Coronary artery dissection, combined aortic valve replacement and coronary bypass grafting in osteogenesis imperfecta.

Osteogenesis imperfecta is an inherited connective tissue disorder. Aortic root dilation, aortic insufficiency and mitral valve prolapse are uncommon cardiovascular manifestations of osteogenesis imperfecta. Cardiac surgery in patients with osteogenesis imperfecta involves a high risk of complication rate. We report a case of coronary artery dissection induced by coronary angiogram in a patient with osteogenesis imperfecta and severe aortic regurgitation. In this case, the dissection of a coronary artery was not completely sealed by coronary stenting, and followed by successful combined aortic valve replacement and coronary artery bypass grafting on an emergency basis.

Heart rate variability and progression of coronary atherosclerosis.

Low heart rate (HR) variability is associated with increased risk of cardiovascular morbidity and mortality, but the causes and mechanisms of this association are not well known. This prospective study was designed to test the hypothesis that reduced HR variability is related to progression of coronary atherosclerosis. Average HR and HR variability were analyzed in 12-hour ambulatory ECG recordings from 265 qualified patients participating in a multicenter study to evaluate the angiographic progression of coronary artery disease in patients with prior coronary artery bypass surgery and low high-density lipoprotein cholesterol concentrations (<1.1 mmol/L). Participants were randomized to receive a placebo or gemfibrozil therapy. The progression of coronary atherosclerosis was estimated by quantitative, computer-assisted analysis of coronary artery stenoses from the baseline angiograms and from repeated angiograms performed an average of 32 months later. The progression of focal coronary atherosclerosis of the patients randomized to placebo therapy was more marked in the tertile with the lowest standard deviation of all normal to normal R-R intervals (SDNN, 74+/-13 ms; mean decrease in the per-patient minimum luminal diameter -0.17 mm; 95% confidence interval [CI], -0.23 to -0.12 mm) than in the middle tertile (SDNN, 107+/-7 ms; mean decrease -0.05 mm; 95% CI, -0.08 to -0.01 mm) or highest tertile (SDNN, 145+/-25 ms; mean change 0.01 mm; 95% CI, -0. 04 to 0.02 mm) (P<0.001 between the tertiles). This association was abolished by gemfibrozil. SDNN was lower (P<0.001) and minimum HR was faster (P<0.01) in the patients with marked progression than in those with regression of focal coronary atherosclerosis. In multiple regression analysis including HR variability, minimum HR, demographic and clinical variables, smoking, blood pressure, glucose, lipid measurements and lipid-modifying therapy, progression of focal coronary atherosclerosis was independently predicted by the SDNN (beta=0.24; P=0.0001). Low HR variability analyzed from ambulatory ECG predicts rapid progression of coronary artery disease. HR variability provided information on progression of focal coronary atherosclerosis beyond that obtained by traditional risk markers of atherosclerosis.

Unexplained severe pulmonary hypertension in two brothers.

Unexplained pulmonary hypertension of nearly simultaneous onset is reported in two brothers, aged 17 and 26 yrs. Echocardiography revealed right ventricular hypertrophy and dilatation, paradoxical septal motion and an enlarged main pulmonary artery. In the right catheterization highly elevated pulmonary arterial pressures (107/58 and 84/46 mmHg) were seen. Doppler echocardiography showed significant leakage of the pulmonary and tricuspid valves in the younger brother, who died suddenly three weeks later. An initial decline in pulmonary arterial systolic pressure was achieved in the older brother by drug therapy. Eight months later, however, the pressure had risen to the pretreatment level. Dyspnoea increased and the patient underwent heart-lung transplantation but subsequently died. In the family study a third brother, father and mother were healthy.

Early cardiac changes related to radiation therapy.

To investigate the incidence and severity of possible radiation-induced cardiac changes, 21 women without heart disease were investigated serially by echocardiography and by measuring systolic time intervals before and up to 6 months after postoperative radiation therapy because of breast cancer. Radiation was associated with a decrease in fractional systolic shortening of the left ventricular (LV) minor-axis diameter, from 0.35 +/- 0.05 to 0.32 +/- 0.06 (p less than 0.005), and in the systolic blood pressure/end-systolic diameter ratio, from 4.4 +/- 1.2 to 3.9 +/- 0.9 mm Hg/mm (p less than 0.005). The mitral E point-septal separation increased, from 2.8 +/- 1.5 to 4.2 +/- 2.5 mm (p less than 0.005). The preejection period/LV ejection time ratio of systolic time intervals increased, but only the decrease within 6 months after therapy was significant (p less than 0.005). All these changes reflect slight transient depression of LV function, which became normalized within 6 months after therapy. Up to 6 months after therapy, a slight pericardial effusion was found in 33% of the patients. Hence, conventional radiation therapy appeared to cause an acute transient and usually symptomless decrease in LV function, and later, slight pericardial effusion in one-third of the patients.

