Long-term monitoring of respiratory rate in patients with heart failure: the Multiparametric Heart Failure Evaluation in Implantable Cardioverter-Defibrillator Patients (MULTITUDE-HF) study.

BACKGROUND: Monitoring respiratory rate (RR) is recommended at the time of hospital presentation for acute decompensation in heart failure (HF). Device-based continuous monitoring of RR may be helpful for diagnostic and prognostic stratification after implantable cardioverter-defibrillator (ICD) implantation. This study was undertaken to analyze short- and long-term changes in ICD-measured RR and to relate RR with the patient's clinical status and the occurrence of HF events. METHODS: One hundred twenty-four consecutive HF patients who received ICD endowed with this diagnostic capability (Boston Scientific Inc., Natick, MA, USA) were prospectively enrolled. Patients were followed up for 12 months. RESULTS: At the baseline, the proportion of New York Heart Association (NYHA) class III-IV was higher among patients with daily maximum RR >27 breaths/min (third tertile) than those with <24 breaths/min (first tertile) (43 vs. 23%, p < 0.05). Moreover, the ejection fraction was lower (27 ± 7 vs. 34 ± 8%, p < 0.05). In patients with HF hospitalizations (33 events) and urgent visits for HF (15 events), the weekly average of RR calculated over the 7 days preceding hospital accesses did not differ from values recorded at the baseline and before scheduled follow-up visits. However, the weekly variation in RR (i.e., the difference between maximum and minimum values collected over the week) was significantly higher prior to hospitalization (p < 0.05). A weekly variation >3 breaths/min in maximum RR predicted an impending hospital admission for HF with sensitivity of 73 % and specificity of 57%. CONCLUSIONS: In this study, elevated values of ICD-monitored RR identified patients with worse functional status and lower systolic function. The weekly variation in RR increased before HF exacerbation. This monitoring technology may represent a useful tool in the clinical management of patients with HF.

Ventricular Rate Stabilization In Patients With Permanent Atrial Fibrillation And Single-Chamber Ventricular Pacemaker: RARE-PEARL Study.

Background: In patients with permanent atrial fibrillation (AF) rate irregularity can cause symptoms and impair the pumping function of the heart. Ventricular pacing at a rate close to the mean spontaneous ventricular rate can result in a more stable ventricular rate. Specific algorithms for automatic Ventricular Rate Stabilization (VRS) were designed and implemented in commercially available pacemakers. To assess this dynamic rate control we designed the RARE-PEARL study: prospective, randomized, cross-over, double-blinded. Methods: Patients with permanent AF, symptomatic episodes of brady-tachycardia, left ventricular ejection fraction (LVEF) >40%, NYHA class I/II/III, were eligible for enrolment. Each patient (n = 67) was implanted with a single-chamber VVIR pacemaker (models C20 or T20, Vitatron BV, The Netherlands) equipped with the VRS algorithm. At the end of a four week stabilization period, patients were randomized to VRS algorithm ON or OFF (2 months) and then crossed-over for the second phase (2 months). Primary endpoint was patient's preference. Results: Sixty six patients ended the study: 19 (29%) had no preference; 15 (23%) preferred algorithm OFF, 32 (48%) algorithm ON (p<0.0001, algorithm ON vs OFF). In 58% of patients the algorithm ON caused an increase of ventricular pacing percentage > 10%. The ventricular pacing percentage was 82±10% with algorithm ON vs 59±26% with algorithm OFF (p<0.0001). Symptoms did not differ significantly. Conclusions: The VRS algorithm significantly increases the ventricular pacing percentage in patients with permanent AF. This pacing function is preferred by the majority of patients implanted with a single-chamber VVIR pacemaker.

Association between frequent cardiac resynchronization therapy optimization and long-term clinical response: a post hoc analysis of the Clinical Evaluation on Advanced Resynchronization (CLEAR) pilot study.

