Le VDT

Dan Med J. 2017 May;64(5). pii: B5352.

Patients with moderate to severe aortic stenosis (AVA <1.3 cm2) who were judged,
by a referring cardiologist, as asymptomatic or equivocal symptomatic from the
aortic stenosis were included in the study. Patients with left ventricular
ejection fraction <50% were not included. Twenty-nine percent of the referred
patients were judged asymptomatic and 71% equivocal symptomatic from their valve
disease. The mean age was 72 years and 90% of the patients had an AVA-index <0.6
cm2/m2. By clinical evaluation in the outpatient clinic, 48% were judged as
having functional limitation corresponding to NYHA≥II. The study participants had
cardiopulmonary exercise testing (CPX) at inclusion, and, if relevant, pre- and
nine months post-aortic valve replacement (AVR). CPX was feasible in 130 of 131
study participants recruited across 19 months. The coefficient of variability by
test-retest was 5.4% and 4.6% for peak oxygen consumption (pVO2) and peak oxygen
pulse (pO2pulse= pVO2/peak heart rate), respectively. The stroke volume generally
increased with exercise, also in those with peak flow velocity across the aortic
valve (Vmax) >5 m/s, >4 m/s, and <4 m/s but with high valvuloarterial impedance
(Zva >5.5 mm Hg/(mL·m2 )). This was found both when assessed by inert gas
rebreathing and by the pO2pulse/hemoglobin index. Both resting and exercise
stroke volume were lower for the latter group, with Vmax <4 m/s but high
valvuloarterial impedance. A pVO2 <83% of the predicted, which corresponds to the
lower 95% percentile found in the healthy sedentary population, was predicted
independently by lower stroke volume during exercise, lower heart rate during
exercise, lower FEV1, and by higher ventilation/carbon dioxide exhaustion rate
(VE/VCO2), but not by the severity of the aortic stenosis as determined by
echocardiography. According to the CPX results, the patients were prospectively
grouped into 3 groups, as follows: 1) normal pVO2 (>83% of predicted) and
pO2pulse (>95% of predicted); 2) subnormal pVO2 or pO2pulse that according to CPX
could be explained by causes other than hemodynamic compromise; 3) subnormal pVO2
and pO2pulse. Groups 1 and 2 followed an initial conservative strategy, whereas
Group 3 was referred for angiogram and Heart Team evaluation for AVR. The
patients were followed for an average of 24 months and, in Groups 1 and 2, one
patient (0.9%) suffered cardiac death and seven were hospitalized with heart
failure (6.7%). The patient who died and another patient with heart failure had
both previously, during the study, declined AVR. For Groups 1 and 2, the rate of
the combined endpoint progression to cardiac death, hospitalization with heart
failure, or AVR was 37.5%, which seems lower than what was reported in the
literature by conventional assessment and strategy for younger asymptomatic
patients with comparable echocardiographic severity of aortic stenosis. The
endpoint progression to cardiac death, hospitalization with heart failure, or AVR
with improvement in pVO2 or in the Physical Component Score of the SF-36
health-related quality of life score was reached in 25.6% in Groups 1+2 and in
62.5% in Group 3 (p=0.003). A decreased pO2pulse, which expresses stroke volume
at peak exercise, predicted this endpoint. In 73 operated patients without left
ventricular dysfunction and no coronary stenosis, including 37 patients from the
above-mentioned study, a CPX 9 months post-AVR showed that the pVO2, on average,
was less than that predicted (mean 89% of the predicted ) and 35% of the patients
had a subnormal pVO2 (<83% of that predicted). A preoperative mean gradient <40
mm Hg across the aortic valve, the presence of atrial fibrillation, and a
permanent pacemaker post-AVR all predicted a post-AVR pVO2 <83% of that
predicted. For the 37 patients with a pre-AVR CPX, a postoperative decrease >10%
in the absolute pVO2 was noted in 30% and an increase >10% in 24% of patients. A
decrease >10% in pVO2 was predicted by preoperative mean gradient <40 mm Hg and
an increase in pVO2 was predicted by preoperative AVAI <0.4 cm2/m2 and
preoperative pO2pulse <the median in the study population (<98% of that
predicted).CONCLUSIONS: In this group of patients, where clinical assessment is
difficult and conventional exercise testing is regarded as less useful, CPX
showed high feasibility and reproducibility. CPX therefore has potential as a
useful tool for serial monitoring. In general, the stroke volume increased during
exercise, including in patients with severe aortic stenosis or decreased resting
stroke volume. CPX gives information on hemodynamics and the physiologic
components that determine decreased pVO2. CPX seems useful to identify 1)
patients with a low risk of cardiac death and low risk of progression to symptoms
from the aortic stenosis, and 2) patients with hemodynamic compromise who improve
in functional capacity after AVR. Patients with a preoperative mean gradient <40
mm Hg across the aortic valve, with the presence of atrial fibrillation or who
have a permanent pacemaker, postoperatively seem to benefit less from AVR,
whereas the benefit seems larger in those with more severe aortic stenosis and a
decreased pO2pulse. These findings may be of importance for decisions and
information of patients before AVR.

