Mitral valve prolapse syndrome: The effect of adrenergic stimulation

Previous studies demonstrating increased adrenergic tone in symptomatic patients with mitral valve prolapse prompted a study of the response of symptomatic patients with mitral valve prolapse to adrenergic stimulation. Sixteen such patients had plasma catecholamines and 24 hour urinary epinephrine plus norepinephrine values that were greater than those of control subjects (473.3 ± 92.8 pg/ml versus 292 ± 15 and 44.7 ± 2.3 μg/g creatinine versus 29.8 ± 2.3; p < 0.01 and < 0.001, respectively). Twenty-four hour urinary sodium was lower in the patient group than in the control group (75 ± 7.4 versus 141 ±11 mEq; p < 0.01), with an inverse relation between urinary sodium and norephinephrine in the patient group (r = - 0.78) but not in the control group.Isoproterenol infusions, 0.5, 1.0 and 2.0 μg/min for 6 minutes, produced a dose-related, greater increase in heart rate in the mitral valve prolapse group than in the control group (16.1 ± 2.3 versus 10 ± 2; 31.8 ± 3.5 versus 19.6 ± 3; 48 ± 4.1 versus 27 ± 3; p< 0.01 with 0.5, 1.0 and 2.0 μg, respectively). The greater increase in heart rate resulted in a significantly shorter diastolic time in the patient group than in the control group (26.4 ± 2 s/min versus 30.6 ± 2; 27 ± 1.5 versus 30.6 ± 2; 26.6 ± 2 versus 30.9 ± 2; p < 0.01 with 0.5, 1.0 and 2.0 μg, respectively). The QT interval was 25 ms shorter than electromechanical systole (QS2) in the normal group and 26.5 ms shorter than QS2in the mitral valve prolapse group at rest; during isoproterenol infusion QT-QS2values were different in the mitral valve prolapse and control groups (3.3 ± 3 versus -7.0 ± 3; 31.9 ± 2.8 versus 10 ± 4; 52 ± 9.2 versus 29 ± 8; p < 0.01 with 0.5, 1.0 and 2.0 μg/min, respectively). Isoproterenol infusion also reproduced symptoms on a dose-related basis in 14 patients with mitral valve prolapse but not in control subjects (excluding palpitation).Symptomatic patients with mitral valve prolapse and high rest values of catecholamines were hypersensitive to isoproterenol infusion, suggesting that some of the symptoms are catecholamine-related or mediated

Floppy mitral valve/mitral valve prolapse syndrome: Beta-adrenergic receptor polymorphism may contribute to the pathogenesis of symptoms

AbstractBackgroundCertain patients with floppy mitral valve (FMV)/mitral valve prolapse (MVP) may have symptoms that cannot be explained on the severity of mitral valvular regurgitation (MVR) alone; hypersensitivity to adrenergic stimulation has been suggested in this group defined as the FMV/MVP syndrome.MethodsNinety-eight patients (75 men, 23 women) with mitral valve surgery for FMV/MVP were studied. Of those 41 (42%) had symptoms consistent with FMV/MVP syndrome [29 men (39%), 12 women (52%)]; median age of symptom onset was 30 years (range 10–63 years) and median duration of symptoms prior to valve surgery was 16 years (range 3–50 years). Ninety-nine individuals (70 men, 29 women) without clinical evidence of any disease were used as controls. Genotyping of β1 and β2 adrenergic receptors was performed.Resultsβ-Adrenergic receptor genotypes (β1 and β2) were similar between control and overall FMV/MVP patients. Subgroup analysis of patients, however, demonstrated that the genotype C/C at position 1165 resulting in 389 Arg/Arg of the β1 receptor was more frequent in women compared to those without FMV/MVP syndrome and to normal control women (p<0.025). This polymorphism may be related to hypersensitivity to adrenergic stimulation as reported previously in these patients.ConclusionThis study shows a large proportion of patients with FMV/MVP, predominantly women, had symptoms consistent with the FMV/MVP syndrome for many years prior to the development of significant MVR, and thus symptoms cannot be attributed to the severity of MVR alone. Further, women with FMV/MVP syndrome, symptoms at least partially may be related to β1-adrenergic receptor polymorphism, which has been shown previously to be associated with a hyperresponse to adrenergic stimulation

The marfan syndrome: Abnormal aortic elastic properties

Aortic distensibility and aortic stiffness index were measured at the ascending aorta (3 cm above the aortic valve) and the mid-portion of the abdominal aorta from the changes in echocardiographic diameters and pulse pressure in 14 patients with the Marfan syndrome and 15 age- and gender-matched normal control subjects. The following formulas were used: 1) Aortic distensibility = 2(Changes in aortic diameter)/(Diastolic aortic diameter) (Pulse pressure); and 2) Aortic stiffness index = ln(Systolic blood pressure)/(Diastolic blood pressure)(Changes in aortic diameter)/Diastolic aortic diameter. Pulse wave velocity was also measured.Compared with normal subjects, patients with the Marfan syndrome had decreased aortic distensibility in the ascending and the abdominal aorta (2.9 ± 1.3 vs. 5.6 ± 1.4 cm2 dynes-1, p < 0.001 and 4.5 ± 2.1, vs. 7.7 ± 2.5, cm2 dynes-1, p < 0.001, respectively) and had an increased aortic stiffness index in the ascending and the abdominal aorta (10.9 ± 5.6 vs. 5.9 ± 2.2, p < 0.005 and 7.1 ± 3.1 vs. 3.9 ± 1.2, p < 0.005, respectively). Aortic diameters in the ascending aorta were larger in these patients than in normal subjects, but those in the abdominal aorta were similar in the two groups. Linear correlations for both aortic distensibility and stiffness index were found between the ascending and the abdominal aorta (r = 0.85 and 0.71, respectively). Pulse wave velocity was more rapid in the patients than in the normal subjects (11.6 ± 2.5 vs. 9.5 ± 1.4 m/s, respectively, p < 0.01).Thus, aortic elastic properties are abnormal in patients with the Marfan syndrome irrespective of the aortic diameter, which suggests an intrinsic abnormality of the aortic arterial wall

