Incidence and predictors of pacemaker reprogramming: potential consequences for remote follow-up.

AIMS: Remote follow-up (FU) enables to cope with the expanding number of pacemaker (PM) FU. Although remote FU offers comparable monitoring options to in-office FU, reprogramming of device settings is not available, thereby imposing a potentially important restriction to the applicability of remote FU.  The aim of this study was to assess in a large cohort of bradycardia PM recipients, the incidence of PM reprogramming during long-term FU and its predictors, to judge the possibilities for remote FU. METHODS AND RESULTS: Between 2003 and 2010 all in-office FU of 1517 bradycardia PM recipients included in the FOLLOWPACE study were recorded. Only 24.5% of all 13 258 recorded FU visits >3 months after implantation were visits-with-reprogramming (VWRs), occurring in 1158 patients (79%). Fifty percent of patients were free of reprogramming at 9 months, and 29% at 24 months. Using multivariable binary logistic regression analysis, the following patient characteristics were predictive for frequent PM reprogramming, defined as >3 VWRs during 3 year FU: age, a history of atrial arrhythmias, PM complication <3 months after implantation, congestive heart failure, PM indication, and lead fixation method. This model had a receiver operating characteristic area of 0.66 (95% confidence interval 0.61-0.71). CONCLUSION: This study observed a low proportion of VWR (∼25%) during a mean FU of 5.3 years; however, those patients at high risk for PM reprogramming cannot easily be predicted. The vast majority of patients (>80%) do not need frequent reprogramming, suggesting a potential benefit of using remote FU to reduce the number of unnecessary in-office visits.

Pacemaker follow-up: are the latest guidelines in line with modern pacemaker practice?

AIMS: Guidelines regarding pacemaker (PM) follow-up (FU) are not precisely defined. The study aim is to describe long-term routine in-hospital FU, evaluate compliance to guidelines, and assess the portion of visits-with-an-action (VWA). METHODS AND RESULTS: The multicentre prospective FOLLOWPACE study collected data in the period 2003-2010, regarding FU of 1517 patients with a first PM for bradycardia indications in 23 Dutch hospitals. A total of 15 472 visits were analysed with a median FU of 4.9 years, adding up to 6750 patient years. The median time to the first three visits was 35, 127, and 303 days, respectively. Thereafter the median interval between visits was 180 days. Most patients had 2 FU/year, 22% had 1 FU/year, and 18% had >3 FU/year. Seventy-three percent of patients with single-chamber PMs had at least 1 FU/year, whereas 36% of patients with dual-chamber PMs received at least 2 FU/year. During the first year, 52% of visits were VWA, as opposed to 17% after 6 years. Battery status was assessed in 98%, and stimulation and sensing thresholds in 90% and 77% of visits, respectively. Reprogramming markedly declined from ≈ 60% in the first FU visit to 10-20% after the fifth visit. CONCLUSION: Although the measurements during PM FU are according to guidelines, the frequency of FU is not. Moreover, in the vast majority of performed FU, PM programming is left unchanged. This suggests that a large portion of FU visits is redundant, such that their frequency after the first year can be diminished, or replaced by remote FU.

Long-term outcome of cardiac pacing in octogenarians and nonagenarians.

AIMS: The number of patients >80 years receiving pacemakers (PMs) is increasing. Little is known about survival and complications in this specific subgroup. We aim to determine predictors of long-term survival. METHODS AND RESULTS: Pacemaker-related complications and death occurring in patients receiving a first PM for conventional bradycardia indications were systematically documented (the FollowPace registry). This report describes 481 patients ≥80 years during a mean follow-up of 5.8 (SD 1.2) years. Within 2 months 54 PM complications occurred in 47 patients (9.8%). During follow-up, 35 adverse PM events were reported in 33 patients (6.9%). Complication rates in patients ≥80 years were comparable with those for patients <80 years. Survival rates were 86, 75, and 49% after 1, 2, and 5 years, respectively, and were comparable with survival for age- and sex-matched controls from the general Dutch population. Most patients died of non-cardiac causes. Age at the time of implantation, male gender, the presence of congestive heart failure, coronary pathology, and diabetes mellitus were independent predictors of all-cause mortality. CONCLUSION: This large study of long-term cardiac pacing for bradycardia in octogenarians and nonagenarians showed a cumulative 5-year survival of ~50%, which compares with that of age- and sex-matched controls. These data suggest a beneficial impact of bradycardia pacing, restoring life expectancy to previous levels. The occurrence of PM complications during long-term follow-up is not infrequent with 18.1% of patients experiencing a PM-related complication during a mean of 5.8 years follow-up. The complication rate was not higher than in younger PM patients.

