Relationship between pre-implant ejection fraction and outcome after cardiac resynchronization therapy in symptomatic patients.

BACKGROUND: Left-ventricular ejection fraction (LVEF) is regarded as a strong predictor for morbidity and mortality in heart failure patients. The aim of the analysis was to assess the relationship between pre-implant LVEF and outcome of patients with advanced heart failure who received cardiac resynchronization therapy (CRT). METHODS: We analysed the two-year follow-up of 366 patients who had been enrolled in the MASCOT study which included NYHA class III/IV patients with a class I CRT indication. Pre-implant LVEF was stratified by tertile. RESULTS: The boundaries for pre-implant LVEF were < 22% (n = 128; 18.2 +/- 3.1%; T(low)), 22% to 28% (n = 121; 25.4 +/- 1.4%; T(middle)) and > 28% (n = 117; 32.6 +/- 3.9%; T(high)) for each tertile.Two-year post-implant LVEF was 32.0 +/- 11.5% (T(low)), 33.7 +/- 10.8% (T(middle)) and 36.4 +/- 9.9% (T(high)). T(Iow) had a greater increase between pre- and post-implant LVEF compared to T(middle) (P = 0.03) and T(high) (P = 0.0001). NYHA class improved similarly among the three groups as well as the quality of life score. No significant differences were detected between the three groups for all-cause mortality, cardiac death, all-cause hospitalization, and hospitalization due to worsening heart failure. CONCLUSIONS: Symptomatic heart failure patients with a wide QRS complex and a severe impaired LV function had a better improvement of their pre-implant LVEF than patients with a more preserved LVEF. This may be one reason that in these patient groups long-term morbidity and mortality were not related to their pre-implant LVEF. Pre-implant LVEF was in symptomatic CRT patients not predictive for their long-term cardiovascular morbidity and mortality.

Lead complications, device infections, and clinical outcomes in the first year after implantation of cardiac resynchronization therapy-defibrillator and cardiac resynchronization therapy-pacemaker.

AIMS: The decision to implant a cardiac resynchronization therapy (CRT) system with (defibrillator, CRT-D) or without (pacemaker, CRT-P) cardioverter defibrillator should weigh its benefits and risks. This study examined the (i) incidence of loss of capture and infectious complications and (ii) 1-year clinical outcomes of 402 CRT-D and CRT-P recipients enrolled in the MASCOT study. METHODS AND RESULTS: The indications for CRT-D or CRT-P were posed by the implanting physicians. All (i) losses of atrial and right and left ventricular capture, (ii) system-related infections, and (iii) clinical outcomes, including hospitalizations for worsening heart failure (HF) and deaths from all causes, were recorded up to 1 year of follow-up. Cardiac resynchronization therapy-defibrillator was implanted in 228 (57%) and CRT-P in 174 (43%) patients. The incidence of loss of capture was greater in CRT-D with 21 patients (9.2%) than in CRT-P with 6 patient (3.5%) recipients (P = 0.01), while the infection rates were 1.3% (3 patients) and 1.2% (2 patients), respectively (ns). In the CRT-D group, 42 of 228 patients (18.4%) died or were hospitalized for HF, compared with 38 of 174 patients (21.8%) in the CRT-P group (ns). In the CRT-D group, 23 patients (10.1%) were hospitalized for worsening HF and 20 (8.8%) patients died, vs. 22 (12.6%) and 19 (10.9%) patients, respectively, in the CRT-P group (ns for both comparisons). CONCLUSIONS: Cardiac resynchronization therapy-defibrillator was implanted in 57% of candidates for CRT. Within 1 year after device implant, the incidence of loss of capture at any lead was nearly three-fold greater among CRT-D than among CRT-P recipients. System-related infections were infrequent and clinical outcomes were similar in both groups.

The feasibility of fully automated pacemaker advise in treating atrial tachyarrhythmias.

