An interventional study of Left ventricular coronary sinus (BiV) configuration and Conduction system pacing-only configuration in Heart Failure, sponsored by Medtronic Cardiac Rhythm and Heart Failure. Completed at 12 sites in 4 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-04-15.
Sponsored by Medtronic Cardiac Rhythm and Heart Failure · Not applicable, Interventional, and Treatment
The purpose of the CSPOT study is to determine the best mode of cardiac resynchronization therapy (CRT) pacing for different populations of CRT patients, comparing traditional biventricular or left ventricular pacing (BiV), conduction system pacing (CSP)-only, and conduction system pacing optimized therapy (CSPOT) also known as a combination of conduction system pacing (CSP) and left ventricular (LV) pacing. Additionally, safety of the system will be assessed.
5,701 studies on the registry are indexed under Heart Failure; 1,220 are open to participants now.
This study's enrollment of 60 is below the median of 72 across 3,736 interventional studies indexed under Heart Failure.
Browse Heart Failure studies →Medtronic Cardiac Rhythm and Heart Failure is the lead sponsor of 239 studies on the registry; 6 are open to participants now.
Of its 19 completed or terminated interventional studies of FDA-regulated products, 17 (89%) have results posted.
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Exclusion Criteria:
Patients will undergo 1) Conduction System Pacing Optimized Therapy (CSPOT) lead placement, then the 2) acute pacing protocol, and then 3) device implant. During the acute pacing protocol (step 2), all patients will undergo three types of pacing configurations and for each pacing configuration several delay settings, as defined in Assigned Interventions. For each intervention, defined as a unique combination of pacing configuration and delay setting, the protocol will alternate for several heartbeats between AV pacing and intervention (5 sections of AV pacing and 4 sections of intervention). For each set of 9, Left Ventricular dP/dt max will be calculated continuously, and Standard Deviation of Activation Time will be selected from one of the sections for atrial-only pacing and one of the intervention sections. Device implant (step 3) will be with either a CRT-D or CRT-P. Each patient's device will be programmed to CSPOT pacing. Patients will be followed for 6 months.
Device: Left ventricular coronary sinus (BiV) configuration · Device: Conduction system pacing-only configuration · Device: Conduction System Pacing Optimized Therapy (CSPOT) configuration
For subjects with a pacemaker, pacing of the left ventricular coronary sinus only. For subjects with a defibrillator, biventricular pacing of the left ventricular coronary sinus and the right ventricle. During the acute protocol, the five AV delays for this intervention include the default AV delay setting, default + 30 milliseconds (ms) AV delay, default + 60 ms AV delay, default - 30ms AV delay, default - 60ms AV delay. Patients with a defibrillator will receive two additional delays LV precedes default by 30ms and LV precedes default by 60ms.
Conduction System Pacing (CSP) of the left bundle branch. During the acute protocol, the five AV delays for this intervention include the default AV delay setting, default + 30 milliseconds (ms) AV delay, default + 60 ms AV delay, default - 30ms AV delay, and default - 60ms AV delay.
A combination of Left Ventricle pacing and Conduction System Pacing of the left bundle branch. During the acute protocol, the eight delays for this intervention include the default AV delay setting, default + 30 milliseconds (ms) AV delay, default + 60 ms AV delay, default - 30ms AV delay, default - 60ms AV delay, CSP precedes default by 30ms, LV precedes default by 30ms and LV precedes default by 60ms.
Electrical Synchronization Response
Standard Deviation of Activation Times (SDAT) is a measurement of dyssynchrony, taken by the ECG belt. As described in the SDAT Acute Protocol (below) and intervention sections, percent change in SDAT from AV-only pacing was calculated for each patient-pacing configuration combination over the 5 AV delays. Within each patient the difference between CSPOT SDAT and CSP SDAT and the difference between CSPOT SDAT and BiV SDAT were taken. The mean of those differences across patients was calculated along with a 95% confidence interval.
Time frame: At implant during acute protocol
Hemodynamic Response
Left Ventricular (LV) dP/dt max, a measurement of the initial velocity of myocardial contraction. As described in the LV dP/dt max (below) and intervention sections, percent change in LV dP/dt max from AV-only pacing was calculated for each patient-pacing configuration combination over the 5 AV delays. Within each patient the difference between CSPOT SDAT and CSP SDAT and the difference between CSPOT SDAT and BiV SDAT were taken. The mean of those differences across patients was calculated along with a 95% confidence interval.
Time frame: At implant during acute protocol
Left Ventricular Ejection Fraction (LVEF)
Left ventricular ejection fraction will be measured, based on echocardiography, at the baseline visit and again at the 6-month follow-up visit. Change will be calculated as the value observed at baseline subtracted from the value observed at 6 months.