Upgrading to biventricular pacing guided by pressure-volume loop analysis during implantation.

INTRODUCTION: cardiac resynchronization therapy (CRT) may improve prognosis in patients with chronic right ventricular (RV) pacing, and optimal lead position can decrease nonresponders. We evaluated the clinical and echocardiographic response to CRT in patients with previous chronic RV pacing, using pressure-volume loop analyses to determine the optimal left ventricular (LV) lead position during implantation. METHODS AND RESULTS: In this single-blinded, randomized, controlled crossover study, 40 patients with chronic RV apical pacing and symptoms of heart failure, decreased LV ejection fraction (LVEF) or dyssynchrony were included. During implantation, stroke work (SW), LVEF, cardiac output, and LV dP/dt(max) were assessed by a conductance catheter. Clinical and echocardiographic response was studied during a 3-month period of RV pacing (RV period, LV lead inactive) and a 3-month period of biventricular pacing (CRT period). At the optimal LV lead position, SW (37 ± 41%), LVEF (16 ± 13%), cardiac output (29 ± 16%), and LV dP/dt(max) increased (11 ± 11%) significantly during biventricular pacing compared to baseline. Additional benefit could be achieved by pressure-volume loop guided selection of the best left-sided pacing location. RV outflow tract pacing did not improve hemodynamics. During follow-up, symptoms improved during CRT, VO(2,max) increased 10% and significant improvements in LVEF, LV volumes, and mitral regurgitation were observed as compared to the RV period. CONCLUSIONS: CRT in patients with chronic RV pacing causes significant improvement of both LV function as measured by pressure-volume loops during implantation and clinical and echocardiographic improvement during follow-up. Pressure-volume loops during implantation may facilitate selection of the most optimal pacing site.

Effects of pacing rates on global and regional myocardial blood flow.

BACKGROUND: Information is scarce on the effects of right ventricular apical (RVA) pacing on regional and global myocardial blood flow (MBF). The purpose of this study was to assess the relationship between pacing rate and both regional and global MBF. METHODS: Four patients with exclusive atrial pacing and six patients with exclusive RVA pacing underwent three consecutive H(2) (15)O positron emission tomography scans at 60, 90, and 130 pulses per minute (ppm). For each pacing rate, regional and global MBF was determined. In all patients, the left ventricular (LV) function was normal. RESULTS: By varying the atrial pacing rate from 60 to 130 ppm, the mean global MBF increased from 0.94 to 1.40 mL/g/min, whereas the mean septal to lateral MBF ratio decreased from 1.09 to 0.83. In ventricular-paced patients at corresponding rates, the mean global MBF also increased from 1.07 to 1.52 mL/g/min but here the mean septal to lateral MBF ratio increased from 0.83 to 1.0. CONCLUSIONS: During both acute atrial and RVA pacing, regional and global MBF increases with higher pacing rates. However, the septal to lateral MBF ratio decreases with atrial pacing and increases with RVA pacing in patients with normal LV function. In RVA pacing, these different rate-dependent effects on regional MBF can be considered as a favorable factor that helps to understand why in some long-term paced patients, LV function is preserved.

Myocardial perfusion SPECT identifies patients with left bundle branch block patterns at high risk for future coronary events.