BACKGROUND: Modern pacemakers continuously store significant cardiac-related events. Interpreting these data and reprogramming the pacemaker can be time-consuming and demands expert knowledge. A software-based expert system, the therapy advisor (TA), was developed, which analyzes stored data and provides reprogramming recommendations. This study addresses whether pacemaker experts consider the messages that are automatically generated appropriate in the management of atrial tachyarrhythmias/atrial fibrillation (AT/AF). METHODS: This observational, international, multicenter study follows 150 patients with suspected or documented atrial arrhythmias who received a dual-chamber pacemaker (model Vitatron T-70, Medtronic Inc., Minneapolis, MN, USA) incorporating the TA. The TA summarizes technical and clinical data stored in the pacemaker into key messages and may suggest programming changes. Twenty-five cardiologists examined their patients per normal practice during two follow-up visits. They reported the therapy changes they deemed necessary without initially reviewing the TA messages. Next, they rated their satisfaction with and the clinical relevance of the TA messages and recorded the final therapy changes. RESULTS: The TA generated (mostly AT/AF-related) main observations in 49% and programming advice in 33% of the patients. The experts rated 95% of the TA messages as satisfactory and deemed therapy changes necessary in roughly half the patients. Pacemaker changes in AT/AF therapy or general settings were prompted primarily by the diagnostic information stored in the device. Medication changes were mostly led by the symptoms reported by the patient. CONCLUSION: This study demonstrates that experienced cardiologists agree with 95% of the observations and programming suggestions that the TA automatically generates.

[Present-day treatment of arterial hypertension]. / Aktuelle Therapie der Hypertonie.

The treatment goal of patients with arterial hypertension is to reduce the blood pressure below 140/90 mmHg with the aim to lower the risk of subsequent cardiovascular diseases and to prolong patient's longevity. There are five main classes for blood pressure treatment: ACE-inhibitors, angiotensin II receptor blockers, beta-receptor blockers, calcium channel blockers, and thiazide diuretics. All these antihypertensive drugs have in common that they are able to lower the arterial blood pressure in a similar range. If drugs have similar effects, those with additional beneficial effects on patient's comorbidity should be preferred. Some antihypertensive drugs such as inhibitors of the renin-angiotensin-aldosteron system (RAAS) additionally have organ protective properties. ACE-inhibitors and angiotensin receptor blockers should be preferred in patients with a high cardiovascular risk such as coronary heart disease, heart failure, diabetes, and chronic kidney disease. A preferred approach is the initial prescription of a low dose combination to bring more hypertensive patients to their target blood pressure. Most combination drugs contain a thiazide diuretic. A better combination especially for diabetics seems to be a calcium channel blocker together with a RAAS inhibitor. A possible combination for patients with coronary heart disease or heart failure is a RAAS inhibitor combined with a beta-receptor blocker.

A prospective randomized evaluation of VV delay optimization in CRT-D recipients: echocardiographic observations from the RHYTHM II ICD study.

BACKGROUND: All current cardiac resynchronization therapy (CRT) devices allow the programming of the atrioventricular (AV/PV) delays and the sequential stimulation of the ventricles via the inter ventricular (VV) delay. AIM: This post hoc analysis of the RHYTHM II study was conducted to compare the reverse remodeling associated with VV delay optimization in patients randomly assigned to simultaneous (SIM) biventricular stimulation versus patients assigned to optimized VV delay programming (OPT) (1:3 randomization scheme). METHODS: The analysis included 14 patients assigned to the SIM group and 34 patients to the OPT group who completed the 6-month follow-up period with paired echocardiographic recordings. RESULTS: In both study groups, changes consistent with left ventricular (LV) remodeling were observed between baseline and 6 months, with significant improvements in LV function and decrease in LV dimensions. In the OPT group, there was also a decrease in left atrial diameter and mitral valve closure to opening time. At 6 months, the overall proportion of echocardiographic responders (> or =10% decrease in LV end-systolic volume or > or =5% absolute increase in LV ejection fraction) was similar in both groups. The optimal AV/VV delays, evaluated by maximization of LV outflow tract velocity time integral, changed over time. CONCLUSIONS: Ventriculo-ventricular delay optimization was associated with better immediate hemodynamic function than simultaneous biventricular stimulation, though did not promote additional reverse remodeling at 6 months and did not increase the proportion of echocardiographic responders to CRT. Optimization of both the AV and VV intervals was patient-specific and optimal values changed over time.

Atrial fibrillation in recipients of cardiac resynchronization therapy device: 1-year results of the randomized MASCOT trial.

