What is HV interval in ECG?
HV interval reflects conduction through the His-Purkinje system and is measured on the His bundle electrogram from beginning of the His deflection to the earliest identified ventricular activity on the surface ECG. Normal value is 35-55 msec.
What is HV in cardiology?
Cardiology A value measured by electrophysiologic studies of the heart equal to the time from the beginning of the H deflection to the earliest onset of ventricular depolarization recorded in any lead.
What is a normal HV interval?
The normal AH interval is 54-130 msec; the normal HV interval 31-55 msec. 8 HV intervals alone were measured in patients with atrial fibrillation.
What is AV interval?
The length of time in a dual-chamber pacemaker between a sensed or paced atrial event and a paced ventricular event.
How is SNRT measured?
Measurement of SNRT is achieved by pacing the atrium. Pacing should be performed from a catheter placed in the high right atrium (HRA) near the SN at the junction of the superior vena cava (SVC) and the RA for 4-6 trials of 30 seconds each.
How is SACT measured?
SACT can be calculated as the interval from the PAC to the next spontaneous SN beat, which includes conduction through the perinodal tissue into the SN, resetting the SN, and conduction through the same perinodal tissue back into the HRA (ie, [return interval – SCL]/2).
What is incremental pacing?
Definitions and Types of PES Incremental Pacing – is pacing the heart at a fixed rate. The rate is increased (pacing interval decreased) with each set of beats.
What is infra Hisian block?
Infra-Hisian block is defined as an impaired conduction in the electrical system of the heart that occurs below the atrioventricular node.
What is sinus node recovery time?
Sinus node recovery times have been used to evaluate sinus node function in adults and children. Normal values for corrected sinus node recovery time (CSNRT) are generally accepted as 275 and 500-550 msec in young children and adults, respectively.
What is AV in echocardiography?
The next step is programming for the pacemaker a long AV interval (AV long ), followed by determination of “b”. This value “b” is the temporal interval between the ventricular contraction spike and the end of the A wave. AV long – b defines the duration of the undisturbed maximal diastolic left ventricular filling.
Why do we need rate responsive pacemaker?
Rate adaptive pacemakers are useful for patients who cannot increase their heart rate appropriately on exercise. The goal of new technologies is to come as close as possible to sinus node electrical activity, combining the need of regular ventricular rate to a better quality of life.