Time frame: Baseline and 6 months
Left Ventricular End Systolic Volume (LVESV)
Left ventricular end systolic volume will be measured, based on echocardiography, at the baseline visit and again at the 6-month follow-up visit. The change will be calculated as difference between the 6-month and baseline values, divided by the baseline value.
Time frame: Baseline and 6 months
Clinical Composite Score (CCS)
The Clinical Composite Score (CCS) is a validated 3-level categorical variable that can take the values - Improved, Unchanged, or Worsened - at each follow-up visit. It is based on mortality, HF events, termination of device function, NYHA score, and patient global assessment. Briefly, the scoring system is as follows: * A patient is considered "worsened" if they die, demonstrate a worsened NYHA class, report at least moderately worsened heart-failure symptoms, or are hospitalized or permanently discontinue therapy because of or associated with worsening heart-failure * A patient is considered "improved" if they have not "worsened" and either demonstrate improvement in NYHA class or report at least moderately improved heart-failure symptoms * A patient is considered "stabilized" if they have not "worsened" or "improved" * A patient is considered "unavailable" if they did not complete 6-month visit and was not "worsened"
Time frame: 6 months
Absolute Percent Change in SDAT by QRS Subgroup
Percent change in SDAT (as described in Primary Outcome 1: Arm/Group Description) by baseline QRS subgroup for each pacing configuration CSP, BiV, CSPOT during acute protocol at implant. The QRS subgroups were subjects with QRS width greater than 171ms and QRS width less than or equal to 171ms as measured by 12-lead ECG
Time frame: At Implant during acute protocol
Absolute Percent Change in SDAT Split by Subjects With Pure LBBB and With Other Conduction Disorders
Percent change in SDAT (as described in Primary Outcome 1: Arm/Group Description) split by subjects with pure Left Bundle Branch Block (LBBB) and with other Conduction Disorders for each pacing configuration CSP, BiV and CSPOT during acute protocol.
Time frame: At Implant during acute protocol
Absolute Percent Change in SDAT Split by Subjects With Ischemic Cardiomyopathy and Those With Non-Ischemic Cardiomyopathy
Absolute Percent change in SDAT (as described in Primary Outcome 1: Arm/Group Description) split by subjects with Ischemic Cardiomyopathy and those with Non-Ischemic Cardiomyopathy for each pacing configuration CSP, BiV and CSPOT during acute protocol.
Time frame: At Implant during acute protocol
Percent Change in LV dP/dt Max Split by Subjects With Ischemic Cardiomyopathy and Those With Non-Ischemic Cardiomyopathy
Percent change in LV dP/dt max (as described in Primary Outcome 2: Arm/Group Description)split by subjects with Ischemic Cardiomyopathy and those with Non-Ischemic Cardiomyopathy for each pacing configuration CSP, BiV and CSPOT during acute protocol.
Time frame: At Implant during acute protocol
Percent Change in LV dP/dt Max Split by Subjects With Pure Left Bundle Branch Block (LBBB) and With Other Conduction Disorders (NIVCD)
Percent change in LV dP/dt max (as described in Primary Outcome 2: Arm/Group Description) split by subjects with pure Left Bundle Branch Block (LBBB) and with other Conduction Disorders (NIVCD) for each pacing configuration CSP, BiV and CSPOT during acute protocol
Time frame: At Implant during acute protocol
Improvement in LV dP/dt Max by QRS Subgroup
Percent change in LV dP/dt max (as described in Primary Outcome 2: Arm/Group Description) by QRS subgroup for each pacing configuration CSP, BiV and CSPOT during acute protocol. The QRS subgroups were subjects with QRS width greater than 171ms and QRS width less than or equal to 171ms as measured by 12-lead ECG
Time frame: At Implant during acute protocol
| Milestone | Single Arm |
|---|---|
| Started | 60 |
| Implant attempt | 55 |
| Completed | 42 |
| Not completed | 18 |
| Withdrew: Adverse event | 4 |
| Withdrew: Death | 2 |
| Withdrew: Withdrawal by subject | 4 |
| Withdrew: Physician decision | 2 |
| Withdrew: Lost to follow-up | 2 |
| Withdrew: Screen failure | 2 |
| Withdrew: Unsuccessful procedure | 2 |
Standard Deviation of Activation Times (SDAT) is a measurement of dyssynchrony, taken by the ECG belt. As described in the SDAT Acute Protocol (below) and intervention sections, percent change in SDAT from AV-only pacing was calculated for each patient-pacing configuration combination over the 5 AV delays. Within each patient the difference between CSPOT SDAT and CSP SDAT and the difference between CSPOT SDAT and BiV SDAT were taken. The mean of those differences across patients was calculated along with a 95% confidence interval.