AIMS: The long-term clinical value of the optimization of atrioventricular (AVD) and interventricular (VVD) delays in cardiac resynchronization therapy (CRT) remains controversial. We studied retrospectively the association between the frequency of AVD and VVD optimization and 1-year clinical outcomes in the 199 CRT patients who completed the Clinical Evaluation on Advanced Resynchronization study. METHODS AND RESULTS: From the 199 patients assigned to CRT-pacemaker (CRT-P) (New York Heart Association, NYHA, class III/IV, left ventricular ejection fraction <35%), two groups were retrospectively composed a posteriori on the basis of the frequency of their AVD and VVD optimization: Group 1 (n = 66) was composed of patients 'systematically' optimized at implant, at 3 and 6 months; Group 2 (n = 133) was composed of all other patients optimized 'non-systematically' (less than three times) during the 1 year study. The primary endpoint was a composite of all-cause mortality, heart failure-related hospitalization, NYHA functional class, and Quality of Life score, at 1 year. Systematic CRT optimization was associated with a higher percentage of improved patients based on the composite endpoint (85% in Group 1 vs. 61% in Group 2, P < 0.001), with fewer deaths (3% in Group 1 vs. 14% in Group 2, P = 0.014) and fewer hospitalizations (8% in Group 1 vs. 23% in Group 2, P = 0.007), at 1 year. CONCLUSION: These results further suggest that AVD and VVD frequent optimization (at implant, at 3 and 6 months) is associated with improved long-term clinical response in CRT-P patients.

Prevention of syncope through permanent cardiac pacing in patients with bifascicular block and syncope of unexplained origin: the PRESS study.

BACKGROUND: Syncope in patients with bifascicular block (BFB) is a common event whose causes might be difficult to assess. METHODS AND RESULTS: Prevention of syncope through permanent cardiac pacing in patients with bifascicular block (PRESS) is a multicenter, prospective, randomized, single-blinded study designed to demonstrate a reduction in symptomatic events in patients with bifascicular block and syncope of undetermined origin implanted with permanent pacemaker. Device programming mode (NASPE/BPEG code) at DDD with a lower rate of 60 ppm is compared with backup pacing at DDI with a lower rate of 30 ppm. The end point consisted of (1) syncope, (2) symptomatic presyncopal episodes associated with a device intervention (ventricular pacing), and (3) symptomatic episodes associated with intermittent or permanent atrioventricular block (any degree). One hundred one patients were enrolled and randomized. Primary end point events at 2 years were observed in 23 patients, with a significant lower incidence in the study group (hazard ratio, 0.32; 95% confidence interval [CI], 0.10-0.96; P=0.042). Reduction of any symptoms, associated or not with device intervention, was superior in DDD60 compared with DDI30 (hazard ratio, 0.4; 95% confidence interval, 0.25-0.78; P=0.0053). Fourteen patients developed other rhythm diseases and met class I indication for pacing. The annual incidence of rhythm disease development was 7.4%. CONCLUSIONS: In patients with bifascicular block and syncope of undetermined origin, the use of a dual chamber pacemaker programmed to DDD60 led to a significant reduction of syncope or symptomatic events associated with a cardioinhibitory origin, compared with DDI30 programming. Symptoms associated with a new onset of rhythm disease were found in 15% of the population at 2 years.

Risk stratification of ischaemic patients with implantable cardioverter defibrillators by C-reactive protein and a multi-markers strategy: results of the CAMI-GUIDE study.

