Myocardial collagen turnover in hypertrophic cardiomyopathy.

BACKGROUND: Myocardial interstitial fibrosis is a characteristic of hypertrophic cardiomyopathy (HCM). This study evaluates the collagen turnover in HCM and its impact on left ventricular (LV) diastolic function. METHODS AND RESULTS: Thirty-six HCM patients and 14 sex- and age-matched controls were studied. Collagen turnover was assessed as follows. By radioimmunoassay, a byproduct of collagen III synthesis (PIIINP) and 3 peptides resulting from collagen I synthesis (PICP and PINP) and degradation (ICTP) were measured. By ELISA, matrix metalloproteinases (MMPs) were determined, as follows: active MMP-2; active MMP-9; and MMP-1 as active, free (as active MMP-1 plus its precursor), and total (as free MMP-1 plus MMP-1/tissue inhibitor complexes). Tissue inhibitor of metalloproteinases-1 (TIMP-1) was also assayed. All patients underwent echocardiography. The difference in duration between transmitral forward (A) and pulmonary venous retrograde (AR) waves (A-Ar) was considered an estimate of passive diastolic function. Furthermore, restrictive or pseudonormal LV filling patterns were considered to identify patients with passive diastolic dysfunction. Patients had higher levels of PIIINP, ICTP, MMP-2, MMP-9, and total TIMP-1 than did controls. PIIINP was inversely related to LV end-diastolic diameter. A-Ar was inversely related to PICP, PINP, and their differences with ICTP (estimates of collagen I buildup). Furthermore, A-Ar was directly related to MMP-1 and MMP-2. CONCLUSIONS: As compared with controls, collagen turnover is enhanced in HCM patients. As collagen I synthesis prevails over degradation and MMP-1 and MMP-2 are inhibited, passive diastolic dysfunction occurs in patients with HCM.

Determinants of atrial fibrillation development in patients with hypertrophic cardiomyopathy.

Predictors of the development of atrial fibrillation (AF) in patients who have hypertrophic cardiomyopathy (HC) have not been extensively studied, although, in these patients, AF contributes to the exacerbation of symptoms and the development of heart failure. The present study determined the role of left atrial (LA) function in the development of AF in patients who have HC. One hundred fifty consecutive patients who had HC, had no history of AF, and who were followed for 5.2 +/- 2.9 years constituted the study population. Using M-mode echocardiography, we measured LA function as global LA fractional shortening and LA diameter. LA volume was measured from 2-dimensional 4-chamber views by the method of disks. During follow-up, 20 patients developed AF. LA function was an independent predictor of AF (odds ratio 0.716, p = <0.001), whereas LA diameter and volume were predictors in addition to age. Kaplan-Meier analysis showed that LA dysfunction carried a high risk of AF. Thus, in patients who have HC, LA function is a strong predictor of AF development and is independent of age.

Operator exposure to x-ray in left and right radial access during percutaneous coronary procedures: OPERA randomised study.

OBJECTIVE: Left radial access (LRA) and right radial access (RRA) have been shown to be safe and effective for coronary arteries catheterisation. However, the differences between the two approaches in terms of radiation exposure are still unclear. The aim of the present investigation is to evaluate in a randomised study, the dose of radiation absorbed by operators using either LRA or RRA. DESIGN: Randomised, prospective, double arm, single centre study. SETTING: University Hospital. PATIENTS: Male or female subjects with stable, unstable angina and silent ischaemia. INTERVENTIONS: The present study is a comparison of LRA and RRA for coronary artery catheterisation in terms of operators' radiation exposure. MAIN OUTCOME MEASURES: The primary outcome measure was the radiation dose absorbed by operators; secondary outcome measures were fluoroscopy time, dose-area product and contrast delivered. RESULTS: A total of 413 patients were enrolled; 209 were randomly selected to undergo diagnostic procedures with RRA and 204 with LRA. The operator's radiation exposure was significantly lower in the left radial group (LRA 33±37 µSv vs RRA 44±32 µSv, p=0.04). No significant differences were observed in  fluoroscopy time (LRA 349±231s vs RRA 370±246 s p=0.09) and dose-area product (LRA 7011.42±3617.30 µGym(2) vs RRA 7382.38±5226.61 µGym(2), p=0.80), even though in both there was a trend towards a lower level in the LRA. No differences were observed in contrast medium delivered (LRA 89.92±32.55 ml vs RRA 88.88±35.35 ml, p=0.45). CONCLUSIONS: The LRA was associated in the present report with a lower radiation dose absorbed by the operator during coronary angiography.

Myocardial texture in hypertrophic cardiomyopathy.

BACKGROUND: This study was conceived to assess associations between integrated backscatter signal at end diastole (IBS) and diastolic properties in patients with hypertrophic cardiomyopathy. METHODS: In 46 patients with hypertrophic cardiomyopathy, septal IBS was calculated by both applying an appropriate regression correction (IBSc) and by relating it to pericardial reflectivity (IBSp). Difference in duration between transmitral forward and pulmonary venous backward velocities (A-Ar) was measured as an estimate of passive diastolic filling. In all, 38 patients underwent ambulatory electrocardiogram monitoring for 48 hours. RESULTS: IBS inversely correlated to both A-Ar (IBSc, r = -.522, P < .001; IBSp, r = -.302, P = .041) and mitral peak velocity at atrial contraction (IBSc, r = -.464, P = .002; IBSp, r = -.413, P = .004). Moreover, IBS was greater in patients with sustained or nonsustained ventricular tachycardia (IBSc, 28.5 +/- 3.8 vs 25.4 +/- 3.8 dB, P = .034). CONCLUSIONS: Septal IBS correlates with Doppler parameters of left ventricular chamber stiffness in patients with hypertrophic cardiomyopathy. Increased IBS is associated with presence of ventricular arrhythmias.