Tibor Sydó

Impaired Heart Rate Response to Exercise in Diabetes and Its Long-term Significance

OBJECTIVE To investigate the effect of diabetes mellitus on exercise heart rate and the role of impaired heart rate in excess mortality in diabetes. PATIENTS AND METHODS Patients without cardiovascular disease who underwent exercise testing from September 1, 1993, through December 31, 2010, were included. Mortality was determined from Mayo Clinic records and the Minnesota Death Index. Multivariate linear regression was used to compare heart rate responses in patients with vs without diabetes. Cox regression was used to determine the effect of abnormal heart rate recovery and abnormal chronotropic index on survival. RESULTS A total of 21,396 patients (65.4% men) with a mean ± SD age of 51±11 years, including 1200 patients with diabetes (5.4%), were included. Patients with diabetes had a higher resting heart rate (81±14 vs 77±13 beats/min), lower peak heart rate (154±20 vs 165±19 beats/min), heart rate reserve (73±19 vs 88±19 beats/min), chronotropic index (0.86±0.22 vs 0.99±0.20), and heart rate recovery (15±8 vs 19±9 beats/min) vs patients without diabetes. There were 1362 deaths (6.4%) during a mean ± SD follow-up of 11.9±4.9 years. Adjusting for age, sex, and heart rate-lowering drug use, a chronotropic index less than 0.8 contributed significantly to risk in patients with diabetes (hazard ratio [HR], 2.21; 95% CI, 1.62-3.00; P<.001) and patients without diabetes (HR, 1.94; 95% CI, 1.71-2.20; P<.001), as did abnormal heart rate recovery (patients with diabetes: HR, 2.21; 95% CI, 1.60-5.05; P<.001; patients without diabetes: HR, 1.75; 95% CI, 1.55-1.97). CONCLUSIONS Patients with diabetes exhibit abnormal heart rate responses to exercise, which are independently predictive of reduced long-term survival in patients with diabetes as in patients without diabetes.

Prognostic Performance of Heart Rate Recovery on an Exercise Test in a Primary Prevention Population

Background Heart rate (HR) recovery has been investigated in specific patient cohorts, but there is less information about the role of HR recovery in general populations. We investigated whether HR recovery has long‐term prognostic significance in primary prevention. Methods and Results Exercise tests performed between 1993 and 2010 on patients aged 30 to 79 years without cardiovascular disease were included. Mortality was determined from Mayo Clinic records and Minnesota Death Index. Total, cardiovascular, and non‐cardiovascular mortality was reported according to HR recovery <13 bpm using Cox regression. 19 551 patients were included, 6756 women (35%), age 51±10 years. There were 1271 deaths over follow‐up of 12±5 years. HR recovery declined after age 60, and was also lower according to diabetes mellitus, hypertension, obesity, current smoking, and poor cardiorespiratory fitness but not sex or β‐blockers. Adjusting for these factors, abnormal HR recovery was a significant predictor of total (hazard ratio [95% confidence interval]=1.56 [1.384–1.77]), cardiovascular (1.95 [1.57–2.42]), and non‐cardiovascular death (1.41 [1.22–1.64]). Hazard ratios for cardiovascular death according to abnormal HR recovery were significant in all age groups (30–59, 60–69, 70–79), in both sexes, in patients with and without hypertension, obesity, and diabetes mellitus, but not in patients taking β‐blockers, current smokers, and patients with normal cardiorespiratory fitness. Conclusions HR recovery is a powerful prognostic factor predicting total, cardiovascular, and non‐cardiovascular death in a primary prevention cohort. It performs consistently well according to sex, age, obesity, hypertension, and diabetes mellitus but shows diminished utility in patients taking β‐blockers, current smokers, and patients with normal cardiorespiratory fitness.

Prevalence of physiological and pathological electrocardiographic findings in Hungarian athletes

UNLABELLED In Hungary, ECG is a keystone of routine athletic screening. Its significance is based on simplicity, quickness and high informative value as well as the fact that appearance of pathological ECG signs can precede the formation of structural heart diseases. During screening of healthy athletes, we studied the incidence of athletic ECG changes and pathological ECG abnormalities. METHODS We performed detailed analysis of 12-lead ECG recordings of asymptomatic elite, non-elite and master athletes and controls. RESULTS 227 athletes (male: 180, age: 27.2 ± 8.7 years) and 89 controls (male: 57, age: 28.1 ± 6.8 years) were examined. Benign ECG signs: sinus bradycardia, early repolarization and isolated Voltage criteria of left ventricular hypertrophy were common and more often in athletes compared to controls. Potentially pathological ECG signs: ST- (6.6% vs. 1.1%, p < 0.05) and T-wave (15.0% vs. 5.6%, p < 0.05) changes and signs of pathological left ventricular hypertrophy (5.3% vs. 0%, p < 0.05) occurred more frequently in athletes compared to controls. CONCLUSIONS Signs of pathological left ventricular hypertrophy and repolarization abnormalities are more often in athletes. No structural heart disease could be verified in the background of the disorders. However, athletes having pathological ECG should be kept under tight cardiology control. Exact definition and widespread knowledge of pathological ECG changes is essential in early recognition of high risk athletes.

