PMC7308433_01
Initial presentation: 12-lead-ECG with a regular sustained small QRS-Complex tachycardia, P-vector -60 , a delay of the atrioventricular conduction, RP > PR and a QRS-complex amplitude alternans.
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F1
RP interval was significantly longer than PR:interval (i.e., long-RP-tachycardia) and we thought about a permanent orthodromic supraventricular tachycardia first (such as permanent junctional reciprocating tachycardia) (Figure 1) and gave Adenosine intravenously.
ECG recordings at different time points of the therapy showing no significant changes in the time intervals and de- or repolarisation. (A) Monotherapy with Esmolol before start of Ivabradine. Time intervals PQ 120 ms, QRS 60 ms, QT 260 ms, QTcB 427 ms. (B) After start of Ivabradine, in combination therapy with Esmolol. Time intervals PQ 110 ms, QRS 65 ms, QT 270 ms, QTcB 417 ms. (C) Follow up after 10 weeks combination therapy Ivabradine with Metoprolol. Time intervals PQ 110 ms, QRS 60 ms, QT 280 ms, QTcB 404 ms.
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F2
Subsequent ECG recordings showed sinus rhythms with regular AV conduction and no abnormalities of de- or repolarization (Figure 2).
Holter recording (follow up). (A) 24 h Heart rate recording showing a physiologic diurnal heart rate spectrum (heart rate maximum 157 beats/min, minimum 90 beats/min, mean 116 beats/min). (B) ECG with alternating sinus rhythm and ectopic atrial rhythm during a period with physical activity and accelerated heart rate in the afternoon (4.00-6.00 pm).
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F3
The 12-lead-ECG and Holter evaluation showed alternating ectopic atrial and sinus rhythm with a physiologic diurnal heart rate spectrum and a regular response to physical activity (Figure 3).