Current status of monophasic action potential recording: theories, measurements and interpretations

Franz, Michael R.

doi:10.1016/s0008-6363(98)00268-5

Cited by 161 publications

(142 citation statements)

References 78 publications

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“…This is because MAP recording involves endocardial pressure such that the myocardium subjacent to the electrode tip is inactivated 7 and the ST segments of contact UEs in the vicinity are invariably elevated. However, MAP durations have not been directly compared with reconstructed T-wave morphology but with timing measurements of UE derivatives.…”

Section: Limitationsmentioning

confidence: 99%

Determination of Human Ventricular Repolarization by Noncontact Mapping

et al. 2004

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Background-Noncontact mapping (NCM) has not been validated as a clinical technique to measure ventricular repolarization. We used NCM to determine repolarization characteristics by analysis of reconstructed unipolar electrograms (UEs) at the same sites as monophasic action potential (MAP) recordings in the human ventricle. Methods and Results-MAPs were recorded from a total of 355 beats at 46 sites in the left or right ventricle of 9 patients undergoing ablation of ventricular tachycardia guided by NCM (EnSite system). Measurements were made during sinus rhythm, constant right ventricular pacing, and ventricular extrastimuli during restitution-curve construction. The EnGuide locator signal was used to document MAP catheter locations on the endocardial geometry. UE-determined activation-recovery interval (ARI) measured at the maximum derivative of the T wave (Wyatt method) and the minimum derivative of the positive T wave (alternative method) was correlated with MAP measured at 90% repolarization (MAP90%) at the same sites. ARI correlated with MAP90% during steady state by the Wyatt method (rϭ0.83, PϽ0.001) and the alternative method (rϭ0.94, PϽ0.001). Restitution curves constructed from MAP and UE data exhibited the same characteristics, with a mean correlation coefficient of 0.95 (range, 0.90 to 0.99, PϽ0.001). The error between ARI and MAP90% was greater over a shorter diastolic coupling interval but was not influenced by distance of the sampling site from the multielectrode array. Conclusions-NCM accurately determines steady-state and dynamic endocardial repolarization in humans. Global, high-density, NCM data could be used to characterize abnormalities of human ventricular repolarization. (Circulation.

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Section: Limitationsmentioning

confidence: 99%

Determination of Human Ventricular Repolarization by Noncontact Mapping

et al. 2004

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“…Stable endocardial contact was verified by MAP morphology. 5 The catheter was used for inducing VF and recording MAPs. The left ventricular catheter, right ventricular electrode, and TEE probe were omitted.…”

Section: Animal Preparationmentioning

confidence: 99%

“…5 The APD at each of these amplitudes (APD 30 , APD 60 , and APD 90 ) was measured relative to the fast initial MAP stroke.…”

Section: Measurementsmentioning

confidence: 99%

“…In this setting, prominent repolarization abnormalities occur that are characterized by shortening of the APD and change to a more triangular shape, decreased amplitude, APD alternans, and afterdepolarizations. 5,13 APD shortening is partly explained by opening of sarcolemmal K ϩ ATP channels. 14 However, recent evidence also implicates NHE-1 activation.…”

Section: Postresuscitation Ventricular Arrhythmias and Apdmentioning

confidence: 99%

“…The effects on APD and ventricular ectopic activity were investigated by use of a monophasic action potential (MAP) recording/pacing catheter. 4,5 …”

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confidence: 99%

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Sodium-Hydrogen Exchange Inhibition During Ventricular Fibrillation

Ayoub

Kolarova

et al. 2003

Circulation

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Background-Inhibition of the sarcolemmal sodium-hydrogen exchanger isoform-1 (NHE-1) is emerging as a promising novel strategy for ameliorating myocardial injury associated with ischemia and reperfusion. We investigated whether NHE-1 inhibition (with cariporide) could minimize mechanical and electrical myocardial abnormalities that develop during ventricular fibrillation (VF) and improve outcome using a porcine model of closed-chest resuscitation. Methods and Results-Two groups of 8 pigs each were subjected to 8 minutes of untreated VF and randomized to receive either a 3-mg/kg bolus of cariporide or 0.9% NaCl immediately before an 8-minute interval of conventional closed-chest resuscitation. Cariporide prevented progressive increases in left ventricular free-wall thickness (from 1.0Ϯ0.2 to 1.5Ϯ0.3 cm with NaCl, PϽ0.001 versus 0.9Ϯ0.1 to 1.1Ϯ0.3 cm with cariporide, PϭNS), maintained the coronary perfusion pressure above resuscitability thresholds (10Ϯ8 versus 19Ϯ3 mm Hg before attempting defibrillation, PϽ0.05), and increased resuscitability (2 of 8 versus 8 of 8, PϽ0.005). In 2 additional groups of 4 pigs each subjected to a briefer interval of untreated VF, cariporide ameliorated postresuscitation shortening of the action potential duration (APD) at 30%, 60%, and 90% repolarization (ie, APD 60 at 2 minutes after resuscitation; 75Ϯ29 versus 226Ϯ16 ms, PϽ0.05), minimized postresuscitation ventricular ectopic activity preventing recurrent VF, and lessened postresuscitation myocardial dysfunction. Conclusions-NHE-1 inhibition may represent a highly potent novel strategy for resuscitation from VF that can ameliorate myocardial manifestations of ischemic injury and improve the effectiveness and outcome of closed-chest resuscitation.

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