BACKGROUND: Atrial fibrillation (AF) is associated with increased morbidity and mortality in patients suffering from heart failure (HF). Patients in New York Heart Association HF classes III or IV, with systolic dysfunction and a wide QRS, are candidates for cardiac resynchronization therapy (CRT), and might benefit from atrial overdrive pacing (AOP). METHODS: The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) trial enrolled 409 CRT device recipients (79% men), who were randomly assigned to AOP ON (n = 197), versus AOP OFF (n = 197) and followed up for 1 year. Their mean age was 68 +/- 10 years, left ventricular ejection fraction 25 +/- 6%, QRS duration 163 +/- 29 milliseconds. New York Heart Association class III was present in 86% of patients and 19% had a history of paroxysmal AF. The primary study end point was incidence of permanent AF at 1 year. RESULTS: Atrial overdrive pacing increased the percentage of atrial pacing from 30% to 80% (P < .0001), was well tolerated, and did not interfere with (a) delivery of CRT (95% mean ventricular pacing in both groups), (b) response to CRT (70% responders in the control vs 67% in the treatment group), or (c) cardiac function (left ventricular ejection fraction increased from 24.5% +/- 6.2% to 32.7% +/- 10.9% in the control and from 25.8% +/- 6.8% to 33.1% +/- 12.6% in the treatment group). The incidence of permanent AF was 3.3% in both groups. By logistic regression analysis, a history of AF (P < .001) and absence of antiarrhythmic drugs (P = .002) were associated with permanent AF. CONCLUSIONS: In this first trial of a specific AF prevention algorithm in CRT recipients, AOP was safe and did not worsen HF. The prevention algorithm did not lower the 1-year incidence of AF.

Percent ventricular pacing with managed ventricular pacing mode in standard pacemaker population.

AIMS: Unnecessary right ventricular pacing has deleterious effects and becomes more significant when cumulative percent ventricular pacing (Cum%VP) exceeds 40% of time. The Managed Ventricular Pacing (MVP) mode has been shown to significantly reduce the percent ventricular pacing compared to the DDD/R mode. This study assessed the percent of ventricular pacing in a standard pacemaker population programmed to MVP and for which patients it is possible to achieve a Cum%VP < or = 40%. METHODS AND RESULTS: Unselected, consecutive patients were implanted with a dual chamber pacemaker with a mean follow-up period of 76 days. The Cum%VP was calculated from device diagnostics between pre-hospital discharge (PHD) and the 1-month post implant visit. The median Cum%VP of 107 patients (age 67.2 +/- 14 years; 53% male) who were programmed to MVP was 3.9%. The median Cum%VP was 1.4% in patients with sinus node disease (SND) and 28.8% in patients with AV block (AVB). Cum%VP < or = 40% was observed in 72% of all patients, in 50% of AVB patients, and in 86% of SND patients. CONCLUSION: The MVP mode is capable of achieving a low percent of ventricular pacing in a standard pacemaker population with SND and AVB. In addition, 72% of patients in MVP mode demonstrated Cum%VP < or = 40%.

Patient-tailored implantable cardioverter defibrillator testing using the upper limit of vulnerability: the TULIP protocol.

AIMS: We evaluated the feasibility of the TULIP (Threshold test using Upper Limit during ImPlantation) protocol, which was designed to provide a confirmed, low defibrillation energy value during implantable cardioverter defibrillator (ICD) implantation with only two induced ventricular fibrillation (VF) episodes. METHODS AND RESULTS: Ninety-eight patients (62 +/- 12 years, 86 male) from 13 clinical centres underwent an active can ICD implantation. A single coupling interval derived from electrocardiogram lead II during ventricular pacing was used for VF induction shocks at 13, 11, 9, and 6 J in a step-down manner until the upper limit of VF induction (ULVI) was determined. If ULVI >or=9 J, a defibrillation energy of ULVI + 4 J was tested. For ULVI <9 J, the defibrillation test energy was 9 J. In 79/98 patients (80.6%), two induced VF episodes were sufficient to obtain confirmed defibrillation energy of 11.1 +/- 3.3 J. The mean strength of the successful VF induction shock was 6.8 +/- 4.3 J, the coupling interval was 303 +/- 35 ms, and the number of delivered induction shocks until the first VF induction was 3.9 +/- 1.6. CONCLUSION: TULIP is a safe and simple device testing procedure allowing the determination of confirmed, low defibrillation energy in most patients with two VF episodes induced at a single coupling interval.

