The resetting response of ventricular tachycardia to single and double extrastimuli: Implications for an excitable gap

Stamato, Nicholas J.; Rosenthal, Mark E.; Almendral, Jesús; Josephson, Mark E.

doi:10.1016/0002-9149(87)90312-2

Cited by 33 publications

(8 citation statements)

References 12 publications

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“…In a series of elegant studies, Almendral and colleagues [49][50][51][52][53] analyzed the response of a VT to a single extrastimulus. The interaction of a single extrastimulus with a tachycardia was termed resetting, and its presence implied the presence of an excitable gap in the tachycardia circuit.…”

Section: Figure 2 Site Specificity Of Induction Of Ventricular Tachymentioning

confidence: 99%

Electrophysiology of Ventricular Tachycardia:

Josephson

2003

Cardiovasc electrophysiol

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Section: Figure 2 Site Specificity Of Induction Of Ventricular Tachymentioning

confidence: 99%

Electrophysiology of Ventricular Tachycardia:

Josephson

2003

Cardiovasc electrophysiol

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“…Prema-T he presence of a less than compensatory pause after a premature beat indicates reset of a cardiac rhythm and has been described for both normal and abnormal automaticityl2 as well as for reentry.3-6 The response to premature stimulation has gained special importance in the treatment of ventricular tachycardia (VT) after myocardial infarction,7,8 which most likely is due to reentry.9-11 In a number of studies, premature stimulation has provided evidence that during clinical VT a partially or fully excitable gap exists in the circuit. [3][4][5][6] The response of VT to premature stimulation also is used to evaluate the effects of antiarrhythmic drugs on the reentrant circuit. '2-14 Although the reset response may reveal some of the conduction properties within and around the reentrant circuit,S it has not yet been determined whether clinical ventricular tachycardia is based on reentry around a functional or an anatomic barrier.…”

Section: Mapping Of Reset Of Anatomic and Functional Reentry In Anisomentioning

confidence: 99%

Mapping of reset of anatomic and functional reentry in anisotropic rabbit ventricular myocardium.

et al. 1994

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BACKGROUND Premature stimulation is used to characterize the reentrant circuit during ventricular tachycardia (VT) in patients. The goal of this study was to compare the effects of premature stimulation on functional and anatomic reentrant VT. METHODS AND RESULTS In 18 Langendorff-perfused rabbit hearts, thin layers of anisotropic left ventricular subepicardium were created by a cryoprocedure. In 8 hearts, rapid pacing induced reentry around a line of functional conduction block; in 10 hearts, reentry occurred around a fixed epicardial obstacle created by a cryoprobe. The cycle lengths (CL) of functional and anatomic VT were 110 +/- 10 and 167 +/- 17 milliseconds, respectively. During anatomic VT, the excitable gap measured 43% of the CL and premature stimuli could always reset VT (44 +/- 12 milliseconds). During early premature beats, conduction of the orthodromic wave was slightly depressed, but anatomic VT was never terminated. Reset curves at different sites in the ventricle revealed three different response types, both determined by and characterizing the spatial and temporal relation between pacing and recording sites. Premature stimulation during functional VT revealed a local excitable gap at the pacing site measuring 27% of the cycle length of VT. However, in only 3 of 8 hearts, premature stimuli could reset functional VT by 8%. In 5 VTs, advancement of the paced activation was fully compensated by prolongation of the return cycle, and VT was not reset. Due to slow conduction both toward and inside the circuit, the paced orthodromic wave lost its prematurity already within a distance of 6 to 10 mm from the pacing site. CONCLUSIONS Both during anatomic and functional reentry, an excitable gap is present in the reentrant circuit. Three different response curves reveal the localization of the pacing and recording sites in the circuit. Anatomic VT can always be reset by premature stimuli, whereas in 5 of 8 hearts, functional VT could not be reset. In the other 3 hearts, VT could only be reset for less than 7% to 11% of the VT interval. Therefore, it seems very unlikely that clinical VT based on functional reentry can be reset.

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“…[1][2][3][4][5][6] Flat portions were short, unlike in clinical responses where flat portions occur over as much as 50% of the cycle. 1 This difference may be related to different substrates forming reentrant circuits (discussed below).…”

Section: Resetting Response Curves Of Canine Ventricular Tachycardiamentioning

confidence: 97%

“…[1][2][3][4][5][6] Almendral et al 1 noted 3 resetting responses-flat, increasing, and mixed-based on changes in return cycles after progressively premature impulses. They postulated that a flat response indicated a fully excitable gap in the circuit; an increasing response, a partially excitable gap; and a mixed response, a combination of the two.…”

mentioning

confidence: 99%