Herzig D; Asatryan B; Brugger N;Eser P; Wilhelm M;

Frontiers In Physiology [Front Physiol] 2018 Jun 19; Vol. 9, pp. 756. Date of Electronic Publication: 2018 06 19

Heart rate variability (HRV) is a widely used marker of cardiac autonomic nervous activity (CANA). Changes in HRV with exercise training have often been interpreted as increases in vagal activity. HRV is strongly associated with heart rate, which in turn, is associated with heart size. There is strong evidence from basic studies that lower heart rate in response to exercise training is caused by morphological and electrical remodeling of the heart. In a cross-sectional study in participants of a 10 mile race, we investigated the influence of endurance exercise on HRV parameters independently of heart size and heart rate. One-hundred-and-seventy-two runners (52 females and 120 males) ranging from novice runners with a first participation to an endurance event to highly trained runners, with up to 15 h of training per week, were included in the analysis. R-R intervals were recorded by electrocardiography over 24 h. Left ventricular end diastolic volume indexed to body surface area (LVEDVI) was assessed by transthoracic echocardiography and peak oxygen consumption (VO2peak) by cardiopulmonary exercise testing. Exercise was quantified by VO2peak, training volume, and race performance. HRV was determined during deep sleep. HRV markers of vagal activity were moderately associated with exercise variables (standardized β = 0.28-0.40, all p < 0.01). These associations disappeared when controlling for heart rate and LVEDVI. Due to the intrinsic association between heart rate and HRV, conclusions based on HRV parameters do not necessarily reflect differences in CANA. Based on current evidence, we discourage the use of HRV as a marker of CANA when measuring the effect of chronic exercise.

Hock J; Häcker AL; Reiner B; Oberhoffer R;Hager A; Ewert P; Müller J;

Archives Of Disease In Childhood [Arch Dis Child] 2018 Jul 03. Date of Electronic Publication: 2018 Jul 03.

Objective: Functional outcome measures are of growing importance in the aftercare of patients with congenital heart disease. This study addresses the functional status with regard to exercise capacity, health-related physical fitness (HRPF) and arterial stiffness in a recent cohort of children, adolescents and young adults with tetralogy of Fallot (ToF) after repair.
Design: Single-centre, uncontrolled and prospective cohort study.
Setting: Outpatient department of the German Heart Centre Munich; July 2014-January 2018.
Patients: One hundred and six patients with ToF after repair (13.5±3.7 years, 40 females) were included. Data were compared with a recent cohort of healthy controls (HCs) (n=1700, 12.8±2.6 years, 833 females).
Main Outcome Measures: Patients underwent a symptom-limited cardiopulmonary exercise test, performed an HRPF test (FitnessGram) and had an assessment of their arterial stiffness (Mobil-O-Graph).
Results: Compared with HC, patients with ToF showed lower predicted [Formula: see text]O2 peak (ToF: 80.4% ± 16.8% vs HC: 102.6% ± 18.1%, p<0.001), impaired ventilatory efficiency (ToF: 29.6 ± 3.6 vs HC: 27.4 ± 2.9, p<0.001), chronotropic incompetence (ToF: 167 ± 17 bpm vs HC: 190 ± 17 bpm, p<0.001) and reduced HRPF (ToF z-score: -0.65 ± 0.87 vs HC z-score: 0.03 ± 0.65, p<0.001). Surrogates of arterial stiffness, central and peripheral systolic blood pressure, did not differ between the two groups.
Conclusions: Contemporary children, adolescents and young adults with ToF still have functional limitations. How impaired HRPF and limited exercise capacity interact and how they can be modified needs to be evaluated in further intervention studies.