| Difference in percent change in SDAT | SDAT Acute Protocol |
|---|---|
| CSPOT vs CSP | 15.18 (4.26 to 26.09) |
| CSPOT vs BiV | 17.04 (4.32 to 29.76) |
Left Ventricular (LV) dP/dt max, a measurement of the initial velocity of myocardial contraction. As described in the LV dP/dt max (below) and intervention sections, percent change in LV dP/dt max from AV-only pacing was calculated for each patient-pacing configuration combination over the 5 AV delays. Within each patient the difference between CSPOT SDAT and CSP SDAT and the difference between CSPOT SDAT and BiV SDAT were taken. The mean of those differences across patients was calculated along with a 95% confidence interval.
| Difference in % change LV dP/dt max | LV dP/dt Max Acute Protocol |
|---|---|
| CSPOT vs CSP | 10.33 (7.15 to 13.51) |
| CSPOT vs BiV | -1.31 (-4.75 to 2.13) |
Left ventricular ejection fraction will be measured, based on echocardiography, at the baseline visit and again at the 6-month follow-up visit. Change will be calculated as the value observed at baseline subtracted from the value observed at 6 months.
| Change in percentage of LVEF | Single Arm |
|---|---|
| Left Ventricular Ejection Fraction (LVEF) | 15.24 (10.16 to 20.32) |
Left ventricular end systolic volume will be measured, based on echocardiography, at the baseline visit and again at the 6-month follow-up visit. The change will be calculated as difference between the 6-month and baseline values, divided by the baseline value.
| percent change lvesv | Single Arm |
|---|---|
| Left Ventricular End Systolic Volume (LVESV) | -43.28 (-51.51 to -35.06) |
The Clinical Composite Score (CCS) is a validated 3-level categorical variable that can take the values - Improved, Unchanged, or Worsened - at each follow-up visit. It is based on mortality, HF events, termination of device function, NYHA score, and patient global assessment. Briefly, the scoring system is as follows: * A patient is considered "worsened" if they die, demonstrate a worsened NYHA class, report at least moderately worsened heart-failure symptoms, or are hospitalized or permanently discontinue therapy because of or associated with worsening heart-failure * A patient is considered "improved" if they have not "worsened" and either demonstrate improvement in NYHA class or report at least moderately improved heart-failure symptoms * A patient is considered "stabilized" if they have not "worsened" or "improved" * A patient is considered "unavailable" if they did not complete 6-month visit and was not "worsened"
| Participants | Single Arm |
|---|---|
| Improved | 35 |
| Stabilized | 2 |
| Worsened | 6 |
| Unavailable | 3 |
Percent change in SDAT (as described in Primary Outcome 1: Arm/Group Description) by baseline QRS subgroup for each pacing configuration CSP, BiV, CSPOT during acute protocol at implant. The QRS subgroups were subjects with QRS width greater than 171ms and QRS width less than or equal to 171ms as measured by 12-lead ECG
| abs percent change in SDAT | QRS Greater Than 171ms | QRS Less Than or Equal to 171ms |
|---|---|---|
| CSPOT | 42.77 (30.21 to 55.32) | 42.46 (31.6 to 53.32) |
| BIV | 34.61 (23.94 to 45.28) | 19.72 (-7.96 to 47.41) |
| CSP | 34.26 (26.1 to 42.42) | 22.05 (-2.18 to 46.28) |
Percent change in SDAT (as described in Primary Outcome 1: Arm/Group Description) split by subjects with pure Left Bundle Branch Block (LBBB) and with other Conduction Disorders for each pacing configuration CSP, BiV and CSPOT during acute protocol.
| abs percent change in SDAT | LBBB | NIVCD |
|---|---|---|
| CSPOT | 51.47 (41.44 to 61.5) | 38.01 (27.22 to 48.79) |
| BIV | 36.28 (28.36 to 44.2) | 21.31 (-2.24 to 44.87) |
| CSP | 40.18 (33.91 to 46.44) | 20.28 (0.14 to 40.42) |
Absolute Percent change in SDAT (as described in Primary Outcome 1: Arm/Group Description) split by subjects with Ischemic Cardiomyopathy and those with Non-Ischemic Cardiomyopathy for each pacing configuration CSP, BiV and CSPOT during acute protocol.
| abs percent change in SDAT | Non-Ischemic | Ischemic |
|---|---|---|
| CSPOT | 48.96 (41.32 to 56.61) | 28.95 (10.75 to 47.15) |
| BIV | 36.95 (29.71 to 44.20) | 3.74 (-44.37 to 51.85) |
| CSP | 38.83 (32.17 to 45.49) | 2.23 (-37.24 to 41.71) |
Percent change in LV dP/dt max (as described in Primary Outcome 2: Arm/Group Description)split by subjects with Ischemic Cardiomyopathy and those with Non-Ischemic Cardiomyopathy for each pacing configuration CSP, BiV and CSPOT during acute protocol.
