Biomedical subjects

Anne S Hellkamp

Publications and source records attributed to Anne S Hellkamp.

At least 19 recordsLinked to original sources

PubMed2006

Treatment crossovers did not affect randomized treatment comparisons in the Mode Selection Trial (MOST).

OBJECTIVES: We evaluated the impact of treatment crossovers on study results in the Mode Selection Trial (MOST). BACKGROUND: The MOST study, a 2,010-patient, 6-year trial comparing dual-chamber pacing (DDDR) and ventricular pacing (VVIR) in sinus node dysfunction, demonstrated no difference in death or stroke and modest reductions in heart failure hospitalization (HFH) and atrial fibrillation (AF) with DDDR pacing. However, a moderate proportion of VVIR-randomized patients were temporarily or permanently crossed over to DDDR pacing. METHODS: Intent-to-treat (ITT) analyses compared treatment arms by randomized pacing mode. On-treatment analyses used time-dependent covariates to account for all crossovers. All analyses used Cox proportional hazards models and included covariates prespecified in the study design: age, gender, Charlson index, and prior stroke, heart failure, myocardial infarction, supraventricular tachyarrhythmia, and ventricular tachycardia or fibrillation. RESULTS: Of 996 VVIR-randomized patients, 375 (38%) were DDDR paced at some time, accounting for 27% of follow-up days among all VVIR-randomized patients. Of 1,014 DDDR-randomized patients, 53 (5%) were VVIR paced at some time, accounting for 1.5% of follow-up days among all DDDR-randomized patients. On-treatment analyses showed slightly lower hazard ratios favoring DDDR versus VVIR compared with ITT: death or stroke 0.88 (on-treatment) versus 0.91 (ITT); death 0.94 versus 0.95; stroke 0.74 versus 0.81; HFH 0.72 versus 0.73; and AF 0.72 versus 0.77. Interpretation of treatment effects was unchanged. CONCLUSIONS: Although treatment crossovers accounted for >25% of follow-up time in the VVIR-randomized group, this did not affect study results. End point comparisons between randomized modes are accurate reflections of DDDR versus VVIR pacing in this study population.

Aged↗

PubMed2006

Heart failure during cardiac pacing.

BACKGROUND: Right ventricular apical (RVA) pacing creates abnormal left ventricular contraction, hypertrophy, and reduced pump function. The adverse effects of ventricular desynchronization may explain the association of RVA pacing with an increased risk of heart failure hospitalization (HFH) in clinical trials. METHODS AND RESULTS: Baseline and postimplantation variables were used to predict HFH in the Mode Selection Trial, a 2010-patient, 6-year trial of dual-chamber (DDDR) versus ventricular (VVIR) pacing in sinus node dysfunction. A Cox model showed that New York Heart Association (NYHA) class at baseline and follow-up predicted HFH (hazard ratio [HR], 3.99; 95% confidence interval [CI], 2.74-5.79 for NYHA class III/IV and HR, 2.17; 95% CI, 1.54-3.04 for NYHA class II versus class I); other predictors were heart failure (HR, 2.30; 95% CI, 1.70-3.11), atrioventricular (AV) block (HR, 1.48; 95% CI, 1.11-1.97), and myocardial infarction (MI)(HR, 1.37; 95% CI, 1.00-1.86). Postimplantation predictors were VVIR cumulative percent ventricular pacing (Cum%VP) >80 (HR, 3.58; 95% CI, 1.72-7.45), DDDR Cum%VP >40 or VVIR Cum%VP < or =80 (HR, 1.81; 95% CI, 0.94-3.50) versus DDDR Cum%VP < or =40; whether QRS duration (QRSd) was paced or spontaneous (HR, 2.21; 95% CI, 1.39-3.54; spontaneous versus paced); and drugs for atrial fibrillation (HR, 1.60; 95% CI, 1.19-2.15). Low baseline ejection fraction (EF) and postimplantation RVA-paced or spontaneous QRSd predicted HFH; the increased risk with QRSd was steeper for normal versus low EF (HR, 1.18; 95% CI, 1.11-1.27; versus HR, 1.08; 95% CI, 1.01-1.15; for a 10-ms increase); at a QRSd of approximately 200 ms, normal- and low-EF patients had equivalent risk. HFH risk nearly doubled when VVIR Cum%VP was < or =80 or DDDR Cum%VP was >40 versus DDDR Cum%VP < or =40 and was additive with other risk factors. CONCLUSIONS: Differences in HFH risk can be explained by interactions between substrate (atrial fibrillation, AV conduction, heart failure, MI, EF) and pacing promoters (ventricular desynchronization-paced QRSd and Cum%VP, and AV desynchronization-pacing mode). Management of RVA pacing is important for reducing the risk of HFH, particularly among patients with low EF and heart failure.