BACKGROUND: The value of myocardial perfusion SPECT (MPS) for patients with left bundle branch block (LBBB) or right ventricular apical (RVA) pacing seems reduced. The prognosis of patients with only abnormal activation related perfusion defects (AARD) due to LBBB or RVA-pacing is similar to those with a normal MPS. We assessed the prognostic value of MPS in patients with LBBB or RVA pacing. METHODS: Patients with LBBB or RVA pacing referred for vasodilator stress MPS between April 2002 and January 2006 were analyzed. Group 1 are patients with normal MPS and MPS with AARD. Group 2 are patients with an MPS with a perfusion defect extending outside the AARD area. Events were cardiac death, acute myocardial infarction and coronary revascularization. RESULTS: In Group 1 (101 patients) 12 events and in Group 2 (96 patients) 45 events occurred during a mean follow-up of 2.6 +/- 1.5 years. The prognosis of Group 2 was significantly worse (49%) compared with Group 1 (91%). The annual cardiac death rate was 0.7%/year in Group 1 and 6.4%/year in Group 2 (P < .001). The prognosis of patients with LBBB was not different from those with RVA pacing. CONCLUSION: Group 2 had a significantly worse cardiac prognosis compared to Group 1. The annual cardiac death rate of <1% in Group 1 warrants a watchful waiting strategy, whereas the cardiac death rate in Group 2 warrants aggressive invasive coronary strategies.

Radiological and electrocardiographic characterization of right ventricular outflow tract pacing.

AIMS: The right ventricular outflow tract (RVOT) is used as an alternative pacing site, but its superiority to the RV apex remains to be established. This lack of proof may in part be explained by heterogeneity within the RVOT-paced group, due to poor definitions of the RVOT. The aim of the present study is to characterize the RVOT in terms of fluoroscopic and electrocardiographic parameters. METHODS AND RESULTS: One hundred and forty-three patients who underwent pacemaker implantation with a ventricular lead in the RVOT were included. Lead position was determined by fluoroscopy. The RVOT was divided into three areas: anterior, septal, and free wall (FW). On a 12-lead electrocardiogram (ECG) during forced ventricular pacing, QRS duration, configuration, and amplitude was determined. Lead position was judged to be anterior in 52 (36%), septal in 43 (30%), and FW in 48 (34%) patients, respectively. QRS duration is not significantly different between groups. QRS axis differs significantly between pacing sites (septal 79 ± 31°, anterior 60 ± 46°, FW 47 ± 38°, P < 0.05). QRS vector in lead I and QRS morphology and vector in lead aVL differ significantly between pacing sites. Precordial transition is earlier (towards V1) in septal pacing. CONCLUSIONS: This study demonstrates heterogeneity of pacing site and depolarization pattern within a cohort of patients paced form the RVOT. However, due to considerable overlap, we could not define clear cut-off point or devise flow-charts to match ECG and pacing site.

Pressure-volume loop analysis during implantation of biventricular pacemaker/cardiac resynchronization therapy device to optimize right and left ventricular pacing sites.

AIMS: To evaluate the clinical utility of pressure-volume loop analyses during pacemaker/implantable cardioverter defibrillator (ICD) implantations to assess the optimal right ventricular (RV) and/or left ventricular (LV) lead position. METHODS AND RESULTS: 29 patients with heart failure and chronic RV apical pacing were studied. Stroke work (SW), LV ejection fraction (LVEF), cardiac output (CO), and LV dP/dt(max) were assessed using a conductance catheter in the LV during RV apical, RV outflow tract, single-site LV, and biventricular pacing at different left-sided pacing locations. Left ventricular ejection fraction was 34.3 +/- 9.8%. Compared with baseline, RV outflow tract pacing showed a small increase of 4.0 +/- 6.4% in LV dP/dt(max) and no improvement in SW, LVEF, or CO. In the optimal biventricular configuration, SW increased 39 +/- 41%, LVEF increased 22 +/- 13%, CO increased 16 +/- 16%, and LV dP/dt(max) increased 10 +/- 11% (all P < 0.05). In 45% of the patients, the optimal LV lead position was found at a different location as the 'first choice' postero-lateral or lateral target vein. CONCLUSION: Pressure-volume loop analysis during pacemaker/ICD implantations facilitates to determine the optimal LV pacing site. Patients with chronic RV pacing showed a significant acute improvement in LV function when LV pacing or biventricular pacing is applied.

The prognostic significance of typical perfusion defects on vasodilator stress myocardial perfusion SPECT in patients with left bundle branch block or right ventricular apical pacing.

