News Column

Patent Issued for Pacing Sequence Optimization

July 28, 2014



By a News Reporter-Staff News Editor at Cardiovascular Week -- From Alexandria, Virginia, NewsRx journalists report that a patent by the inventors Hedberg, Sven-Erik (Kungsangen, SE); Hollmark, Malin (Solna, SE); Hjelm, Stefan (Balsta, SE); Broome, Michael (Ekero, SE), filed on October 10, 2012, was published online on July 15, 2014 (see also St. Jude Medical AB).

The patent's assignee for patent number 8781580 is St. Jude Medical AB (Jarfalla, SE).

News editors obtained the following quote from the background information supplied by the inventors: "The conventional approach in cardiac resynchronization therapy (CRT) involves pacing from an electrode provided close to the right ventricular (RV) apex, an electrode on a transvenous left ventricular (LV) lead, typically in the lateral or postero-lateral vein, and optionally an electrode in the right atrium (RA).

"In such a case, the optimal interventricular (VV) delay between RV and LV pacing pulses and the optimal atrioventricular (AV) delay between atrial and ventricular pacing need to be determined. Several prior art solutions to such optimization problems have been suggested. U.S. Pat. No. 5,514,163 optimizes an AV delay based on far field R wave sense (FFRS) duration. U.S. Pat. Nos. 6,751,504; 6,804,555 use the width of the QRS in order to set optimal VV delays. In another document, U.S. Pat. No. 7,848,807, optimal AV and VV delays are determined based on the width of a P wave from a sensed far-field electrocardiogram.

"A problem with the prior art CRT is that several heart failure patients do not respond well to the selected biventricular CRT. Thus, there is a need for a CRT that is capable of achieving physiologically suitable heart contraction and thereby lead to improvements also for the non-responding heart failure patient.

"U.S. Pat. No. 6,522,923 is directed towards finding optimal AV and VV delays by testing a set of randomly selected AV and VV delays within a defined AV/VV space. The most optimal of the tested AV and VV combinations is found and a new set of randomly selected AV and VV delays are tested within a smaller AV/VV space centered at the most optimal AV/VV-combination. This procedure is repeated multiple times with ever smaller AV/VV spaces until a final optimal combination of AV and VV delays is found.

"Zuber et al., Pace 2008, 31: 802-811 discloses a comparison of acoustic cardiography and echocardiography for optimizing pacemaker settings in CRT. It was concluded that for CRT optimization acoustic cardiography provides results similar to echocardiography but with improved reproducibility and ease of use.

"Zuber et al., Europace 2008, 10: 367-373 discloses a comparison of different approaches for optimization of AV and VV delay in biventricular pacing. The authors conclude that it is advisable to measure a full grid of AV and VV delays to identify optimal settings rather than optimizing one of the two delays first.

"There is, however, still a need for efficient techniques to determine optimal pacing sequence for an implantable medical device having a multipolar cardiac lead."

As a supplement to the background information on this patent, NewsRx correspondents also obtained the inventors' summary information for this patent: "An aspect of the embodiments defines an implantable medical device (IMD) comprising a connector that is connectable to a multipolar left ventricular (LV) lead having multiple pacing electrodes configured to be arranged at multiple respective sites in connection with a patient's left cardiac ventricle. The connector is also connectable to an implantable sensor configured to generate a sensor signal recorded from the heart. Alternatively, the implantable sensor is comprised within the implantable medical device. A ventricular pulse generator is configured to generate pacing pulses to be applied to the multiple electrodes of the multipolar LV lead. The ventricular pulse generator is controlled by a pulse generator controller that controls the ventricular pulse generator to generate pacing pulses according to multiple different pacing sequences of a sequence set. Each such pacing sequence defines a pacing order at which pacing pulses are applied to the multiple electrodes of the multipolar LV lead and pulse-to-pulse delays of applying these pacing pulses to the multiple electrodes. An activation detector is connected to the connector and configured to detect onset of activation of the left ventricle for a cardiac signal. A valve closure processor of the IMD is configured to process the sensor signal from the implantable sensor to determine a respective time point of closure of the mitral valve following application of pacing pulses according to the different pacing sequences. A time interval processor determines a time interval for each pacing sequence corresponding to the time from onset of LV activation to the time point of closure of the mitral valve for a cardiac cycle during which the left ventricle is paced according to the particular pacing sequence. The IMD also comprises a selector configured to select the pacing sequence of the sequence set that resulted in the shortest time interval as determined by the time interval processor. Information of this selected pacing sequence is stored in a memory of the IMD to thereby enable identification of the selected pacing sequence as the currently optimal pacing sequence for the patient.

"Another aspect of the embodiments relates to a method of selecting a pacing sequence for an IMD. The method comprises applying pacing pulses to the multiple electrodes of a multipolar LV lead according to multiple different pacing sequences of a sequence set. Onset of activation of the left ventricle is determined for each application of pacing pulses. A respective time point of closure of the mitral valve of the heart is determined for at least one respective cardiac cycle during which the heart is paced according to the respective pacing sequences of the sequence set. A respective time interval from onset of LV activation until the time point of closure of the mitral valve is determined for each pacing sequence of the sequence set. The pacing sequence resulting in the shortest time interval is then selected and identified as the currently optimal pacing sequence for the patient."

For additional information on this patent, see: Hedberg, Sven-Erik; Hollmark, Malin; Hjelm, Stefan; Broome, Michael. Pacing Sequence Optimization. U.S. Patent Number 8781580, filed October 10, 2012, and published online on July 15, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8781580.PN.&OS=PN/8781580RS=PN/8781580

Keywords for this news article include: Cardio Device, Cardiology, Heart Valves, Medical Devices, Mitral Valve, St. Jude Medical AB.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


For more stories covering the world of technology, please see HispanicBusiness' Tech Channel



Source: Cardiovascular Week


Story Tools






HispanicBusiness.com Facebook Linkedin Twitter RSS Feed Email Alerts & Newsletters