775-2 Deleterious Effect of Smoking on the Elastic Properties of the Aorta

Cigarette smoking alters vascular reactivity and thus may alter the elastic properties of the aorta (Ao). To test this hypothesis, serial pressure-diameter loops (figure A) were obtained from the simultaneous recordings of the thoracic Ao diameter (D) and pressure (P) before and atterthe initiation of smoking of one cigarette (nicotine content 1.3mg) in 20 healthy smokers who underwent diagnostic cardiac catheterization. Ao 0 were measured by a Yshaped catheter, developed in our institution, which incorporates at its distal tips a pair of ultrasonic dimension crystals (Crystal Biotech, MA). This highdefinition diameter gauge was validated in in-vitro and experimental studies. Ao Pwere recorded by a Millar micromanometer. The pressure-diameter relationship changed significantly with smoking (figure A). Ao distensibility (=2Δd/dx ΔP, where Δd and ΔP: changes from systole to diastole of the Ao D and P respectively, and d: diastolic Ao D) was decreased significantly after smoking (figure B). These changes suggest that the Ao became stiffer atter smoking.This effect of smoking on the elastic properties of the aorta adds to the multiple other deleterious effects of smoking on human health

Urinary catecholamines and mitral valve prolapse in panic-anxiety patients

Free norepinephrine and epinephrine were measured in two consecutive 12-hour urine collections gathered during normal activity and sleep from 23 panic-anxiety patients and 9 normal subjects. Mitral value prolapse (MVP) was found in 7 of 20 patients who had echocardiograms. Mean nighttime norepinephrine and epinephrine excretion in panic-anxiety patients without MVP was significantly higher than that of control subjects, and was significantly higher than that of anxiety patients with MVP. In the daytime, all groups had higher catecholamine (CA) levels, but the differences between the groups were less pronounced. Medication significantly relieved symptoms and was associated with decreased CA levels. Elevated basal CA levels may characterize the subgroup of panic-anxiety patients who do not have MVP.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25817/1/0000380.pd

Mechanical behaviour and rupture of normal and pathological human ascending aortic wall

The mechanical properties of aortic wall, both healthy and pathological, are needed in order to develop and improve diagnostic and interventional criteria, and for the development of mechanical models to assess arterial integrity. This study focuses on the mechanical behaviour and rupture conditions of the human ascending aorta and its relationship with age and pathologies. Fresh ascending aortic specimens harvested from 23 healthy donors, 12 patients with bicuspid aortic valve (BAV) and 14 with aneurysm were tensile-tested in vitro under physiological conditions. Tensile strength, stretch at failure and elbow stress were measured. The obtained results showed that age causes a major reduction in the mechanical parameters of healthy ascending aortic tissue, and that no significant differences are found between the mechanical strength of aneurysmal or BAV aortic specimens and the corresponding age-matched control group. The physiological level of the stress in the circumferential direction was also computed to assess the physiological operation range of healthy and diseased ascending aortas. The mean physiological wall stress acting on pathologic aortas was found to be far from rupture, with factors of safety (defined as the ratio of tensile strength to the mean wall stress) larger than six. In contrast, the physiological operation of pathologic vessels lays in the stiff part of the response curve, losing part of its function of damping the pressure waves from the heart

Abnormal shortened diastolic time length at increasing heart rates in patients with abnormal exercise-induced increase in pulmonary artery pressure

<p>Abstract</p> <p>Background</p> <p>The degree of pulmonary hypertension is not independently related to the severity of left ventricular systolic dysfunction but is frequently associated with diastolic filling abnormalities. The aim of this study was to assess diastolic times at increasing heart rates in normal and in patients with and without abnormal exercise-induced increase in pulmonary artery pressure (PASP). Methods. We enrolled 109 patients (78 males, age 62 ± 13 years) referred for exercise stress echocardiography and 16 controls. The PASP was derived from the tricuspid Doppler tracing. A cut-off value of PASP ≥ 50 mmHg at peak stress was considered as indicative of abnormal increase in PASP. Diastolic times and the diastolic/systolic time ratio were recorded by a precordial cutaneous force sensor based on a linear accelerometer.</p> <p>Results</p> <p>At baseline, PASP was 30 ± 5 mmHg in patients and 25 ± 4 in controls. At peak stress the PASP was normal in 95 patients (Group 1); 14 patients (Group 2) showed an abnormal increase in PASP (from 35 ± 4 to 62 ± 12 mmHg; P < 0.01). At 100 bpm, an abnormal (< 1) diastolic/systolic time ratio was found in 0/16 (0%) controls, in 12/93 (13%) Group 1 and 7/14 (50%) Group 2 patients (p < 0.05 between groups).</p> <p>Conclusion</p> <p>The first and second heart sound vibrations non-invasively monitored by a force sensor are useful for continuously assessing diastolic time during exercise. Exercise-induced abnormal PASP was associated with reduced diastolic time at heart rates beyond 100 beats per minute.</p

Diastolic time – frequency relation in the stress echo lab: filling timing and flow at different heart rates

A cutaneous force-frequency relation recording system based on first heart sound amplitude vibrations has been recently validated. Second heart sound can be simultaneously recorded in order to quantify both systole and diastole duration