AIMS: Patients at risk of sudden cardiac death (SCD) after myocardial infarction (MI) can be offered therapy with implantable cardioverter defibrillators (ICDs). Whether plasma biomarkers can help risk stratify for SCD and ventricular arrhythmias (VT/VF) is unclear. METHODS AND RESULTS: The primary objective of the CAMI-GUIDE study is to assess the predictive role of C-reactive protein for SCD or VT/VF in ischaemic patients with the ejection fraction <30% and ICDs. Secondary endpoints included all-cause mortality, hospitalizations, and death from heart failure. Additional analyses incorporated cystatin-C and NT-ProBNP in multi-marker approach for the prediction of adverse outcomes. A total of 300 patients were enrolled. All-cause mortality at 2 years was 22.6%, mortality from heart failure was 8.3%. Primary endpoint occurred in 17.3%. At a competing risk multivariable analysis adjusted for baseline variables, no significant difference in primary endpoint was found between patients with C-reactive protein ≤3 vs. >3 mg/L [heart rate (HR) 0.91 (0.50-1.64) P = 0.76], while C-reactive protein >3 mg/L was strongly associated with mortality due to heart failure [HR: 3.17 (1.54-6.54) P = 0.002]. NT-proBNP above median was significantly associated with the primary endpoint [adjusted HR: 1.46 (1.020-2.129) P = 0.042]. A risk function, including the three biomarkers, NYHA class and resting HR, allowed stratification of patient mortality risk from 5 to 50%. CONCLUSION: C-reactive protein >3 mg/L is not associated with SCD or fast VT/VF, however, is a strong predictor of HF mortality. Biomarkers combined with clinical markers allow an excellent risk stratification of mortality at 2 years.

Performance of a ventricular automatic-capture algorithm in a wide clinical setting.

BACKGROUND: The optimal programming of a pacemaker (PM) voltage output considers both efficiency (prolonging battery cell longevity) and patient safety (adequate safety margin). Currently, automatic capture (AC) algorithms are designed to ensure safe automatic stimulation threshold determination and pacing with a safety margin. METHODS: The aims of this prospective observational study were (1) to evaluate, over a short-term follow-up, the extent of backup pacing in patients implanted with an AC-featured PM produced by Boston Scientific (Insignia) and a wide range of ventricular leads; (2) to identify patient- or lead-specific predictors of ventricular threshold increase or missed detection of the ventricular pacing threshold; and (3) to analyze day-to-day fluctuations in the ventricular pacing threshold and the relationship between their magnitude, the characteristics of patients, and the system implanted. RESULTS: Five hundred and seventy-nine patients implanted with 89 different leads were followed up for a median of 2.1 months. Five hundred and thirty-six patients (92.5%) never experienced failure of automatic threshold testing; 571 (98.6%) did not experience permanent failure requiring continuous backup pacing at high energy. On multivariate analysis, none of the patient or lead characteristics predicted the occurrence of high-energy backup pacing during the study period. Day-to-day threshold fluctuations were associated only with higher thresholds (>1 V). CONCLUSION: AC algorithm reliably measures ventricular pacing thresholds in most patients: in only 1.4% of patients the system is permanently unable to detect the ventricular threshold. Backup pacing is not dependent on lead or patient characteristics, including lead polarization, polarity, and maturation.

A randomized comparison of amiodarone and class IC antiarrhythmic drugs to treat atrial fibrillation in patients paced for sinus node disease: the Prevention Investigation and Treatment: A Group for Observation and Research on Atrial arrhythmias (PITAGORA) trial.

BACKGROUND: Rhythm control is an important goal in the treatment of recurrent atrial tachyarrhythmias (AT). The PITAGORA study was a randomized trial in patients paced for sinus node disease (SND), designed to test the noninferiority of class IC antiarrhythmic drugs (AADs) to amiodarone in terms of a primary end point composed of death, permanent AT, cardiovascular hospitalization, atrial cardioversion, or AAD change. METHODS: Randomization was stratified to assign 2 patients to amiodarone and 2 patients to class IC AADs: propafenone or flecainide. One hundred seventy-six patients (46% men, 72 +/- 8 years) were enrolled. Device diagnostics continuously monitored AT recurrences and duration. RESULTS: In a mean follow-up of 20 +/- 9 months, the primary end point occurred in 23 (30.7%) of 75 class IC patients and in 28 (40.0%) of 70 amiodarone patients. The absolute difference in the end point incidence (-9.3%; 95% CI between 3.7% and -22.3%) confirmed the noninferiority of class IC to amiodarone (P = .007). Kaplan-Meier 1-year freedom from AT episodes >10 minutes, 1 day, and 7 days was 40%, 73%, and 91% for amiodarone and 28%, 78%, and 86% for class IC AADs (P = nonsignificant). CONCLUSIONS: In patients paced for SND and suffering from AT, class IC AADs proved not to be inferior to amiodarone in terms of the primary composite end point described or end points which were differently composed of mortality, efficacy, or AAD side effects. The AADs studied also showed similar results in terms of symptoms, quality of life, and freedom from AT recurrences.

