Combination of low blood pressure response, low exercise capacity and slow heart rate recovery during an exercise test significantly increases mortality risk

Aims: We investigated the combination of low systolic blood pressure (SBP) response, low exercise capacity (EC) and slow heart rate recovery (HRR) during an exercise test in mortality prediction.Patients and methods: Our population consisted of 3456 patients from the Finnish Cardiovascular Study. A failure of SBP to increase >42 mmHg was defined as a low response. Low EC was defined as  < 8 metabolic equivalents. 1-minute HRR ≤18 bpm from maximum was defined as slow HRR.Results: During a median follow up of 10.0 years, 537 participants died. Reduced SBP response, low EC and slow HRR were independent predictors of all-cause and CV mortality (p < .001 for all). Patients with reduced SBP response, low EC and slow HRR had a very high mortality rate of 42.1% during follow up compared to only 4.5% of the patients without any of these risk factors. The hazard ratios for all-cause mortality in patients with one, two or three of the studied risk factors were 3.2, 6.0, and 10.6, respectively (p < .001 for all).Conclusion: The combination of reduced SBP response, low exercise capacity, and reduced HRR in an exercise test is associated with very high mortality and can be used in risk stratification.Key messagesThe combination of low blood pressure response, low exercise capacity and slow heart rate recovery in an exercise test is able to identify a group of patients in a very high mortality risk.These parameters are easily derived from an exercise test.All parameters are commonly available in clinical practice.

Long-term follow-up after ventricular septal defect repair in children: cardiac autonomic control, cardiac function and exercise capacity

OBJECTIVES

Survival after surgical repair of a ventricular septal defect (VSD) is good, but, as in almost all congenital heart diseases, late complications are frequent in adulthood. The exact mechanisms, timing and who is at risk are not fully understood. Altered cardiac autonomic nervous system (ANS) activity might play a role in these long-term sequelae. The aim of this study was to extensively evaluate children late after VSD repair including their cardiac ANS activity, cardiac function and exercise capacity.

METHODS

Thirty-three patients after surgical VSD repair and 66 healthy age-matched controls underwent 24-h monitoring of ANS control and cardiac output using impedance cardiography, detailed echocardiography and cardiopulmonary exercise testing.

RESULTS

Ambulatory cardiac ANS control was not different between the patients and the controls. Right ventricular function, exercise capacity and ambulatory cardiac output were decreased in patients compared with the controls. No relationships were found between cardiac ANS activity and cardiac function.

CONCLUSIONS

Long (average time after repair was 9.9 years) after successful surgical correction of a VSD, cardiac ANS control is not different from the controls. Right ventricular function and exercise capacity are impaired in VSD patients. Post-surgical outcome in these patients may be less benign than presently assumed; therefore, follow-up should be continued into adulthood to detect adverse outcomes in a timely fashion.

The Duke treadmill score with bicycle ergometer: Exercise capacity is the most important predictor of cardiovascular mortality

Background

The Duke treadmill score, a widely used treadmill testing tool, is a weighted index combining exercise time or capacity, maximum ST-segment deviation and exercise-induced angina. No previous studies have investigated whether the Duke treadmill score and its individual components based on bicycle exercise testing predict cardiovascular death.

Design

Two populations with a standard bicycle testing were used: 3936 patients referred for exercise testing (2371 men, age 56 ± 13 years) from the Finnish Cardiovascular Study (FINCAVAS) and a population-based sample of 2683 men (age 53 ± 5.1 years) from the Kuopio Ischaemic Heart Disease study (KIHD).

Methods

Cox regression was applied for risk prediction with cardiovascular mortality as the primary endpoint.

Results

In FINCAVAS, during a median 6.3-year (interquartile range (IQR) 4.5–8.2) follow-up period, 180 patients (4.6%) experienced cardiovascular mortality. In KIHD, 562 patients (21.0%) died from cardiovascular causes during the median follow-up of 24.1 (IQR 18.0–26.2) years. The Duke treadmill score was associated with cardiovascular mortality in both populations (FINCAVAS, adjusted hazard ratio (HR) 3.15 for highest vs. lowest Duke treadmill score tertile, 95% confidence interval (CI) 1.83–5.42, P < 0.001; KIHD, adjusted HR 1.71, 95% CI 1.34–2.18, P < 0.001). However, after progressive adjustment for the Duke treadmill score components, the score was not associated with cardiovascular mortality in either study population, as exercise capacity in metabolic equivalents of task was the dominant harbinger of poor prognosis.

Conclusions

The Duke treadmill score is associated with cardiovascular mortality among patients who have undergone bicycle exercise testing, but metabolic equivalents of task, a component of the Duke treadmill score, proved to be a superior predictor.

Heritability of heart rate recovery and vagal rebound after exercise

Purpose

The prognostic power of heart rate recovery (HRR) after exercise has been well established but the exact origin of individual differences in HRR remains unclear. This study aims to estimate the heritability of HRR and vagal rebound after maximal exercise in adolescents. Furthermore, the role of voluntary regular exercise behavior (EB) in HRR and vagal rebound is tested.

