Myocardial Contractility Is Not Constant During Spontaneous Atrial Fibrillation in Patients

Brookes, Carl; White, Paul A.; Staples, Maurice; Oldershaw, Paul; Redington, Andrew N.; Collins, Peter; Noble, Mark I. M.

doi:10.1161/01.cir.98.17.1762

Cited by 70 publications

(53 citation statements)

References 33 publications

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“…The mean EW efficiency (13%) of the arrhythmic beats was, however, significantly smaller than the stable EW efficiency (15%) of the regular beats (Table 1). This confirms the already known experimental and clinical findings [18][19][20][21].…”

Section: Discussionsupporting

confidence: 91%

Mode of frequency distribution of external work efficiency of arrhythmic beats during atrial fibrillation remains normal in canine heart

et al. 2008

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The external work (EW) efficiency of individual arrhythmic beats of the left ventricle (LV) cannot directly be obtained since LV O 2 consumption (VO 2 ) of each beat cannot directly be measured under beat-to-beat varying contractile and loading conditions. We, however, have recently reported that VO 2 of each arrhythmic beat can reasonably be estimated by VO 2 = aPVA ? bE max ? c even under varying PVA and E max . Here, PVA is the LV pressure-volume (P-V) area as a measure of the LV total mechanical energy, E max is the LV end-systolic elastance as an index of the LV contractility, a is a constant O 2 cost of PVA, b is a constant O 2 cost of E max , and c is the basal metabolic VO 2 of the beat, all on a per-beat basis. Using the above formula in this study, we calculated VO 2 of the individual arrhythmic beats from their measured PVA and E max during electrically induced atrial fibrillation (AF) in normal canine hearts. We then calculated their LV EW efficiency by dividing their measured EW with the estimated VO 2 . We found that the thus calculated EW efficiency of the arrhythmic beats had a rightward skewed distribution with a mode of 15% and a maximum of 18% around a mean of 13% on average in six hearts. This mode remained comparable to the efficiency (15%) at regular tachycardia though 22% lower than mean arrhythmic tachycardia.

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Section: Discussionsupporting

confidence: 91%

Mode of frequency distribution of external work efficiency of arrhythmic beats during atrial fibrillation remains normal in canine heart

et al. 2008

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“…Од-нако нельзя исключить, что слишком затянутый период усиленной продукции NO может вести к перенапряжению и последующей декомпенса-ции механизмов, способствующих синтезу ок-сида азота. Кроме того, дополнительный вклад в развитие эндотелиальной дисфункции в мик-роциркуляторном русле при ФП, вероятно, мо-жет вносить нерегулярное и разноамплитудное по силе воздействие на эндотелиоциты ткане-вых микрососудов пульсовой волны, что объяс-няется неритмичными и неодинаковыми по си-ле сокращениями желудочков [14].…”

Section: неинвазивная аритмологияunclassified

Characteristics of NO-dependent autoregulation of tissual blood flow at idiopathic atrial fibrillation

Bockeriа¹,

Bockeria²,

Bazarsadaeva³

et al. 2013

Ann aritmol

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“…Irregular ventricular rate itself decreases the cardiac output (Clark et al, 1997) and coronary blood flow (Wichmann et al, 1983). Myocardial contractility is not constant during AF because of force-interval relationships associated with variations in cycle length, this contributes to the largely variable pulse pressures and stroke volumes (Brookes et al, 1998). Rapid ventricular rate during AF may adversely impact mitral valve function, increasing mitral regurgitation, due to the relationship between left atrial and left ventricular pressures.…”

Section: Wwwintechopencommentioning

confidence: 99%

Atrioventricular Conduction in Atrial Fibrillation: Pathophysiology and Clinical Implications

Róka¹

2012

Atrial Fibrillation - Basic Research and Clinical Applications

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Myocardial Contractility Is Not Constant During Spontaneous Atrial Fibrillation in Patients

Abstract: Myocardial contractility is constantly changing from beat to beat in atrial fibrillation because of the influence of the force-interval relationships.

Cited by 70 publications

References 33 publications

Mode of frequency distribution of external work efficiency of arrhythmic beats during atrial fibrillation remains normal in canine heart

Mode of frequency distribution of external work efficiency of arrhythmic beats during atrial fibrillation remains normal in canine heart

Characteristics of NO-dependent autoregulation of tissual blood flow at idiopathic atrial fibrillation

Atrioventricular Conduction in Atrial Fibrillation: Pathophysiology and Clinical Implications

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