Results of the SCART study: selection of candidates for cardiac resynchronisation therapy.

OBJECTIVE: To prospectively determine whether prespecified electrocardiographic, echocardiographic and tissue Doppler imaging (TDI) selection criteria may predict a positive response to cardiac resynchronisation therapy (CRT). METHODS: In this multicentre, prospective, non-randomised study, 96 heart failure patients with New York Heart Association class III-IV symptoms, an ejection fraction of < or =35%, and at least one marker of ventricular dyssynchrony according to prespecified electrocardiographic, echocardiographic or TDI criteria were enrolled. The primary endpoint was an improvement in the clinical composite score at 6 months. RESULTS: At enrolment, 70 patients fulfilled the electrocardiographic criterion (QRS duration > or =150 ms), 77 patients showed echocardiographic signs of dyssynchrony, and 37 patients met the TDI dyssynchrony criteria. The overall responder rate was 78/96 (81%). In particular, the primary endpoint was reached in 68 patients who fulfilled the echocardiographic criteria as compared with 10 patients who did not (88 vs. 53%, P = 0.001). The patients who met the echocardiographic criteria showed a significant greater reduction in left ventricular end-systolic diameter (P = 0.029) and a higher improvement in quality of life (P = 0.017) than patients who did not. Neither electrocardiographic nor TDI criteria seemed to predict a positive response to CRT. CONCLUSIONS: In our patient population, mechanical indexes of dyssynchrony as assessed by echocardiography appeared to identify CRT responders. Although TDI is useful for evaluating ventricular dyssynchrony after CRT, the prespecified TDI inclusion criteria adopted in this investigation did not increase the number of CRT responders.

Biventricular upgrading in patients with conventional pacing system and congestive heart failure: results and response predictors.

BACKGROUND: There are few studies on cardiac resynchronization therapy (CRT) in heart failure (HF) patients with preexisting right ventricular (RV) pacing. The purpose of this study was to determine the efficacy of CRT upgrading in RV-paced patients and the predictivity of electromechanical dyssynchrony parameters (EDP) evaluated by standard echocardiography (ECHO) and tissue Doppler imaging (TDI). METHODS: Thirty-eight consecutive patients with HF [New York Heart Association (NYHA) class III or IV, LVEF < 35%], prior continuous RV pacing, and absence of atrial fibrillation were enrolled in the presence of a paced QRS > or = 150 ms and evaluated by ECHO and TDI. A responder was defined as a patient with a favorable change in NYHA class and neither HF hospitalization nor death, plus an absolute increase of LVEF > or = 10 units. RESULTS: At six-months follow-up, the whole study population had significant improvement in symptoms, systolic function, and QRS duration (P < 0.001); 32 (84%) patients had a favorable clinical outcome, 25 (66%) were considered responders according to the previous definition. Postimplant QRS was similarly reduced in both responders and nonresponders, whereas EDP had a significant improvement only in responders (P < 0.05). Using EDP, 23 (79%) patients were responders compared with 2 (22%) patients without mechanical dyssynchrony (P = 0.002). CONCLUSIONS: In HF patients with previous RV pacing, CRT is effective to improve clinical, functional outcome, and LV performance and to reduce electromechanical dyssynchrony in a large proportion of patients. Dyssynchrony evaluated by standard and TDI ECHO can be useful for CRT selection of paced patients.

Efficacy of cardiac resynchronization therapy in very old patients: the Insync/Insync ICD Italian Registry.

