Lifelong physical training prevents the age-related impairment of heart rate variability and exercise capacity in elderly people.

AIM: Aging is associated with a reduction on heart rate variability (HRV) and working capacity. Aim of this study was to evaluate in a group of elite master athletes the effect of a lifelong history of endurance running on HRV and exercise working capacity. METHODS: Twenty athletes (males, age 68.5+/-4.5 years) who practiced endurance running for at least 40 years, and 20 age-sex-matched control subjects with sedentary lifestyle were studied. All the participants underwent a maximal stepwise electrocardiogram (ECG) on effort (work-rate increments of 25 Watts every 2 min) and a 24-hour ECG monitoring. RESULTS: All the time domain measures of HRV and the LF and HF powers were significantly higher in elderly athletes than in sedentary subjects (P<0.001), while the LF/HF ratio was comparable between the 2 groups. Athletes exhibited significantly higher workload than controls (1610+/-489 vs 687+/-236 W, P<0.0001). Both the groups achieved, at maximum workload, similar heart rate (142+/-10 vs 138+/-18 bpm, ns), systolic blood pressure (226+/-18 vs 220+/-16 mmHg, ns), and rate-pressure product (32,596+/-2952 vs 30,838+/-3675, ns). Maximum work-rate attained in athletes was 225 W. By contrast, none of the controls reached a work-rate higher than 150 W. In the whole group we also showed a positive correlation between the time domain HRV parameter SDNN and maximum workload (r=0.58, P<0.001). CONCLUSION: Long-term endurance training induces in elderly subjects an increased HRV and a higher exercise working capacity, which are well-established predictors of cardiovascular and overall mortality.

Left ventricular function and calcium phosphate plasma levels in uraemic patients.

UNLABELLED: BACKGROUND. Recent investigations have focused on the pathogenetic role of disturbances of calcium phosphate metabolism in causing cardiovascular morbidity and mortality in haemodialysis patients. The aim of the present study was to assess left ventricular function and its relationship to phosphate and calcium plasma levels in stable uraemic patients on haemodialysis treatment. METHODS: Twenty uraemic patients (mean age 51+/-13 years) on maintenance haemodialysis and free from overt cardiac dysfunction, and 20 healthy volunteers underwent standard echocardiography, tissue Doppler-derived early (E(m)) and late (A(m)) diastolic velocities, tissue characterization with cyclic variations of integrated backscatter (CV-IBS), and serum biochemistry. RESULTS: With respect to tissue Doppler imaging (TDI), uraemic patients showed a lower E(m) peak, a higher A(m) peak, and a reduced E(m)/A(m) ratio of both interventricular septum and lateral wall (0.01>P<0.001) than controls. CV-IBS of both septum and posterior wall was significantly smaller in uraemic patients than in the control subjects (P<0.001). Moreover, the E(m)/A(m) ratio of septum and lateral wall were negatively related to serum phosphorus and to calcium phosphate product (P<0.001 for all). Accordingly, an inverse relationship was also found between CV-IBS of septum and lateral wall and calcium phosphate product and phosphorus (P<0.05 for all). CONCLUSIONS: These results showed early cardiac impairment of diastolic myocardial function evaluated by TDI and IBS analysis, and a close relationship between these changes and the calcium-phosphate plasma levels. These findings are well in keeping with the important role of hyperphosphataemia as a risk factor for cardiovascular damage, and justify the effort for optimal control of calcium phosphate metabolism in uraemic patients.

Effect of nebivolol on QT dispersion in hypertensive patients with left ventricular hypertrophy.