Methods

491 healthy adolescent twins and their siblings were recruited for maximal exercise testing, followed by a standardized cooldown with measurement of the electrocardiogram and respiratory frequency. Immediate and long-term HRR (HRR60 and HRR180) and vagal rebound (heart rate variability in the respiratory frequency range) were assessed 1 and 3 min after exercise. Multivariate twin modeling was used to estimate heritability of all measured variables and to compute the genetic contribution to their covariance.

Results

Heritability of HRR60, HRR180 and immediate and long-term vagal rebound is 60 % (95 % CI: 48–67), 65 % (95 % CI: 54–73), 23 % (95 % CI: 11–35) and 3 % (95 % CI: 0–11), respectively. We find evidence for two separate genetic factors with one factor influencing overall cardiac vagal control, including resting heart rate and respiratory sinus arrhythmia, and a specific factor for cardiac vagal exercise recovery. EB was only modestly associated with resting heart rate (r = −0.27) and HRR (rHRR60 = 0.10; rHRR180 = 0.19) with very high genetic contribution to these associations (88–91 %).

Conclusions

Individual differences in HRR and immediate vagal rebound can to a large extent be explained by genetic factors. These innate cardiac vagal exercise recovery factors partly reflect the effects of heritable differences in EB.

Exercise capacity and mortality - a follow-up study of 3033 subjects referred to clinical exercise testing

BACKGROUND

Exercise stress testing is used as a diagnostic and prognostic tool. We determined the prognostic significance of exercise test findings for cardiovascular (CVD) and all-cause mortality in men and women.

MATERIAL AND METHODS

3033 subjects underwent a symptom-limited bicycle exercise test. Exercise capacity was defined as the mean of last four minutes of exercise workload.

RESULTS

During an average follow-up of 19 years, 186 (11.6%) CVD and 370 (20.6%) all-cause deaths in men and 57 (5.0%) CVD and 155 (12.5%) all-cause deaths in women occurred. Among exercise test variables (workload, ECG, BP, HR), exercise capacity was the strongest predictor of mortality. Low exercise capacity (1st quartile) was associated with a hazard ratio of 4.2 (95% CI: 1.7, 10.8) for CVD and 4.0 (95% CI: 2.5, 6.4) for all-cause mortality compared with high exercise capacity (4th quartile) among men and in women with a 5.4-fold (95% CI: 1.2, 24.0) risk for CVD and 2.3-fold (95% CI: 1.2, 4.3) risk for all-cause mortality, respectively. The relationship between other exercise test variables and mortality was much weaker.

CONCLUSIONS

Among exercise test variables exercise capacity was the strongest predictor of CVD and all-cause mortality in both genders, and especially CVD deaths in women. Key Messages Exercise capacity was the most powerful predictor of CVD and all-cause mortality in both men and women. Low exercise capacity is a strong predictor of CVD death, especially among women.

ST segment/heart rate hysteresis improves the diagnostic accuracy of ECG stress test for coronary artery disease in patients with left ventricular hypertrophy

BACKGROUND

The exercise electrocardiographic stress test (ExET) is the most widely used non-invasive diagnostic method to detect coronary artery disease. However, the sole ST depression criteria (ST-max) have poor specificity for coronary artery disease in patients with left ventricular hypertrophy. We hypothesised that ST-segment depression/heart rate hysteresis, depicting the relative behaviour of ST segment depression during the exercise and recovery phase of the test might increase the diagnostic accuracy of ExET for coronary artery disease detection in such patients.

METHODS

In three cardiology centres, we studied 113 consecutive patients (mean age 66 ± 2 years; 88% men) with hypertension-related left ventricular hypertrophy at echocardiography, referred to coronary angiography after an ExET. The following ExET criteria were analysed: ST-max, chronotropic index, heart rate recovery, Duke treadmill score, ST-segment depression/heart rate hysteresis.

RESULTS

We detected significant coronary artery disease at coronary angiography in 61 patients (53%). At receiver-operating characteristic analysis, ST-segment depression/heart rate hysteresis had the highest area under the curve value (0.75, P < 0.001 when compared with the 'neutral' receiver-operating characteristic curve value of 0.5). Area under the curve values were 0.68 (P < 0.01) for the chronotropic index, 0.58 (P = NS) for heart rate recovery, 0.57 (P = NS) for ST-max and 0.52 (P = NS) for the Duke treadmill score.

CONCLUSIONS

Among currently available ExET diagnostic variables, ST-segment depression/heart rate hysteresis offers a substantially better diagnostic accuracy for coronary artery disease than conventional criteria in patients with hypertension-related left ventricular hypertrophy.

Occult coronary artery disease in middle-aged sportsmen with a low cardiovascular risk score: The Measuring Athlete's Risk of Cardiovascular Events (MARC) study

BACKGROUND

Most exercise-related cardiac arrests in men aged ≥45 years are due to coronary artery disease (CAD). The current sports medical evaluation (SME) of middle-aged sportsmen includes medical history, physical examination and resting and exercise electrocardiography (ECG). We investigated the added value of low-dose cardiac computed tomography (CCT) - both non-contrast CT for coronary artery calcium scoring (CACS) and contrast-enhanced coronary CT angiography (CCTA) - in order to detect occult CAD in asymptomatic recreational sportsmen aged ≥45 years without known cardiovascular disease.