Atrioventricular Node↗

PubMed2006

Comparing classifications of death in the Mode Selection Trial: agreement and disagreement among site investigators and a clinical events committee.

Clinical events committees (CECs) are the current standard for endpoint adjudication in clinical trials. However, little data exist with which to compare CEC and site investigator determinations or to evaluate internal agreement among CEC members. Using data from the Mode Selection Trial in Sinus Node Dysfunction (MOST), we analyzed classifications of death in order to compare internal agreement among CEC physician reviewers and agreement between the CEC and site investigators. Death was classified at 2 levels: by major cause (cardiac, noncardiac, or unknown) and by minor subclassification of the major classifications. Reviewer agreement was tabulated at the major and minor levels, and standard and weighted kappa statistics were calculated. Disagreement at both levels was also determined. Individual decision-making was tabulated in terms of frequency in classifying death as unknown. All 404 deaths were classified by the CEC. Site investigators determined major classifications in 382 cases and minor classification in 379 cases. The CEC and the site investigators disagreed in classifying 41 cases (10.7%) at the major level and 117 (30.9%) at the minor level. CEC reviewers disagreed internally at the major level in 64 cases (15.8%), at the minor level in 63 cases (15.6%), and at any level in 127 cases (31.4%) (kappa = 0.60, 95% confidence interval (CI) [0.55, 0.66]; weighted kappa = 0.66, 95% CI [0.62, 0.75]). In resolving internal disagreements, the full CEC agreed with 1 of 2 CEC reviewers in 85.9% of cases. Disagreements occurred between site investigators and CEC reviewers in classifying deaths. Endpoint determination and decision-making varied among individual CEC reviewers, but second-tier reviews by the full CEC resolved all disagreements. These findings support continued use of CECs for endpoint adjudication in clinical trials.

Cause of Death↗

PubMed2006

The association of the heart failure score with mortality and heart failure hospitalizations in elderly patients: insights from the Mode Selection Trial (MOST).

BACKGROUND: Patient and physician preferences as well as cost favor an increasingly higher threshold for hospital admission for heart failure (HF) treatment. This trend risks masking the severity and prevalence of HF as hospitalization for HF may decrease. METHODS: Heart Failure Score (HFS) has 4 ordinal subscales assessing (1) HF symptoms, physical signs of left (2) and (3) right HF, and (4) therapy changes for HF. Heart Failure Score was calculated for 1257 of 2010 (63%) patients enrolled in the MOST trial in sinus node dysfunction, who survived and had complete first-year HFS data at 4 postpacemaker implant visits (1, 3, 6, and 12 months). Heart Failure Score was summed and ranged from 0 to 14, with lower scores representing less HF. RESULTS: There were 1257 patients (median age 74 years [interquartile range 68-79], 47% were women, 61% had hypertension, 20%, diabetes mellitus, and 23%, prior myocardial infarction). The median HFS accumulated during 1 year was 4 (interquartile range 1-8). Of patients with a benign first year, those with a higher HFS were more likely to die during subsequent follow-up compared with patients with lower HFS (hazard ratio 1.07, 95% CI 1.04-1.10 for each 1-point increase, P < .001). CONCLUSIONS: Increasing HFS is associated with an increased risk of mortality in mostly elderly patients without pre-existing HF. Heart Failure Score may be a useful surrogate HF end point for clinical trials.

Aged↗

PubMed2006

Role of amiodarone or implantable cardioverter/defibrillator in patients with atrial fibrillation and heart failure.