Evidence of impaired left ventricular performance after an uninterrupted competitive 24 hour run.

The effect of extremely exhaustive exercise on left ventricular performance was studied echocardiographically in 13 experienced male ultramarathon runners who took part in a competitive 24 hr run, completing distances of 114 to 227 km. Although the left ventricular end-diastolic dimension (EDD) was reduced by 7% (54 +/- 5 to 50 +/- 7 mm; p less than .005), the end-systolic dimension (ESD) increased slightly (33 +/- 5 to 34 +/- 6 mm; NS). As a consequence, the stroke dimension (21 +/- 2 to 16 +/- 2 mm; p less than .005) and fractional shortening (38 +/- 5% to 32 +/- 5%; p less than .005) declined by 24% and 16%, respectively. The reduction in fractional shortening was related to delta ESD (r = -.66; p less than .05) but not to delta EDD (r = .22; NS). In spite of reduced afterload, the mean velocity of circumferential fiber shortening also decreased by an average of 9% (p less than .01) in proportion to the distance completed (r = -.69; p less than .01). The systolic blood pressure/ESD ratio was 21% lower after the race (4.2 +/- 0.9 to 3.3 +/- 0.6; p less than .005). Body weight loss was not related to any alterations in left ventricular dimensions or ejection phase indexes. The stroke dimension and ejection phase indexes continued to decline within the last 6 hr of the race but returned to the prerace level 2 to 3 days after the race. Total serum creatine kinase peaked at 3917 to 64740 U/liter (mean 27427) and its MB percentage peaked at 2% to 6%.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional limitation in aortic valve disease: superiority of bicycle test to symptom-rated appraisal?

The overall functional capacity in aortic valve disease was evaluated using the New York Heart Association criteria and symptom-limited bicycle ergometry in 80 patients who underwent cardiac catheterization. The correlations between exercise performance and resting cardiac haemodynamics and clinical class were poor. Similar exercise tolerance appeared to be associated with comparable resting left ventricular (LV) performance in each haemodynamic subgroup. Limitation in exercise tolerance in aortic stenosis (n = 25), as defined by peak work-load achieved and work-pulse index, together with an inability to raise systolic blood pressure during exercise, appeared to be associated not only with a more significant reduction in LV systolic pump function and compliance but also with greater LV dilatation. A lack of correlation between exercise performance and resting LV function was seen in patients with aortic regurgitation (n = 35); and, to large extent, in those with combined lesion (n = 20). The severity of the valvular lesion was not indicated by functional limitation in any of the subgroups, although greater systolic blood pressure during exercise appeared to reflect more significant valvular leakage in the combined lesion group. It is concluded that objective tests of exercise tolerance are to be preferred in monitoring the course of the disease and the therapy provided. Aortic regurgitation appears to cause as great a limitation in exercise tolerance as does aortic stenosis alone, but may not be associated with greater deterioration in LV function at a similar level of functional limitation. Pressure overload to the LV may explain the ability of impaired LV function to reflect the limitation in exercise tolerance in cases of aortic stenosis.

Response to progressive bicycle exercise before and following aortic valve replacement.

The O2 uptake response to symptom-limited progressive bicycle exercise that was performed serially before and up to 1 year after uncomplicated isolated aortic valve replacement (AVR) was evaluated in 37 patients. Before surgery, an unusually rapid exercise O2 uptake response was seen in about half the patients, while the AVR appeared to result in a change in O2 uptake kinetics to within normal limits in the majority of the patients within the first 3 postoperative months. The inappropriate O2 uptake response was found to be associated with more significant limitation in exercise tolerance, and it appeared to be mediated not only by a pronounced exercise heart rate response but, probably, also by an exaggerated arteriovenous O2 difference. These findings suggest that peripheral vascular responses in patients with chronic aortic valve disease may play a major role in the different O2 uptake responses to progressive bicycle exercise. The physiological significant of O2 kinetics during exercise, however, requires further study.