The normal heart rate is linearly related to oxygen consumption during exercise. The maximum heart rate of the normal sinus node is approximated by the formula: HRmax = (220-age) with a variance of approximately 15%. However, the nominal upper rate of most permanent pacemakers is 120 beats/min, a value that remains unchanged for many patients. As this nominal setting falls well below the maximum predicted heart rate for most patients, it is possible that the chronotropic response of rate adaptive pacemakers during moderate and maximal exercise workloads may be less than optimal. The purpose of this study was to determine the effect of the upper programmed rate on oxygen kinetics during submaximal exercise workloads and maximum exercise performance during symptom-limited treadmill exercise. Exercise performance with an upper rate programmed to 220-age was compared with an upper rate of 120 beats/min. Eleven patients (5 men and 6 women, mean age 54 +/- 10 years) with complete heart block following catheter ablation of the atrioventricular junction for refractory atrial fibrillation who were implanted with permanent, rate-modulating VVIR pacemakers comprised the study population. The rate adaptive sensors were based on activity in 8 patients, minute ventilation in 2 patients, and mixed venous oxygen saturation in 1 patient. After performing a symptom-limited treadmill exercise test to determine maximum exercise capacity and to optimized programming of the rate adaptive sensor, each subject performed two treadmill exercise tests in random sequence with a rest period of at least 1 hour between tests. During one of the tests the upper rate was programmed to a value calculated by the formula: HRmax = (220-age). During the other exercise test the upper rate was programmed to 120 beats/min. Patients were blinded as to their programmed values and to the hypothesis of the study. A novel treadmill exercise protocol was used that consisted of a 6 minute, constant-workload phase at approximately 50% of maximum workload followed immediately by incremental, symptom-limited exercise using a modified Chronotropic Assessment Exercise Protocol(CAEP) with 1 minute stages until; peak exertion. Breath-by-breath analysis of expired gases was performed with subjective scoring of exertional difficulty at the end of the constant workload phase and during each stage of incremental exercise using the Borg Perceived Exertion Scale. Exercise duration was significantly longer (637 +/- 47 vs 611 +/- 48 seconds, P < 0.005) with the higher programmed upper rate. Oxygen kinetics were also significantly improved with an age predicted upper rate with a lower O2 deficit (258 +/- 88 vs 395 +/- 155 mL, P = 0.002) and higher VO2 rate constant (3.6 +/- 1.0 vs 2.4 +/- 0.7, P < 0.001). The VO2max during peak exertion was higher with an age predicted upper rate than with an upper rate of 120 beats/min (1807 +/- 751 vs 1716 +/- 702 mL/min, P = 0.04). The mean Borg score was lower during the last common treadmill stage during maximum exercise with an age predi...

ObjectiveLow quality and unwarranted clinical variation harm patients and increase unnecessary costs. Effective approaches to improve clinical and economic value have been difficult. The Ochsner Health System looked to improve clinical care quality and reduce unnecessary costs in cardiology using active measurement and customised feedback.MethodsWe serially measured care decisions using online, simulated cases to capture clinical details of cardiology practice and provide individual feedback. Fifty cardiologists cared for two simulated patients in each of six assessment rounds occurring 4 months apart. Simulated patients presented with heart failure (HF), coronary artery disease (CAD), supraventricular tachyarrhythmia (SVT) or valvular heart disease. Using Ochsner’s patient-level data, we performed real-world pre–post analyses of physician practice changes, patient outcomes and costs.ResultsBetween baseline and final rounds, overall simulated quality-of-care scores improved 14.1% (p<0.001). In the same period, we found cost-of-care variation decreased in patient-level data, with larger decreases for more severely ill patients. The total per-patient direct costs decreased $493 in SVT, $305 in HF and $55 in CAD (p<0.05 for SVT and HF). Readmission rates fell significantly for HF (from 20.0% to 11.9%) and SVT (from 14.5% to 7.8%) (both p<0.001) and non-significantly for CAD (from 13.7% to 11.3%, p=0.112). The cost avoidance/revenue generation opportunity from reduced readmissions and direct costs amounted to annual savings of $4.34 million, with no significant changes to in-hospital mortality rates (p>0.05).ConclusionsUsing simulated patients to serially measure and provide individual feedback on clinical practice significantly raises quality and reduces practice variation and costs without negatively impacting outcomes.

No abstract

No abstract

No abstract