Automatic home monitoring of implantable cardioverter defibrillators.

AIMS: With the expanding indications for implantable cardioverter defibrillator (ICD) and reports of unexpected ICD failures, home monitoring (HM) was proposed to decrease follow-up workload and increase patient safety. Home monitoring implantable cardioverter defibrillators offer wireless, everyday transfer of ICD status and therapy data to a central HM Service Center, which notifies the attending physician of relevant HM events. We evaluated functionality and safety of HM ICDs. METHODS AND RESULTS: A total of 260 patients with HM ICDs were monitored for a mean of 10 +/- 5 months. Time to HM events [medical (ventricular tachycardia/ventricular fibrillation) and technical (ICD system integrity)] since ICD implantation and since the latest in-clinic follow-up was analysed. Mean number of HM events per 100 patients per day was calculated, without and with a 2-day blanking period for re-notifying the same type of event. About 41.2% of the patients had HM events (38.1% medical, 0.8% technical, and 2.3% both types). Probability of any HM event after 1.5 years was 0.50 (95% confidence interval: 0.42-0.58). More than 60% of new HM event types occurred within the first month after follow-up. A mean of 0.86 event notifications was received per 100 patients per day or 0.45 with the 2-day blanking period. CONCLUSION: Home monitoring is feasible and associated with an early detection of medical and technical events.

Closed loop stimulation and accelerometer-based rate adaptation: results of the PROVIDE study.

AIMS: We compared pacing rate adaptation based on closed loop stimulation (CLS) or accelerometer sensor (AS) during acute mental and physical stress in the same patient. METHODS AND RESULTS: One month after Protos (Biotronik, Germany) pacemaker implantation, 131 chronotropically incompetent patients were randomized to AS or CLS for 3 months with crossover. Arithmetic and 6 min walk tests were performed in the non-rate-adaptive mode and AS and CLS rate-adaptive modes, respectively. At the end, patients had to select the individually preferred pacemaker sensor. Heart rate during mental stress was higher (3.0 +/- 9.2 bpm) in the CLS than in the AS mode (P = 0.004). Benefit in the walking distance compared with non-rate-adaptive pacing was similar for the two modes: added 27 +/- 96 m (AS, P = 0.013) and 30 +/- 116 m (CLS, P = 0.025). At the end of the walk, heart rate was higher by 4.8 +/- 21.4 bpm in AS than in CLS (P = 0.049). Twice as many patients preferred CLS over AS (P < 0.01). CONCLUSION: The arithmetic test was associated with a significantly higher heart rate for CLS than for AS, showing a greater sensitivity of CLS-based rate adaptation to mental stress. Performance during physical stress was comparable. Patients preferred CLS.

Effects of continuous and triggered atrial overdrive pacing on paroxysmal atrial fibrillation in pacemaker patients.

BACKGROUND: The aim of the study was to compare the effects of different pacing strategies to prevent paroxysmal atrial fibrillation (AF): triggered atrial overdrive pacing versus the combination of triggered and continuous overdrive pacing. METHODS: Patients with an indication for dual-chamber pacing (Selection 9000, Prevent AF; Vitatron B.V., Arnhem, the Netherlands) and a history of paroxysmal AF were randomized to triggered atrial pacing (three pacing functions, "triggered group": PAC Suppression, Post-PAC Response, and Post-Exercise Response) or to the combination of continuous (Pace Conditioning) and triggered atrial pacing (four pacing functions, "combined group"). After 3 months, there was a crossover to the other pacemaker setting. RESULTS: In 171 enrolled patients, the median AF burden of the combined group was with 2.1% versus 0.1% in the triggered group (P = 0.014). Fewer AF episodes were observed in the triggered (median: 7) than in the combined group (median: 116; P = 0.016). The combined group had more frequent atrial pacing (median 97%) than the triggered group with 85% (P < 0.001), but ventricular pacing was not significantly different with 95% and 96% in the combined and triggered group, respectively. After the crossover, the AF burden increased in the triggered group to 0.3% and decreased in the combined group to 0.4%. CONCLUSIONS: Triggered atrial pacing functions alone resulted in a low AF burden. The additional activation of continuous atrial overdrive pacing increased the percentage of atrial pacing, but had no beneficial effects on the prevention of paroxysmal AF.

