Combination of the best pacing configuration and atrioventricular and interventricular delays optimization in cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy optimization can be pursued by left ventricular pacing vector selection and atrioventricular (AV) and interventricular (VV) delays optimization. The combination of these methods and its comparison with multipoint pacing (MPP) is scarcely studied. METHODS: Using noninvasive cardiac output (CO) measurement, the best of five left ventricular pacing vectors was determined, then AV and VV delays optimization was applied on top of the best vector. Response to the optimization protocol was defined as a >5% CO increase compared to the standard biventricular configuration. RESULTS: Twenty-two patients (18 men, age 71 ± 9 years) were included. Standard biventricular configuration increased CO compared to baseline (4.65 ± 1.55 L/min vs 4.27 ± 1.53 L/min, respectively, P = 0.02). The best quadripolar configuration increased CO to 4.85 ± 1.67 L/min (P = 0.03 compared to the standard biventricular configuration). AV then VV delay optimization both provided additional benefit (final CO 5.56 ± 2.03 L/min, P = 0.001 compared to the best quadripolar configuration). Fifteen (68%) patients responded to the optimization protocol. Anatomical MPP (based on maximal anatomical separation between electrodes) and electrical MPP (based on maximal electrical activation difference between electrodes) were evaluated in 16 patients and yielded a CO similar to that of the optimization procedure. CONCLUSIONS: The combination of choosing the best quadripolar pacing configuration and optimizing atrioventricular and interventricular delays resulted in an improvement of cardiac output compared to standard biventricular stimulation in 68% of patients. The final cardiac output was comparable to multipoint pacing.

Long-term outcome of implantable cardioverter-defibrillator implantation in secondary prevention of sudden cardiac death.

BACKGROUND: Little is known about the long-term outcomes of patients who receive an implantable cardioverter-defibrillator (ICD) for purely secondary prevention indications. AIMS: To assess the rates and predictors of appropriate therapies over a very long-term follow-up period in this population. METHODS: Between June 2003 and August 2006, 239 consecutive patients with structural left ventricular disease and a secondary prophylaxis indication for ICD therapy (survivors of life-threatening ventricular tachyarrhythmias) were prospectively enrolled. An extended follow-up of these patients was carried out. The primary endpoint was the occurrence of appropriate device therapy. Secondary endpoints were all-cause death, electrical storm and inappropriate therapy. RESULTS: The study population consisted of 239 patients (90% men; mean age 64±12 years; 72% ischaemic cardiomyopathy; left ventricular ejection fraction 37±12%). During a median follow-up of 7.8 (3.5-9.3) years, appropriate device therapy occurred in 139 (58.2%) patients. Death occurred in 141 patients (59%), electrical storm in 73 (30.5%) and inappropriate therapy in 42 (17.6%). Multivariable analysis identified patients whose presenting arrhythmia was ventricular fibrillation as being less likely to require appropriate device therapy than those whose presenting arrhythmia was ventricular tachycardia (sub-hazard ratio 0.62, 95% confidence interval 0.40-0.97; P=0.04). Independent predictors of all-cause death were age at implantation (P<0.0001), wide QRS complexes (P=0.024), creatinine concentration (P=0.0002) and B-type natriuretic peptide at implantation (P=0.0001). CONCLUSION: Secondary prevention ICD recipients exhibit a high risk of appropriate device therapy and death over prolonged follow-up. Patients who presented initially with ventricular fibrillation were less likely to require the delivery of appropriate device therapy.

Relationship between two-dimensional speckle-tracking septal strain and response to cardiac resynchronization therapy in patients with left ventricular dysfunction and left bundle branch block: a prospective pilot study.

BACKGROUND: Previous studies have demonstrated variable patterns of longitudinal septal deformation in patients with left ventricular (LV) dysfunction and left bundle branch block. This prospective single center study was designed to assess the relationship between septal deformation patterns obtained by two-dimensional speckle-tracking echocardiography and response to cardiac resynchronization therapy (CRT). METHODS: One hundred one patients with New York Heart Association class II to IV heart failure, LV ejection fractions ≤ 35%, and left bundle branch block underwent echocardiography before CRT. Longitudinal two-dimensional speckle-tracking strain analysis in the apical four-chamber view identified three patterns: double-peaked systolic shortening (pattern 1), early pre-ejection shortening peak followed by prominent systolic stretch (pattern 2), and pseudonormal shortening with a late systolic shortening peak and less pronounced end-systolic stretch (pattern 3). CRT response was defined as a relative reduction in LV end-systolic volume of ≥ 15% at 9-month follow-up. CRT super-response was defined as an absolute LV ejection fraction of ≥ 50% associated with a relative reduction in LV end-systolic volume of ≥ 15% and an improvement in New York Heart Association functional class. Cardiac death or hospitalization for heart failure during follow-up was systematically investigated. RESULTS: Ninety-two percent of patients with pattern 1 or 2 were responders to CRT compared with 59% with pattern 3 (P < .0001). Thirty-six percent of patients with pattern 1 were super-responders compared with 15% of those with pattern 2 and 12% of those with pattern 3 (P = .037). The improvement in LV volumes, LV ejection fraction, and global longitudinal strain after CRT was better in patients with pattern 1 or 2 compared with those with pattern 3 (P < .0001 for all). Eighteen-month outcomes were excellent in patients with pattern 1 or 2, with event-free survival of 95 ± 3% compared with 75 ± 7% in patients with pattern 3 (P = .010). CONCLUSIONS: Septal deformation strain pattern 1 or 2 is highly predictive of CRT response. Further studies are needed to identify predictors of "nonresponse" in patients with a pattern 3.

Quantitative assessment of primary mitral regurgitation using left ventricular volumes: a three-dimensional transthoracic echocardiographic pilot study.

AIMS: To investigate the value of assessment of mitral regurgitant fraction (RF) using left ventricular (LV) volumes obtained by three-dimensional echocardiography (3DE) to quantify primary mitral regurgitation (MR). METHODS AND RESULTS: Sixty patients with primary MR in sinus rhythm were prospectively enrolled. RF was calculated using either 2DE or 3DE LV volumes obtained as follows: (LV total stroke volume - LV forward stroke volume by Doppler)/LV total stroke volume. Severity of MR was graded independently by two cardiologists blinded to LV volumetric data using an integrative approach, as recommended by current guidelines. Sixty patients with LV ejection fraction >50% and no MR were also studied. In patients without MR, 3D total LV stroke volume was more strongly correlated with LV forward stroke volume than 2D total LV stroke volume (r = 0.75, P < 0.0001 vs. r = 0.62, P < 0.0001, respectively). The 3D method had a feasibility of 90% in patients with MR. Inter-reader concordance for MR grading (four grades) was excellent with a Kappa-value of 0.90, P < 0.0001. A significant correlation was observed between grade of MR severity and 3D RF (r = 0.83, P < 0.0001) and 2D RF (r = 0.74, P < 0.0001). Comparisons between individual grades for 3D RF were significant (P < 0.05) except for 3+ vs. 4+ MR (P = 0.213). All patients with 3D RF ≥40% had ≥3+ or 4+ MR and those with 3D RF ≤30% had 1+ or 2+ MR with a 'grey' overlap zone between 30 and 40%. CONCLUSIONS: RF can be routinely determined using 3D LV volumes with a high feasibility in patients with primary MR and is reliable for identification of Grade 3+ or Grade 4+ MR. The incorporation of this parameter into the currently recommended multiparametric integrative approach might be helpful to discriminate significant MR.