BACKGROUND: Heart failure complicated by atrial fibrillation (AF) is associated with excessive mortality and morbidity. The aim of the study was to determine the role of amiodarone or implantable cardioverter/defibrillator (ICD) in patients with AF and heart failure. METHODS: Patients were determined to be in sinus rhythm (SR) or AF on the baseline electrocardiogram. Mortality, ICD discharge, or change in rhythm was assessed. RESULTS: Of the 2521 patients at baseline, 2328 were in SR and 173 were in AF. Overall, after adjusting for differences in baseline variables, there was no difference in mortality between patients with SR and patients with AF (P = .98), nor within assigned groups: placebo (P) (P = .82), amiodarone (A) (P = .68), and ICD (P = .40). For patients with SR, ICD decreased mortality (P vs ICD, P = .004; A vs ICD, P = .004; P vs A, P = .75). For patients with AF, there were no differences in mortality among groups (P vs ICD, P = .99; A vs ICD, P = .88; P vs A, P = .88). Of patients with SR at baseline, 11% (264) developed AF by any electrocardiogram during follow-up (P 12%, A 8%, ICD 15%; A vs P, P = .019; A vs ICD, P = .001; P vs ICD, P = .044). Of patients with AF, 70% (121) developed SR during follow-up (P 66%, A 67%, ICD 75%, all P = not significant against each other). Any ICD shock was seen in 52% (34) of patients with AF vs 30% (222) of patients with SR (P = .001). Inappropriate shocks were seen in 37% (24) of patients with AF vs 14% (107) of patients with SR (P = .001). Appropriate shocks were more often seen in AF vs SR (P = .03). CONCLUSION: After adjustments for baseline differences, patients with AF and patients with SR have similar overall mortality rates. Compared to P or A, ICD improves survival in patients with SR, but may not in patients with AF. Amiodarone is effective in reducing new AF, but not in converting AF to SR. Implantable cardioverter/defibrillator, inappropriate, and appropriate shocks were more often seen in AF than in SR.

Aged↗

PubMed2005

Association of prolonged QRS duration with death in a clinical trial of pacemaker therapy for sinus node dysfunction.

BACKGROUND: Prolonged QRS duration (QRSd) is an important prognostic indicator for death and heart failure hospitalization in patients with systolic heart failure. The relationship of baseline QRSd to death and heart failure hospitalization in patients with sinus node dysfunction who require pacemaker therapy is unknown. METHODS AND RESULTS: Baseline QRSd from 12-lead ECGs before pacemaker implantation were analyzed in the Mode Selection Trial (MOST), a 6-year, 2010-patient randomized trial of dual-chamber versus ventricular pacing in sinus node dysfunction. Baseline QRSd was > or =120 ms in 23.4% of patients and was associated with older age, lower ejection fraction, cardiomyopathy, and prior heart failure. Adjusted Cox models demonstrated baseline QRSd > or =120 ms was a strong independent predictor of death (hazard ratio [95% CI] 1.35 [1.07, 1.70], P=0.010) but not heart failure hospitalization. The risk of death increased with increased QRSd from 60 to 120 ms (P=0.002 and hazard ratio [95% CI] 1.14 [1.05, 1.23] for 10-ms increase in this range) after adjustment for other death predictors. CONCLUSIONS: Baseline QRSd > or =120 ms was associated with increased risk of death during pacemaker therapy for sinus node dysfunction.

Aged↗

PubMed2005

Heart failure hospitalization is more common in pacemaker patients with sinus node dysfunction and a prolonged paced QRS duration.

OBJECTIVES: The purpose of this study was to determine whether a prolonged paced QRS duration increases the risk of cardiac dysfunction. BACKGROUND: Right ventricular apical pacing mimics left bundle branch block, results in a prolonged QRS duration of variable duration, and causes ventricular desynchronization. METHODS: In the Mode Selection Trial (MOST), QRS duration was measured in patients who had at least one paced ventricular complex recorded on 12-lead ECG within 3 months of enrollment (early) and after 9 months (late). Clinical endpoints including heart failure hospitalization, mortality, and atrial fibrillation were analyzed. A total of 1,026 patients were included in the analysis. Median age was 75 years (25th, 75th percentiles = 69, 80) and median ejection fraction prior to implant was 55% (45, 60). The cumulative percent ventricular pacing (DDDR and VVIR) was 81% over a median follow-up of 33 months. During period, 123 patients had heart failure hospitalization, 197 died, and 261 patients had atrial fibrillation. RESULTS: Cox proportional hazards models demonstrated that paced QRS duration was a strong predictor of heart failure hospitalization (hazard ratio 1.15; 95% confidence interval 1.07,1.23) for each 10-ms increase in paced QRS duration (P = .001). The increased risk was unaffected by adjustment for other known predictors of heart failure hospitalization in the study. Paced QRS duration was not significant for mortality (P = .41) or atrial fibrillation (P = .20) when baseline QRS duration and other predictors were included. CONCLUSIONS: Paced QRS duration is a significant, independent predictor of heart failure hospitalization in patients with sinus node dysfunction. A very long paced QRS duration is associated with increased heart failure hospitalization.

