Stephanie C Haberman

Impact of scar burden by single-photon emission computed tomography myocardial perfusion imaging on patient outcomes following cardiac resynchronization therapy.

AIMS Ischaemic heart disease negatively impacts response to cardiac resynchronization therapy (CRT), yet the impact of infarct scar burden on clinical outcomes and its interaction with mechanical dyssynchrony have not been well described. METHODS AND RESULTS We studied 620 NYHA classes III-IV heart failure patients with ejection fraction (EF) ≤ 35% and QRS duration ≥120 ms referred for CRT. Included were 190 ischaemic cardiomyopathy (ICM) CRT recipients with scar burden quantified by rest-redistribution Tl(201) myocardial perfusion imaging using a 17-segment (0 = normal to 4 = absence of uptake) summed rest score (SRS). Non-ICM (NICM) CRT recipients (n = 380) and 50 patients referred for CRT with unsuccessful LV lead implant comprised the comparison groups. Echocardiographic dyssynchrony analysis was performed in a subgroup of 150 patients. Follow-up left ventricular EF (LVEF) and volumes were examined at 7 ± 3 months in 143 patients. The outcome of death, cardiac transplant, or mechanical circulatory support was assessed in all. Over 2.1 ± 1.6 years, ICM patients had significantly worse survival and less LVEF improvement than NICM patients (P < 0.01). Ischaemic cardiomyopathy patients with low scar burden (SRS < 27) had favourable survival and LVEF improvement, similar to NICM patients. A high scar burden (SRS ≥ 27) was associated with reduced survival and lack of LV functional improvement (P ≤ 0.01), similar to those with unsuccessful LV lead implant, whereas baseline dyssynchrony was not predictive of outcome in these patients. CONCLUSION Extensive scar burden in ICM patients unfavourably affected clinical and LV functional outcomes after CRT, regardless of baseline dyssynchrony measures. Patients with ICM and lower scar burden had significantly better outcomes, similar to NICM patients.

Mechanistic Features Associated With Improvement in Mitral Regurgitation After Cardiac Resynchronization Therapy and Their Relation to Long-Term Patient Outcome

Background—Mechanisms of mitral regurgitation (MR) reduction with cardiac resynchronization therapy (CRT) are complex, and their association with long-term outcome is unclear. We sought to elucidate mechanistic features of reduction in MR with CRT, which impact long-term patient survival. Methods and Results—A prospective longitudinal study of 277 patients with heart failure with QRS width ≥120 ms and ejection fraction ⩽35% for CRT was performed. Quantitative echocardiography, including dyssynchrony analysis, was performed at baseline. MR was quantified by color Doppler before and 6 months after CRT. Predefined end points of death, transplant, or left ventricular assist device were tracked during 4 years. There were 114 (48%) patients with CRT with significant MR (≥moderate) at baseline; of whom 48 (42%) patients had MR improvement, and 24 (19%) patients had MR worsening after CRT. The 66 events (47 deaths, 10 transplantations, and 9 left ventricular assist devices) were strongly associated with significant MR after CRT (hazard ratio, 3.58; 95% confidence interval, 2.18–5.87; P<0.0001). Three echocardiographic features were independently associated with amelioration of significant MR after CRT by multivariable analysis: anteroseptal to posterior wall radial strain dyssynchrony >200 ms, lack of severe left ventricular dilatation (end-systolic dimension index <29 mm/m2), and lack of echocardiographic scar at papillary muscle insertion sites (all P<0.05) and, when combined, were additively associated with long-term survival (P=0.0001). Conclusions—Significant MR after CRT was strongly associated with less favorable long-term survival. Echocardiographic mechanistic features were identified that were associated with improvement in MR after CRT and favorable long-term survival.

Mechanistic Features Associated with Improvement in Mitral Regurgitation Following Cardiac Resynchronization Therapy and Their Relation to Long Term Patient Outcome

Background—Mechanisms of mitral regurgitation (MR) reduction with cardiac resynchronization therapy (CRT) are complex, and their association with long-term outcome is unclear. We sought to elucidate mechanistic features of reduction in MR with CRT, which impact long-term patient survival. Methods and Results—A prospective longitudinal study of 277 patients with heart failure with QRS width ≥120 ms and ejection fraction ⩽35% for CRT was performed. Quantitative echocardiography, including dyssynchrony analysis, was performed at baseline. MR was quantified by color Doppler before and 6 months after CRT. Predefined end points of death, transplant, or left ventricular assist device were tracked during 4 years. There were 114 (48%) patients with CRT with significant MR (≥moderate) at baseline; of whom 48 (42%) patients had MR improvement, and 24 (19%) patients had MR worsening after CRT. The 66 events (47 deaths, 10 transplantations, and 9 left ventricular assist devices) were strongly associated with significant MR after CRT (hazard ratio, 3.58; 95% confidence interval, 2.18–5.87; P<0.0001). Three echocardiographic features were independently associated with amelioration of significant MR after CRT by multivariable analysis: anteroseptal to posterior wall radial strain dyssynchrony >200 ms, lack of severe left ventricular dilatation (end-systolic dimension index <29 mm/m2), and lack of echocardiographic scar at papillary muscle insertion sites (all P<0.05) and, when combined, were additively associated with long-term survival (P=0.0001). Conclusions—Significant MR after CRT was strongly associated with less favorable long-term survival. Echocardiographic mechanistic features were identified that were associated with improvement in MR after CRT and favorable long-term survival.

SURVIVAL BENEFIT FROM CARDIAC RESYNCHRONIZATION THERAPY IN PATIENTS WITH BORDERLINE QRS DURATION

Background: Cardiac resynchronization therapy (CRT) has been shown to improve survival in patients with wide QRS. However, the effects of CRT on patients with borderline QRS duration (100 - 130ms) with echocardiographic dyssynchrony is not clear. Methods: To test the hypothesis that patients with borderline QRS and echo dyssynchrony have similar survival as patients with wide QRS after CRT, we studied 301 class III - IV heart failure patients with ejection fraction <35%. Borderline QRS patients had echo dyssynchrony assessed as: radial dyssynchrony by speckle tracking ≥130ms, opposing wall delay by tissue Doppler analysis ≥ 65ms or interventricular mechanical delay ≥ 40 ms. Survival free from transplant or left ventricular assist device after CRT was followed for 4 years. Results: Of the 301 patients, 192 had wide QRS 165±23 ms with age 66±12 yrs 55% ICM and 33% female; 63 had borderline QRS 116 ± 8ms with similar clinical features age 61±12 yrs 55% ICM, 28% female. Also, 46 patients (age 65 ± 15 years , QRS 170±31 ms , 53% ICM and 34% female) with attempted but failed CRT were used as a control. Both wide and borderline QRS patients had similar and significantly better event free survival after CRT than patients with failed CRT (p< 0.001). Conclusions: Patients with borderline QRS duration selected for CRT using echocardiographic dyssynchrony appear to have a similarly favorable event free survival as those with wide QRS and has potential clinical implications.