ERP/APD₉₀ ratios at the two RV sites.

<p>RVA  =  right ventricular apex, RVOT  =  right ventricular outflow tract.</p

Representative restitution curves.

<p>APD₉₀ restitution curves from one patient with DCM recorded at the right ventricular apex (RVA) and the right ventricular outflow tract (RVOT). For both recording sites, the restitution curves of S₂, S₃, and S₄ are shown. The linear fit to the 40 ms diastolic interval (DI) with the maximum slope is superimposed on the respective curve. The maximum slope value is denoted adjacent to the curve.</p

APD₉₀ restitution slope characteristics.

<p>RVA  =  right ventricular apex, RVOT  =  right ventricular outflow tract.</p

Baseline clinical characteristics.

<p>ACE  =  angiotensin-converting enzyme, ARB  =  angiotensin-receptor blocker, ICD  =  implantable cardioverter-defibrillator, MAP  =  monophasic action potential recording, PVS  =  programmed ventricular stimulation.</p

Representative MAP recordings.

<p>Monophasic action potentials (MAPs) recorded at the right ventricular apex (RVA) in a patient with ICM during baseline pacing (A) and during programmed ventricular stimulation (PVS) (B). Basic cycle length (S₁–S₁) was 500 ms, respectively. (A) Action potential durations (APD) were measured from MAP onset to the 90% repolarization level (APD₉₀). Diastolic interval (DI) span from APD₉₀ of the preceding MAP to the onset of the current MAP. (B) MAP recordings were obtained during PVS using three extrastimuli. In this example, the first two extrastimuli (S₂ and S₃) were already delivered at the shortest coupling intervals (S₁–S₂ 235 ms, S₂–S₃ 218 ms), while the introduction of the third extrastimulus (S₄) was still in progress and the shortest possible S₃–S₄ interval had not been reached yet.</p

Survival curves.

<p>Kaplan-Meier survival curves for event-free survival of 74 patients with ischemic and dilated cardiomyopathy. (A) Based on maximum APD₉₀ restitution slope S₂<1 or ≥1, there was no difference in reaching the combined end-point of death and/or appropriate ICD (implantable cardioverter-defibrillator) therapy (<i>p</i> = 0.79). (B) Based on dichotomized ERP/APD₉₀ ratios for S₁, there was no difference in reaching the combined end-point of death and/or appropriate ICD therapy (<i>p</i> = 0.57). (C) Kaplan-Meier survival curves based on negative or positive programmed ventricular stimulation (PVS). Mortality and/or appropriate ICD therapy was higher in patients with positive PVS (<i>p</i> = 0.006).</p