Aged↗

PubMed2005

Clinical and quality of life comparison of accelerometer, piezoelectric crystal, and blended sensors in DDDR-paced patients with sinus node dysfunction in the mode selection trial (MOST).

INTRODUCTION: Permanent pacemakers are capable of increasing heart rate in response to physical activity by a variety of sensors including accelerometers, piezoelectric crystals, or blended sensors. The impact of these different physiologic sensors on cardiovascular events and quality of life is not known. METHODS: Of 2,010 patients randomized in the Mode Selection Trial, 1,245 patients were selected with the most commonly used pacemakers with these three sensors. Clinical characteristics and quality of life were compared between groups at baseline, 3 months, and then yearly. RESULTS: There were 449 patients with an accelerometer sensor device, 682 with a piezoelectric sensor, and 114 with a blended sensor. The groups were similar in terms of age (mean 74 years), gender, and cardiac risk factors but differences existed in weight, heart rate, mitral regurgitation, revascularization history, and drug therapy. The median ventricular pacing frequency was 80% (25th, 75th percentiles 42, 97). After a median follow-up of 33.1 months, the risk of death, heart failure hospitalization, atrial fibrillation, and the combined endpoint of mortality and stroke was not significantly different between the sensor types, after adjustment for baseline differences. Quality of life analyses demonstrated that patients with blended sensors had significantly worse (P < 0.01) physical function than did patients with the other two sensor systems. Moreover, patients receiving blended sensors had the poorest absolute scores, without reaching statistical significance, on 9 of 13 quality of life measures after adjusting for differences in the groups. CONCLUSION: We found no significant differences among the three most utilized sensors in clinical endpoints. Those patients who received blended sensors had worse physical function quality of life scores. However, clinical selection of the most sophisticated sensor for the most ill patients cannot be excluded as an explanation of these results.

Aged↗

PubMed2005

Bailout use of platelet glycoprotein IIb-IIIa inhibition during coronary stent implantation: observations from the ESPRIT trial.

Glycoprotein (GP) IIb/IIIa inhibitors are often used as a rescue or bailout therapy to manage complications arising during percutaneous coronary intervention, rather than as prophylactic treatment. We sought to identify the characteristics and outcomes of patients requiring bailout treatment. The ESPRIT trial randomized 2,064 patients to receive eptifibatide or placebo starting immediately before percutaneous coronary intervention (PCI). Bailout therapy was used in 77 patients: 43 (4.2%) randomized to placebo and 34 (3.3%) to eptifibatide (p = 0.3). Bailout therapy for thrombosis was used more often in the placebo group (2.1% versus 1.0%; p = 0.03). Multivariable predictors of bailout included a greater than or equal to 90% stenosis, or visible thrombus on the baseline angiogram, and no aspirin pre-treatment before PCI. However, overall the model predicted bailout poorly (c-index = 0.64). The need for bailout cannot be reliably predicted using baseline characteristics. Patients experiencing complications have poor clinical outcomes despite bailout use of GP IIb/IIIa inhibitors.

Aged↗

PubMed2004

Optimal duration of eptifibatide infusion in percutaneous coronary intervention (an ESPRIT substudy).

Although randomized trials have clearly demonstrated the clinical efficacy with regimens of platelet glycoprotein IIb/IIIa antagonists that result in >80% inhibition of baseline platelet aggregation in percutaneous coronary intervention (PCI), there are no data available concerning the optimal duration of infusion of these agents. In an era when the length of hospitalization has a major impact on health care costs, the determination of the optimal duration of the infusion of these drugs after PCI is of great relevance. The investigators therefore sought to determine the optimal length of the infusion of eptifibatide after PCI by analyzing the outcomes of patients enrolled in the Enhanced Suppression of the Platelet IIb/IIIa Receptor With Integrilin Therapy trial who were randomized to treatment with eptifibatide.

Angioplasty, Balloon, Coronary↗

PubMed2004

High incidence of pacemaker syndrome in patients with sinus node dysfunction treated with ventricular-based pacing in the Mode Selection Trial (MOST).