AIMS: To assess the effects of cardiac resynchronization therapy (CRT) in > or =80-year-old patients vs. patients <80 years, in terms of clinical, functional, and echocardiographic parameters after 12 month of CRT, survival, and incidence of arrhythmic events. METHODS AND RESULTS: The study population consisted of 1181 CRT patients (85 were > or =80 years old). They were enrolled in a national observational registry and underwent baseline evaluation and periodical follow-up visits. In the overall population, New York Heart Association class and ejection fraction (EF) improved and ventricular diameters decreased. Similar changes were observed in the two groups. In the study population, 157 patients died, 144 (13%) in the <80 years group and 13 (15%) in the > or =80 years group. There was a higher all-cause mortality (log-rank test, P = 0.015) among > or =80 years patients, with a trend towards higher sudden cardiac death (SCD) (P = 0.057), but similar non-SCD (P = 0.293). Using the combined endpoint of SCD or appropriate shock from a defibrillator for ventricular fibrillation, no significant differences resulted between groups (P = 0.455). In both groups, lower EF was associated with higher mortality. CONCLUSION: Cardiac resynchronization therapy demonstrated similar efficacy in patients aged > or =80 years and in those under 80, in terms of clinical and functional parameters and reverse remodelling. Similarly, CRT resulted in comparable effects on death for heart failure and on SCD.

Rate control in patients with pacemaker affected by brady-tachy form of sick sinus syndrome.

BACKGROUND: In sinus node disease (SND) atrial tachyarrhythmias (ATs) may frequently occur, after implant of a pacemaker for bradycardia, and are to be managed by rate or rhythm control. METHODS: We evaluated ventricular heart rate (HR) during AT, AT-related symptoms and hospitalizations in 333 patients who received DDDRP pacemakers for SND. RESULTS: In days with 24 hours of AT, mean daily HR during AT was > 80, 90, 100, 110, and 120 beats per minute (bpm) in 191 (57%), 114 (34%), 55 (16%), 23 (7%), and 11 (3%) patients, respectively. The proportion of patients with a mean daily HR > 80 bpm during AT despite the use of rate control agents was 28% among patients treated with calcium-channel blockers, 43% with digoxin, 49% with a combination of agents, 54% with amiodarone, 64% with sotalol, and 69% with beta blockers. Patients with HR > 100 bpm experienced a higher prevalence of both AT-related hospitalizations and cardiovascular hospitalizations than those with HR < or = 100 bpm (36% vs 21%, P = .013; 42% vs 28%, P = .003) and a significantly higher number of AT-related symptoms (1.8 +/- 0.9 vs 1.4 +/- 1.0, P = .008). CONCLUSIONS: Limited attention has been dedicated to rate control in patients with pacemaker. This is the first study to evaluate the prevalence and implications of inappropriate rate control in patients with pacemaker. We found that in a substantial proportion of patients with SND who have recurrent ATs despite pacing, mean daily HR during AT is high and that these patients present increased hospitalizations and more symptoms, thus suggesting the need to improve rate control.

Cardioinhibitory carotid sinus hypersensitivity predicts an asystolic mechanism of spontaneous neurally mediated syncope.

AIMS: We correlated the finding of cardioinhibitory carotid sinus hypersensitivity (CSH) with that observed during a spontaneous syncopal relapse by means of an implantable loop recorder (ILR). METHODS AND RESULTS: We included 18 consecutive patients with suspected recurrent neurally mediated syncope and positive cardioinhibitory response during carotid sinus massage (max pause 5.5 +/- 1.6 s) who had subsequent documentation of a spontaneous syncope by means of an ILR. They were compared with a 2:1 age- and sex-matched group of 36 patients with a clinical diagnosis of recurrent neurally mediated syncope and negative response to carotid sinus massage, tilt testing and ATP test. Asystole >3 s was observed at the time of the spontaneous syncope in 16 (89%) of CSH patients and in 18 (50%) of the control group (P = 0.007). Sinus arrest was the most frequent finding among CSH patients but not among controls (72 vs. 28%, P = 0.003). After ILR documentation, 14 CSH patients with asystole received dual-chamber pacemaker implantation; during 35 +/- 22 months of follow-up, 2 syncopal episodes recurred in 2 patients (14%), and pre-syncope occurred in another 2 patients (14%). Syncope burden decreased from 1.68 (95% confidence interval 1.66 - 1.70) episodes per patient per year before to 0.04 (0.038-0.042) after pacemaker implant (98% relative risk reduction). CONCLUSIONS: In patients with suspected neurally mediated syncope, the finding of cardioinhibitory CSH predicts an asystolic mechanism at the time of spontaneous syncope and, consequently, suggests a possible benefit of cardiac pacing therapy.

