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The Retrograde P‐Wave Theory: Explaining ST Segment Depression in Supraventricular Tachycardia by Retrograde AV Node Conduction
Author(s) -
RIVERA SANTIAGO,
PAZ RICAPITO MARIA DE LA,
CONDE DIEGO,
VERDU MARIANO BADRA,
ROUX JEAN FRANÇOIS,
PAREDES FÉLIX AYALA
Publication year - 2014
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/pace.12394
Subject(s) - medicine , supraventricular tachycardia , cardiology , depression (economics) , tachycardia , node (physics) , electrical conduction system of the heart , thermal conduction , electrocardiography , economics , macroeconomics , materials science , structural engineering , engineering , composite material
Background Pseudo ischemic ST segment changes during supraventricular tachycardia (SVT) are not yet fully understood. Our aim was to determine whether venticulo‐atrial (VA) conduction during SVT may be a possible mechanism for ST depression (STd) in SVT. Methods Patients undergoing SVT ablation (2010–2012) were analyzed (n = 72).Typical atrioventricular node reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) were included. Those with STd were compared to those without STd. VA interval length, tachycardia cycle length (TCL), and retrograde P‐wave activation during SVT were assessed. Retrograde P waves arriving simultaneously with the ST segment (PWST) during SVT were considered, whenever an atrial electrogram (measured from the high right atrium) was “on time” with the ST segment. Results Patients with STd during SVT presented longer VA intervals than those without STd (VA 100 ± 37 ms vs VA 69 ± 22 ms; P = 0.006). No differences in TCL were observed (TCL 333 ± 35 ms vs TCL 360 ± 22 ms; P = 0.1). PWST was observed in 38.5% of patients with AVNRT and STd versus 0% in those without STd. The TCL was similar in both groups (355 ± 25 ms vs 334 ± 18 ms; P = 0.1). In patients with AVRT and STd, PWST was present in 81% of cases versus 0% in those without STd. The TCL was also similar (330 ± 29 ms vs 346 ± 17 ms; P = 0.1). Conclusions STd during SVT is observed at long VA intervals when the retrograde P wave matches the ST segment, without dependence on the TCL. This suggests that STd is not necessarily rate dependent but a result of a fusion between the ST segment and the P wave.