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Background: Our objective was to evaluate the systolic index (SI), the ratio between rate-corrected left ventricular ejection time (LVETc), and a preejection period surrogate (PEPsu), to assess cardiac function in patients with DDD and cardiac resynchronization therapy (CRT) pacemakers., Methods: LVETc and PEPsu were automatically measured from electrocardiogram and finger photoplethismography. Atrioventricular (AV) and mode switch (CRT to DDD) were used as hemodynamic challenges. Performance of SI, beat-by-beat systolic blood pressure (SBP), and Doppler aortic velocity/time integral (AoVTI) were compared in 36 patients, and SI's detection of CRT to DDD mode switch in nine patients, responders to CRT. AVs were changed from 30 ms to 250 ms (20 ms steps) at constant paced heart rate, alternating with a reference AV (RefAV), to reduce hemodynamic drift. The coefficient of variation (standard deviation/mean) of SI, SBP, and AoVTI during all RefAVs were used as error marker. The percentage detection of hemodynamic changes during AV transitions was a marker of sensitivity., Results: Fifty-five patients (males 62%, age 69.6 ± 17) were studied. SI detected 441 of 544 transitions (81%) versus 361 (66%) of SBP (P = 0.005). Error during RefAVs was smaller for SI (3.4%) as compared to AoVTI (7.8%, P = 0.015) and to SBP (5.7%, P = 0.005). SIs correlated with AoVTI (R from 0.71 to 0.98, all P < 0.001). SI detected all CRT to DDD changes (P < 0.001)., Conclusion: The noninvasive SI obtained with a simple, observer-independent hemodynamic assessment procedure has higher accuracy than SBP and AoVTI and better sensitivity than SBP. It detects mechanical resynchronization in CRT and allows programming a suitable AV delay., (©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.)

Background: Implantable cardioverter defibrillators (ICDs) have been used in the treatment of either sustained ventricular tachycardia or ventricular fibrillation in patients with Chagas' cardiomyopathy. This study aimed at determining mortality rate and risk factors of all-cause 1-year mortality in primary and secondary ICD patients with Chagas' cardiomyopathy., Methods: One hundred and forty-eight Chagas' patients with ICDs were included from the Medtronic ICD Registry Latin America. All patients were followed for 1 year., Results: At implant, mean age was 60.1 ± 9.4 years and 72.9% were male. Mean left ventricular ejection fraction (LVEF) was 40.1 ± 11%. Mean follow-up was 12 ± 7 months. During the follow-up, 15 patients died (10.2%). Patients who died were older (64 ±10.8 years vs 59 ± 9.1; P = 0.04), had more atrial fibrillation (13.3% vs 3.8%; P = 0.02), had lower LVEF (33.4%± 9.8 vs 40.9%± 11.3; P = 0.01), and worse functional class (III/IV 40% vs 21.8%; P = 0.03). The multivariate analysis showed that two independent predictors of all-cause 1-year mortality remained statistically significant: age more than 65 (hazard ratio [HR] = 2.85, 95% confidence interval [CI] 1.77-3.92; P = 0.03) and LVEF less than 30% (HR = 2.68, 95% CI 1.57-3.79; P = 0.04)., Conclusion: This analysis showed that patients older than 65 years of age and with LVEF less than 30% were independent predictors of all-cause 1-year mortality in patients with chronic Chagas' cardiomyopathy., (©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.)

Unlabelled: The time to first ICD shock has been extensively studied in patients with coronary artery disease (CAD). However, there are no published data on ICD shocks in patients with Chagas cardiomyopathy (ChC). The occurrence of the first appropriate ICD shock during the first 6 months of follow-up in 20 patients with ChC (group 1) and 35 CAD patients (group 2) was analyzed retrospectively. All patients had received a third-generation pectoral ICD for ventricular tachycardia or fibrillation (VT/VF). Indications for ICD implantation were refractoriness to drug therapy or noninducibility of VT/VF at EPS in cardiac arrest survivors., Results: The mean age, left ventricular ejection fraction (LVEF), and sex in groups I and II were 57.4 +/- 7 years versus 64 +/- 9 (P < 0.01), 30.9% +/- 10% versus 32.9% +/- 10% (P = NS), and 10 men versus 31 women (P < 0.005), respectively. Six months after ICD implantation, 85% (17/20) group I patients received appropriate ICD shocks versus 51% (18/35) in group 2, a statistically significant difference (P < 0.02, RR: 1.65, OR: 5.35)., Conclusions: The incidence of appropriate ICD shocks within the first 6 months postimplantation was significantly higher in ChC patients than in CAD patients. ChC patients were younger and more often women than CAD patients.