Significance of an Increase in Diastolic Blood Pressure During a Stress Test in Terms of Comorbidities and Long-Term Total and CV Mortality

BACKGROUND A decrease in diastolic blood pressure (DBP) with exercise is considered normal, but the significance of an increase in DBP has not been validated. Our aim was to determine the relationship of DBP increasing on a stress test regarding comorbidities and mortality. METHODS Our database was reviewed from 1993 to 2010 using the first stress test of a patient. Non-Minnesota residence, baseline cardiovascular (CV) disease, rest DBP <60 or >100 mm Hg, and age <30 or ≥80 were exclusion criteria. DBP response was classified: normal if peak DBP-rest DBP < 0, borderline 0-9, and abnormal ≥10 mm Hg. Mortality was determined from Mayo Clinic records and Minnesota Death Index. Logistic regression was used to determine the relationship of DBP response to the presence of comorbidities. Cox regression was used to determine total and CV mortality risk by DBP response. All analyses were adjusted for age, sex, and resting DBP. RESULTS Twenty thousand seven hundred sixty patients were included (51 ± 11 years, female n = 7,314). Rest/peak averaged DBP 82 ± 8/69 ± 15 mm Hg in normal vs. 79 ± 9/82 ± 9 mm Hg in borderline vs. 76 ± 9/92 ± 11 mm Hg in abnormal DBP response. There were 1,582 deaths (8%) with 557 (3%) CV deaths over 12 ± 5 years of follow-up. In patients with borderline and abnormal DBP response, odds ratios for obesity, hypertension, diabetes, and current smoking were significant, while hazard ratios for total and CV death were not significant compared with patients with normal DBP response. CONCLUSIONS DBP response to exercise is significantly associated with important comorbidities at the time of the stress test but does not add to the prognostic yield of stress test.

Effect of Cardiorespiratory Fitness on Co-Morbidities and Mortality in Never, Past, and Current Smokers

Smoking is a strong risk factor for cardiovascular (CV) disease and mortality, but quitting may cause weight gain and increase the risk of co-morbidities. Our aim was to investigate the effect of smoking and exercise on weight-associated co-morbidities and mortality. We included Minnesota residents without baseline CV disease who underwent exercise testing from 1993 to 2010. Mortality was determined from Mayo Clinic records and Minnesota Death Index. Total, CV and cancer mortality by smoking status and cardiorespiratory fitness (CRF): (1) <80%, (2) 80% to 99%, (3) ≥100%. Differences were tested using logistic and Cox regression adjusting for age and gender. A total of 21,981 patients (7,090 past, 2,464 current smokers) were included. Past smokers had more obesity, hypertension, diabetes, and low CRF compared with never smokers. Current smokers did not show increased risk factor prevalence compared with never smokers but had higher rates of low CRF. There were 1,749 deaths; mean follow-up was 12 ± 5 years. Mortality was only slightly increased in past versus never smokers (Hazard Ratio: 1.2; 95% confidence interval 1.12 to 1.38) but was much higher in current smokers (Hazard Ratio 2.4; 95% confidence interval 2.05 to 2.80). Mortality in never, past, and current smokers was inversely related to CRF level. In conclusion, past smokers showed higher rates of co-morbidities and low CRF, but mortality was only mildly increased versus never smokers, whereas current smokers carried a high mortality risk. Our data suggest that quitting smoking is beneficial despite the increased co-morbidities. Exercise may potentially mitigate the risk of co-morbidities and death in those who quit smoking.

EXERCISE TEST PREDICTS BOTH CARDIOVASCULAR AND NON-CARDIOVASCULAR MORTALITY IN PATIENTS WITHOUT CARDIOVASCULAR DISEASE

Background: Exercise test variables have been shown to predict total mortality in several cardiovascular (CV) diseases. Is this because cardiovascular mortality constitutes many of the deaths in the published studies, or may these prognostic factors also predict non-CV mortality? Our aim was to

CARDIOVASCULAR FITNESS REDUCES THE RISK OF WEIGHT-ASSOCIATED COMORBIDITIES AND ALL-CAUSE MORTALITY IN PAST SMOKERS

Smoking is a powerful risk factor for cardiovascular disease (CVD) and mortality, but quitting may cause weight gain and increase in comorbidities. Our aim was to study if better functional aerobic capacity (FAC) on a stress test is associated with lower risk of obesity, diabetes, hypertension, and