Temporal variability of atrial fibrillation in pacemaker recipients for bradycardia: implications for crossover designed trials, study sample size, and identification of responder patients by means of arrhythmia burden.

BACKGROUND: Most clinical trials that have tested pacing therapies to prevent and treat atrial tachyarrhythmias (AT) have chosen endpoints such as AT frequency or burden (defined as percentage of time a patient is in AT), but failed to show unequivocal evidence of a clinical impact. AIM: The aim of our multicenter prospective observational study was to measure the variability of AT burden and estimate its impact on study outcomes. METHODS AND RESULTS: Two hundred and fifty patients indicated for permanent pacing and suffering from AT (age 71 +/- 9 years; 47.2% male) received a dual-chamber pacemaker. AT burden was measured in two consecutive, 2-month observation periods; the Monte Carlo method was then applied to simulate findings of a crossover design study. We simulated several models of therapy impact, each model being characterized by the percentage of responder patients and the percentage reduction in AT burden. To show a significant impact of AT therapies in a sample of 250 patients in whom 100, 75, or 50% would be theoretical responders to therapies, AT burden reduction should be at least 27, 32, or 57%, respectively. Temporal fluctuations in AT burden were so high that about 60% of patients would falsely appear as responders or nonresponders in a crossover study, regardless of AT burden reduction. CONCLUSIONS: In patients paced for bradycardia and suffering from AT, high intrapatient variability in AT burden was measured. Various models of therapy impact showed that, in crossover trials of AT therapies, time-related fluctuations in AT burden negatively impact on sample sizes and impair the ability to identify patients as responders or nonresponders.

Prediction of response to cardiac resynchronization therapy: the selection of candidates for CRT (SCART) study.

BACKGROUND: The aim of this study was to evaluate the ability of baseline clinical and echocardiographic parameters to predict a positive response to CRT. METHODS: We analyzed 6-month data from the first 133 consecutive patients enrolled in a multicenter prospective study. These patients had symptomatic heart failure (HF) refractory to pharmacological therapy (NYHA class II-IV), left ventricular ejection fraction (LVEF) < or =35%, and prespecified electrocardiographic, echocardiographic or tissue Doppler imaging markers of left ventricular (LV) dyssynchrony. RESULTS: After a follow-up period of 6 months, 1 patient died and 13 were hospitalized for worsening HF. There were significant (P < 0.01) clinical, functional, and echocardiographic improvements that included: New York heart Association Class, Quality-of-Life Score, QRS duration, LVEF, LV end-diastolic and end-systolic diameter (LVESD), and severity of mitral regurgitation A positive response was documented in 90/133 (68%) patients who presented an improved clinical composite score associated to an increase in LVEF > or = 5 units. A multivariate analysis identified that a smaller LVESD (OR = 0.957, 95% CI 0.920-0.996; P = 0.030) and longer interventricular mechanical delay (IVMD) (OR = 1.017, 95% CI 1.005-1.029, P = 0.007) as independent predictors of a positive response. Receiver-operating curve analysis showed that a positive response to CRT may be predicted in patients with IVMD > 44 ms (with a sensitivity of 66% and a specificity of 55%) or with LVESD < 60 mm (with a sensitivity of 66% and a specificity of 61%). CONCLUSIONS: Our results confirm the limited value of QRS duration in the selection of patients for CRT. A less-advanced stage of disease and echocardiographic evidence of interventricular dyssynchrony demonstrated to predict response to CRT, while intraventricular dyssynchrony did not predict response.

The risk profile for obstructive sleep apnea does not affect the recurrence of atrial fibrillation.

