Chronotropic incompetence in a young adult: case report and literature review.

Chronotropic incompetence (CI) is the inability of heart rate response to meet metabolic demand. CI is associated with sinus node dysfunction, atrial fibrillation, or structural heart disease, and can lead to functional impairment. We report the case of a 34-year-old man with CI secondary to sinus node dysfunction who demonstrated significant improvement in functional capacity with rate-responsive pacing. Therapy for CI should be guided by the treatment of the underlying cause with consideration for rate-responsive pacing in symptomatic patients. The prognosis of CI is variable and dependent on underlying etiology.

Marked low-density lipoprotein cholesterol reduction below current national cholesterol education program targets provides the greatest reduction in carotid atherosclerosis.

BACKGROUND: Current National Cholesterol Education Program (NCEP) guidelines recognize low-density lipoprotein cholesterol (LDL-C) below 100 mg/dl as an optimal level. Evidence supporting this is scant. Both LDL-C and C reactive protein (CRP) are known correlates of atherosclerosis progression. HYPOTHESIS: We examined the effect of final LDL-C and CRP obtained with statin therapy on carotid intima-media thickness (CIMT), a valid surrogate for clinical benefit of lipid-lowering therapies. METHODS: In a randomized, single-center trial, 161 patients were assigned to statin therapy of different potencies (pravastatin 40 mg, n = 82; atorvastatin 80 mg, n = 79). The effects on CIMT were assessed in relationship to LDL-C and CRP levels obtained after 12 months of therapy. RESULTS: Changes in CIMT were directly related to the final LDL-C level obtained on statin therapy after 12 months (R = 0.219, p = 0.015). Carotid intima-media thickness regression was seen in 61% of the subjects in the lowest quartile of final LDL-C (< 70 mg/dl) versus 29% of the subjects with the highest quartile of final LDL-C (> or = 114 mg/dl, p = 0.008). No threshold value was seen, with more favorable effects on absolute change in CIMT with lower values of LDL-C (decrease in CIMT of 0.06 +/- 0.17 mm in the lowest quartile compared with an increase of 0.06 +/- 0.09 in the highest quartile of LDL-C, p = 0.008). On-treatment LDL and CRP concentrations both below the group median values were associated with the greatest likelihood of CIMT regression. CONCLUSIONS: Regression of carotid atherosclerosis is directly related to the absolute LDL-C level on statin therapy. The greatest regression was obtained with an LDL-C < 70 mg/dl, supporting marked LDL-C reduction to levels below current NCEP guidelines.

Effect of atorvastatin and pravastatin on serum C-reactive protein.

BACKGROUND: Extra-lipid effects of statins, such as anti-inflammatory actions, may contribute to their clinical benefit. These effects, with important implications for the concept of a statin "class effect," may be drug specific or may be related to the extent of lipid lowering. METHODS: We randomized 130 patients to treatment with either atorvastatin (80 mg daily, n = 63) or pravastatin (40 mg daily, n = 67), and measured serum lipids, C-reactive protein, and fibrinogen at baseline and after 3 months of therapy. RESULTS: Mean C-reactive protein (CRP) levels were significantly reduced in both groups, with a 36% reduction in the atorvastatin group (0.39 +/- 0.36 to 0.25 +/- 0.27, P =.001) and a 22% reduction observed in the pravastatin group (0.40 +/- 0.33 to 0.31 +/- 0.32, P =.003). A reduced or unchanged CRP level was seen in 67.2% of pravastatin-treated patients (45/67) and 73% of atorvastatin- treated patients (46/63) (P =.47). There was no difference between drugs in either the absolute or relative reductions in CRP levels. However, whereas the reduction of CRP with pravastatin was unrelated to the degree of low-density lipoprotein reduction (r = -.05, P =.69), atorvastatin-induced CRP reductions correlated directly to the change in low-density lipoprotein-C (r =.33, P =.009). CONCLUSIONS: High-dose atorvastatin and pravastatin both reduce CRP levels. However, whereas pravastatin's effect on CRP is independent of lipid-lowering efficacy, these data suggest that lipid-dependent mechanisms are, at least in part, active in atorvastatin-treated patients.

ARBITER: Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol: a randomized trial comparing the effects of atorvastatin and pravastatin on carotid intima medial thickness.

BACKGROUND: Whether marked LDL reduction to levels well below 100 mg/dL would further reduce the burden of cardiovascular disease is controversial. We compared the effects of 2 statins with widely differing potencies for LDL reduction (pravastatin 40 mg/d and atorvastatin 80 mg/d) on carotid intima-media thickness (CIMT). METHODS AND RESULTS: This was a single-center, randomized, clinical trial of 161 patients (mean age, 60 years; 71.4% male; 46% with known cardiovascular disease) that met National Cholesterol Education Program (NCEP) II criteria for lipid-lowering therapy. The effects of atorvastatin (80 mg/d; n=79) and pravastatin (40 mg/d; n=82) on CIMT were compared using blinded, serial assessments of the far wall of the distal common carotid artery. Baseline CIMT and other characteristics were similar between study groups. As anticipated, atorvastatin was substantially more potent for LDL reduction after 12 months: in the atorvastatin group, LDL cholesterol was 76+/-23 mg/dL after 12 months (-48.5%); LDL cholesterol was 110+/-30 mg/dL in the pravastatin group (-27.2%; P<0.001). Atorvastatin induced progressive CIMT regression over 12 months (change in CIMT, -0.034+/-0.021 mm), whereas CIMT was stable in the pravastatin group (change of 0.025+/- 0.017 mm; P=0.03). CONCLUSIONS: Marked LDL reduction (<100 mg/dL) with a high-potency statin provides superior efficacy for atherosclerosis regression at 1 year. This early effect on CIMT, a surrogate for clinical benefit, suggests that marked LDL reduction with synthetic statins may provide enhanced reduction in clinical coronary event rates.