The COGNITION study rationale and design: influence of closed loop stimulation on cognitive performance in pacemaker patients.

BACKGROUND: Several studies showed the beneficial effect of pacemaker implantation on cognitive performance in patients with bradycardia. But it has never been investigated if patients with chronotropic incompetence may improve their cognitive performance if treated by a rate-adaptive system reacting to mental stress in comparison to the most frequently used accelerometer-driven pacing. METHODS: The randomized, single-blind, multicenter COGNITION study evaluates if closed loop stimulation (CLS) offers incremental benefit in the speed of cognitive performance and the overall well-being of elderly patients with bradycardia compared with accelerometer-based pacing. Four hundred chronotropically incompetent patients older than 55 years will be randomized 3-6 weeks after implantation to CLS or accelerometer sensor. Follow-up visits are performed after 12 and 24 months. The speed of cognitive performance, which is the underlying function influencing all other aspects of cognitive performance, will be assessed by the number connection test, a standardized psychometric test for the elderly. Secondary endpoints include patient self-assessment of different aspects of health (by visual analogue scales), quality of life (by SF-8 health survey), the incidence of atrial fibrillation (episodes lasting for longer than 24 hours), and the frequency of serious adverse events. CONCLUSION: In the ongoing COGNITION study, we aim at long-term comparison of two rate-adaptive systems, focusing on the cognitive performance of the patients, which was neglected in the past evaluation of pacemaker sensors.

[Diagnostics of patients with syncope of unknown origin: indications for hospital admission and for in- and out-hospital services?]. / Synkopendiagnostik: wann ambulant, wann stationär?

The diagnostic challenge of patients with syncope is to assess the underlying cause leading to the symptom syncope. In addition, the patient's risk for an increased mortality and for recurrent syncope has to be evaluated. Initial evaluation identifies most of these patients. Depending on the local medical health services this can be performed in an emergency department, an in- and out-hospital service or at a general practitioner. Major criteria for hospital admission are risk stratification especially for patients with a suspected rhythm-related reason for syncope and treatments to prevent syncopal recurrences. Hospital admission is not necessary for patients with a single attack or infrequent episodes who show no evidence of a cardiac cause for the syncope or of a structural heart disease. Patients who have no findings indicating the presence of life-threatening rhythm disorders can be further evaluated in a hospital or an out-clinic setting depending on the predetermined requirements of local professional bodies.

The German Competence Network on Atrial Fibrillation (AFNET).

The German Competence Network on Atrial Fibrillation (AFNET) is an interdisciplinary national research network funded by the Federal Ministry of Education and Research (BMBF) since 2003. The AFNET aims at improving treatment of atrial fibrillation (AF), the most frequent sustained arrhythmia of the heart. The AFNET has established a nationwide patient registry on manifestation, diagnostics, and therapy of AF in Germany. The data analyzed to date demonstrate that patients with AF are likely to have multiple comorbidities (hypertension, valvular heart disease, coronary artery disease, diabetes mellitus) and an advanced age. Regarding oral anticoagulation, guideline adherence is very high. Basic research has identified specific changes in atrial tissue during AF-induced remodeling providing the rationale for novel therapeutic interventions. Clinical trials are being carried out to optimize pharmacological and nonpharmacological treatments. The ANTIPAF trial is designed to prove that angiotensin II receptor blockers reduce the incidence of paroxysmal AF. The Flec-SL trial tests the efficacy of a short-term treatment with antiarrhythmic drugs after cardioversion. The Gap-AF trial investigates the impact of complete pulmonary vein (PV) isolation versus incomplete circumferential PV ablation on AF recurrences. The effect of preventive pacing on the recurrence of paroxysmal AF is studied in the BACE-PACE trial.

[Event-recorder]. / Event-Rekorder.

