Annihilation, entrainment and modulation of ventricular parasystolic rhythms

Castellanos, Agustín; Luceri, Richard M.; Moleiro, Federico; Kayden, David S.; Trohman, Richard G.; Zaman, Liaqat; Myerburg, Robert J.

doi:10.1016/0002-9149(84)90190-5

Cited by 59 publications

(14 citation statements)

References 41 publications

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“…Phase response curves have not become a standard experimental tool outside of the circadian rhythm field (Castellanos et al . ; Goldberg et al . ).…”

Section: Discussionmentioning

confidence: 99%

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The phase response and state space of slow wave contractions in the small intestine

Parsons

Huizinga

2017

Experimental Physiology

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What is the central question of this study? What are the dynamical rules governing interstitial cell of Cajal (ICC)-generated slow wave contractions in the small intestine, as reflected in their phase response curve and state space? What is the main finding and its importance? The phase response curve has a region of phase advance surrounding a phase delay peak. This pattern is important in generating a stable synchrony within the ICC network and is related to the state space of the ICC; in particular, the phase delay peak corresponds to the unstable equilibrium point that threads the ICC's limit cycle. Interstitial cells of Cajal (ICCs) generate electrical oscillations in the gut. Synchronization of the ICC population is required for generation of coherent electrical waves ('slow waves') that cause muscular contraction and thereby move gut content. The phase response curve (PRC) is an experimental measure of the dynamical rules governing a population of oscillators that determine their synchrony and gives an experimental window onto the state space of the oscillator, its dynamical landscape. We measured the PRC of slow wave contractions in the mouse small intestine by the novel combination of diameter mapping and single pulse electrical field stimulation. Phase change (τ) was measured as a function of old phase (ϕ) and distance from the stimulation electrode (d). Plots of τ(ϕ, d) showed an arrowhead-shaped region of phase advance enclosing at its base a phase delay peak. The phase change mirrored the perturbed pattern of contraction waves in response to a pulse. The (ϕ, d) plane is the surface of a displacement tube extending from the limit cycle through state space. To visualize the state space vector field on this tube, latent phase (ϕ ) was calculated from τ. At the transition from advance to delay, isochrons made boomerang turns before tightening and winding around the phase delay peak corresponding to the unstable equilibrium point that threads the limit cycle. This isochron foliation had previously been observed in oscillator models such as the Fitzhugh-Nagumo but has not been demonstrated experimentally. The spatial extension of the PRC afforded by diameter mapping allows a better understanding of the dynamical properties of ICCs and how they synchronize as a population.

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“…Phase response curves have not become a standard experimental tool outside of the circadian rhythm field (Castellanos et al . ; Goldberg et al . ).…”

Section: Discussionmentioning

confidence: 99%

“…Phase response curves have not become a standard experimental tool outside of the circadian rhythm field (Castellanos et al 1984;Goldberg et al 2007). One reason for this could be the high degree of precision required in the presence of instrumental and environmental noise typical of biological systems.…”

Section: Coupling and Prc Measurementmentioning

confidence: 99%

The phase response and state space of slow wave contractions in the small intestine

Parsons

Huizinga

2017

Experimental Physiology

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“…17,18 This means that nonparasystolic beats falling close to the parasystolic beats can cause (1) maximal delay, (2) maximal acceleration, (3) lesser effects, (4) practically no effect, or (5) pacemaker annihilation of the parasystolic focus. 16,19 Nonparasystolic beats falling during the first half of the parasystolic interval induce a prolongation of this interval, those occurring during the second half of the parasystolic cycle length cause an abbreviation of this interval. The electrotonic modulation (causing either prolongation or shortening of the parasystolic cycle length) is maximal at the middle point of the parasystolic interval.…”

Section: Discussionmentioning

confidence: 99%

“…The electrotonic modulation (causing either prolongation or shortening of the parasystolic cycle length) is maximal at the middle point of the parasystolic interval. 19 Thus, the coupling interval of the ectopic focus may not be constant in modulated parasystole and interectopic interval may also show variation. Modulation may also cause coupling intervals to be fixed, and the fixed coupling intervals may suggest a reciprocating bigeminy.…”

