Anabolic androgenic steroids produce dose-dependant increase in left ventricular mass in power atheletes, and this effect is potentiated by concomitant use of growth hormone.

Power athletes abuse anabolic androgenic steroids (AASs) and growth hormone (GH) to gain their muscular mass and strength. We wanted to determine how massive, self-administered doses of AASs with or without GH affect the left ventricular (LV) dimensions in power athletes. These substances are assumed to increase LVmass mainly by thickening the ventricular walls. Anecdotal evidence suggests a higher risk of cardiovascular events in AAS abusers. We were interested to see if LV dimensions and function in AAS abusers would indicate this increased risk. Twenty healthy male power athletes using massive doses of AAS without (n = 16) or with (n = 4) GH volunteered for the study. The controls were 15 sedentary male non-users of hormones. LV mass, geometry and filling were studied using standard echocardiographic methods. We found a significant association between LV mass and AAS dose (r = 0.54, p < 0.015). In contrast to the controls, LV mass (274 g in the athletes, 167 g in the controls) among the AAS abusers did not correlate with body weight or height. Concomitant use of AAS and GH further increased LV mass and associated with concentric remodelling of LV. Multiple regression analysis indicated that the mean AAS dose accounted for 29 %, age for 14 % and systolic blood pressure for 17 % of the variance in LV mass. We concluded that AAS abuse associates dose-dependently with myocardial hypertrophy and that concomitant use of GH associates with concentric remodelling of the LV. Our findings suggest that AASs and GH have a direct effect on the myocardium.

Ambulatory electrocardiographic findings in young athletes between 14 and 16 years of age.

Ambulatory electrocardiographic recordings were obtained from 35 male athletes between 14 and 16 years old, and from 35 male non-athlete controls of the same ages, in order to determine the effects of regular physical training on cardiac electrical activity. In the young athletes, the heart rates were significantly (P less than 0.01) lower than in the nonathletes. Sinus intervals over 2.00 s were present in five athletes (14%) and one control (3%). First-degree atrioventricular block was detected in eight athletes (23%) and four controls (11%), and second-degree block was detected in seven athletes (20%) and one control (3%) (P less than 0.05). Ventricular premature beats were present in 60% of athletes and 57% of controls. The bradycardia in athletes did not predispose to ventricular ectopic activity, since heart rates at the times of occurrence of extrasystoles were higher in athletes than in controls. Even after two years of regular physical training there are significant differences in sinus nodal function and atrioventricular conduction as between young athletes and controls.

Ambulatory electrocardiographic recording in mild or moderate myotonic dystrophy and myotonia congenita (Thomsen's disease).

Ambulatory electrocardiographic recording (AER) was performed on 27 adult patients with mild or moderate myotonic dystrophy (MD) and in 12 adult patients with mild myotonia congenita (MC) to determine whether characteristic arrhythmias and conduction disturbances occur in the early stages of these myotonic disorders. In MD and MC, AER showed at least one finding regarded as normal in 93% and 0% of cases, respectively. The most common abnormalities in MD were first degree atrioventricular (A-V) block (in 70% of cases) and QTc greater than or equal to 0.46 s (in 33%). Abnormal sinus intervals and frequent second degree A-V block were rare, each occurring in 4% of patients. Ventricular tachycardia did not occur. It is concluded that signs of involvement of cardiac conductive tissue in the MD disease process are very common, even in the early stages. Delayed A-V conduction in the most common single finding. Sinus nodal dysfunction, severe disturbances in A-V conduction, and ventricular arrhythmias are not common in mild disease. Repeated AER is indicated, to evaluate whether conduction disturbances in MD are progressing.

Ambulatory electrocardiographic recording in endurance athletes.

