vulnerable period


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period

 [pēr´e-od]
an interval or division of time; the time for the regular recurrence of a phenomenon.
absolute refractory period the part of the refractory period from phase 0 to approximately −60 mV during phase 3; during this time it is impossible for the myocardium to respond with a propagated action potential, even with a strong stimulus. Called also effective refractory period.
blanking period a period of time during and after a pacemaker stimulus when the unstimulated chamber is insensitive to avoid sensing the electronic event in the stimulated chamber.
effective refractory period absolute refractory period.
ejection period the second phase of ventricular systole (0.21 to 0.30 sec), between the opening and closing of the semilunar valves, while the blood is discharged into the aorta and pulmonary artery. Called also sphygmic period.
gestation period see gestation period.
incubation period see incubation period.
isoelectric period the moment in muscular contraction when no deflection of the galvanometer is produced.
latency period
latent period a seemingly inactive period, as that between exposure to an infection and the onset of illness (incubation period) or that between the instant of stimulation and the beginning of response (latency, def. 2).
refractory period the period of depolarization and repolarization of the cell membrane after excitation; during the first portion (absolute refractory period), the nerve or muscle fiber cannot respond to a second stimulus, whereas during the relative refractory period it can respond only to a strong stimulus.
relative refractory period the part of the refractory period from approximately −60 mV during phase 3 to the end of phase 3; during this time a depressed response to a strong stimulus is possible.
safe period the period during the menstrual cycle when conception is considered least likely to occur; it comprises approximately the ten days after menstruation begins and the ten days preceding menstruation. See the section on fertility awareness methods, under contraception.
sphygmic period ejection period.
supernormal period in electrocardiography, a period at the end of phase 3 of the action potential during which activation can be initiated with a milder stimulus than is required at maximal repolarization, because at this time the cell is excitable and closer to threshold than at maximal diastolic potential.
vulnerable period that time at the peak of the T wave during which serious arrhythmias are likely to result if a stimulus occurs.
Wenckebach's period a usually repetitive sequence seen in partial heart block, marked by progressive lengthening of the P–R interval; see also dropped beat.

vul·ner·a·ble pe·ri·od

, vulnerable period of heart
a brief time during the cardiac cycle when stimuli are particularly likely to induce repetitive activity like tachycardia, flutter, or fibrillation which persists after the stimulus has ceased; for the ventricle, it occurs during the latter part of systole, during the relative refractory period coincident with the inscription of the latter half of the T wave of the electrocardiogram.

vul·ner·a·ble pe·ri·od

, vulnerable period of heart (vŭlnĕr-ă-bĕl pērē-ŏd, hahrt)
Moment during the cardiac cycle when stimuli are particularly likely to induce repetitive activity like tachycardia, flutter, or fibrillation that persists after the stimulus has ceased; for the ventricle, it occurs during the latter part of systole, during the relative refractory period coincident with the inscription of the latter half of the T wave of the electrocardiogram.
References in periodicals archive ?
Is this yet another example of a multinational company trying to influence mothers during a most vulnerable period through 'scare tactics'?
This was a course of behaviour during a very vulnerable period of her life.
Maternal and neonatal tetanus can be prevented through simple injections given during pregnancy, to protect both a mother and her unborn child during this vulnerable period.
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"We are in a very, very severe and vulnerable period in our lives," he said.
Heather Hill-Vasquez in Sacred Players examines medieval drama in its most vulnerable period, early Protestant England, suggesting we should see it as "an important second life for the religious drama in England" rather than as a time of decline (3).
Much like a traditional sense of the word, incubators help young companies survive the early years, a company's most vulnerable period, according to the National Business Incubation Association.
This underscored the notion that adolescence is the most vulnerable period for the onset of SAD, and would be the logical focus of early intervention efforts aimed at reducing its burden and preventing secondary depression, according to Dr.
Myelination as a vulnerable period in brain development.
Brigade watch manager Steve Johnson who devised the scheme with Eleanor Burns, patient services manager, said: "This particular long-term working practice will help individuals who may be at a very high risk following hospitalisation, enabling us to assist them during this vulnerable period."
"A lightning rod for the commission during a vulnerable period," TR helped to institutionalize the hitherto "precarious and ill-supported experiment" of civil service (p.
Before an audience of around 1,000 participants, both midwives and obstetricians, this initiative was taken on, in the context of Africa, where still so many women and children die during that vulnerable period of their lives.