Electrogram-based optimal atrioventricular and interventricular delays of cardiac resynchronization change individually during exercise.

BACKGROUND: Limited data suggest that optimal atrioventricular (AV) and interventricular (VV) delays are different at rest than during exercise in patients with heart failure. We assessed the feasibility and reproducibility of an electrogram-based method of optimization called QuickOpt at rest and during exercise. METHODS: Patients with a St Jude Medical cardiac resynchronization therapy implantable cardioverter-defibrillator were subjected to a graded treadmill test, and QuickOpt was repeatedly measured prior to, during, and after the exercise. RESULTS: Twenty-four patients (16 males, aged 67.4 ± 7.7 years) participated. At rest, delays (in ms) were 110.4 ± 20.1 for sensed AV delay and -70 (LV pacing first) to +20 (RV pacing first) for VV delay. The changes in QuickOpt-derived delays at rest were not significant despite change in body position. During exercise, QuickOpt-derived AV delays did not change in 11 patients, were shorter during peak exercise in 8 patients, and were longer in 3 patients (average value during peak exercise was 126.5 ± 15.8 ms, P = 0.04 compared to baseline). The QuickOpt-derived VV delay gradually shifted toward earlier right ventricular pacing during exercise in 19 patients, while no changes were seen in 3 patients, and a shift occurred toward earlier left ventricular pacing in 2 patients (average value during peak exercise was -30.7 ± 22.2; P = 0.001 compared to baseline). There was no correlation between changes in the QuickOpt-derived AV and VV delays and heart rate. CONCLUSIONS: The application of electrogram-based algorithm is feasible both at rest and during exercise. The results are reproducible. QuickOpt-derived AV and VV delays individually change during exercise.

A randomized controlled trial of cognitive behavior therapy tailored to psychological adaptation to an implantable cardioverter defibrillator.

OBJECTIVES: To evaluate a eight-session cognitive behavior therapy (CBT) intervention tailored to adaptation in implantable cardioverter defibrillator (ICD) patients; and to test for treatment group by gender interaction effects. METHODS: Patients receiving their first ICD implant were randomized to CBT or usual cardiac care. Primary outcomes measured at baseline, 6-month, and 12-month follow-ups were symptoms of anxiety and depression (Hospital Anxiety and Depression Scale), posttraumatic stress disorder symptoms (Impact of Events Scale-Revised), and phobic anxiety (Crown-Crisp Experiential Index). Secondary outcomes were quality of life (Short Form-36 Physical Component Summary and Short Form-36 Mental Component Summary) and ICD shocks or antitachycardia pacing therapies. RESULTS: Of 292 eligible patients, 193 consented and were randomized to CBT (n = 96) or usual cardiac care (n = 97). Eighty percent were male; mean age was 64.4 years (standard deviation = 14.3); and 70% received an ICD for secondary prevention. No baseline differences were observed between the treatment conditions; however, women scored worse than men on all psychological and quality of life variables (p < .05). Eighty-three percent completed follow-up. Repeated-measures analyses of covariance revealed significantly greater improvement with CBT on posttraumatic stress disorder total and avoidance symptoms for men and women combined (p < .05) and significantly greater improvement in depressive symptoms and Short Form-36 Mental Component Summary only in women (p < .01). No differences were observed between treatment conditions on ICD therapies over follow-up. CONCLUSION: A CBT intervention to assist adaptation to an ICD enhanced psychological functioning over the first year post implant.

Limitations in the current screening practice of assessing left ventricular ejection fraction for a primary prophylactic implantable defibrillator in southern Ontario.