Hypertensive patients with left ventricular hypertrophy (LVH) have increased QT dispersion, which is considered an early indicator of end-organ damage and a non-invasive marker of risk for clinically important ventricular arrhythmias and cardiac mortality. The purpose of this study was to examine the effect of nebivolol antihypertensive therapy on QT dispersion in hypertensive subjects. Twenty-five subjects (15 men and 10 women, mean age 53.6 +/- 4.5 years) with essential arterial hypertension and mild-to-moderate LVH (blood pressure: 147.2 +/- 6.2/90.6 +/- 3.8 mmHg; left ventricular mass indexed: 149.1 +/- 10.7 g/m(2)) were compared with 25 age-matched healthy control subjects. All the participants underwent a complete clinical examination, including electrocardiogram for QT interval measurements. The QT dispersion was defined as the difference between the longest and the shortest QT interval occurring in the 12-lead electrocardiogram. The QT dispersion was corrected (QTc) with Bazett's formula. Hypertensive subjects were treated with 5 mg daily of nebivolol. The ECG and echocardiogram were repeated after four weeks of treatment. At baseline, hypertensive patients showed QT dispersion (56.9 +/- 6.4 vs. 31.7 +/- 8.4 ms, P < 0.001) and QTc dispersion (58.3 +/- 6.2 vs. 33.2 +/- 7.8 ms, P < 0.001) significantly higher than control subjects. Four-week nebivolol treatment reduced blood pressure from 147.2 +/- 6.2/90.6 +/- 3.6 mmHg to 136.3 +/- 3.1/83.3 +/- 2.5 mmHg (P < 0.0001), and resting heart rate from 75.3 +/- 4.7 to 64.2 +/- 3.0 bpm (P < 0.001), without significant change in left ventricular mass (LVMi: 149.1 +/- 10.7 vs. 151.4 +/- 9.8 g/m(2), ns). Nebivolol-based treatment improved QT dispersion (56.9 +/- 6.4 vs. 40.5 +/- 5.8 ms, P < 0.001) and QTc dispersion (58.3 +/- 6.2 vs. 42.2 +/- 5.6 ms, P < 0.001), which remained higher than in control subjects (P < 0.001 in both cases). The reduction of QT dispersion did not correlate with arterial BP reduction. In conclusion, nebivolol reduced increased QT dispersion in hypertensive subjects after four weeks. This effect, occurred without any change in LVM, did not seem to be related to the blood pressure lowering and could contribute to reduce arrhythmias as well as sudden cardiac death in at-risk hypertensive patients.

Antihypertensive effect of oral potassium aspartate supplementation in mild to moderate arterial hypertension.

BACKGROUND: Previous studies showed that potassium chloride (48-120 mmol/day) supplementation reduced arterial blood pressure (BP) in hypertensive patients. OBJECTIVES: Our aim was to evaluate the effect of a lower dose of potassium aspartate salt on BP in individuals with essential arterial hypertension. METHODS: One hundred and four patients (65 males, age 53 +/- 12 years) with mild to moderate essential hypertension (systolic/diastolic BP 154.2/96.2 +/- 10.8/5.4 mmHg) were allocated in two comparable groups of 52 to receive or not 30 mmol/day per os of potassium aspartate supplementation for four weeks. Office and 24-h BP, as well as serum and urinary electrolytes, were measured at baseline and at the follow-up visit after four weeks. RESULTS: Office and 24-h BP did not change in the control group, while these values were significantly reduced in the potassium supplementation group. Changes in office (systolic BP: 154.4 +/- 8.2 vs. 142.2 +/- 7.6 mmHg; diastolic BP: 95.0 +/- 5.6 vs. 87.2 +/- 4.3 mmHg, P < 0.001 for both) and 24-h BP (systolic BP: 142.7 +/- 8.2 vs. 134.8 +/- 6.3 mmHg; diastolic BP: 90.8 +/- 4.4 vs. 84.6 +/- 3.8 mmHg, P < 0.001 for both) following potassium supplementation were highly significant. The changes in day time and night time BP were similar. The treated group showed significantly increased potassium serum level and 24-h urinary excretion of potassium (P < 0.01 in both cases) after four weeks, while the untreated group showed no significant changes of the same parameters. Urinary Na/K ratio decreased significantly with potassium supplementation (P < 0.001). In the treated group changes in office (r = 0.58, P < 0.001) and 24-h SBP (r = 0.51, P < 0.001), but not in DBP (r = 0.29 and r = 0.25, n.s.), correlated positively with the urinary Na/K ratio at baseline. CONCLUSIONS: A relatively low supplementation of 30 mmol/day of potassium as aspartate lowered office and 24-h ambulatory BP in subjects with mild to moderate essential hypertension. The antihypertensive effect was sustained throughout the day, and was greater in the patients with high basal urinary Na/K ratio.