PURPOSE: Left bundle branch block (LBBB) and ventricular pacing may induce typical artefacts that appear as perfusion defects in myocardial perfusion single photon emission computed tomography (MPS). We assessed the prognosis of patients with LBBB or right ventricular apical (RVA) pacing who had chest pain and an MPS with only abnormal activation-related defects (AARD). METHODS: All patients with LBBB or ventricular pacing referred for vasodilator stress MPS between April 2002 and January 2006 were analyzed. AARD were defined as small, nontransmural, fixed defects and small reversible defects in well-defined regions always accompanied with concomitant wall motion abnormalities. RESULTS: Ninety-seven patients were included, with a mean follow-up period of 3+/-1.3 years. MPS showed AARD in 57 and it was completely normal in 40 patients. No significant difference in cumulative cardiac event-free follow-up was observed between patients with AARD (93%) and normal MPS (85%). The average annual cardiac event rate was not significantly different between the groups (1.7 and 4.3% per year, respectively). No difference was found between patients with LBBB and RVA pacing. CONCLUSION: Patients with chest pain and LBBB or RVA pacing who show AARD on MPS have a comparable prognosis as patients with abnormal activation and a normal MPS. This justifies MPS for risk stratification of patients with chest pain and LBBB or RVA pacing.

Clinical response of cardiac resynchronization therapy in the elderly.

BACKGROUND: Although prevalence of heart failure increases with age, in most clinical trials of cardiac resynchronization therapy (CRT), older patients are not included. Observational studies of effects of CRT in older patients had a small sample size. In the present study, the clinical and echocardiographic response to CRT in a larger group of elderly (age > 75 years) patients was evaluated. METHODS: In this prospective observational study of 266 consecutive patients, CRT was performed in 107 elderly patients (40%) and 159 (60%) younger patients (age < or = 75 years). Echocardiographic and clinical parameters were evaluated at baseline and at 3, 12, and 24 months. RESULTS: In the elderly group, mean age was 79 years compared with 67 years in patients aged < or = 75 years. Clinical baseline characteristics between the 2 groups were comparable. During follow-up, there was a comparable and sustained improvement in both groups according to New York Heart Association (NYHA) class, quality of life score, and left ventricular (LV) ejection fraction. Clinical response, defined as survival with improvement (> or = 1 score) of NYHA class without hospital admittance for heart failure, was seen in 67% and 69% (group aged < or = 75 years) versus 65% and 60% (group aged > 75 years) after 3 months and 1 year, respectively. Reverse LV remodeling defined as LV end-systolic volume reduction > or = 10% was seen in 79% and 87% (group aged < or = 75 years) versus 71% and 79% (group aged > 75 years) after 3 months and 1 year, respectively. Hospitalization for heart failure decreased significantly in both groups in the year after CRT. A subgroup analysis of 39 octogenarians (> 80 years) also showed a significant improvement in NYHA class and LV ejection fraction in this subgroup. Also, LV reverse remodeling occurred in a similar extent (75% and 84%) after 3 months and 1 year, respectively. CONCLUSIONS: This study shows a clinical and echocardiographic improvement of CRT in patients aged > 75 years and even so in octogenarians.

Predictors of improved quality of life 1 year after pacemaker implantation.

BACKGROUND: Patient's health-related quality of life (HRQoL) of pacemaker (PM) patients has increasingly become an important issue of health care evaluation. Currently, knowledge of pacing performance and technology is more or less outlined. However, determinants of poor or good HRQoL of paced patients require further elucidation. OBJECTIVES: The purpose of this study is to determine the HRQoL 1 year after PM implantation and predictors of differences in HRQoL between pre- and post-PM implantation. METHODS: We quantified the mean differences between HRQoL before implantation (baseline) and 1 year later, assessed with the generic Medical Outcomes Survey 36-Item Short-Form Survey and EuroQol (EQ5D), and the PM patient-specific AQUAREL (Assessment of QUality of life And RElated events) questionnaires, in 501 consecutively included patients in the Dutch multicenter longitudinal FOLLOWPACE cohort study. Multivariable linear regression modeling was then performed to determine predictive factors of the HRQoL 1 year after implantation. RESULTS: The HRQoL of the patients increased markedly in the first year after implantation. Seventy percent of the patients considered their health improved, whereas 11% experienced a complete recovery in HRQoL. The most important predictors for improved HRQoL after 1 year were HRQoL at baseline, age, presence of cardiac comorbidities, and atrial fibrillation with slow ventricular response as indication for chronic pacing. CONCLUSION: In most patients receiving a PM, HRQoL increased in the first year after PM implantation. Knowledge of the predictors of this increase may aid physicians to timely differentiate between patients who most likely will benefit most from PM implantation in terms of HRQoL.

