Case 44 Familial Sudden Death

Patient: 18-year-old boy whose father died suddenly at the age of 46, with a history of dilated cardiomyopathy. The boy showed exercise-related ventricular premature beats and short runs of polymorphic ventricular tachycardia, probably originating in the right ventricular outflow tract. After catheter ablation, an ICD was implanted.

Complaint: palpitations in spite of metoprolol.

Figure 6.44a.

ICD pulse generator: Prizm DR 1861 (Guidant Inc, St Paul, MN, USA).

Tachycardia settings

Discrimination: stability = 30 ms; onset = 16%; V > A = ON. Therapy: VF = shock; VT = monitoring.

Bradycardia settings Mode: DDI 40bpm. Modeswitch = OFF. AV = 180 ms.

Interpretation of holter strip

The holter strip shows ventricular bigeminy with a short salvo of ventricular premature beats.

Electrogram interpretation (See Figure 6.44b)

1. Presence of tachyarrhythmia?: Yes.

2. Assessment of the onset of the tachyarrhythmia triggering device detection: the shock electrogram is helpful to assess the onset of the tachyarrhythmia. Fusion beats (*) initiate short tachyarrhythmias, falling in the VF detection zone.

Figure 6.44b. From top to bottom: atrial electrogram, ventricular electrogram, shock electrogram, and markers. Markers: AS = atrial sensing; VF = fibrillation sense; VS = ventricular sense; VT = tachycardia sense.

3. Comparison between atrial and ventricular rate: rate branch VV < AA, based on the marker channel.

4. Description of the atrial rhythm: the atrial electrogram shows two deflections for every ventricular activity during baseline rhythm. The small deflection represents far-field oversensing of the ventricular activity. The large deflection represents an atrial rhythm, cycle length «425 ms. The atrial electrogram demonstrates sinus tachycardia with far-field R-wave oversensing.

5. Characteristics of the ventricular electrogram during the tachyarrhythmia: the morphology of the shock electrogram during tachycardia changed as compared to the baseline rhythm. The morphology of the ventricular activity is consistent in the shock electrogram during tachycardia. The ventricular rhythm has a cycle length of «245 ms, with a stability of «60 ms.

Diagnosis: sinus tachycardia with non-sustained ventricular tachyarrhythmias.

Action: adjustment of antiarrhythmic drug therapy. With regard to the far-field R-wave oversensing, no reprogrammation of the device is needed as the oversensing is captured in the blanking period after every sensed ventricular activity.

Case 45 TGA and Recurrent Atrial Flutter

Patient: 25-year-old male with surgically corrected transposition of the great arteries (Mustard operation), poor ventricular function, and recurrent atrial flutter.

Index arrhythmia: out-of-hospital cardiac arrest.

Problem: wide complex tachycardia after implantation detected on the monitor. This was not shocked.

Figure 6.45a. Rhythm strip after implantation.

ICD pulse generator: Jewel AF 7250 (Medtronic Inc, Minneapolis, MN, USA).

Tachycardia settings

Detection: VF = 280 ms; VT = 340 ms. Discrimination: stability = 30 ms; PR Logic ON. Therapy: VF = shock; VT = monitoring.

Bradycardia settings

Mode: DDD 64-120 bpm. Mode switch = ON. AV = 150 ms.

Proposal: non-invasive induction with the ICD, with atrial stimulation.

Electrogram from EP study (See Figure 6.45b)

Electrogram during wide complex tachycardia (See Figure 6.45c)

Diagnosis: ventricular tachycardia. Undersensing of ventricular rhythm possible and demonstrated during ventricular fibrillation.

OW JjLiftU 11 U.d HIV/ DDI

^-1-f—i—t-*-1-1-f-1-1-f-*-i-f-1-1 t- t-f-f---- »

^-1-f—i—t-*-1-1-f-1-1-f-*-i-f-1-1 t- t-f-f---- »

1, 1, 1, 1, 1,

: § MA£KE£ CH^NN^L £ ? £ p £ £ 1 1 1 1 1 1 1 1 1 1 1

1 i 1 1

1 1 1 1 1;

Was this article helpful?

0 0

Post a comment