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Figure 1. 12-lead ECG during tachycardia. (A) 12-lead ECG during tachycardia in the patient presented in the 'Clinical vignette'section. This shows a narrow complex tachycardia with a ventricular rate of 187 bpm and difficult-to-characterize p-waves. (B) Tachycardia gradually slowed without any sudden transition and a second ECG now shows sinus tachycardia (upright p-waves in leads 1, aVL, II, III, aVF, biphasic p-wave in V1 and negative p-wave in lead aVR) at 115 bpm.
(Figure omitted. See article PDF.)
Figure 2. Holter monitor showing persistent sinus tachycardia. A 24-h Holter monitor in the same patient presented in the 'Clinical vignette'section showing an average heart rate of 130 bpm (range: 102-213 bpm).
(Figure omitted. See article PDF.)
Figure 3. Intracardiac ECG recordings during inappropriate sinus tachycardia. Shown are surface leads II, aVF and V1, and intracardiac recordings from the electrophysiologic diagnostic catheters positioned in the high right atrium, His-bundle region, coronary sinus and right ventricular apex. P-waves are upright in inferior leads and atrial activation sequence is high-to-low (indicated by the arrow line) and similar to normal sinus rhythm. The earliest atrial activation (marked by the star) during tachycardia is recorded on the high right atrial catheter positioned close to anatomical location of sinus node. Stim: Stimulus.
(Figure omitted. See article PDF.)
Figure 4. Sinus node modification by catheter ablation. (A) Noncontact 3D-activation map of IST (Ensite(TM) balloon array; St Jude Medical, MN, USA) in the right lateral view. The white dot shows the earliest activation during IST to be at the posterolateral right atrium in the location of the superior aspect of the anatomical sinus node. The red dots show radiofrequency lesions delivered in a craniocaudal fashion. The yellow dot shows that, after the initial ablation lesions, the earliest activation during tachycardia have shifted to a more caudal location. The ablation catheter and the balloon array used to do noncontact activation mapping are also shown. In box: virtual unipolar electrograms at the site of earliest activation showing a QS pattern. (B) Intracardiac tracings showing slowing of sinus heart rate during radiofrequency catheter ablation at the location of the earliest activation. Note a gradual decrease in sinus heart rate from 94 bpm to a stable baseline of 70 bpm. Shown are surface leads II, aVF and...