Effects of cardiac rehabilitation on atrial wave in patients after myocardial infarction.

Cardiac rehabilitation (CR) can improve cardiac hemodynamic performance in patients after myocardial infarction (MI). Little evidence is provided concerning the consequences of CR on atrial wave duration, and less is known about the link between pre-arrhythmogenic patterns and the cardiovascular performance improvement in these subjects. Twenty-six patients, post-MI 0 to 7 days, underwent a complete CR cycle and a signal-averaged electrocardiogram (SAECG) for the evaluation of atrial activation parameters (group 1) to appreciate if physical training can promote parallel improvement in cardiovascular and intra-atrial conduction parameters. A control group of 24 well-matched nonischemic subjects (group 2) was chosen for data comparison. Resting heart rate (p < 0.01) and resting double product (p < 0.01) decreased after CR in groups 1 and 2, while diastolic blood pressure at maximal stress was decreased in group 1 (p < 0.01) with a parallel increase in the time of physical training (p < 0.05). SAECG parameters of atrial activation were unchanged in group 1 after the comparison and only total atrial duration activation (dA) reached statistical significance (113.3 +/- 17.2 msec vs 120.8 +/- 14.2 msec, subjects after CR vs before CR, p < 0.01). CR could improve intra-atrial activation in subjects after MI, but the consequences of hemodynamic adjustment of the trained heart must undergo a more accurate evaluation to verify if CR can prevent adverse arrhythmogenic complications of MI through cardiovascular performance improvement.

Left ventricular function, cardiac dysrhythmias, atrial activation, and volumes in nondipper hypertensive individuals with left ventricular hypertrophy.

BACKGROUND: Arrhythmic patterns and left ventricular geometric adaptations to pressure overload were investigated in 76 patients with untreated borderline-to-moderate sustained essential hypertension studied by 2-dimensional and M-mode echocardiography, 12-lead, Holter, and signal-averaged electrocardiography, and ambulatory blood pressure monitoring. METHODS AND RESULTS: Sixty-two age- and sex-matched normal adults were chosen for data comparison. Hypertrophic hypertensive patients were subdivided into 2 subgroups: 44 patients with nocturnal blood pressure reduction (dippers) and 32 patients without it (nondippers). Common afterload and diastolic function indexes were found to be lower in combined nondipper and dipper groups, but only fractional shortening decreased in nondippers. The number of premature atrial and ventricular contractions per hour was high in dippers and nondippers, with no statistically significant differences between them; atrial and ventricular complex dysrhythmias were similar. Signal-averaged electrocardiography showed a prolonged P-wave duration in dipper and nondipper patients with high atrial volumes but no late ventricular potentials and no difference in quantitative P-wave analysis. Left atrial volumes, P-wave duration, and premature atrial contractions were found to be positively linked to left ventricular hypertrophy. In nondipper patients a linear correlation was observed between left atrial volume and P-wave duration, although supraventricular ectopic activity was connected to left atrial volume enlargement both in dipper and nondipper patients. CONCLUSIONS: These data suggest that the nondipper pattern is not linked to a worse arrhythmogenic substrate; only atrial volume increase may be related to significant supraventricular activity and prolonged atrial activation in nondipper patients, but late ventricular potentials are uncommon in hypertrophic hypertensive patients.

Effects of slow-release verapamil and nitrendipine on office and 24-hour ambulatory blood pressure in hypertensive patients.

The aim of the present study was to compare the effects of slow-release verapamil (V), 240 mg and nitrendipine (N), 20 mg, administered once daily, on office (OBP) and 24-h ambulatory blood pressure (ABP) in patients with mild-to-moderate hypertension. Twenty patients were entered into this open, randomized, two-group (V, N) parallel study. The study groups had similar age and sex distribution. The OBP (V, 155/103 +/- 19/8 mm Hg; N, 141/98 +/- 13/4 mm Hg), heart rate (HR) (V, 74 +/- 7 beats/min; N, 77 +/- 10 beats/min), daytime systolic ABP (V, 149 +/- 14 mm Hg; N, 147 +/- 13 mm Hg), and nighttime ABP of the two groups were not statistically different after a 2-week washout period. The daytime diastolic ABP (V, 99 +/- 6 mm Hg; N, 93 +/- 6 mm Hg) was slightly lower (p less than 0.05) in group N. Both the OBP (V, 136/90 +/- 19/9 mm Hg; N, 135/85 +/- 10/4 mm Hg) and daytime ABP (V, 132/85 +/- 14/4 mm Hg; N, 136/87 +/- 13/8 mm Hg) dropped in the two groups after 8 weeks of treatment. Nonparametric analysis did not show statistical differences between the groups in OBP and ABP percentage drop. There was no significant change in nighttime ABP, HR (V, 73 +/- 10 beats/min; N, 74 +/- 12 beats/min), ECG, and laboratory exams. We conclude that both verapamil SR and nitrendipine are effective in reducing blood pressure in hypertensive patients without altering the HR.

Analysis of high-resolution atrial activation: report on 403 cases.

The findings of a study carried out on a sample of 403 P waves, selected over the 50 to 300 Hz frequency range, by a portable microcomputer system capable of averaging 512 P waves, are reported. Detailed analysis of P waves was attempted in healthy subjects and in patients affected by pathologic processes where atrial involvement had been observed. An attempt was made to individualize P wave parameters which may be associated with these pathologic conditions. On each atrial signal a 512-point fast Fourier transform was used. The original sample was divided into 18 classes, and the mean values of some parameters of each class were computed. The results of fast Fourier transform computing and of the mean values of parameters for both patients and healthy subjects show two different behaviors with respect to the amplitude-frequency relationships and mean peak-to-peak amplitude, respectively. The present results indicate that this technique may be useful for further detailed analysis of P waves.