Diastole


Diastole
Heart during ventricular diastole.

Diastole (play /dˈæstəl/) is the period of time when the heart fills with blood after systole (contraction). Ventricular diastole is the period during which the ventricles are relaxing, while atrial diastole is the period during which the atria are relaxing. The term diastole originates from the Greek word διαστολη, meaning dilation.[1]

Contents

Inside the heart

Wiggers diagram, showing various events during diastole (duration marked at bottom).

During ventricular diastole, the pressure in the (left and right) ventricles drops from the peak that it reaches in systole. When the pressure in the left ventricle drops to below the pressure in the left atrium, the mitral valve opens, causing accumulated blood from the atrium to flow into the ventricle. An easy way to think about this, though untrue, is that diastole is a sump that induces suction of blood into the heart to prepare for the next pump of systole. The heart is actually filled by the momentum of the blood flowing from the previous systolic cycle, with the "atrial kick" serving as a way to "hoist" the ventricular myocardium over the mass of blood contained within the chamber just prior to systole.

The ventricular filling velocity or flow into the ventricles have two main components; First an early (E) diastolic one caused by accumulation of blood in the atria during previous systole, and second, a late one created by atrial contraction (A). The E/A ratio can be used as a diagnostic measure, since it is reduced in diastolic dysfunction.[2]

Inside the arteries

The adjective "diastolic" is used to refer to filling of the heart with blood between muscle contractions. It is used to describe the opposite portion of the cardiac cycle related to contraction. More typically it is used as one component of measurement of blood pressure. "Diastolic pressure" refers to the lowest pressure within the arterial blood stream occurring during each heart beat. The other component of blood pressure is systolic pressure, which refers to the highest arterial pressure during each heart beat.

When blood pressure is stated for medical purposes, it is usually summarized as a "ratio" of systolic to diastolic pressure; for example: 120/80 mmHg. However, this is not a true ratio: it cannot be reduced into lower terms.

See also

References

  1. ^ Diastole. Merriam-Webster Online Dictionary. 24 August 2008.
  2. ^ [1] Abdul Latif Mohamed, Jun Yong, Jamil Masiyati, Lee Lim, Sze Chec Tee. The Prevalence Of Diastolic Dysfunction In Patients With Hypertension Referred For Echocardiographic Assessment of Left Ventricular Function. Malaysian Journal of Medical Sciences, Vol. 11, No. 1, January 2004, pp. 66-74

External links


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  • diastole — [ djastɔl ] n. f. • 1541; gramm. v. 1340; gr. diastolê « dilatation » ♦ Physiol. Phase de dilatation du cœur et des artères qui alterne avec la phase de contraction ou systole. ● diastole nom féminin (grec diastolê, dilatation) Période qui suit… …   Encyclopédie Universelle

  • diástole — f. cardiol. Período de dilatación o relajación del corazón o de las arterias durante el aflujo sanguíneo. Durante este período las cuatro cavidades (aurículas y ventrículos) abren las válvulas auriculoventriculares (tricúspide y mitral) y cierran …   Diccionario médico

  • Diastole — diastolė statusas T sritis Kūno kultūra ir sportas apibrėžtis Prieširdžių ir skilvelių išsiplėtimas, per kurį į širdį priteka kraujo. kilmė gr. diastolē – išsiplėtimas, ištempimas atitikmenys: angl. diastole vok. Diastole, f rus. диастола …   Sporto terminų žodynas

  • diastole — diastolė statusas T sritis Kūno kultūra ir sportas apibrėžtis Prieširdžių ir skilvelių išsiplėtimas, per kurį į širdį priteka kraujo. kilmė gr. diastolē – išsiplėtimas, ištempimas atitikmenys: angl. diastole vok. Diastole, f rus. диастола …   Sporto terminų žodynas

  • diastolė — statusas T sritis Kūno kultūra ir sportas apibrėžtis Prieširdžių ir skilvelių išsiplėtimas, per kurį į širdį priteka kraujo. kilmė gr. diastolē – išsiplėtimas, ištempimas atitikmenys: angl. diastole vok. Diastole, f rus. диастола …   Sporto terminų žodynas

  • Diástole — Saltar a navegación, búsqueda Diástole como la fase del funcional en la cual el músculo cardíaco se relaja y dilata, y el corazón se llena de sangre, véase ciclo cardíaco. Diástole (figura literaria) (o éctasis). Obtenido de Di%C3%A1stole… …   Wikipedia Español

  • diastole — DIASTOLE. s. f. Terme d Anatomie. Mouvement naturel et ordinaire du coeur lorsqu il se dilate. C est dans le mouvement de la diastole que le sang des veines entre dans le coeur. La systole et la diastole du coeur …   Dictionnaire de l'Académie Française 1798

  • diastole — /di astole/ s.f. [dal lat. tardo diastŏle, gr. diastolḗ dilatazione ]. 1. (metr.) [nella metrica classica, allungamento di una vocale breve; nella metrica italiana, spostamento dell accento di una parola per ragioni ritmiche] ◀▶ sistole. 2.… …   Enciclopedia Italiana

  • diastole — 1570s, from medical L. diastole, from Gk. diastole drawing asunder, dilation, from diastellein, from dia through, thoroughly, entirely (see DIA (Cf. dia )) + stellein to set in order, arrange, array, equip, make ready, from PIE *stel yo ,… …   Etymology dictionary

  • diástole — ‘Movimiento de dilatación del corazón’. Los diccionarios de la Academia lo calificaron de masculino hasta fines del xix, lo que explica su frecuente uso con ese género en textos de esa época. Pero hoy solo se considera correcto el femenino, que… …   Diccionario panhispánico de dudas

  • diástole — (Del lat. diastŏle, y este del gr. διαστολή, dilatación). 1. f. Biol. Movimiento de dilatación del corazón y de las arterias, cuando la sangre penetra en su cavidad. 2. Biol. Movimiento de dilatación de la duramáter y de los senos del cerebro. 3 …   Diccionario de la lengua española