified as septal pathways. The remaining 15% are right freewall pathways.

Occasionally one may encounter APs that do not insert along the AV valves. Examples include atriofascicular, nodoventricular, nodofascicular, and atrionodal pathways.

Atriofascicular pathways connect the right atrium to the distal ramifications of the right bundle branch and are capable of only anterograde conduction.

Nodoventricular and nodofascicular pathways connect the AV node to the right ventricular myocardium and the specialized conduction system, respectively.

Atriofascicular and nodoventricular/nodofascicular connections are also notable for their decremental conduction properties.

Atrionodal pathways are rare and connect the right atrial myocardium to the AV node.

(Ref: Cardiac Electrophysiology: From Cell to Bedside: 6th edition, Page : 755)

 

MCQ 11.04.2015

Q. Localize the accessory pathway (AP) from the ECG

ANTEROSEPTAL AP

A. Left free wall AP

B. Posteroseptal AP

C. Right free wall AP

D. Anteroseptal AP

Please post your answers as comments.

Keywords: Cardiology, Multiple choice questions, medical students, Electrophysiology

One MCQ a day – 10.04.2015

One Cardiology MCQ a day

I will  post one MCQ on cardiology per day and next day I will submit the answer. So lets test our knowledge on cardiology.

Q.  Which of the following statements about location of accessory pathways (AP) is correct?

A.  10% of APs  are left free-wall pathways, 80% are septal and 10-15% are right freewall     pathways

B. 60% of APs  are left free-wall pathways, about one-fourth are septal and 15% are right freewall  pathways

C.  60% of APs  are left free-wall pathways, about 10% are septal and 30% are right freewall  pathways

D.  40% of APs  are left free-wall pathways, about 15% are septal and 45% are right freewall  pathways

Answers please (Tomorrow I will post the answer)