Address for correspondence: Roy M. John,
MD, PhD, Section of Cardiology, Lahey Clinic Medical Center, 41 Mall
Road, Burlington, MA 01805. Email: roy.m.john@lahey.org
A 70 year old male with coronary artery disease,
severe left ventricular dysfunction (LVEF 20%), first degree AV block and
underlying QRS of 154 msec underwent upgrade of an existing dual
chamber ICD system with a Medtronic Insync Model 7272. The device was programmed
to provide atrial synchronized biventricular pacing in the DDD mode. He
experienced significant improvement in heart failure symptoms following
cardiac resynchronization therapy. His ICD was programmed for single zone
detection in the VF zone at 182 bpm with first shock therapy of 24J. Pacing
was programmed in the DDD mode with lower rate limit of 70 and upper rate
limit of 120ppm.
He presents
with an ICD shock while seated watching television. He had minimal prodromal
symptoms prior to the shock although he admitted to being more dyspneic
for the past two days. Data recovered during ICD interrogation is shown below:
Click here to enlarge
Click here to enlarge
Figure 1: Electrograms and
markers obtained during ICD interrogation. The top and bottom panels show
the onset and termination of arrhythmia respectively. In each panel, the
following information is displayed from top to bottom: atrial electrogram,
ventricular electrogram, atrial marker channel with cycle length and ventricular
marker channel with cycle length.
Which of the following is a true
statement regarding this arrhythmia?
1. A supraventricular tachycardia is a present
2. Programming of the ICD as a two zone device with activation of
the SVT discrimination algorithm may have delayed or prevented this ICD
shock
3. A ventricular tachycardia with 1:1 VA conduction is successfully
terminated by the ICD shock
4. This arrhythmia is best treated with radiofrequency ablation of
the AV node
5. Separate atrial and ventricular arrhythmias are present
Arrhythmia
Quiz 3 - Answer