BACKGROUND: Obstructive sleep apnea (OSA) has been linked to increased prevalence and recurrence of atrial fibrillation (AF). We hypothesized that OSA may aggravate AF in patients with pacemakers implanted for sinus bradycardia who had documented paroxysmal AF. METHODS: Seventy-two patients (36 M, aged 77 +/- 6 years) completed the study. All patients received a dual-chamber pacemaker equipped with diagnostic and preventive functions for AF. OSA was diagnosed with the Berlin Questionnaire, which is validated to identify patients with OSA. Four-month continuous pacemaker recordings were collected for all patients. RESULTS: OSA was diagnosed in 28% of patients. Patients at high risk for OSA (HR group) and patients at low risk for OSA (LR group) were equivalent for gender, age, and body mass index. The rate of hypertension was higher in HR than in LR group (90% vs 44%, P < 0.01). The prevalence of paroxysmal AF during the study period was similar in HR and LR group (53% vs 44%, P = NS). Overall number of AF episodes per month was not significantly different between HR and LR group (7 +/- 13 vs 36 +/- 122, P = NS). Similarly, AF burden (AF%) was not significantly different between HR and LR group (0.3 +/- 0.6 vs 2.0 +/- 4.8, P = NS). Circadian distribution of AF episodes was similar in both groups. CONCLUSION: Long-term pacemaker recording of AF recurrence, AF burden, and its circadian distribution is similar in patients with paroxysmal AF at high risk for OSA and those at low risk for OSA.

Randomized comparison between Ramp and Burst+ atrial antitachycardia pacing therapies in patients suffering from sinus node disease and atrial fibrillation and implanted with a DDDRP device.

AIMS: Atrial tachycardia and flutter frequently occur in association with atrial fibrillation and may be treated by overdrive pacing in patients who receive pacemakers with antitachycardia pacing (ATP) capabilities. The PITAGORA trial was a multi-centre, randomized, cross-over study aimed at comparing two different ATP modes for atrial tachyarrhythmia (AT) termination in patients suffering from sinus node disease (SND). METHODS AND RESULTS: One hundred and seventy-six patients (72 M, age 71+/-9 years) received a Medtronic AT500 pacemaker. All patients were on class IC or III antiarrhythmic drugs. After a 5-month observation period, 170 patients were randomized to either Ramp or Burst+ ATP therapy; 4 months later they crossed over. One hundred and fifty-seven patients completed the 13 months of follow-up; 114 (72.6%) suffered 6088 AT episodes. In 75 patients, 1904 AT episodes were treated and 934 (49.1%) successfully terminated. The median value of individual patients' ATP efficacy was 60%. Burst+ terminated 387 out of 873 AT episodes (44%) in 58 patients. Ramp terminated 547 out of 1031 AT episodes (53%, P<0.001) in 56 patients. Ramp efficacy was significantly (P<0.01) and directly correlated with AT cycle length (ATCL), whereas Burst+ efficacy was not. Ramp showed higher (P<0.001) termination efficacy than Burst+ for ATCL >240 ms. Quality of life, as measured by the EuroQoL questionnaire, and number of symptoms significantly improved in the overall population. This improvement was significantly higher in patients with ATP efficacy >60%. CONCLUSION: In patients suffering from SND and AT, Ramp therapy shows higher termination efficacy than Burst+ therapy in AT episodes with ATCL >240 ms. Further studies are required to show the impact of ATP on clinical outcomes.

Is a dual-sensor pacemaker appropriate in patients with sino-atrial disease? Results from the DUSISLOG study.

