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

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

[Advanced classification for cardiovascular devices]. / Erweiterte Klassifikation für kardiovaskuläre Geräte.

Increasing complexity and many technical solutions for cardiovascular devices make it reasonable to introduce an advanced classification. The proposed classification has three levels. The first level distinguishes between implantable and wearable devices and the second level between therapeutic and diagnostic devices. The third level describes group-specific characteristics for each of the four subgroups. The aim of the classification is to differentiate the devices from each other and to easily describe interactions between two or more different devices. In addition, the classification should facilitate communication about these devices.

Prevalence of renal insufficiency in hospitalised patients with venous thromboembolic events: a retrospective analysis based on 6,725 VTE patients.

Renal impairment (RI) is an important factor in the selection of anticoagulant therapy in venous thromboembolic event (VTE) patients. In particular, the risk of bleeding events is higher for VTE patients with a glomerular filtration rate (GFR) below 30 mL/min. The aim of this study was to collect data on the prevalence of RI in hospitalised VTE patients in Germany. Furthermore, we investigated how renal function changed during inpatient treatment. We conducted a retrospective chart review in six German hospitals. All patients with a VTE diagnosis who were treated as inpatients from 2007-2011 were included. Patients were categorised according to their renal function. RI was estimated from serum creatinine values. Persistent RI was defined as an estimated glomerular filtration rate (eGFR) of <30 mL/min over at least 72 hours. Renal function could be determined for 5,710 VTE patients. Of these 21.4% had an eGFR>90 mL/min, 38.1% had an eGFR of 60-89 mL/min, 17.3% had an eGFR of 45-59 mL/min, 12.5% had an eGFR of 30-44 mL/min, 7.2% had an eGFR of 15-29 mL/min and 3.6% of the VTE patients had end-stage renal disease. Persistent severe RI was observed in 74.8% of patients with an eGFR <30 mL/min. Overall, 40.6% of the VTE patients investigated had an eGFR <60 mL/min; 10.8% had an eGFR <30 mL/min. Almost three quarters of RI-VTE patients suffered from persistent severe RI. These results suggest that more than one in ten VTE patients is exposed to a high risk of accumulating anticoagulants; most of these RI patients also face an increased risk of mortality.

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

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

Gender-related safety and efficacy of cardiac resynchronization therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an established therapy for patients with chronic heart failure (CHF) and a broad QRS complex. Gender-related safety and efficacy data are necessary for informed patient decision-making for female patients with CHF. The aim of the study was to assess the effects of gender on the outcome of CRT in highly symptomatic heart failure patients. HYPOTHESIS: Gender may have an effect on the outcome of heart failure patients undergoing cardiac resynchronisation therapy. METHODS: The study analyzed the 2-year follow-up of 393 New York Heart Association (NYHA) class III/IV patients with a class I CRT indication enrolled in the Management of Atrial Fibrillation Suppression in AF-HF Comorbidity Therapy (MASCOT) study. RESULTS: In female patients (n = 82), compared with male patients (n = 311), CHF was more often due to dilated cardiomyopathy (74% vs 44%, respectively; P < 0.0001). Females also had a more impaired quality-of-life score and a smaller left ventricular end-diastolic diameter (LVEDD). Women were less likely than men to have received a CRT defibrillator (35% vs 61%, respectively; P < 0.0001). After 2 years, the devices had delivered more biventricular pacing in women than in men (96% ± 13% vs 94% ± 13%, respectively; P < 0.0004). Women had a greater reduction in LVEDD than did men (-8.2 mm ± 11.1 mm vs -1.1 mm ± 22.1 mm, respectively; P < 0.02). Both genders improved similarly in NYHA functional class. Women reported greater improvement than men in quality-of-life score (-21.1 ± 26.5 vs -16.2 ± 22.1, respectively; P < 0.0001). After adjustment for cardiovascular history, women had lower all-cause mortality (P = 0.0007), less cardiac death (P = 0.04), and fewer hospitalizations for worsening heart failure (P = 0.01). CONCLUSIONS: Females exhibited a better response to CRT than did males. Because females have such impressive benefits from CRT, improved screening and advocacy for CRT implantation in women should be considered.

One-year outcome after CRT implantation in NYHA class IV in comparison to NYHA class III patients.

BACKGROUND: The aim of the analysis was to compare the outcome of heart failure patients in New York Heart Association (NYHA) class IV to that of NYHA class III patients 1 year after implantation of a CRT device. METHODS: The analysis was based on the 405 CRT patients enrolled in the MASCOT trial. At enrollment, 350 patients (86%) were in NYHA class III and 55 (14 %) were in NYHA class IV. RESULTS: At 1-year follow-up, the improvement of the ejection fraction was not statistically significantly different between NYHA class III (+7.6 ± 11.7%) and NYHA class IV patients (+9.2 ± 14.2 %; p = 0.78). NYHA class IV patients had a better mean NYHA class reduction with -1.93 ± 0.83 than NYHA class III patients with -0.93 ± 0.70 (p < 0.0001). There was a greater mean quality of life improvement in NYHA class IV (-27.2 ± 20.9) compared to NYHA class III (-17.7 ± 23.9; p = 0.02). All-cause mortality as well as cardiac mortality remained higher in NYHA class IV with 25.5 and 16.4% than in NYHA class III with 7.1 and 3.1% (p < 0.0001). CONCLUSIONS: In this study, 14% of all patients receiving a CRT device had NYHA class IV at implantation. The data support the concept to implant a CRT device in NYHA class IV patients, because at 1 year after implantation, they experienced better symptomatic improvement compared to NYHA class III patients. The higher cardiac as well as non-cardiac mortality resulted in a fivefold higher all-cause mortality compared to NYHA class III patients.

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

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

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

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

Home telemonitoring in patients with chronic heart failure: a chance to improve patient care?

BACKGROUND: Telemonitoring can improve the medical care, quality of life, and prognosis of chronically ill patients. This review article summarizes the current status of health services research on telemonitoring, focusing on patients with chronic congestive heart failure. METHOD: The Medline database was selectively searched for articles appearing from June 2001 to May 2008, with an emphasis on randomized, controlled trials. RESULTS: The available scientific data on vital signs monitoring are limited, yet there is evidence for a positive effect on some clinical endpoints, particularly mortality. Nonetheless, any possible improvement of patient-reported outcomes, such as the quality of life, still remains to be demonstrated. CONCLUSIONS: The data suggest that telemonitoring is effective, yet there is no evidence for superior outcomes with any particular model of care incorporating telemonitoring (i.e., monitoring of vital signs versus structured telephone monitoring). A valid criticism is that the individual components of home telemonitoring have not yet been separately tested in order to compare their individual effects.

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

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

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

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

[Event-recorder]. / Event-Rekorder.

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

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

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

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

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

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

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

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

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

Automatic home monitoring of implantable cardioverter defibrillators.

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

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

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