Mendes FAR; França-Pinto A; Martins MA; Cukier A; Stelmach R; Giavina-Bianchi P; Carvalho CRF;

The Journal Of Asthma: Official Journal Of The Association For The Care Of Asthma [J Asthma] 2018 Jul 04, pp. 1-19.

Objective: To investigate whether patients with moderate to severe asthma who commence an exercise training program in winter or summer show differences in exercise capacity, health-related quality of life (HRQoL) and asthma symptoms.
Methods: Forty-two consecutive subjects visiting the outpatient clinic were enrolled in the 17-week rehabilitation program. One group of patients received the intervention from summer to winter (SWG, n = 21), and the other group participated from winter to summer (WSG, n = 21). Before and after the exercise training program, all patients were evaluated by cardiopulmonary exercise test, pulmonary function test, quality of life questionnaire and a daily diary that evaluated clinical asthma symptoms.
Results: After the training period, both groups improved similarly in health-related quality of life (HRQoL) and aerobic capacity. The WSG patients had a greater increase that those in the SWG in asthma symptom-free days (p < 0.05, Table 2).
Conclusions: Our results indicate that seasonal variations affect the improvement in asthma symptoms after an exercise training program but have no effect on health-related quality of life, exercise capacity or pulmonary function.

Vainshelboim B, Amin A, Christle JW, Hebbal S, Ashley EA, Myers J

Int J Cardiol. 2017 Dec 15;249:287-291. doi: 10.1016/j.ijcard.2017.09.028. Epub
2017 Sep 14.

BACKGROUND: Exercise oscillatory ventilation (EOV) has been shown to be a
powerful prognostic marker in chronic heart failure (CHF). However, EOV is poorly
defined, its measurement lacks standardization and it is underutilized in
clinical practice. The purpose of this pilot study was to investigate the
prognostic value of a modified definition of EOV in patients with CHF.
METHODS: Eighty-nine CHF patients (56.5±8.4years) (64% NYHA class III-IV)
underwent cardiopulmonary exercise testing. EOV was defined as meeting all the
following criteria: (1) ≥3 consecutive cyclic fluctuations of ventilation during
exercise; (2) average amplitude over 3 ventilatory oscillations ≥5L; and (3) an
average length of three oscillatory cycles 40s to 140s. Adverse cardiac events
were tracked during 28±19months follow up. Cox proportional hazard analysis was
used to determine the association between cardiac events and EOV.
RESULTS: Forty-eight patients (54%) met all three criteria and were determined to
have EOV. These patients exhibited significantly increased risk for adverse
cardiac events [hazard ratio=2.2, 95% CI (1.2 to 4.1), p=0.011] compared to
patients without EOV. After adjusting for age and established prognostic
covariates (peak VO2 and VE/VCO2 slope), the modified EOV definition was the only
significant variable in the multivariate model [hazard ratio=2.0, 95% CI (1.1 to
3.7), p=0.035].
CONCLUSIONS: The proposed method for determining EOV was independently associated
with increased risk for adverse cardiac events in CHF patients. While larger
prospective studies are needed, this definition provides a relatively simple and
more objective characterization of EOV, suggesting its potential application in
clinical practice.

Wagner J; Agostoni P; Arena R;Belardinelli R; Dumitrescu D; Hager A; Myers J; Riley M; Takken T; Schmidt-Trucksäss A;

American Heart Journal [Am Heart J] 2018 May 22; Vol. 202, pp. 116-126. Date of Electronic Publication: 2018 May 22.