Routine follow-up after pacemaker implantation: frequency, pacemaker programming and professionals in charge.

AIMS: To describe current evidence of the frequency, contents, and involved professionals of the routine follow-up visits in patients who have received a pacemaker (PM). METHODS AND RESULTS: The multicentre FOLLOWPACE study prospectively collected data during implantation and follow-up of 1526 patients who received a PM for the first time. A total of 4914 follow-up visits were studied. Mean follow-up was 394 days with a mean of 3.2 visits per patient. At all follow-up visits, the battery condition was tested in >93%, the stimulation threshold in >91%, and sensing in >87%. The pacemaker parameters as stimulation and sensing thresholds, lead impedances, and percentages of pacing remained stable over time, but these values did depend on the lead location, lead fixation, and pulse duration. The majority of PM (re-)programming was performed during implantation and/or shortly before hospital discharge (50%). PM re-programming during follow-up was most frequently performed by the PM technician alone (95%). CONCLUSION: Crucial PM parameters are regularly checked. Re-programming of PM parameters declined during the first year after PM implantation. The majority of PM checks were carried out by the PM technician, indicating the major influence of the allied professional on the quality and safety of the pacing therapy.

Poor health-related quality of life of patients with indication for chronic cardiac pacemaker therapy.

BACKGROUND: Studies on health-related quality of life (HRQoL) of patients awaiting pacemaker (PM) implantation are scarce, or executed in specific patient subgroups (regarding age or specific cardiac rhythm disorders). The purpose of this study was to systematically assess the HRQoL in a large unselected cohort of patients with a conventional indication for PM therapy. METHODS: Pre-PM implantation HRQoL (measured with the SF-36 questionnaire, completed at hospital admission) of 818 consecutive Dutch patients included in the FOLLOWPACE study was compared with the HRQoL in a sample of the general Dutch population, and with several cohorts of patients with other conditions. Linear regression analysis was performed to analyze determinants of this HRQoL. RESULTS: Almost all SF-36 subscale scores were substantially and significantly lower in the PM patients compared to the general population, with P-values < 0.001 in all SF-36 subscales except for "pain" and "general health perception." In the PM patients, presence of comorbidities, gender, and age were significantly associated with the overall physical component summary score (mean 38.8 +/- 27 standard deviation) whereas the overall mental component summary score (46.8 +/- 27.0) was associated with gender and age. CONCLUSION: The HRQoL of patients before first PM implantation is significantly lower than that of a general population and also various other patient populations. Physicians should be aware of this unfavorable condition and keep the time interval between the diagnosis of a cardiac rhythm disorder requiring PM implantation and the implantation procedure as short as possible.

Right ventricular outflow and apical pacing comparably worsen the echocardiographic normal left ventricle.

AIMS: A depressed left ventricular function (LVF) is sometimes observed during right ventricular apical (RVA) pacing, but any prediction of this adverse effect cannot be done. Right ventricular outflow tract (RVOT) pacing is thought to deteriorate LVF less frequently because of a more normal LV activation pattern. This study aims to assess the acute effects of RVA and RVOT pacing on LVF in order to determine the contribution of echocardiography for the selection of the optimum pacing site during pacemaker (PM) implantation. METHODS AND RESULTS: Fourteen patients with a DDD-pacemaker (7 RVA, 7 RVOT) and normal LVF without other cardiac abnormalities were studied. PM dependency, because of sick sinus syndrome with normal atrioventricular and intraventricular conduction, was absent in all, allowing acute programming changes. Wall motion score (WMS), longitudinal LV strain, and tissue Doppler imaging for electromechanical delay were assessed with echocardiography during AAI pacing constituting baseline and DDD pacing. The WMS was normal at baseline (AAI pacing) in all patients and LV dyssynchrony was absent. Acute RVA and RVOT pacing deteriorated WMS, electromechanical delay, and longitudinal LV strain, but no difference of the deterioration between both pacing sites was present and dyssynchrony did not emerge. CONCLUSION: Both acute RVA and RVOT pacing negatively affect WMS, longitudinal LV strain, and mechanical activation times, without clear differences between both pacing sites. Thus echocardiographic techniques do not facilitate the selection between RVOT and RVA pacing to exclude adverse effects on LVF during PM implantation in patients with a normal LVF.