BACKGROUND: Rate-responsive pacemakers (PMs) are often supplied with accelerometer (XL) and minute ventilation (MV) sensors to provide a physiologic rate response according to patient needs. No information is available about the real benefit of dual-sensor rate-responsive pacing on the daily life of patients. METHODS: DUSISLOG (Dual Sensor vs Single Sensor comparison using patient activity LOGbook) is a two-arm prospective, randomized, multicenter study that enrolled 105 patients who received a rate-responsive PM (Insignia), Guidant Corp.). After 1 month of DDD pacing at 60 ppm lower rate, a single sensor (XL or MV, randomized) was activated for 3 months at the manufacturer's suggested nominal settings, followed by a 3-month period with dual sensors optimized with automatic response. During the last month of each period, the following data concerning patient physical activity were retrieved from PM diagnostics (Activity Log): mean percentage of physical activity, mean intensity of activity. Quality of life (QoL) scores and 6-minute walk test (WT) were also recorded. RESULTS: Single-sensor rate-responsive pacing resulted in symptomatic benefit equally with XL and MV sensors while no additional benefit was found using dual sensor. In a subgroup analysis, patients (17%) with marked chronotropic incompetence and with 0% atrial sensing received benefits from single sensor with an additional advantage from sensor (QoL: +21 +/- 14% P < 0.05; WT: +17 +/- 7% P < 0.02). CONCLUSION: In most patients with rate-responsive devices, a single sensor is sufficient to achieve a satisfactory rate response. A dual sensor combination and optimization provides an additional benefit only in a selected population with an advanced atrial chronotropic disease.

Safety and feasibility of coronary sinus left ventricular leads extraction: a preliminary report.

BACKGROUND: transvenous positioning of the left ventricular (LV) lead in a branch of the coronary sinus (CS) is generally the preferred implantation technique in biventricular pacing. Very few data are reported about removal of LV pacing leads positioned in a CS branch. Aim of the study was to describe our experience with percutaneous extraction of LV pacing leads in order to evaluate feasibility and safety of this procedure. METHODS: we enrolled 392 patients who underwent a biventricular pacing implant. The indication for catheter removal was considered in case of definite diagnosis of infection and in some cases of lead dislodgement or diaphragmatic stimulation. LV lead extraction was first attempted by manual traction; in case of failure a locking stylet or locking stylet plus radiofrequency could be used. RESULTS: twelve of 392 patients implanted needed LV lead removal. The leads had been in place for 13.9 +/- 11.7 months. Extraction was indicated in 5 of them for LV lead dislodgement or diaphragmatic stimulation, and in 7 patients for lead infection. In all cases manual traction succeeded to remove the LV lead. In 7 cases of infection, the right atrial and ventricular leads were removed. The mean total procedure time was 69 +/- 22 min. No complications were observed. CONCLUSIONS: our study suggests that CS leads could be easily and safely removed without any complication, also when placed in a CS branch, at least for relatively young catheters.

A randomized, double-blind, placebo-controlled study of permanent cardiac pacing for the treatment of recurrent tilt-induced vasovagal syncope. The vasovagal syncope and pacing trial (SYNPACE).

AIMS: Recently, some studies revealed the efficacy of pacemaker implantation in decreasing recurrences in patients with vasovagal syncope. As these studies were not blinded or placebo-controlled, the benefits observed might have been due to a bias in the assessment of outcomes or to a placebo effect of the pacemaker. We performed a randomized, double-blind, placebo-controlled study in order to ascertain if pacing therapy reduces the risk of syncope relapse. METHODS AND RESULTS: Twenty-nine patients (53 +/- 16 years; 19 women) with severe recurrent tilt-induced vasovagal syncope (median 12 syncopes in the lifetime) and 1 syncopal relapse after head-up tilt testing underwent implantation of a pacemaker, and were randomized to pacemaker ON or to pacemaker OFF. During a median of 715 days of follow-up, 8 (50%) patients randomized to pacemaker ON had recurrence of syncope compared to 5 (38%) of patients randomized to pacemaker OFF (p = n.s.); the median time to first syncope was longer in the pacemaker ON than in pacemaker OFF group, although not significantly so (97 [38-144] vs 20 [4-302] days; p = 0.38). There was also no significant difference in the subgroups of patients who had had a mixed response and in those who had had an asystolic response during head-up tilt testing. CONCLUSION: Our data were unable to show a superiority of active pacing versus inactive pacing in preventing syncopal recurrence in patients with severe recurrent tilt-induced vasovagal syncope.