BACKGROUND: Screening echocardiography (ECHO) is commonly performed to determine whether the patient's left ventricular ejection fraction (LVEF) is appropriate for primary prophylactic implantable cardiac defibrillator (ICD) referral. However, radionuclide ventriculography (RNA) is used by many implantation centres for decision making. OBJECTIVE: To determine whether current screening ECHO techniques are effective in identifying patients suitable for primary prophylactic ICD referral. METHODS: Correlation, sensitivity, specificity and likelihood ratios (LRs) of semiquantitative and numerical quantitative ECHO LVEFs were calculated for predicting RNA LVEFs that met implantation criteria (LVEF less than 30% and less than 35%). RESULTS AND DISCUSSION: Among 193 patients, the LRs for a semiquantitative ECHO predicting an RNA LVEF of less than 30% (negative LR was 0.21 to 0.69 and positive LR was 1.22 to 2.83) or RNA LVEF of less than 35% (negative LR was 0.24 to 0.73 and positive LR was 1.33 to 3.46) demonstrated that current screening ECHO techniques are ineffective. However, the positive predictive value of grade 4 ECHO was 93.0%, suggesting that these patients may not require further LVEF investigation before implantation. Among 102 patients, current quantitative ECHO techniques did not improve the screening characteristics. CONCLUSIONS: Current screening ECHO techniques may not be adequate for screening patients for consideration of a primary prophylactic ICD, but a grade 4 ECHO finding has a high positive predictive value in meeting implantation LVEF criteria. Improved screening standards should increase the number of patients referred with appropriate LVEF for primary prophylactic ICD implantation.

Validation of a new simple scale to measure symptoms in atrial fibrillation: the Canadian Cardiovascular Society Severity in Atrial Fibrillation scale.

BACKGROUND: Atrial fibrillation (AF) is commonly associated with impaired quality of life. There is no simple validated scale to quantify the functional illness burden of AF. The Canadian Cardiovascular Society Severity in Atrial Fibrillation (CCS-SAF) scale is a bedside scale that ranges from class 0 to 4, from no effect on functional quality of life to a severe effect on life quality. This study was performed to validate the scale. METHODS AND RESULTS: In 484 patients with documented AF (62.2+/-12.5 years of age, 67% men; 62% paroxysmal and 38% persistent/permanent), the SAF class was assessed and 2 validated quality-of-life questionnaires were administered: the SF-36 generic scale and the disease-specific AFSS (University of Toronto Atrial Fibrillation Severity Scale). There is a significant linear graded correlation between the SAF class and measures of symptom severity, physical and emotional components of quality of life, general well-being, and health care consumption related to AF. Patients with SAF class 0 had age- and sex-standardized SF-36 scores of 0.15+/-0.16 and -0.04+/-0.31 (SD units), that is, units away from the mean population score for the mental and physical summary scores, respectively. For each unit increase in SAF class, there is a 0.36 and 0.40 SD unit decrease in the SF-36 score for the physical and mental components. As the SAF class increases from 0 to 4, the symptom severity score (range, 0 to 35) increases from 4.2+/-5.0 to 18.4+/-7.8 (P<0.0001). CONCLUSIONS: The CCS-SAF scale is a simple semiquantitative scale that closely approximates patient-reported subjective measures of quality of life in AF and may be practical for clinical use.

Outcomes in heart failure patients referred for consideration of implantable cardioverter defibrillator for primary prophylaxis of sudden cardiac death: what are the risks of waiting?

BACKGROUND: Clinical trials have confirmed that implantable cardioverter defibrillators (ICDs) reduce mortality in patients with a left ventricular ejection fraction below 30%. The 'real-world' prognosis before ICD implantation in such patients is not known. The estimated risk of death is 0.8% per month, and this forms the basis for wait-time recommendations. OBJECTIVES: To determine the consequences of waiting for ICD implantation among heart failure patients eligible for primary prophylactic ICD. METHODS: The present retrospective study evaluated consecutive patients who were deemed eligible for primary prophylactic ICD implantation. Survival outcomes were tracked for patients who declined an ICD, those who accepted and received an ICD, and patients who accepted an ICD but died while waiting. RESULTS: Of 470 patients referred for evaluation, 218 were deemed eligible for an ICD. A total of 174 of 218 patients (79.8%) accepted an ICD; 39 (17.9%) declined, and five (2.3%) were deemed to be at too great a risk for the procedure. The mortality rate at two years among patients who accepted an ICD was 18.8% before ICD implantation and 12.2% after ICD implantation. Among patients who declined ICD implantation, the two year mortality rate was 5.3%. Among patients waiting for an ICD, five of 19 deaths were out-of- hospital sudden deaths. Of 12 patients who died after ICD implantation, there were no documented out-of-hospital sudden deaths. CONCLUSION: Consistent with current estimates, the mortality rate at two years among patients who accepted and were waiting for an ICD implant was 18.8%. After receiving an ICD, the mortality rate was 12.2% at two years.