The influence of myocardial scar and dyssynchrony on reverse remodeling in cardiac resynchronization therapy.

AIM: The influence of location and extent of transmural scar and its relation with dyssynchrony in cardiac resynchronization therapy (CRT) was investigated as posterolateral scar tissue has been invoked as a cause of non-response to CRT. METHODS AND RESULTS: Fifty-seven patients eligible for CRT were assessed for transmural scar with gadolinium-enhanced MRI and for left ventricular (LV) dyssynchrony with tissue Doppler. After implant, both atrioventricular and interventricular pacing intervals were optimized. LV reverse remodeling was defined as >/=10% decrease in LV end-systolic volume after 3 months. Sixteen patients had transmural scar in the posterolateral (PL) area (LV lead location), 14 at a remote site (non-PL) and 27 patients had no scar. LV reverse remodeling was observed in respectively 25%, 64% and 89% (P = 0.0001). Univariate analyses showed a relation with LV dyssynchrony (P = 0.004) and with absence of PL scar (P = 0.04) but not with QRS duration and the extent of LV scar tissue. In multivariate analysis, only LV dyssynchrony (OR: 19.62; 95% CI: 2.5-151.9; P = 0.004) independently predicted LV reverse remodeling. CONCLUSION: In this study LV dyssynchrony remains the most important determinant of response to CRT, even in the presence of posterolateral scar provided atrioventricular and interventricular pacing intervals are optimized.

Leadless pacemaker versus transvenous single-chamber pacemaker therapy: A propensity score-matched analysis.

BACKGROUND: The recent introduction of leadless pacemakers (PMs) was aimed to eliminate transvenous lead- and pocket-related complications. While the initial results with the leadless PMs seem promising, the nonrandomized nature, limited implant experience of operators, and short follow-up period of these studies preclude a simple comparison to transvenous PMs. OBJECTIVES: The objective of this study was to provide a balanced comparison of leadless and transvenous single-chamber PM therapies through a propensity score-matched analysis. METHODS: Leadless patients from 3 experienced leadless implant centers were propensity score-matched to VVI-R patients from a contemporary prospective multicenter transvenous PM registry. The primary outcome was device-related complications that required invasive intervention during mid-term follow-up. Separate analyses including and excluding PM advisory-related complications were performed. RESULTS: A total of 635 patients were match-eligible (leadless: n = 254; transvenous: n = 381), of whom 440 patients (median age 78 years; interquartile range 70-84 years; 61% men) were successfully matched (leadless: n = 220 vs transvenous: n = 220). The complication rate at 800 days of follow-up was 0.9% (95% confidence interval [CI] 0%-2.2%) in the leadless group vs 4.7% (95% CI 1.8%-7.6%) in the transvenous group when excluding PM advisory-related complications (P = .02). When including these PM advisory-related complications, the complication rate at 800 days increased to 10.9% (95% CI 4.8%-16.5%) in the leadless group vs 4.7% (95% CI 1.8%-7.6%) in the transvenous group (P = .063). CONCLUSION: This study reveals favorable complication rates for leadless compared to transvenous single-chamber pacing therapy at mid-term follow-up in a propensity score-matched cohort. When including PM advisory-related complications, this advantage is no longer observed.

Improvement in diastolic function and left ventricular filling pressure induced by cardiac resynchronization therapy.