Event or loop recorders monitor heart rhythm using discontinuous ECG storage which enables them to obtain a correlation between symptoms and the underlying heart rhythm in patients with infrequent, short-lasting episodes. External event recorders with intermittent monitoring, i.e., with electrodes within the device, are suitable for patients with palpitations or tachycardia who remain conscious. External event recorders with continuous monitoring are tolerated by patients for a few weeks and have a limited diagnostic impact in patients with recurrent syncope. The implantable loop recorder (ILR) monitors heart rhythm for one year and after patient-triggered or automatic activation stores a one-lead ECG up to 42 minutes prior to device activation. The diagnostic benefit of ILR in comparison to conventional approaches has been demonstrated in randomised studies. Furthermore, an ILR identifies patients with recurrent syncope of unknown origin in whom a pacemaker implantation can avoid further episodes. Additional possible indications are the monitoring of atrial fibrillation, the diagnostics of infrequent palpitations and patients with seizures.

[Indications for loop recorder implantation for syncope]. / Indikationen zur Loop-Rekorder-Implantation bei Synkope.

Implantable loop recorder with discontinuous ECG recording enables monitoring of heart rhythm over several years. Consequently, in patients with recurrent syncope it is possible to record an ECG during the next syncopal event to obtain symptom-ECG correlations. In patients with recurrent syncope of unknown origin, the implantation of a loop recorder leads to an earlier diagnosis and an asystole is more often detected as the cause of the recurrent syncope. In addition, the loop recorder identifies patients who will benefit from pacemaker implantation. An established indication for early implantation of a loop recorder is given in patients with recurrent syncope and no high-risk marker, e. g., reduced left ventricular function, valve disease, history of myocardial infarction or ECG findings such as bifascicular block, pre-excitation, long QT syndrome or an epsilon wave. These patients should receive a complete cardiological work-up with the aim of detecting the underlying heart disease. Patients with no conclusive findings should also receive a loop recorder. A relative indication is given for patients with recurrent syncope and injuries in order to predict the effect of pacemaker implantation. Possible indication is given for patients with transient loss of consciousness to rule out an arrhythmogenic origin.

New insights into the initiation of atrial fibrillation: a detailed intraindividual and interindividual analysis of the spontaneous onset of atrial fibrillation using new diagnostic pacemaker features.

BACKGROUND: This study investigated onset scenarios of atrial fibrillation (AF), the first phase of the Atrial Fibrillation Therapy (AFT) trial, to determine potential arrhythmogenic triggers as targets for atrial pacing algorithms that have been proposed for prevention of AF. METHODS AND RESULTS: Ninety-eight patients (58 men; age 65+/-11 years) with recurrent, symptomatic, drug-refractory AF and a conventional pacemaker indication in 31 of 98 received a dual-chamber pacemaker. Using novel diagnostic pacemaker features AF onset scenarios were prospectively evaluated in 612 AF episodes during a 2-month monitoring period, with atrial pacing limited to 40 bpm. The most common onset scenario was premature atrial complexes (PACs) before AF (48% onsets per patient), followed by bradycardia (33%), sudden onset (17%), and tachycardia (0%). Combinations of onset scenarios were frequent (median 2 different scenarios per patient). A main study finding was the significance of repetitive AF, with 33% of onsets per patient being initiated within 5 minutes of a previous AF episode. Sudden onsets were more frequent among patients with than without repetitive AF (24% versus 0% onsets per patient, P=0.011), whereas the proportion of PACs before AF was not statistically different (50% versus 37%, P=0.52); however, patients with repetitive AF had more PACs per hour (72 versus 29, P=0.023) and a higher number of AF episodes per day (17 versus 0, P=0.001) and were more likely to have at least 1 PAC-related onset (90% versus 53%, P<0.0001). CONCLUSIONS: Novel diagnostic pacemaker features allowed a detailed individual analysis of rate and rhythm changes before AF and thus uncovered a substantial intraindividual and interindividual variability of AF onset scenarios.

Correlation of postural blood pressure test and head-up tilt table test in patients with vasovagal syncope.