OBJECTIVES: We evaluated the incidence, predictors, and treatment of pacemaker syndrome in patients with sinus node dysfunction treated with ventricular-based (VVIR) pacing in the Mode Selection Trial (MOST). BACKGROUND: Pacemaker syndrome, or intolerance to VVIR pacing, consists of cardiovascular signs and symptoms induced by VVIR pacing. METHODS: The definition of pacemaker syndrome required that a patient with single-chamber VVIR pacing develop either congestive signs and symptoms associated with retrograde conduction during VVIR pacing or a >or=20 mm Hg reduction of systolic blood pressure during VVIR pacing, associated with reproducible symptoms of weakness, lightheadedness, or syncope. RESULTS: Of 996 patients randomized to VVIR pacing, 182 (18.3%) met criteria for pacemaker syndrome in follow-up. Pacemaker syndrome occurred early in most patients (13.8% at 6 months, 16.0% at 1 year, increasing to 19.7% at 4 years). Baseline univariate predictors of pacemaker syndrome included a lower sinus rate and higher programmed pacemaker rate. Previous heart failure, ejection fraction, and drop in systolic blood pressure with VVIR pacing at implantation did not predict the development of pacemaker syndrome. Post-implantation predictors of pacemaker syndrome were a higher percentage of paced beats, higher programmed low rate, and slower underlying spontaneous sinus rate. Quality of life decreased at the time of diagnosis of pacemaker syndrome and improved with reprogramming to atrial-based pacing. CONCLUSIONS: Severe pacemaker syndrome developed in nearly 20% of VVIR-paced patients and improved with reprogramming to the dual-chamber pacing mode. Because prediction of pacemaker syndrome is difficult, the only way to prevent pacemaker syndrome is to implant atrial-based pacemakers in all patients.

Aged↗

PubMed2004

Predictors of stroke in patients paced for sick sinus syndrome.

OBJECTIVES: This study was an analysis of factors associated with stroke in a population of patients paced for sinus node dysfunction in a large prospective clinical trial (Mode Selection Trial [MOST]). BACKGROUND: The effects of dual-chamber versus single-chamber ventricular pacing on subsequent stroke in patients with sinus node dysfunction are not known. METHODS: A total of 2,010 patients with sinus node dysfunction were randomized to ventricular or dual-chamber pacing and followed for a median of 33.1 months. RESULTS: The median participant age was 74 years. During 5,664 patient-years of follow-up, 90 strokes (11 hemorrhagic) occurred. By life-table analysis, the rate of stroke was 2.2% (95% confidence interval [CI] 1.6 to 2.9) at one year and 5.8% (95% CI 4.5 to 7.1) at four years. The incidence of stroke was not significantly different in dual-chamber (4%) as compared with ventricular-paced patients (4.9%) (hazard ratio [HR] 0.82, 95% CI 0.54 to 1.25, p = 0.36). Multivariable analysis demonstrated that significant predictors of stroke included prior stroke or transient ischemic attack, Caucasian race, hypertension, prior systemic embolism, and New York Heart Association functional class III or IV (p < 0.05); pacing mode remained non-significant after adjustment for these factors (p = 0.37). Clinically reported atrial fibrillation after implantation was a risk factor for stroke in this cohort after adjustment for other predictors of stroke (p = 0.042, HR 1.68 [95% CI 1.02 to 2.76]). CONCLUSIONS: Clinical characteristics, but not mode of pacing, were associated with subsequent stroke in patients paced for sinus node dysfunction.

Age Factors↗

PubMed2004

Prospective randomized study of mode switching in a clinical trial of pacemaker therapy for sinus node dysfunction.

