Masataka Nasu

Value of plasma B type natriuretic peptide measurement for heart disease screening in a Japanese population

Background: Conflict exists regarding the usefulness of measuring plasma B type natriuretic peptide (BNP) concentrations for identifying impaired left ventricular (LV) systolic function during mass screening. Various cardiac abnormalities, regardless of degree of LV dysfunction, are prone to carry a high risk of cardiovascular events. Objective: To examine the validity of plasma BNP measurement for detection of various cardiac abnormalities in a population with a low prevalence of coronary heart disease and LV systolic dysfunction. Design and setting: Participants in this cross sectional study attended a health screening programme in Iwate, northern Japan. Plasma BNP concentrations were determined in 1098 consecutive subjects (mean age 56 years) by direct radioimmunoassay. All subjects underwent multiphasic health checkups including physical examination, ECG, chest radiography, and transthoracic echocardiography. Results: Conventional diagnostic methods showed 39 subjects to have a wide range of cardiac abnormalities: lone atrial fibrillation or flutter in 11; previous myocardial infarction in seven; valvar heart disease in seven; hypertensive heart disease in six; cardiomyopathy in six; atrial septal defect in one; and cor pulmonale in one. No subjects had a low LV ejection fraction (< 40%). To assess the utility of plasma BNP measurement for identification of such patients, receiver operating characteristic analysis was performed. The optimal threshold for identification was a BNP concentration of 50 pg/ml with sensitivity of 89.7% and specificity of 95.7%. The area under the receiver operating characteristic curve was 0.970. The positive and negative predictive values at the cutoff level were 44.3% and 99.6%, respectively. Conclusion: Measurement of plasma BNP concentration is a very efficient and cost effective mass screening technique for identifying patients with various cardiac abnormalities regardless of aetiology and degree of LV systolic dysfunction that can potentially develop into obvious heart failure and carry a high risk of a cardiovascular event.

Electrocardiographic nature of restored sinus rhythm after Cox maze procedure in patients with chronic atrial fibrillation who also had other cardiac surgery.

OBJECTIVE: To characterise heart rate variability and high frequency components of restored sinus rhythm after the maze procedure. The maze procedure for chronic atrial fibrillation may prevent thrombotic events and improve the quality of life. However, the electrocardiographic nature of restored sinus rhythm after the maze procedure has not been fully elucidated. PATIENTS AND METHODS: Between March 1993 and August 1995, 104 consecutive patients undergoing the maze procedure in combination with other cardiac surgery were studied. There were 100 long-term survivors (78 with mitral valve disease, 9 with aortic valve disease, 8 with congenital heart disease, and 5 others). Twenty age-matched patients with mitral valve disease who were in normal sinus rhythm preoperatively were enrolled as a control group. 30 days after surgery, the presence of arrhythmias and the circadian changes of heart rate variability were estimated by ambulatory electrocardiographic monitoring and the filtered P duration was evaluated by signal-averaged electrocardiogram. RESULTS: Restoration of sinus rhythm was observed in 73 of 100 cases. Subjects were classified into three groups according to their postoperative ambulatory electro-cardiographic monitoring findings: patients in group 1 (n = 73) (1a: 58 regular sinus rhythm; 1b: 15 sinus rhythm with frequent premature atrial contractions (> 1000/day); patients in group 2 (n = 21) still had persistent atrial fibrillation; and patients in group 3 (n = 6) required permanent pacemaker implantation because of sick sinus syndrome. The success rate of restoration of sinus rhythm was 88.3% if left atrial diameter was small (< 65 mm). Circadian changes in the low frequency to high frequency power ratio in group 1a were significantly diminished compared with control group (P < 0.01). Furthermore, the filtered P duration in group 1a (150 (20) ms) and group 1b (158 (23) ms) were longer than in the control group (122 (11) ms) (P < 0.01). CONCLUSIONS: The maze procedure may result in a decreased sinus response and non-uniform transmission of impulses in the atrium.

Aortic valve repair in dominant aortic regurgitation.