Section: Discussionmentioning

confidence: 99%

Unusual Incessant Ventricular Tachycardia

Shenthar

2015

Circ: Arrhythmia and Electrophysiology

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V entricular tachycardia (VT) is defined as a tachycardia with a rate of >100 per minute, with ≥3 consecutive beats that originates from the ventricles, and is independent of atria or atrioventricular nodal conduction. Of all the VTs, 10% occurs in those with structurally normal heart and these are called as idiopathic VTs, and the rest 90% occurs in patients with structural heart disease. VTs may be classsified based on the clinical characteristic (clinical VT, hemodynamically stable or unstable, repetitive, incessant, etc.), morphology (monomorphic, multiple morphologies, pleomorphic, polymorphic, bidirectional, etc.) or mechanisms (scar-related reentry, automaticity, and triggered activity). Incessant VT is defined as continuous sustained VT during several hours, which recurs promptly despite repeated intervention for termination. VT storm is considered as ≥3 separate episodes of sustained VT within 24 hours, each requiring termination by an intervention. Monomorphic VT has a uniformly similar QRS configuration from beat-to-beat, with either right or left bundle configuration depending on whether the dominant deflection in lead V1 is R or S wave. Multiple monomorphic VTs refer to >1 morphologically distinct monomorphic VT, occurring as different episodes, or induced at different times. Polymorphic VT has continuously changing QRS configuration from beat-to-beat indicating a changing ventricular activation sequence. Pleomorphic VT has >1 morphologically distinct QRS complex occurring during the same episode of VT, but the QRS is not continuously changing. Bidirectional VT (BVT) is characterized by beat-to-beat alternation of the QRS axis on the ECG and is usually regular. Editor's Perspective see p 1512Here, we describe unusual incessant VT in a young male and discuss evaluation, management, and the possible mechanism. Case ReportA 33-year-old male, nondiabetic, nonhypertensive, presented with history of palpitation, chest discomfort, and fatigue of 6 hours duration. He had been otherwise healthy, not on any medications with no history of tobacco, alcohol, or drug use. At presentation, pulse rate was 144 beats per minute, irregular, blood pressure 96/60 mm Hg, and the rest of physical examination was unremarkable. Twelve-lead ECG revealed a wide complex regularly irregular tachycardia at a rate of 144 beats per minute, right bundle morphology, QRS duration of 200 to 220 ms, QRS axis alternating between +160° and −40°, QRS transition alternating from V3 to V6, and evidence of atrioventricular dissociation (Figure 1). Tachycardia was unresponsive to intravenous lignocaine, esmolol, amiodarone (300 mg during 1 hour), and 2 attempts of biphasic direct current (DC) cardioversion of 200 J. Because the tachycardia was incessant, patient was sedated, intubated, ventilated, and continued on intravenous amiodarone (900 mg/24 hours) with further 4 unsuccessful attempts at DC cardioversion. Tachycardia converted to monomorphic VT with occasional VT complexes of the 2nd morphology (Figure 2), which terminated 6 hours late...

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“…Modulation of parasystole is diagnosed if an early nonparasystolic beat prolongs the ectopic cycle length and a late one has the opposite effect. [5][6][7][8] Modulation of parasystole is also suggested if, during acceleration of the dominant pacemaker, bigeminy begins to alternate with trigeminy or causes a more complex arrhythmic pattern." In this patient, we also stud-ied the effect of spontaneous change of the sinus cycle length on the parasystolic focus during ambulatory ECG recording.…”

Section: Introductionmentioning

confidence: 99%

Modulation of Atrioventricular Junctional Parasystole During Atrial Pacing

Schweitzer

Stern

1988

Pacing Clinical Electrophis

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In this report we describe a case of a 68-year-old man with atrioventricular junctional parasystole in whom atrial pacing caused marked changes in the arrhythmic pattern. During atrial pacing at a cycle length of 960 ms, the duration of the ectopic cycle length was influenced by the interval between the parasystolic and nonparasystolic beat. A shorter interval from nonparasystolic to ectopic beat prolonged the ectopic cycle length and a longer one shortened it. Pacing at a cycle length of 900 ms completely suppressed the parasystole. Both of these changes are most likely due to modulation and entrainment of the parasystolic rhythm. During spontaneous variation of the sinus cycle length over 24 hours of ambulatory ECG recording, modulation could not be confirmed; however, there was parallel variation of the ectopic and sinus cycle lengths which suggests that both pacemakers were under the influence of the autonomic nervous system.

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Annihilation, entrainment and modulation of ventricular parasystolic rhythms

Cited by 59 publications

References 41 publications

The phase response and state space of slow wave contractions in the small intestine

The phase response and state space of slow wave contractions in the small intestine

Unusual Incessant Ventricular Tachycardia

Modulation of Atrioventricular Junctional Parasystole During Atrial Pacing

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