METHODS

Following a normal SME (with resting and bicycle exercise ECG), 318 asymptomatic sportsmen underwent CCT and 300 (94%) had a low European Society of Cardiology Systematic Coronary Risk Evaluation (SCORE) risk. Occult CAD was defined as a CACS ≥100 Agatston units (AU) or obstructive (≥50%) luminal stenosis on CCTA. The number needed to screen (NNS) in order to prevent one cardiovascular event within 5 years with statin treatment was estimated.

RESULTS

Fifty-two (16.4%, 95% confidence interval (CI): 12.7-20.8%) of 318 participants had a CACS ≥100 AU. The CCTA identified an additional eight participants with luminal narrowing ≥50% (and a CACS <100 AU). Taken together, CCT identified CAD in 60 (18.9%, 95% CI: 14.9-23.5%) of 318 participants. The 5-year estimated NNS was 183 (95% CI: 144-236) for CACS and 159 (95% CI: 128-201) for CACS combined with CCTA.

CONCLUSIONS

Coronary CT detects occult CAD in almost one in five asymptomatic sportsmen aged ≥45 years after a normal SME that included resting and bicycle exercise ECG. CACS reveals most of the relevant CAD with limited additional value of contrast-enhanced CCTA. The NNS in order to prevent one cardiovascular event compares favourably to that of other screening tests.

Resting heart rate and measures of effort-related cardiac autonomic dysfunction predict cardiovascular events in asymptomatic type 2 diabetes

BACKGROUND

Autonomic control of the cardiovascular system may be impaired in type 2 diabetes and is associated with increased morbidity and mortality. Parameters obtained during stress testing may reflect early stages of cardiac autonomic dysfunction and provide prognostic information in asymptomatic type 2 diabetes.

METHODS

We performed maximal exercise treadmill testing in 594 patients with type 2 diabetes without known coronary heart disease. The prognostic significance of physiological parameters associated with autonomic dysfunction was assessed, including chronotropic incompetence (<80% heart rate reserve), abnormal heart rate recovery at 1 minute <18 beats/minute, and resting tachycardia >100 beats/minute. Cox proportional hazards analysis was used to determine the association of exercise parameters with a composite outcome of all-cause mortality, myocardial infarction or stroke.

RESULTS

Resting heart rate >100 beats/minute was observed in 18% of patients, chronotropic incompetence in 30% and heart rate recovery at 1 minute <18 beats/minute in 35%. Over 79 ± 16 months, there were 72 (12%) events. Each parameter was significantly associated with event risk in an adjusted multivariate analysis: chronotropic incompetence (hazard ratio 1.89, 95% confidence interval 1.18-3.01; P = 0.008), resting heart rate ≥100 beats/minute (hazard ratio 1.97, 95% confidence interval 1.19-3.26; P = 0.008) and heart rate recovery at 1 minute <18 beats (hazard ratio 1.77, 95% confidence interval 1.12-2.81; P = 0.015). A progressive relationship between the number of abnormal parameters and event risk was observed (log rank P < 0.001).

CONCLUSIONS

Chronotropic incompetence, resting tachycardia and reduced heart rate recovery are independently and additively associated with long-term mortality, myocardial infarction or stroke in type 2 diabetes without known coronary heart disease.

Heart Rate-Dependent Hysteresis of T-Wave Alternans in Primary Prevention ICD Patients

BACKGROUND

T-wave alternans (TWA) is usually performed at accelerated heart rates (HR) during exercise, while recovery TWA is typically not analyzed. Consequently, it is still unknown if TWA shows a HR-dependent hysteresis or not. Thus, the aim of the present study was to investigate TWA dependency on HR during both the exercise and recovery phases of an ergometer test, and to evaluate if recovery TWA may contribute to identify subjects at increased risk of arrhythmic events.

METHODS

Our HR adaptive match filter was used to identify TWA from electrocardiographic recordings acquired during a bicycle ergometer test in 266 patients with implanted cardio-defibrillator. During the 4-year follow-up, 76 patients developed tachycardia or ventricular fibrillation (ICD_Cases) and 190 did not (ICD_Controls).

RESULTS

TWA was statistically lower during exercise than recovery for HRs between 75 and 110 bpm (16-21 μV vs 20-27 μV; P < 0.05), and reverse for HRs between 120 and 130 bpm (41-51 μV vs 28 μV; P < 0.05). ICD_Cases and ICD_Controls showed significantly different TWA at 80 bpm (20 μV vs 15 μV; P < 0.05) and 140 bpm (15 μV vs 22 μV; P < 0.05) during exercise, and at 90 bpm (38 μV vs 21 μV; P < 0.05) and 95 bpm (33-24 μV vs 28 μV; P < 0.05) during recovery.

CONCLUSIONS

TWA shows a HR-dependent hysteresis and there is a different behavior of TWA in ICD_Cases and ICD_Controls groups. Consequently, beside exercise TWA also recovery TWA may contribute to identify subjects at increased risk of arrhythmic events.