Discrepancy between Doppler and catheter measurements of pressure gradients across small-size prosthetic valve.

OBJECTIVES: The exact role of pressure gradient across the prosthetic valve estimated from Doppler flow velocity remains controversial. This in-vivo study was designed to assess the actual discrepancy between Doppler and catheter measurements of the pressure gradients for small bileaflet prosthetic valves in the aortic position. METHODS: Bileaflet prosthetic valves (19 mm-ATS) were implanted into the aortic position in pigs, and pressure gradients across the valves were examined by volume loading under right heart bypass. The pressure gradient obtained by catheter was defined as the conventional peak-to-peak gradient between the left ventricle and aorta. The peak Doppler gradients were calculated from the maximal instantaneous Doppler velocity with the ultrasound probe positioned on the diaphragm at the level of the cardiac apex. RESULTS: There were strong correlations between pressure gradients and cardiac output. The Doppler gradient was constantly higher than the catheter values, and the resultant discrepancy between Doppler and catheter measurements was directly dependent on cardiac output (y=9.9x+0.6, r2=0.55). For cardiac output > or = 5.0 L/min, the difference between Doppler and catheter gradients reached 40 mmHg, and maximum differences of up to 80 mmHg were observed. CONCLUSIONS: In view of the presence of striking overestimation of catheter gradient by Doppler measurement, Doppler ultrasound should be used cautiously to assess small-size bileaflet prosthetic valve function with consideration of the patient's hemodynamic state.

Hepatocyte growth factor improves the survival of rats with pulmonary arterial hypertension via the amelioration of pulmonary hemodynamics.

Hepatocyte growth factor (HGF) is a multifunctional growth factor with mitogenic, anti-apoptotic and anti-fibrotic activities. In this study, we investigated the effect of administration of recombinant human HGF on pulmonary arterial hypertension. Pulmonary arterial hypertension was induced in rats by a single injection of monocrotaline (MCT) and recombinant human HGF (0.12 mg/day) was administered into the right ventricle cavity using osmotic pumps, which were implanted subcutaneously 21 days after MCT injection. Continuous intravenous delivery of recombinant human HGF for 14 days led to prolonged survival of animals suffering from severe MCT-induced pulmonary arterial hypertension. Although a bolus injection of recombinant human HGF did not affect pulmonary arterial pressure, a 14-day administration of recombinant human HGF attenuated the inflammatory cell infiltrate, matrix accumulation and vascular medial thickening. As a consequence, the pulmonary lumen was enlarged and the pulmonary arterial pressure was significantly reduced. Additionally, continuous administration of recombinant human HGF suppressed lung tissue expression of platelet-derived growth factor, which plays an important role in the development of pulmonary arterial hypertension. These results indicate that recombinant human HGF possibly has a great potential for improving symptoms and altering the clinical course of pulmonary arterial hypertension.

Aortic valve replacement for aortic regurgitation in a patient with left ventricular noncompaction.

We present a case of a 61-year-old man who underwent aortic valve replacement for aortic regurgitation complicated with left ventricular noncompaction. The pathogenesis of this condition remains unknown. In advanced form, left ventricular noncompaction produces marked disability and carries a poor prognosis. We underscore that familiarity with this disease entity will help to stimulate early diagnosis and timely treatment when necessary.

Predictor of underlying myocardial damage in normally functioning left ventricle with narrow QRS complex: relationship between QRS duration at right ventricle pacing and iodine-123 metaiodobenzylguanidine myocardial scintigraphy.

OBJECTIVE: Washout rate of iodine-123 metaiodobenzylguanidine (MIBG) myocardial scintigraphy is correlated with the degree of myocardial damage. The aim of this study is to ascertain whether there is any relationship between QRS complex duration at right ventricle (RV) pacing and the degree of myocardial damage assessed by I-123 MIBG myocardial scintigraphy in normally functioning left ventricle. METHODS: The study included 22 patients (10 men and 12 women, ranging in age from 48 to 89 years), with atrioventricular (AV) block (n = 15) and sick sinus syndrome (n = 7). All patients had baseline QRS duration of less than 120 ms and received implantation of a DDD-mode permanent pacemaker. Iodine-123 MIBG myocardial scintigraphy was performed before the pacemaker implantation, and QRS duration at RV pacing at a rate of 70 ppm was calculated immediately after the implantation. RESULTS: With the use of RV pacing, QRS duration was prolonged ranging from 122.4 to 185.6 ms with a mean of 153.2 +/- 15.2 ms. Washout rate of I-123 MIBG myocardial scintigraphy (WR) was calculated as ranging from 5.0 to 83.0% with a mean of 44.2 +/- 17.5%. There was a strong correlation between WR and QRS duration at RV pacing (r = 0.735, p < 0.001). CONCLUSIONS: It was confirmed that WR of I-123 MIBG was correlated positively with QRS duration at RV pacing. Measurement of QRS duration may be helpful to evaluate the degree of underlying myocardial damage even in the normally functioning left ventricle.

Relationship between weather and onset of acute myocardial infarction: can days of frequent onset be predicted?