INTRODUCTION: Atrial fibrillation (AF) is common in pacemaker patients with sinus node dysfunction (SND) and may result in rapid ventricular pacing (RVP) in the DDDR mode. Mode switching (MS) reduces RVP, but its clinical benefit in patients with SND is unknown. METHODS AND RESULTS: Two hundred two patients in the Mode Selection Trial (MOST; 2,010-patient, 6-year trial of DDDR vs VVIR pacing in SND) randomized to DDDR pacemakers with atrial high-rate episode (AHRE) storage capabilities were subrandomized to MS ON (N = 96) or MS OFF (N = 106). Cardiovascular symptoms, quality of life (QOL), reprogramming due to RVP, death, stroke, and heart failure hospitalization (HFH) were compared between groups. The treatment groups were similar with regard to AF history (59% MS ON vs 57% MS OFF). AHREs occurred in 49% patients during median follow-up of 2.2 years. Median AHRE duration (in min; MS ON 116 vs MS OFF 58, P = 0.29), frequency AHREs/week (MS ON 3.5 vs MS OFF 6.4, P = 0.23), and time spent in AHRE (min/week) (MS ON 450, MS OFF 268) were similar. Reprogramming due to any RVP during AHREs occurred more in MS OFF vs MS ON (13.2% vs 3.1%, P = 0.011) and marginally more for symptomatic RVP (8.5% vs 2.1%, P = 0.062). Cardiovascular symptoms occurred in 93.6% MS ON vs 90.2% MS OFF (P = 0.38). Median number of symptoms reported per visit was similar (MS ON 1.3 vs MS OFF 1.5, P = 0.62). Median symptom frequency/severity, summed and averaged over visits, was similar (MS ON 4.3 vs MS OFF 4.5, P = 0.74). QOL was not different between groups. Death, stroke, and HFH were not different between groups. CONCLUSION: MS reduces pacemaker reprogramming due to RVP during AHREs in a small number of patients but does not improve QOL or cardiovascular symptoms overall among patients with SND.

Aged↗

PubMed2003

Complications arising after implantation of DDD pacemakers: the MOST experience.

The purpose of this study was to characterize the incidence, time course, frequency, and spectrum of acute and chronic complications arising from dual-chamber pacemaker implantation. This information may serve as a benchmark when comparing complication rates for dual-chamber pacemaker implantation with those for biventricular pacemaker implantation.

Aged↗

PubMed2003

Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration in a clinical trial of pacemaker therapy for sinus node dysfunction.

BACKGROUND: Dual-chamber (DDDR) pacing preserves AV synchrony and may reduce heart failure (HF) and atrial fibrillation (AF) compared with ventricular (VVIR) pacing in sinus node dysfunction (SND). However, DDDR pacing often results in prolonged QRS durations (QRSd) as the result of right ventricular stimulation, and ventricular desynchronization may result. The effect of pacing-induced ventricular desynchronization in patients with normal baseline QRSd is unknown. METHODS AND RESULTS: Baseline QRSd was obtained from 12-lead ECGs before pacemaker implantation in MOST, a 2010-patient, 6-year, randomized trial of DDDR versus VVIR pacing in SND. Cumulative percent ventricular paced (Cum%VP) was determined from stored pacemaker data. Baseline QRSd <120 ms was observed in 1339 patients (707 DDDR, 632 VVIR). Cum%VP was greater in DDDR versus VVIR (90% versus 58%, P=0.001). Cox models demonstrated that the time-dependent covariate Cum%VP was a strong predictor of HF hospitalization in DDDR (hazard ratio [HR], 2.99 [95% CI, 1.15 to 7.75] for Cum%VP >40%) and VVIR (HR 2.56 [95% CI, 1.48 to 4.43] for Cum%VP >80%). The risk of AF increased linearly with Cum%VP from 0% to 85% in both groups (DDDR, HR 1.36 [95% CI, 1.09, 1.69]; VVIR, HR 1.21 [95% CI 1.02, 1.43], for each 25% increase in Cum%VP). Model results were unaffected by adjustment for known baseline predictors of HF hospitalization and AF. CONCLUSIONS: Ventricular desynchronization imposed by ventricular pacing even when AV synchrony is preserved increases the risk of HF hospitalization and AF in SND with normal baseline QRSd.

Aged↗

PubMed2003

Atrial high rate episodes detected by pacemaker diagnostics predict death and stroke: report of the Atrial Diagnostics Ancillary Study of the MOde Selection Trial (MOST).