Heart failure with reduced ejection fraction (HFrEF) is common in the developed world and results in significant morbidity and mortality. Accurate risk assessment methods and prognostic variables are therefore needed to guide clinical decision making for medical therapy and surgical interventions with the ultimate goal of decreasing risk and improving health outcomes. The purpose of this review is to examine the role of cardiopulmonary exercise testing (CPET) and its most commonly used ventilatory gas exchange variables for the purpose of risk stratification and management of HFrEF. We evaluated five widely studied gas exchange variables from CPET in HFrEF patients based on nine previously used systematic criteria for biomarkers. This paper provides clinicians with a comprehensive and critical overview, class recommendations and evidence levels. Although some CPET variables met more criteria than others, evidence supporting the clinical assessment of variables beyond peak V̇O2 is well-established. A multi-variable approach also including the V̇E-V̇CO2 slope and EOV is therefore recommended.

Woodfield J; Zacharias M; Wilson G; Munro F; Thomas K; Gray A; Baldi J;

Trials [Trials] 2018 Jun 25; Vol. 19 (1), pp. 331. Date of Electronic Publication: 2018 Jun 25

Background: Risk factors, such as the number of pre-existing co-morbidities, the extent of the underlying pathology and the magnitude of the required operation, cannot be changed before surgery. It may, however, be possible to improve the cardiopulmonary fitness of the patient with an individualised exercise program. We are performing a randomised controlled trial (RCT) assessing the impact of High Intensity Interval Training (HIIT) on preoperative cardiopulmonary fitness and postoperative outcomes in patients undergoing major abdominal surgery.
Methods: Consecutive eligible patients undergoing elective abdominal surgery are being randomised to HIIT or standard care in a 1:1 ratio. Participants allocated to HIIT will perform 14 exercise sessions on a stationary cycle ergometer, over a period of 4-6 weeks before surgery. The sessions, which are individualised, aim to start with ten repeated 1-min blocks of intense exercise with a target of reaching a heart rate exceeding 90% of the age predicted maximum, followed by 1 min of lower intensity cycling. As endurance improves, the duration of exercise is increased to achieve five 2-min intervals of high intensity exercise followed by 2 min of lower intensity cycling. Each training session lasts approximately 30 min. The primary endpoint, change in peak oxygen consumption (Peak VO2) measured during cardiopulmonary exercise testing, is assessed at baseline and before surgery. Secondary endpoints include postoperative complications, length of hospital stay and three clinically validated scores: the surgical recovery scale; the postoperative morbidity survey; and the SF-36 quality of life score. The standard deviation for changes in Peak VO2 will be assessed after the first 30 patients and will be used to calculate the required sample size.
Discussion: We want to assess if 14 sessions of HIIT is sufficient to improve Peak VO2 by 2 mL/kg/min in patients undergoing major abdominal surgery and to explore the best clinical endpoint for a subsequent RCT designed to assess if improving Peak VO2 will translate into improving clinical outcomes after surgery.
Trial Registration: Australian New Zealand Clinical Trials Registry, ACTRN12617000587303 . Registered on 26 April 2017.

Boo SH; Joo MC; Lee JM; Kim SC; Yu YM; Kim MS

Aging Clinical And Experimental Research [Aging Clin Exp Res] 2018 Jun 18. Date of Electronic Publication: 2018 Jun 18.

Background: Sarcopenia reduces physical ability and cardiorespiratory fitness (CRF), leading to poor quality of life.
Aim: The aim of this study was to investigate the relationship between skeletal muscle mass and CRF in elderly men.
Methods: We assessed 102 community-dwelling men over 60 years old. Appendicular skeletal muscle mass (ASM) was determined using bioelectrical impedance analysis, and the skeletal muscle mass index (SMI) was calculated as ASM divided by the square of height. Subjects with an SMI less than 7.0 kg/m2 were included in the sarcopenic group, as recommended by the Asian Working Group for Sarcopenia. To investigate CRF parameters, a cardiopulmonary exercise test was performed using the Bruce protocol. CRF parameters were subdivided into aerobic capacity, cardiovascular response, and ventilatory response.
Results: Of the 102 subjects, 15 (14.7%) were included in the sarcopenic group. There were significant correlations between SMI and peak oxygen consumption (VO2peak) (r = 0.597, p < 0.001), and between SMI and VO2peak/weight (r = 0.268, p = 0.024). Moreover, there were positive correlations between SMI and first ventilatory threshold (VT1) (r = 0.352, p = 0.008) and between SMI and VT1/weight (r = 0.189, p = 0.039). Additionally, peak oxygen pulse (O2pulsepeak) was significantly correlated with SMI (r = 0.558, p < 0.001). VO2peak, VO2peak/weight and O2pulsepeak showed significant differences between the sarcopenic and non-sarcopenic groups (p < 0.05, all). In multiple linear regression analyses, the factor related to VO2peak was SMI (β = 0.473, p < 0.001) and that related to O2pulsepeak was also SMI (β = 0.442, p < 0.001).
Discussion and Conclusions: This study demonstrated that skeletal muscle mass might be closely associated with CRF. Therefore, sarcopenia should be appropriately managed to improve an individual’s CRF.

