Inter‐ and Intraindividual Variations in Shortening of Ventricular Effective Refractory Period After an Abrupt Decrease in Pacing Cycle Length

Leerssen, Hendrik M.; Vos, Marc A.; Dulk, Karel den; Zande, Jolanda van der; Begemann, M.J.S.; Wellens, Hein J.J.

doi:10.1111/j.1540-8159.1994.tb03804.x

Cited by 4 publications

(1 citation statement)

References 12 publications

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“…Morgan et al 5 examined the adaptation of VERP and compared it to the action potential duration early after a change in rate by using two stimulators. Leerssen et al 20 studied shortening of VERP in laboratory animals after a decrease in pacing cycle length by applying repeated determinations and were able to demonstrate large interand intraindividual variation in adaptation of VERP. Preliminary experience on the application of the present method has been published recently.…”

Section: Attempts To Determine Changes In Verpmentioning

confidence: 99%

Detection of Rapid Changes in Ventricular Refractoriness in Human Studies

Toivonen

Kettunen

Simelius³

et al. 2002

Pacing Clinical Electrophis

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Conventional determination of the ventricular effective refractory period (VERP) is unsuitable for detection of rapid fluctuations in the effective refractory period (ERP). A programmed stimulation system was developed that adapts continuous atrioventricular sequential pacing, incremental extrastimulus interval (S1S2) scanning, and automatic detection of extrastimulus capture which is followed by shortening of S1S2 to execute repeated scanning. The accuracy of ERP determination was tested using variable incremental (2 and 4 ms) and decremental (4-16 ms) steps of the S1S2 interval. Based on a mean of 82 determinations in eight patients, the average VERP values stayed at 249.8-251.0 ms except during the highest capture frequency. Standard deviation of ERP values ranged from 1.1 to 2.5 ms on average at the tested incremental and decremental steps. One determination was accomplished within 7.8-15.6 seconds on average. The ability to track changes in ERP was tested by changing the drive cycle length. Time constants for the adaptation rate of VERP and ventricular monophasic action potential duration at a 90% level of repolarization were determined from each test, and were similar, 51 +/- 8 seconds (mean +/- SEM) for ERP and 51 +/- 6 seconds for the action potential duration. Thus, the developed method provides accurate ERP measurements during rapid variation in ventricular refractoriness. It allows studying the recovery of excitability and the action potential duration simultaneously, and would be valuable particularly in pathological conditions and pharmacologic interventions where these electrophysiological variables become dissociated.

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Section: Attempts To Determine Changes In Verpmentioning

confidence: 99%

Detection of Rapid Changes in Ventricular Refractoriness in Human Studies

Toivonen

Kettunen

Simelius³

et al. 2002

Pacing Clinical Electrophis

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Daily oral verapamil before but not after rapid atrial excitation prevents electrical remodeling

Kurita

Mitamura

Shiroshita-Takeshita

et al. 2002

Cardiovascular Research

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Steady‐State and Dynamic Behavior of Ventricular Repolarization and Refractoriness in the Dog: The Effect of Multiple Cycle Length Changes and d‐Sotalol Administration

Leerssen

Vos

Bulk

et al. 1998

Pacing Clinical Electrophis

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In anesthetized dogs with chronic, complete AV block we studied the characteristics of ventricular repolarization and refractoriness. Therefore, we determined: (1) steady-state values of ventricular effective refractory period (VERP), action potential duration (APD), and stimulus T interval (STI) before and after d-sotalol treatment at various pacing cycle lengths (PCLs); and (2) the dynamics of VERP, APD, and STI before and after d-sotalol treatment after the abrupt PCL decreases. VERP, APD, and STI showed a normal frequency dependency. All three parameters increased significantly after d-sotalol administration. During steady-state and dynamic measurements, STI was always longer than APD and APD was always longer than VERP in an individual animal, irrespective of PCL and conditions. Standard deviations of steady-state and dynamic values indicated a considerable interindividual variation. However, the dynamics of VERP, APD, and STI after an abrupt decrease in PCL were highly correlated (linear regression analysis: r2 > or = 0.93). The best mathematical model to describe these dynamics was a bi-exponential model (r2 > or = 0.98) with a very short first and a much longer second time constant. We found that there was a very consistent relation between VERP, APD, and STI, not only during steady-state but also in the dynamic situation after various abrupt PCL decreases. This relation does not change after the administration of d-sotalol. Therefore, STI could be used to predict steady-state and dynamic values of VERP and APD. Since STI can be made available online in implantable pacing systems this could lead to the development of new features in these devices.

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Inter‐ and Intraindividual Variations in Shortening of Ventricular Effective Refractory Period After an Abrupt Decrease in Pacing Cycle Length

Cited by 4 publications

References 12 publications

Detection of Rapid Changes in Ventricular Refractoriness in Human Studies

Detection of Rapid Changes in Ventricular Refractoriness in Human Studies

Daily oral verapamil before but not after rapid atrial excitation prevents electrical remodeling

Steady‐State and Dynamic Behavior of Ventricular Repolarization and Refractoriness in the Dog: The Effect of Multiple Cycle Length Changes and d‐Sotalol Administration

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