Data from ambulatory electrocardiographic recording in 35 highly trained endurance athletes and in 35 non-athletic controls of similar ages are given. The minimal, mean hourly, and maximal heart rates were significantly lower in the athletes. Thirteen athletes (37 . 1%) but only two controls (5 . 7%) had sinus pauses exceeding 2 . 0 seconds. First degree atrioventricular block was observed in 13 athletes (37 . 1%) and five controls (14 . 3%), second degree Wenckebach type block in eight athletes (22 . 9%) and two controls (5 . 7%), and second degree block with Mobitz II-like pattern in three athletes (8 . 6%) and no control. All athletes with Mobitz II-type pattern also had first degree and Wenckebach-type second degree atrioventricular block. The behavior of sinus rate on development of atrioventricular block varied, not only interindividually but also intraindividually, from absence of change to an increase or decrease in most subjects in both study groups. A decrease in sinus rate on appearance of atrioventricular block was found constantly in only two athletes and one control. Atrioventricular dissociation with junctional rhythm occurred in seven athletes (20%) and with ventricular rhythm in one athlete. Neither of these phenomena was seen in the group of controls. The athletes had slightly fewer ventricular extrasystoles than controls, and no athlete had ventricular tachycardia, whereas two controls had ventricular tachycardia.

Atrioventricular block, including Mobitz type II-like pattern, during ambulatory ECG recording in young athletes aged 14 to 16 years.

Twenty young male athletes, aged 14 to 16 years, and 20 nonathletic male controls of the same ages were studied with regard to atrioventricular block using ambulatory ECG recording. Among the athletic youngsters, the mean hourly heart rates were significantly (p less than 0.01) lower during most of the night hours and during school hours when activities in both groups were uniform. First degree block was found in the athletes in 3 cases, second degree Wenckebach-type block in 3 cases and second degree block with Mobitz type II-like pattern in 2 cases. Among the nonathletes, first degree block was found in one case and second degree Wenckebach-type block in another. The results indicate that after approximately 3 years of physical training, on average 5 times a week, various forms of atrioventricular block, apparently vagally mediated, are observable in young athletes more often than in nonathlete controls.

Ambulatory ECG recording in patients referred because of syncope or dizziness.

Data are presented on patients referred for ambulatory ECG recording because of syncope or dizziness during a 2-year period. Of the 272 consecutive patients subjected to the recording, 107 (39.3%) had syncope or dizziness as the main indication for referral. Sixteen of these patients (14.9%) experienced the presenting symptom during the recording, and in 8 (50%) of these the simultaneous ECG finding was interpreted as causative. In patients who were symptom-free during the recording, sinus arrests exceeding 2.5 seconds seemed to be a valuable finding to support the cardiac aetiology of the syncopal symptoms, whereas the diagnostic value of second degree AV block with either Wenckebach or Mobitz II like patterns, as such, and of ventricular tachycardia remained mostly unsettled.

Ventricular arrhythmias in healthy young men during physical exhaustion.

The occurrence of ventricular arrhythmias was studied in 25 healthy young men, with the aid of ambulatory ECG monitoring, during maximal bicycle tests, short term running, exhausting route marches, and during a 16 h period after brief and long term exercise. The bicycle test allowed prediction of 4 out of the 12 cases (33%) with ventricular premature beats (VPB) during running. The bicycle test combined with ambulatory ECG monitoring over a 16 h period allowed prediction of 12 out of the 14 cases (86%) with VPBs during marching. All 9 subjects who became exhausted during marching had VPBs, whereas 5 out of the 16 who were not exhausted had VPBs (p less than 0.001). In men with VPBs during all three exercise tests, the heart rates at the time of the VPBs were lowest during exhausting route marching. In conclusion, VPBs can be regarded as a physiological phenomenon if they occur only when exhaustion ensues.

Ventricular arrhythmias during exercise testing, jogging, and sedentary life: a comparative study of healthy physically active men, healthy sedentary men, and men with previous myocardial infarction.

The occurrence of ventricular arrhythmias during exercise testing, jogging, and sedentary life with and without preceding exercise was studied with the aid of ambulatory electrocardiographic monitoring in healthy physically active men, healthy sedentary men, and men with previous myocardial infarction (15 men in each group). Ventricular premature beats of the same grade were found during exercise testing and jogging in ten of the 15 healthy physically active men, in ten of the 15 healthy sedentary men, and in eight of the 15 men with previous myocardial infarction. When unifocal ventricular premature beats were omitted, the corresponding figures were 14/15, 11/15, and 15/15, respectively. Healthy physically active men had less ventricular arrhythmias in all of the tested situations. The greatest number and also the highest grades of ventricular arrhythmias during the exercises were found in healthy sedentary men, whereas the men with previous myocardial infarction had ventricular arrhythmias more during sedentary life.