BACKGROUND: Vasovagal syncope is triggered by complex cerebral and cardiovascular reflex mechanisms leading to general vasodilatation and bradycardia resulting in cerebral hypoperfusion. METHODS: We prospectively studied the correlation of postural blood pressure test (PBT) and head-up tilt table test (TT) in patients with recurrent vasovagal syncope. Sixty-eight patients (37 male, 52.4 +/- 18.6 years) were included in the trial. They were asked to participate in a PBT and a TT. Independent samples t-test, ANOVA and Fisher's exact test were used for statistical analysis. p values <0.05 were considered statistically significant. RESULTS: Thirty patients (44%) showed a positive TT and thirty-four patients (50%) had a positive PBT. PBT did not show any correlation with TT, although pathophysiological mechanisms in vasovagal syncope and orthostatic hypotension are supposed to be similar. Furthermore neither TT nor PBT nor their combination had any predictive value for the patient's risk of syncope recurrence. CONCLUSIONS: TT and PBT are not correlated with each other. Both investigations cannot predict the patient's risk of syncope recurrence.

Atrial overdrive pacing and incidence of heart failure-related adverse events in permanently paced patients.

BACKGROUND: Atrial overdrive pacing algorithms may be effective in preventing or suppressing atrial fibrillation (AF). However, the maintenance of a heart rate incessantly faster than spontaneous could induce left ventricular (LV) dysfunction and promote heart failure (HF) on the long term. OBJECTIVE: This post hoc analysis examined the effects of a new overdrive algorithm on the incidence of HF-related adverse events in 411 patients enrolled in the ADOPT-A trial. MATERIALS AND METHODS: The AF Suppression algorithm was randomly programmed ON in 209 patients (treatment group) versus OFF in 202 patients (control group). The incidence of HF-related adverse events and HF-related deaths over a 6-month follow-up was compared between the two groups. Patients with versus without HF-related clinical events were also compared to each other within each group. RESULTS: There were eight HF-related adverse clinical events (3.8%) in the treatment group and 11 (5.4%) in the control group, including four HF-related deaths (1.9 vs. 2.0%) in each group during follow-up. Baseline NYHA functional class in patients with versus without HF-related adverse events was 1.4 +/- 0.5 versus 1.5 +/- 0.7 in the control, and 1.5 +/- 0.8 versus 1.5 +/- 0.6 in the treatment group. LV ejection fraction (EF) was 49 +/- 7% in patients with, versus 57 +/- 12% in patients without HF-related adverse events, in the control group, and 43 +/- 14% in patients with, versus 56 +/- 13% in patients without HF-related adverse events, in the treatment group. LVEF was lowest and similar in both groups among patients who died from HF (35 +/- 10% in the control and 38 +/- 27% in the treatment group). CONCLUSIONS: In ADOPT-A, HF-related clinical events and deaths were related to LV dysfunction and not to atrial pacing overdriven by the AF suppression algorithm.

Randomized comparison of simultaneous biventricular stimulation versus optimized interventricular delay in cardiac resynchronization therapy. The Resynchronization for the HemodYnamic Treatment for Heart Failure Management II implantable cardioverter defibrillator (RHYTHM II ICD) study.

BACKGROUND: The clinical value of interventricular (V-V) delay optimization in patients with chronic congestive heart failure (CHF) undergoing implantation of a device for cardiac resynchronization therapy (CRT) has not been clearly demonstrated. METHODS: RHYTHM II was a single-blind randomized trial including 121 recipients of a device for CRT with cardioverter/defibrillator capabilities (CRT-D) randomly assigned in a 1:3 ratio to simultaneous (n = 30) versus optimized (OPT) (n = 91) biventricular pacing. V-V delay was optimized by echocardiography. The study end points were (1) freedom from CRT-D system-related complications and (2) changes between preimplant and 6 months of follow-up in (a) New York Heart Association CHF functional class, (b) distance covered during a 6-minute hall walk, and (c) quality of life (QOL). RESULTS: In the OPT group, the V-V delay ranged from 0 to 80 milliseconds, with 28.4% of patients stimulated at an OPT V-V delay of 0 milliseconds. The overall 6-month survival free of adverse events requiring invasive interventions was 81.8%. In the whole cohort, 6 months of CRT-D was associated with a significant decrease in New York Heart Association class, increase in the distance covered during the 6-minute hall walk, and improvement in QOL (each P < .0001). The effects of CRT-D on these end points were similar in both study groups. CONCLUSIONS: Cardioverter-defibrillator capabilities was associated with a significant alleviation of CHF symptoms, increase in functional capacity, and improvement in QOL. The optimization of the V-V delay conferred no additional benefit compared with simultaneous biventricular stimulation.