| percent change in LV dP/dt max | Non-Ischemic | Ischemic |
|---|---|---|
| CSPOT | 30.05 (23.81 to 36.29) | 17.56 (10.82 to 24.31) |
| BIV | 30.64 (22.15 to 39.12) | 17.62 (11.56 to 23.69) |
| CSP | 20.03 (15.96 to 24.1) | 8.32 (2.13 to 14.51) |
Percent change in LV dP/dt max (as described in Primary Outcome 2: Arm/Group Description) split by subjects with pure Left Bundle Branch Block (LBBB) and with other Conduction Disorders (NIVCD) for each pacing configuration CSP, BiV and CSPOT during acute protocol
| percent change in LV dP/dt max | LBBB | NIVCD |
|---|---|---|
| CSPOT | 28.08 (20.4 to 35.76) | 24.59 (17.98 to 31.21) |
| BIV | 29.35 (17.73 to 40.98) | 24.65 (17.05 to 32.25) |
| CSP | 18.02 (12.65 to 23.39) | 15.29 (10.12 to 20.47) |
Percent change in LV dP/dt max (as described in Primary Outcome 2: Arm/Group Description) by QRS subgroup for each pacing configuration CSP, BiV and CSPOT during acute protocol. The QRS subgroups were subjects with QRS width greater than 171ms and QRS width less than or equal to 171ms as measured by 12-lead ECG
| percent change in LV dP/dt max | QRS Greater Than 171ms | QRS Less Than or Equal to 171ms |
|---|---|---|
| CSPOT | 29.28 (21.32 to 37.24) | 22.77 (16.39 to 29.14) |
| BIV | 32.18 (20.68 to 43.68) | 20.88 (15.74 to 26.02) |
| CSP | 18.2 (12.88 to 23.51) | 14.49 (9.16 to 19.82) |
Collected over From enrollment through 6 month follow-up. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Single Arm | 2/60 (3.3%) | 20/60 (33.3%) | 14/60 (23.3%) |
| Event | Single Arm |
|---|---|
| Cardiac perforationCardiac disorders | 2/60 |
| PericarditisCardiac disorders | 2/60 |
| Vascular pseudoaneurysmInjury, poisoning and procedural complications | 2/60 |
| ThrombocytopeniaBlood and lymphatic system disorders | 1/60 |
| Acute myocardial infarctionCardiac disorders | 1/60 |
| ArrhythmiaCardiac disorders | 1/60 |
| Atrioventricular block completeCardiac disorders | 1/60 |
| Supraventricular tachycardiaCardiac disorders | 1/60 |
| Ventricular fibrillationCardiac disorders | 1/60 |
| Adverse drug reactionGeneral disorders | 1/60 |
| Event | Single Arm |
|---|---|
| Atrial fibrillationCardiac disorders | 5/60 |
| Atrioventricular block completeCardiac disorders | 3/60 |
| Ventricular tachycardiaCardiac disorders | 2/60 |
| Implant site haematomaGeneral disorders | 2/60 |
| Non-cardiac chest painGeneral disorders | 2/60 |
| Device stimulation issueProduct Issues | 2/60 |
| OversensingProduct Issues | 2/60 |
| Atrioventricular block second degreeCardiac disorders | 1/60 |
| Cardiac failureCardiac disorders | 1/60 |
| Adrenal massEndocrine disorders | 1/60 |
| Age, Continuous(years) | Single Arm |
|---|---|
| Mean | 68.1 ± 11.1 |
| Sex: Female, Male(Participants) | Single Arm |
|---|---|
| Female | 24 |
| Male | 36 |
| Ethnicity (NIH/OMB)(Participants) | Single Arm |
|---|---|
| Hispanic or Latino | 0 |
| Not Hispanic or Latino | 21 |
| Unknown or Not Reported | 39 |
| Race (NIH/OMB)(Participants) | Single Arm |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 0 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 4 |
| White | 18 |
| More than one race | 0 |
| Unknown or Not Reported | 38 |
| Height(cm) | Single Arm |
|---|---|
| Mean | 171.1 ± 10.5 |
| Weight(kg) | Single Arm |
|---|---|
| Mean | 88.2 ± 18.9 |
| Systolic Blood Pressure(mm Hg) | Single Arm |
|---|---|
| Mean | 121.9 ± 17.5 |
| Diastolic Blood Pressure(mm Hg) | Single Arm |
|---|---|
| Mean | 70.8 ± 10.4 |
1 further baseline measures are reported on the registry.
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Medtronic Cardiac Rhythm and Heart Failure