PA interval

interval [in´ter-val]

the space between two objects or parts; the lapse of time between two events.

AA interval the interval between two consecutive atrial stimuli.

atrioventricular interval (AV interval)

1. P–R interval.

2. in dual chamber pacing, the length of time between the sensed or paced atrial event and the next sensed or paced ventricular event, measured in milliseconds; called also atrioventricular or AV delay.

cardioarterial interval the time between the apical beat and arterial pulsation.

confidence interval an estimated statistical interval for a parameter, giving a range of values that may contain the parameter and the degree of confidence that it is in fact there.

coupling interval the distance between two linked events in the cardiac cycle.

His-ventricular (H-V) interval an interval of the electrogram of the bundle of His, measured from the earliest onset of the His potential to the onset of ventricular activation as recorded on eight of the intracardiac bipolar His bundle leads or any of the multiple surface ECG leads; it reflects conduction time through the His-Purkinje system.

lucid interval

1. a brief period of remission of symptoms in a psychosis.

2. a brief return to consciousness after loss of consciousness in head injury.

PA interval the interval from the onset of the P wave on the standard electrocardiogram (or from the atrial deflection on the high right atrial ECG) to the A wave on the His bundle ECG; it represents intra-atrial conduction time.

postsphygmic interval the short period (0.08 second) of ventricular diastole, after the sphygmic period, and lasting until the atrioventricular valves open.

P–R interval in electrocardiography, the time between the onset of the P wave (atrial activity) and the QRS complex (ventricular activity).

presphygmic interval the first phase of ventricular systole, being the period (0.04–0.06 second) immediately after closure of the atrioventricular valves and lasting until the semilunar valves open.

QRST interval (Q–T interval) in the electrocardiogram, the length of time between ventricular depolarization (the Q wave) and repolarization (the T wave); it begins with the onset of the QRS complex and ends with the end of the T wave.

VA interval [ventricular-atrial interval] the interval between a ventricular stimulus and the succeeding atrial stimulus; it is equal to the AA interval minus the atrioventricular interval.

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PA interval

Cardiology The interval between the onset of the P wave in the surface tracing of the EKG, which slightly precedes the onset of high right atrial recording, and the low right atrial deflection, measured in the His lead; the PAI corresponds to the intra-atrial conduction time, but has little clinical value. Cf AH interval, HV interval.