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Background: The programmed atrioventricular delay (AVD) is an important determinant of the response in left ventricular (LV) systolic performance during cardiac resynchronization therapy (CRT). It is not well established if the optimal AVD for CRT may be influenced by the LV diastolic filling pattern. Methods: Thirty patients were studied pre- and post-CRT at programmed AVD of 60–160 ms. Doppler measurements included the aortic and mitral velocity time integral (VTI), mitral early (E) and late diastolic filling (A) wave velocities, E- and A-wave VTI, and diastolic filling time (DFT). The optimal AVD for each of the Doppler variables was defined by the maximal improvement compared to pre-CRT. Patients were grouped by the pre-CRT mitral inflow pattern as impaired relaxation (IR, mitral E/A ≤1, n = 15) or pseudonormalized/restrictive filling (PNF/RF, mitral E/A >1, n = 15). Results: The percentage of improvement in aortic VTI was greater in the PNF/RF group (P = 0.03). Mitral E-wave velocity decreased in the PNF/RF group (P < 0 .001), E-wave VTI increased in both groups (P < 0 .05) and A-wave VTI increased in the PNF/RF group. DFT increased in both groups. The optimal AVD that maximized aortic VTI was longer than the AVD that improved DFT. Conclusions: The effects of various programmed AVD during CRT on the response in LV stroke volume and diastolic filling are influenced by the pre-CRT LV filling characteristics. AVD optimization based on maximizing DFT is shorter compared to the aortic VTI method. [ABSTRACT FROM AUTHOR]

Background: Conventional insertion of implantable cardioverter-defibrillator (ICD) includes an evaluation of the defibrillation threshold (DFT). Implanting an ancillary defibrillation lead in the azygos vein has been introduced as a therapeutic option in patients with “high” DFT. This study reports the efficacy and stability of azygos defibrillation coils implanted for elevated DFTs. Methods: This is a retrospective review of seven consecutive patients with right and left pectoral, single- and dual-chamber, and biventricular ICDs and elevated DFTs, in whom an azygos defibrillation coil was introduced. Results: Addition of an azygos defibrillator lead achieved a satisfactory safety margin during single energy defibrillation efficacy testing in four out of seven patients, with success at maximum device output in two patients. No satisfactory safety margin was achieved in the remaining patient, despite the further addition of a subcutaneous defibrillation coil. No change in lead position was observed over a mean radiographic follow-up of 8 months. No complications were noted during a mean follow-up of 14 months, including no deaths, and no ICD shocks. Conclusion: Implanting a defibrillation coil into the azygos vein is feasible and safe. In a majority of patients with failed defibrillation efficacy testing, adding an azygos coil achieves success on repeat testing. Therefore, this technique is one option for lowering the defibrillation threshold in patients who fail DFT testing of their ICD. [ABSTRACT FROM AUTHOR]

Background: Patients with ischemic cardiomyopathy (ICM) who have monomorphic ventricular tachycardia (VT) induced by programmed ventricular stimulation (PVS) are at increased risk of sudden cardiac death (SCD). Among a primary prevention population, the prognostic significance of induced polymorphic ventricular arrhythmias is unknown. Methods : A total of 105 consecutive patients who received an implantable cardioverter-defibrillator (ICD) for primary prevention of SCD in the setting of ICM and non-sustained VT were retrospectively evaluated. Seventy-five patients (group I) had induction of monomorphic VT and 30 patients (group II) had a sustained ventricular arrhythmia other than monomorphic VT (ventricular flutter, ventricular fibrillation, and polymorphic VT) induced during PVS. Results : Baseline characteristics were similar between group I and group II except for ejection fraction (25% vs. 31%, P = 0.0001) and QRS duration (123 milliseconds vs. 109 milliseconds, P = 0.04). Sixteen of 75 (21.3%) patients in group I and 6 of 30 (20%) patients in group II received appropriate ICD therapy (P = 0.88). Survival free from ICD therapy was similar between groups (P = 0.54). There was a trend toward increased all-cause mortality among patients in group I by Kaplan-Meier analysis (P = 0.08). However, when adjusted for age, EF, and QRS duration mortality was similar (P = 0.45). Conclusions: There is no difference in rates of appropriate ICD discharge or mortality between patients dichotomized by type of rhythm induced during PVS. These results suggest that patients in this population who have inducible VF or sustained polymorphic VT have similar rates of subsequent clinical ventricular tachyarrhythmias as those with inducible monomorphic VT. [ABSTRACT FROM AUTHOR]

Introduction: Chronic kidney disease (CKD) has been independently associated with increased cardiovascular mortality. Little is known about the benefit of implantable cardioverter defibrillator (ICD) therapy for prevention of sudden death in this large, high-risk population. We sought to evaluate the impact of CKD on survival in patients who received an ICD for primary prevention of sudden death. Methods and Results: In this retrospective study of patients who underwent ICD implantation for primary prevention of sudden death, patients were stratified by CKD, defined as serum creatinine ≥2 mg/dL or dialysis use. Primary endpoint was mortality. CKD was identified in 35 of 229 patients (15.3%). There were 33 deaths during a follow-up period of 18.0 ± 15.2 months: 17 of 35 CKD patients and 16 of 194 patients without CKD (48.6% vs 8.2%, P < 0.00001 by log-rank). One-year survival for patients with and without CKD was 61.2% and 96.3%, respectively. Cox regression analysis controlling for age, sex, comorbidities, ejection fraction, and medications proved CKD to be the strongest independent predictor of death (hazard ratio 10.5; 95% confidence interval 4.8–23.1; P = 0.0001). This risk was dependant on severity of CKD; a 10 mL/min reduction in creatinine clearance was associated with a 55% increase in hazard of death (P < 0.0001). Conclusions: In patients receiving an ICD for primary prevention of sudden death, CKD significantly reduced long-term survival. This poor prognosis may limit the impact of primary prevention ICD therapy in this patient population. [ABSTRACT FROM AUTHOR]