BACKGROUND: Variable results of cardiac resynchronization therapy (CRT) on diastolic function have been described. We investigated 3 and 12 months' effect of CRT on diastolic function and left ventricular (LV) filling pressures and their relation to LV reverse remodeling. METHODS: Fifty-two patients' (36 male, 69 +/- 8 years, QRS duration 170 +/- 29 milliseconds) echo-Doppler was performed before and 3 and 12 months after CRT. Tissue Doppler early diastolic annular (Em) and color M-mode-derived flow propagation (Vp) velocities were used to estimate LV filling pressures by E/Em and E/Vp ratios. RESULTS: After 12 months, LV reverse remodeling (end-systolic volume decrease >15%) was observed in 58%. Despite a significantly more compromised baseline diastolic function of patients without LV reverse remodeling, multivariate analysis revealed that only LV dyssynchrony could predict LV reverse remodeling. Grades 2 and 3 diastolic function improved only in LV reverse remodeling patients (from 34% to 13% to 10%), whereas a nonsignificant increase from 59% to 67% to 72% was observed in patients without reverse remodeling. Irrespective of LV volume response, short-term symptomatic benefit was related to decreased filling pressure. However, after 12 months, E/Em and E/Vp only significantly decreased in patients with LV reverse remodeling (from 16.0 +/- 6 to 10.4 +/- 4 and 2.2 +/- 0.6 to 1.5 +/- 0.4, respectively). CONCLUSIONS: Left ventricular reverse remodeling induced by CRT is accompanied by improvement in diastolic function and estimated LV filling pressure. Short-term symptomatic benefit was related to decreased filling pressure. However, for longer-term symptomatic improvement and decreased filling pressures, LV reverse remodeling appeared mandatory.

Comparison of usefulness of cardiac resynchronization therapy in patients with atrial fibrillation and heart failure versus patients with sinus rhythm and heart failure.

The prevalence of atrial fibrillation (AF) in patients with heart failure is high, but data about the effects of cardiac resynchronization therapy (CRT) in patients with chronic AF are scarce. In this prospective observational study of 263 consecutive patients, CRT was performed in 96 patients (37%) with chronic AF and 167 patients (63%) with sinus rhythm (SR). Echocardiographic and clinical parameters were evaluated at baseline and 3 and 12 months. Reverse left ventricular (LV) remodeling is defined as LV end-systolic volume decrease > or =10%. Hospitalization rates for heart failure in the year before and after implantation were compared. Baseline characteristics between patients with and without AF were similar, but the AF group had smaller LV end-systolic and end-diastolic volumes and larger left atrial dimensions. New York Heart Association class, 6-minute walking distance, quality-of-life score, LV ejection fraction, and mitral regurgitation improved significantly at 3 and 12 months in both groups, and the changes were similar. Reverse LV remodeling after 3 and 12 months was 74% and 82% (AF group) versus 77% and 83%, respectively (SR group, p = 0.79). After 1 year, cardioversion had occurred in 25% of patients with AF. In the year after implantation, significant decreases in hospitalizations for heart failure in both groups (84% and 90%) were documented. Long-term mortality was almost equal in both groups. In conclusion, this large-scale study shows that the benefit of CRT in patients with chronic AF and heart failure is similar to that in patients with SR. Patients with chronic AF and heart failure should be considered candidates for CRT.

Relation of isovolumic times after cardiac resynchronization therapy to improvement in exercise capacity.

Isovolumic times (IVTs) comprise a determinant of exercise capacity in cardiomyopathy. We postulated that an increase in exercise capacity after cardiac resynchronization therapy (CRT) might be related to a more efficient cardiac cycle due to decreasing IVTs and increased filling times. According to standard selection criteria, a CRT device was implanted in 52 patients (37 men; 69 +/- 8 years) with a QRS duration of 174 +/- 30 ms. The etiology was ischemic in 22 and idiopathic in 30 patients. A 6-minute walking test (MWT) and echocardiographic Doppler were performed before and 3 and 6 months after CRT. Timing cycles were obtained with echocardiographic Doppler. An improvement in MWT by >15% (responders) after 6 months of CRT was observed in 46% of patients. The MWT was moderately correlated with baseline time intervals (IVT r = -0.44, filling time r = 0.52), but not to baseline left ventricular ejection fraction (r = -0.06). However, change in the MWT after 3 and 6 months was best related to changes in IVT (r = -0.66 and -0.68, respectively). Receiver-operating characteristic curve analysis of baseline IVT showed that an IVT >29% predicted exercise response with a positive predictive value of 89% and a negative predictive value of 77%. In conclusion, improvement in exercise tolerance after CRT is associated with a decrease in prolonged IVT. Baseline IVT might be used as an adjunctive parameter for selecting symptomatic responders to CRT.