BACKGROUND: The aim of this study was to clarify the relationship between onset of acute myocardial infarction (AMI) and weather conditions, to determine whether days in which AMI onset is likely can be predicted. METHODS AND RESULTS: Of the 929 patients admitted to our hospitals in Kagoshima prefecture with AMI, subjects comprised 611 patients. Days of frequent onset (F-days) were defined as days with > or = 3 patients/day admitted for AMI, with days of non-frequent onset (N-days) defined as days with < 3 patients/day. Meteorological factors were measured, and daily differences in all parameters and intraday temperature differences on the onset day, and 1 and 2 days before onset were calculated. F-days were significantly associated with intraday temperature differences on the onset day (10.3 degrees C vs. 7.9 degrees C, p=0.005), 1 day before onset (10.7 degrees C vs. 7.9 degrees C, p=0.002), and 2 days before onset (11.3 degrees C vs. 7.9 degrees C, p=0.0001). A cutoff intraday temperature difference of > or = 9.4 degrees C on 1 and 2 days before onset was predictive of F-days with 89% sensitivity and 87% specificity. CONCLUSIONS: Intraday temperature differences offer a powerful predictor of F-days. Onset of AMI can be predicted based on weather conditions over the preceding 1-2 days.

Rupture of the left atrial 'basal' appendage due to blunt trauma in an elderly patient.

Blunt traumatic cardiac rupture is associated with a high mortality rate. Motor vehicle accidents account for most cardiac ruptures, but crush injury is relatively rare. We describe a case of a 77-year-old man who had the left atrial 'basal' appendage ruptured through blunt trauma due to a fall. He was surgically treated and recovered without complication.

Progressive congestive heart failure due to common iliac arteriovenous fistula: a case report.

Arteriovenous shunt is one of the causes of heart failure, but heart failure caused by common iliac arteriovenous fistula is relatively rare. A 64-year-old man who developed acute heart failure due to venous perforation of a common iliac aneurysm and also had bilateral aneurysms (diameter 58 mm) was referred to our department. On admission, the patient complained of dyspnea and swollen left leg, so diuretic agent was administered to treat the heart failure. Cardiac catheterization showed a shunt rate of 80.6%, as well as 5.0 Qp/Qs and O2 step-up across perforation of the common iliac vein. Despite the therapy, pleural effusion and ascites exacerbated, and the heart failure became difficult to control, so surgical treatment was performed. The aneurysm was replaced with an artificial vessel, and the fistula was closed by direct suturing. Postoperatively, the symptoms disappeared, and the patient is in good health.

Recurrent pericardial tamponade from atrial hemangioma.

We encountered a 72-year-old woman with a left atrial hemangioma arising in the appendage and growing like an extracardiac mass. Life-threatening cardiac tamponade, recurrent over a 5-year clinical course, was the only sign of this rare tumor. The extraatrial growth pattern of the tumor made it difficult to distinguish the cardiac origin from a paracardiac mass. With the aid of cardiopulmonary bypass, the tumor was removed from the left atrium at the base of the appendage. Pathologic diagnosis was a combination of cavernous- and venous-type hemangioma. The postoperative course was uneventful, and the patient was doing well with no pericardial effusion at the 10-month follow-up.

C-reactive protein and atrial fibrillation. Is inflammation a consequence or a cause of atrial fibrillation?

To clarify whether inflammation is a cause or consequence of atrial fibrillation (AF), we measured high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-alpha) before and after pharmacological cardioversion in 15 patients with paroxysmal AF. Levels of hs-CRP, IL-6, and TNF-alpha after cardioversion were significantly higher than those in controls (P < 0.05). Furthermore, the levels of these indices did not differ significantly even at 24 hours and 2 weeks after cardioversion. These results suggest that inflammation is a causative agent of paroxymal AF.

Effectiveness of angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker on atrial natriuretic peptide.

The aim of this study was to evaluate the effectiveness of an angiotensin-converting enzyne inhibitor (ACEI, quinapril) or angiotensin II receptor blocker (ARB, candesartan) on atrial natriuretic peptide (ANP) activity in rats with hypertension induced by nitric oxide (NO) inhibition. ACEI and ARB have a number of pharmacologic effects, including blood pressure reduction, myocardial preservation, and an unknown effect in the circulation. The changes in ANP in NO inhibitor-induced hypertensive rats were evaluated in order to elucidate the interaction between ANP and NO in the regulation of blood pressure. Thirty-six rats were divided into 4 groups and administered the experimental agents for 8 weeks: group CONTROL was given regular food (n=9), group N(G)-nitro-L-arginine (L-NNA) was administered L-NNA (25 mg. kg(-1). day(-1), n=9), group ACEI was administered L-NNA and quinapril (10 mg. kg(-1). day(-1), n=9), and group ARB was administered L-NNA and candesartan (10 mg. kg(-1). day(-1), n=9). Blood pressure, plasma ANP, atrial ANP, ANP mRNA, and ANP granules were measured. A significant elevation in blood pressure was observed in group L-NNA. However, there were no increases in plasma ANP (L-NNA: 138.8+/-64.4, CONTROL: 86.7+/-36.4), ANP mRNA (L-NNA: 2.2+/-1.0, CONTROL: 1.7+/-0.5) or ANP granules (L-NNA: 61.1+/-10.2, CONTROL: 64.5+/-8.5). No increase in blood pressure was seen in groups ACEI and ARB. However, plasma ANP (ACEI: 1,392.3+/-1,034.4, ARB: 1,142.8+/-667.3), ANP mRNA (ACEI: 52.8+/-29.1, ARB: 42.9+/-21.2), and ANP granules (ACEI: 122.5+/-23.4, ARB: 136.3+/-33.2) increased significantly. NO inhibitor-induced hypertension caused no changes in ANP concentrations. However, the ACEI and ARB had a direct effect on the induction of ANP secretion. The findings suggest that ANP secretion is directly effected by ACEI and ARB, which seems to play a key role in lowering blood pressure, relieving heart failure symptoms, and preserving the myocardium.