30395
document
Enhanced inotropic state of the failing left ventricle by cardiac contractility modulation electrical signals is not associated with increased myocardial oxygen consumption . BACKGROUND Previous studies in patients and in dogs with experimentally induced heart failure ( HF ) showed that electrical signals applied to the failing myocardium during the absolute refractory period improved left ventricular ( LV ) function . We examined the effects these same cardiac contractility modulating ( CCM ) electrical signals on myocardial oxygen consumption ( MVO ( 2 ) ) in both patients and dogs with chronic HF . METHODS AND RESULTS Six dogs with microembolizations-induced HF and 9 HF patients underwent CCM leads and generator ( OPTIMIZER II ) implantation . After baseline measurements , CCM signals were delivered continuously for 2 hours in dogs and for 30 minutes in patients . MVO ( 2 ) was measured before and after CCM therapy . In dogs , CCM therapy increased LV ejection fraction at 2 hours ( 26 +/- 1 versus 31 +/- 2 % , P = .001 ) without increasing MVO ( 2 ) ( 257 +/- 41 versus 180 +/- 34 micromol/min ) . In patients , CCM therapy increased LV peak +dP/dt by 10.1 +/- 1.5 % . As with dogs , the increase in LV function after 30 minutes of CCM therapy was not associated with increased MVO ( 2 ) ( 13.6 +/- 9.7 versus 12.5 +/- 7.2 mL O ( 2 ) /min ) . CONCLUSIONS The study results suggest that unlike cAMP-dependent positive inotropic drugs , the increase in LV function during CCM therapy is elicited without increasing MVO ( 2 ) .
30396
Intervention_Physical
cardiac contractility modulation electrical signals
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Intervention_Physical
electrical signals
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Intervention_Physical
cardiac contractility modulating ( CCM ) electrical signals
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Intervention_Physical
microembolizations-induced HF
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Intervention_Physical
CCM leads and generator ( OPTIMIZER II ) implantation
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Intervention_Physical
CCM signals
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Intervention_Physical
CCM therapy
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Intervention_Physical
CCM therapy
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Intervention_Physical
CCM therapy
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Intervention_Physical
CCM therapy
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Intervention_Physical
CCM therapy
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Outcome_Physical
myocardial oxygen consumption
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Outcome_Physical
left ventricular ( LV ) function
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Outcome_Physical
myocardial oxygen consumption ( MVO ( 2 ) )
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Outcome_Physical
MVO ( 2 )
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Outcome_Physical
LV ejection fraction
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Outcome_Physical
MVO ( 2 )
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Outcome_Physical
LV peak +dP/dt
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Outcome_Physical
LV function
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Outcome_Physical
MVO ( 2 )
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Outcome_Physical
LV function