BACKGROUND: Some current pacing systems can automatically detect and record atrial tachyarrhythmias that may be asymptomatic. We prospectively studied a 312-patient (pt) subgroup of MOST (MOde Selection Trial), a 2010-patient, 6-year randomized trial of DDDR versus VVIR pacing in sinus node dysfunction (SND). The purpose of the study was to correlate atrial high rate events (AHREs) detected by pacemaker diagnostics with clinical outcomes. METHODS AND RESULTS: Pacemakers were programmed to log an AHRE when the atrial rate was >220 bpm for 10 consecutive beats. Analysis was confined to patients with at least 1 AHRE duration exceeding 5 minutes. The 312 patients were median age 74 years, 55% female, and 60% had a history of SVT. 160 of 312 (51.3%) patients enrolled had at least 1 AHRE >5 minutes duration over median follow-up of 27 months. Cox proportional hazards analysis assessed the relationship of AHREs with clinical events, adjusting for prognostic variables and baseline covariates. The presence of any AHRE was an independent predictor of the following: total mortality (hazard ratio AHRE versus no AHRE and 95% confidence intervals=2.48 [1.25, 4.91], P=0.0092); death or nonfatal stroke (2.79 [1.51, 5.15], P=0.0011); and atrial fibrillation (5.93 [2.88, 12.2], P=0.0001). There was no significant effect of pacing mode on the presence or absence of AHREs. CONCLUSIONS: AHRE detected by pacemakers in patients with SND identify patients that are more than twice as likely to die or have a stroke, and 6 times as likely to develop atrial fibrillation as similar patients without AHRE.

Adult↗

PubMed2002

Ventricular pacing or dual-chamber pacing for sinus-node dysfunction.

BACKGROUND: Dual-chamber (atrioventricular) and single-chamber (ventricular) pacing are alternative treatment approaches for sinus-node dysfunction that causes clinically significant bradycardia. However, it is unknown which type of pacing results in the better outcome. METHODS: We randomly assigned a total of 2010 patients with sinus-node dysfunction to dual-chamber pacing (1014 patients) or ventricular pacing (996 patients) and followed them for a median of 33.1 months. The primary end point was death from any cause or nonfatal stroke. Secondary end points included the composite of death, stroke, or hospitalization for heart failure; atrial fibrillation; heart-failure score; the pacemaker syndrome; and the quality of life. RESULTS: The incidence of the primary end point did not differ significantly between the dual-chamber group (21.5 percent) and the ventricular-paced group (23.0 percent, P=0.48). In patients assigned to dual-chamber pacing, the risk of atrial fibrillation was lower (hazard ratio, 0.79; 95 percent confidence interval, 0.66 to 0.94; P=0.008), and heart-failure scores were better (P<0.001). The differences in the rates of hospitalization for heart failure and of death, stroke, or hospitalization for heart failure were not significant in unadjusted analyses but became marginally significant in adjusted analyses. Dual-chamber pacing resulted in a small but measurable increase in the quality of life, as compared with ventricular pacing. CONCLUSIONS: In sinus-node dysfunction, dual-chamber pacing does not improve stroke-free survival, as compared with ventricular pacing. However, dual-chamber pacing reduces the risk of atrial fibrillation, reduces signs and symptoms of heart failure, and slightly improves the quality of life. Overall, dual-chamber pacing offers significant improvement as compared with ventricular pacing.

Aged↗

PubMed2002

Role of target vessel size and body surface area on outcomes after percutaneous coronary interventions in women.

BACKGROUND: Women have higher mortality rates than men after coronary angioplasty. Differences in target vessel size may partially account for these differences. We set out to explore the effects of sex, body surface area (BSA), and target coronary vessel size on clinical outcomes after angioplasty. METHODS: Data from 5 interventional trials and 1 registry were pooled for analysis (n = 3982). RESULTS: Compared with men, women undergoing angioplasty were older, had lower weights and BSA, more coronary risk factors, and slightly smaller target coronary vessel size (as assessed by reference vessel diameter). The correlation between target vessel size and BSA was poor (r = 0.13). At 6 months, women had higher mortality rates (1.7% vs 0.8%, P =.03) but similar rates of myocardial infarction and repeat revascularization. On univariate analysis, advanced age, smaller BSA, and female sex were associated with increased mortality, but target vessel size was not. Advanced age was the only significant multivariate predictor of mortality. Target vessel size and diabetes were independent predictors of repeat revascularization. CONCLUSIONS: Women have higher unadjusted 6-month mortality rates after angioplasty, owing largely to their more advanced age at the time of intervention. Smaller target vessel size is associated with increased risk of restenosis and repeat revascularization; however, it does not appear to be a predictor for downstream mortality. As such, the fact that women have smaller vessels does not account for their higher 6-month mortality after coronary angioplasty.

Aged↗