Chagas' disease is a parasitic affliction, endemic to certain regions of South America, which may lead to a chronic dilated nonischemic cardiomyopathy. Ten Chagasic patients were compared to 18 coronary patients undergoing transvenous ICD implantation for ventricular tachycardia (VT), ventricular fibrillation (VF), or aborted cardiac arrest. Indications for ICD implantation were either drug intolerance or refractoriness, or no inducible tachyarrhythmia at EPS. There were no statistically significant differences between the Chagas and coronary artery disease groups with respect to age (60.2 vs 62.6 yrs), NYHA Class II (50% vs 62%), ejection fraction (31.1% vs 29.7%), and incidence of cardiac arrest (20% vs 33%), respectively. The following ICD implant and long-term follow-up variables were compared between the two groups: pacing threshold (0.94 V vs 0.95 V), defibrillation threshold (19.5 J vs 19.6 J), number of VT episodes (414 vs 435), number of spontaneous VT terminations (86 vs 187), percent efficacy of antitachycardia pacing (93.9% vs 92.1%), and total number of shocks (112 vs 145). These differences were not statistically significant. We conclude that patients with Chagas' disease, compared with coronary artery disease patients, have similar clinical characteristics leading to ICD implantation. Furthermore, no differences were found with respect to ICD and long-term follow-up characteristics between the two groups.

Third-generation implantable cardioverter defibrillators (ICDs) offer tiered therapy and can provide significant advantage in the management of patients with life-threatening arrhythmias. Three different types of ICDs were implanted in 21 patients with ventricular tachycardia (VT) or ventricular fibrillation (VF). Arrhythmia presentation was VT (76%), VF (10%), or both (14%). The mean left ventricular ejection fraction for the group was 32.4 +/- 7%. No surgical mortality occurred. Prior to discharge individual EPS determined the final programmed settings of the ICDs. During a mean follow-up of 13 +/- 1.4 months (range 2-20) the overall patient survival was 85.7%. No sudden arrhythmic or cardiac death occurred. Twenty of 21 patients (95%) received therapy by their device. In 14 patients (67%) antitachycardia pacing (ATP) was programmed "on," 13 of which was self-adaptative autodecremental mode. There were 247 VT episodes, 231 of which were subjected to ATP with 97% success and 3% acceleration or failure. Low energy shocks reverted all other VT episodes. VF episodes were successfully reverted by a single shock (93%), two shocks (6%), or three shocks (1%). We conclude that ATP therapy of VT is successful in the large majority of episodes with rare failures, and that VF episodes are generally terminated by a single ICD shock.

Thirty-four patients underwent implantation of a third generation ICD, the 4210 ATP, for sudden cardiac death or ventricular tachycardia. This device incorporates significant telemetry logs as well as a detailed analysis of each arrhythmia episode detected. During the period of clinical follow-up, a mean of 12.2 months, a total of 26,569 VT or VF detections were made. The vast majority of these were either due to atrial fibrillation, nonsustained VT, or "noise" detection, and only 6% led to device therapy. ATP was successful in 86.3% of episodes, with 3.5% accelerations and 2.4% failure of ATP trains. The majority of inappropriate therapy episodes were clustered in seven patients, and all were easily diagnosed with the aid of the extensive telemetry logs and sense histories. Of five late deaths, three were from congestive heart failure, one from cerebrovascular accident, and one unknown. These data reveal that this "tiered" therapy noncommitted ICD performs to expectations; the stored data is of significant value in diagnosing the cause of ICD therapy. In addition, ATP is an effective modality for termination of VT.