OBJECTIVE We studied immediate and mid-term results after aortic valve repair. METHODS Immediate and mid-term results were studied in 63 patients undergoing aortic valve repair, calculating survival and reoperation free rates. RESULTS Subjects were 49 men and 14 women aged 15 to 76 years (mean: 53 +/- 17 years). Mean preoperative aortic regurgitation grading of 1 to 4 was 3.2 +/- 0.7. Mean preoperative New York Heart Association functional class was 1.9 +/- 0.8. Two in-hospital deaths occurred. (3.2%) Mean aortic regurgitation grade at discharge was 1.3 +/- 0.8 (p < 0.0001; vs preoperative grade) and functional class was 1.1 +/- 0.2 (p < 0.0001; vs preoperative class),--significantly improved. Overall follow-up was 98.4%, and mean follow-up continued 41.4 +/- 22.1 months. Mean functional class at follow-up was 1.2 +/- 0.4 (n = 49), improved from preoperative class (p < 0.0001). Mean aortic regurgitation grading at follow-up was 1.8 +/- 0.8 (n = 41), improved from preoperative grading (p < 0.0001). Five-year survival was 95.1 +/- 2.8%. One-year reoperation freedom was 96.6 +/- 2.4% and 5-year 77.9 +/- 6.9%. CONCLUSIONS Survival after surgery was good, while reoperation was comparable to other reports but less satisfactory compared to reoperation freedom after aortic valve replacement. Based on reoperative findings, a change in indication was made. We believe technical refinements could improve postoperative results.

Recovery of atrial function after combined treatment with surgical repair for organic heart disease and maze procedure for atrial fibrillation

The maze procedure, a new surgical treatment for lone atrial fibrillation, was initially described by Cox and associates. 1 Recently, combined treatment for organic heart disease and atrial fibrillation has been reported, hut there have been few studies on atrial activity after combined treatment with surgical repair for organic heart disease and the maze procedure for atrial fibrillation. It is important to know how well atrial function recovers after combined surgical methods. Therefore we investigated the recovery of atrial funetion after the combined surgical treatment of organic heart disease and atrial fibrillation. Methods. Twelve patients who received cardiac operation with a successful maze procedure were enrolled in this study. The patients consisted of four men and eight women, with a mean age of 60 _+ 11 years. Organic heart diseases were mitral stenosis in two patients, mitral regurgitation in eight, and atrial septal defect in two. All patients underwent symptom-limited cardiopulmonary exercise testing with use of an upright bicycle ergometer with measurements of atrial natriuretic peptide (ANP) before and after exercise testing and Doppler echocardiography 1 week before the operation (control phase), 1 month after the operation (early phase), and 3 months after the operation (late phase). Ventilatory threshold was determined in a standard manner by the V-slope method. Peak velocities of the early filling (E) wave, atrial filling (A) wave, and A/E ratio were determined by Doppler echocardiography. The timevelocity integrals of the E (Ea) and A (Aa) waves were then obtained by planimetry of the flow velocity profile. Left atrial active contractile fraction (LAACF) was expressed as the ratio of the atrial component during active atrial contraction (Aa) to the total diastolic time velocity integral (Ea + Aa) and calculated as LAACF = Aa/(Ea + Aa).

Noninvasive Measurement of Left Coronary Blood Flow Reserve by Transthoracic Doppler Echocardiography: Comparison with Doppler Guidewire Ultrasonography.

The development of new ultrasound instrumentation has made epicardial coronary artery blood flow imaging easier with the use of transthoracic coronary Doppler echocardiography (TCDE). This study was performed to investigate the accuracy of coronary blood flow reserve (CFR) measurement by TCDE. In 15 patients with ischemic heart disease in the absence of valvular disease or atrial fibrillation, coronary flow at rest and flow with hyperemia induced by intravenous dipyridamole infusion were recorded by TCDE and Doppler guidewire ultrasonography. The CFR was determined as the ratio of the maximum hyperemic diastolic time‐averaged peak velocity to the velocity at rest in the proximal or distal left anterior descending coronary artery. It was found that the CFR of the left anterior descending coronary artery measured by TCDE was comparable in accuracy with CFR measured by invasive methods (r = 0.87, P < 0.0001, n = 15).

Left coronary artery ostial stenosis from Takayasu’s arteritis diagnosed using transthoracic color flow and pulsed Doppler echocardiography

Coronary artery stenosis is seen in 10–45% of patients with Takayasu’s arteritis (TA) and coronary ostia are most frequently involved. It may cause angina pectoris and sudden death during the early course of the disease. We describe a 14-year-old girl who first presented with exertional angina and syncope and was diagnosed as having left coronary artery ostial stenosis from TA by using transthoracic echocardiography. This is the first report showing the important role of color flow and pulsed Doppler echocardiography to detect coronary artery stenosis caused by TA.