Abstract: BACKGROUND: The constant rise in the number of old people involves a great interest towards the aging of the cardiovascular system. Many authors have studied age-adjusted limits to echocardiographic and functional parameters. The aim of this study is to evaluate some functional parameters so as to define the cardiovascular modifications of the aging heart. METHODS: We have studied 66 patients, 32 of mean age 71+/-4 years (Group 1) and 34 with mean age 33+/-6 years (Group 2), without cardiovascular diseases, through basal echocardiography and exercise test. RESULTS: In comparison to group 2, in group 1 we have observed at rest normal ventricular dimensions with increase of the thickness (SIV 11.2+/-0.4 vs 9+0.6, p=0.01; PP 10.6+/-0.6 vs 9.2+0.4, p=0.01), of the left atrium (41.2+/-1.08 vs 36.2+1.3, p=0.05), and of the aortic root (33.2+/-1.3 vs, 30.8+0.9, p=0.05), altered diastolic function (E/A 0.7+/-0.14 vs 1.9+/-0.7, p=0.01), with normal systolic indexes. At 100 Watts workload there was an age-related increase in end-diastolic volume (142+/-10.6 vs 127+/-4.3, p=0.01) and an age related decrease in heart rate (HR 100 W 148+/-10.7 vs 169+/-10.9, p=0.05). CONCLUSIONS: In the heart of an elderly subject therefore there are morphological modifications that in the absence of organic pathologies can support the metabolic demands of the organism and adapt to the physiological modifications of the elderly subject.

Abstract: Despite a wide range of therapeutic choice in the treatment of angina pectoris, there is a small but increasing population of patients that doesn't benefit of conventional therapy and whose life is invalidated by frequent attack of anginal pain. For this population, nonresponders to drug therapy not suitable for revascularization (coronary bypass surgery, angioplasty), neurostimulation of dorsal column has been described as an effective and safe therapy. The mechanism of action is not completely known, but is safety is sufficiently established. It may become a useful choice in the treatment of patients with intractable angina.

Abstract: BACKGROUND: Various experimental and clinical observations suggest changes in sympathetic and vagal neural regulatory mechanisms play a critical role in altering cardiac electrical properties and favor the occurrence of arrhythmic events. There is limited information about the influences of the autonomic tone on the development of episodes of paroxysmal atrial fibrillation in patients with no evidence of organic heart disease. The aim of this study was to investigate changes in sympatho-vagal balance 5 minutes before the onset of atrial fibrillation. METHODS: We evaluated 28 patients with no history of heart disease who were not undergoing pharmacological treatment and who had at least one episode of paroxysmal atrial fibrillation recorded during an 24-hour ECG Holter monitoring. We analyzed values of frequency domain heart rate variability parameters 5 minutes before the onset of atrial fibrillation (prefa period) compared to an equivalent period at least 1 hour after from atrial fibrillation (random period). RESULTS: Thirty-six episodes of atrial fibrillation were recorded and our results showed we had two types of episodes. Eighteen were classified as Type A, in which we had an increase of low frequency (LF) (79.15 +/- 10.76 in comparison with 62.64 +/- 19.55) (P = 0.004) and a decrease of high frequency (HF) (20.82 +/- 10.74 in comparison with 37.64 +/- 20.20) (P = 0.004) consistent with an increase of sympathetic tone; and 18 were classified as Type B in which there was a decrease of LF (62.82 +/- 15.38 in comparison with 85.97 +/- 8.48) (P < 0.001), and an increase of HF (36.79 +/- 14.72 compared with 14.01 +/- 8.48) (P < 0.001), consistent with an increase of parasympathetic tone. CONCLUSION: We observed abrupt changes in sympathovagal balance in the last 5 minutes preceding an episode of atrial fibrillation. This can be related to a double behavior in the neurogenic drive: in Type A episodes there is an increase of the LF spectrum, LF:HF ratio, and a decrease of the HF spectrum consistent with an increase of neurogenic sympathetic drive; in Type B episodes there is a reduction of the LF spectrum, LF/HF ratio, and an increase of HF spectrum consistent with an enhancement of the neurogenic parasympathetic drive. In some patients, we found that the two mechanisms operate during different hours of the day and that sometimes there is an increase of sympathetic tone, and in the same instances an increase of parasympathetic tone. Heart-rate variability measures fluctuation in autonomic inputs to the heart rather than the mean level of autonomic impulse; autonomic imbalance is probably more important than the vagal or sympathetic drive alone.

Abstract: BACKGROUND. The aim of this study was to assess the utility of ejection fraction at rest (rEF) and its change during stress (delta EF) as a predictor of cardiac events during the follow-up of patients (pts) with myocardial infarction. METHODS. 74 pts (44 treated with thrombolytic therapy (TR), and 30 not (noTR)), were studied with 99mTcPYP angiography within 2 +/- 1 months, after AMI. By 20 +/- 10 months, 41 pts had no events (Group A) while 33 pts experienced cardiac events (3 deaths, 16 angina, 12 CABG, and 2 PTCA). RESULTS. rEF was similar in both Groups A and B (A 47 +/- 8 vs B 45 +/- 10 p. ns), 44 +/- 15 vs B-noTR 46 +/- 12 p. ns). delta EF was different between Groups A and B. Group A showed a positive delta EF (3.2 +/- 6), and this result was more evident in thrombolyzed AMI (A-TR 4.4 +/- 4.5 vs A-noTR 1.16 +/- 3.9 p. < 0.01). Group B showed a negative delta EF (-4.4 +/- 5.3), and this result was more evident in non thrombolyzed AMI (B-TR -2 +/- 6.4 vs B-noTR -5.8 +/- 8 p. < 0.01). CONCLUSIONS. A decrease in EF during exercise radionuclide angiography is useful in identifying pts with high risk of cardiac events after AMI. Thrombolytic therapy improves stress EF in both Groups A and B.

Abstract: Seven cases of ventricular cross stimulation from a group of 23 patients implanted with DDD devices are presented. In two patients the phenomenon was observed at the moment of DDD programming at nominal values, and in five other patients it was reproduced by increasing the atrial output voltage up to ten volts. In all 23 patients cross stimulation disappeared permanently within 24 hours after implantation. From the onset of cross stimulation to its end, atrial and ventricular threshold voltages were unchanged, while the atrial and ventricular impedances significantly decreased. These results suggest that an important role in the phenomenon occurs by impedance variation at the interface between the pulse generator and body tissue.