[Markers of cardiovascular remodeling in hypertension]. / Marqueurs du remodelage cardiovascularire structural et fonctionnel dans l'hypertension.

UNLABELLED: Our goal was to study the relative influence of systolic blood pressure (SBP) and plasmatic markers of sympathetic and renin-aldosterone systems (RAS) activities to left atrial diameter (LAD), left ventricular posterior wall thickness (LVPWT) and pulse wave velocity (PWV), which reflect cardiovascular remodeling in hypertension. METHODS: In 227 consecutive patients with hypertension (mean age +/- SD: 53.3 years +/- 13.4, 126 men), we measured: PWV, LAD, LVPWT, mean 24-hours SBP, plasma renin activity, and plasma aldosterone and catecholamine levels. Multiples linear regression analyses were performed to test statistical associations between hemodynamic and neurohumoral factors, and cardiovascular remodeling parameters, after adjustment for age, gender and body mass index. RESULTS: LVPWT was positively correlated to SBP as well as to plasma aldosterone and meta-noradrenaline (p < 0.001). LAD and PWV were related to SBP but not to any of the biological variables. Moreover, LAD correlated to PWV independently of SBP (p < 0.05), whereas after SBP inclusion in the model, there was not significant correlation between LAD and LVPWT nor between LVPWT and PWV. CONCLUSION: In hypertension, the development of cardiac hypertrophy depends on SBP and the sympathetic and renin-aldosterone systems activities. The RAS is not involved in the PWV nor LAD modifications. Strong association between LAD and PWV suggest that left atrial enlargement, that may be considered as a marker of diastolic function, may results more from arterial stiffness than from ventricular hypertrophy.

Frequency-domain heart rate variability in 24-hour Holter recordings: role of spectral method to assess circadian patterns and pharmacological autonomic modulation.

Different spectral methodologies for heart rate variability were recently shown to provide the same qualitative results in the context of passive tilt test. However, the impact of the method and the use of normalized power units in long-term ECG monitoring is still debated. Autoregressive and Fast Fourier transform (FFT) spectral approaches were applied to assess circadian modulation and the effect of beta-blocker administration in mild hypertensive patients who underwent continuous ambulatory ECG recording (n = 44, 51 +/- 12 years, 30 men). Spectral analysis was applied to 5-minute sequences and spectral parameters representative of each circadian period (24 hour, day, night) were calculated. In baseline recordings, FFT spectral method provided a smaller estimate of total and very low frequency powers. On the contrary, low- and high-frequency components were systematically larger with FFT. Circadian variations were in favor of an increased overall nocturnal variability but of a reduced low frequency normalized power with both spectral methods. Chronic oral administration of beta-blocker induced an increase of all spectral components except for an unchanged low-frequency normalized power, independently from the spectral approach. In spite of quantitative differences, the qualitative assessment of circadian patterns and beta-blockade effect by autoregressive- and FFT-based spectral analyses is equivalent. The low-frequency component of heart rate variability cannot be considered a reliable direct marker of sympathetic activity in long-term ambulatory ECG recording.

[Compared predictive value of clinical variables and 24-hour Holter monitoring on survival 1 year and 4 years after myocardial infarction]. / Valeur prédictive comparée des variables cliniques et du Holter de 24 heures sur la survie, 1 an et 4 ans après infarctus du myocarde.

The purpose of this study was to determine precisely which additional information on survival at 1 year and 4 years was provided by an ambulatory 24-hour ECG recording performed 3 weeks after myocardial infarction (MI), compared to clinical data. The study was conducted in 107 consecutive patients under 75 years of age who had had MI and were followed up for a mean period of 4 years and 9 months. The clinical variables most closely associated with mortality at both 1 year and 4 years were those which reflected the severity of myocardial damage and left ventricular dysfunction before or during hospitalization, viz.: a history of MI or heart failure (HF), HF in the acute phase, and digitalis-diuretic treatment on discharge. At 4 years a multivariate analysis yielded 3 separate clinical variables which enabled cardiac mortality to be predicted: history of MI (p less than 0.001), presence of HF in the acute phase (p less than 0.001) and history of hypertension (p less than 0.02). Ventricular arrhythmias also were closely associated with mortality, but only during the first year, the 2 most discriminant factors being a mean hourly frequency of ventricular ectopic beats (VEB) greater than 10, and the presence of successive VEB (doublet or burst of ventricular tachycardia). The positive predictive values (PPV) of clinical and ambulatory ECG recording variables taken separately for mortality at 1 year were fairly similar (about one-third) as regards HF in the acute phase, history of MI, successive VEB and mean VEB frequency greater than 10/h, the corresponding risk ratios being 23.9, 13.7, 11.6 and 9.4 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)