Saengsuwan J, Nef T, Hunt KJ.

Clin Physiol Funct Imaging. 2017 Nov;37(6):610-614.

BACKGROUND: Prediction of peak work rate (WRpeak) for incremental exercise
testing (IET) is important to bring subjects to their maximal performance within
the recommended 8-12 min. This study developed a novel method for prediction of
WRpeak for IET on cycles and treadmills.
METHODS: Peak metabolic equivalent of task (METpred) was predicted based on an
existing non-exercise prediction formula, and then, predicted peak work rate
(WRpred) was derived from separate formulae for the cycle and the treadmill.
Eighteen healthy subjects were included.
RESULTS: In males, there was no difference between WRpred versus WRpeak for both
the cycle ergometer (277·7 versus 275·6 W, P = 0·70) and the treadmill (264·1
versus 260·5, P = 0·58). In females, there was no difference between WRpred
versus WRpeak for the cycle ergometer (187·1 versus 188·3 W, P = 0·90), but a
significant difference was found between WRpred versus WRpeak on the treadmill
(178·6 versus 151·9 W, P<0·05). For males, the mean absolute percentage errors
for WRpred versus WRpeak were 4·6% and 5·7% for the cycle and treadmill,
respectively. For females, the errors were 12·2% and 20·8%. The algorithm was
successful in achieving the required duration of 8-12 min in 33 of 36 cases.
CONCLUSIONS: The peak work rate prediction protocol was accurate in male subjects
for both the cycle and the treadmill. In female subjects, the method was accurate
for the cycle, but systematically overpredicted the peak work rate on the
treadmill. The protocol requires further adaptation for females on the treadmill.

Goldraich L, Ross HJ, Foroutan F, Walker M, Braga J, McDonald
MA

J Card Fail. 2017 May;23(5):422-426.

BACKGROUND: Chronotropic incompetence (CI) in heart failure (HF) patients with
cardiac resynchronization therapy (CRT) and activity sensors may vary according
to exercise modality. We hypothesized that chronotropic response and exercise
capacity differ when HF patients with CRT and heart rate (HR) adaptive pacing are
exercised on cycloergometer versus treadmill.
METHODS AND RESULTS: This is a crossover study in which stable HF patients with
CRT and HR-adaptive pacing triggered by activity sensors underwent maximal
symptom-limited cardiopulmonary exercise testing on both a cycloergometer and
treadmill. Adjusted percent of HR reserve (%HRR) was calculated as
HRR/age-predicted HRR. CI was defined as ≤62% of age-predicted HRR. Among 16
patients (59 ± 10 years, ejection fraction 27 ± 12%, 87% on beta-blockers),
prevalence of CI was high irrespective of exercise modality (87.5% on
cycloergometer vs 62.5% on treadmill; P = .12). Chronotropic responses were
better on the treadmill; %HRR was higher on a treadmill vs cycloergometer
(61 ± 26% vs 22 ± 31%; P = .003). Peak oxygen consumption was increased by 24% on
a treadmill vs cycloergometer (15.8 vs 12.7 mL/kg/min; P < .0001).
CONCLUSIONS: In HF patients with CRT and HR-adaptive pacing, treadmill
cardiopulmonary exercise testing enhances chronotropic response, HRR, and peak
oxygen consumption compared with a cycloergometer. These findings may have
implications in exercise prescription and thresholds for advanced therapies such
as heart transplantation and ventricular assist devices.