Ultrasonic backscatter of the carotid wall in young and older athletes.

OBJECTIVES: The aim of this study was to evaluate the effects of habitual exercise on the age-related changes of carotid wall composition defining its acoustic reflectivity by the quantitative approach of integrated backscatter (IBS) analysis. DESIGN: Cross-sectional study. SETTING: University Hospital. SUBJECTS: Fifty-four competitive long-distance runners (males, age range 22-72 years) and 50 healthy sedentary controls. MAIN OUTCOME MEASURES: All the subjects underwent both 2-D conventional ultrasonography and IBS analysis. IBS values were sampled from a region of interest (ROI) placed within five consecutive regions of the common carotid intima-media, and then corrected (C-IBS) for the IBS value of the adventitia. RESULTS: Athletes showed a lower C-IBS (-27.07 +/- 2.9 dB vs. -24.57 +/- 4 dB, P < 0.0001) and a smaller intima-media thickness (IMT: 0.64 +/- 0.16 mm vs. 0.78 +/- 0.21 mm, P < 0.001) respect to sedentary controls. By selecting the lowest (<30 years of age) and the highest (>60 years of age) tertile of age, we assess the influence of age on IMT and IBS. Sedentary older individuals exhibited an IMT higher respect to young controls and to the both trained subgroups (P < 0.0001). C-IBS was lower in both subgroups of athletes, independently of age, and lower in sedentary young people respect to sedentary older subgroup (P < 0.0001). Endurance chronic exercise blunted the difference of C-IBS observed between young and older sedentary individuals. Moreover, C-IBS was positively related to age (r = 0.77, P < 0.0001) and IMT (r = 0.52, P < 0.0001). CONCLUSIONS: The age-related changes of the arterial wall are attenuated by physical training. These modifications can be quantitatively discriminated by ultrasonic backscatter method.

QT dispersion in elderly athletes with left ventricular hypertrophy.

The purpose of this study was to examine the QT dispersion in elderly endurance athletes with left ventricular (LV) hypertrophy. Sixteen athletes (males, mean age 67.6 +/- 4.5 years) with mild to moderate LV hypertrophy, were compared with 16 age-matched hypertensive patients with similar degree of LV hypertrophy and 16 age-matched healthy sedentary controls. All the participants underwent echocardiogram and 12-lead electrocardiogram. QT dispersion was defined as the difference between maximum and minimum QT intervals in the different leads. QT dispersion was corrected (QTc) for heart rate according to Bazett's formula. The results showed in athletes and hypertensive patients comparable LV mass (258.2 +/- 14.2 vs. 262.4 +/- 16.8 g, ns), which was significantly higher than that of controls (p < 0.001). Trained subjects had QT dispersion (38.6 +/- 10.2 ms) and QTc dispersion (39.4 +/- 11.3 ms) significantly lower than hypertensive patients (QT dispersion: 68.4 +/- 11.4 ms; QTc dispersion: 72.2 +/- 8.4, p < 0.001) and comparable with controls (QT dispersion: 44.3 +/- 8.4 ms; QTc dispersion: 46.2 +/- 6.2 ms, ns). In conclusion, in elderly athletes training-induced myocardial hypertrophy was characterized by a QT dispersion significantly lower than hypertensive myocardial hypertrophy. This could provide a simple and inexpensive screening method for differentiating physiologic from pathologic myocardial hypertrophy in elderly subjects.