Relation of Chlamydia pneumoniae infection in Taiwan to angiographically demonstrated coronary artery disease and to the presence of acute myocardial infarction or unstable angina pectoris

Reports of the association of Chlamydia pneumoniae (C. pneumoniae) infection with coronary artery disease (CAD) are scarce in the Oriental population. We therefore conducted a case-control study to explore this issue in Taiwan. There were 242 consecutive subjects (166 men and 76 women) who underwent cardiac catheterization at the National Taiwan University Hospital Cardiac Catheterization Laboratory. Patients with CAD (n = 156) had > or = 1 coronary artery lesion of > 50% diameter stenosis on angiography. Controls (n = 86) had no demonstrable CAD angiographically. Antibodies to C. pneumoniae were tested by using an enzyme-linked immunosorbent assay. The prevalence of antibodies to C. pneumoniae was as follows: immunoglobulin-G (IgG), 50% (122 of 242 patients); immunoglobulin-A (IgA), 72% (176 of 242 patients); and either IgG or IgA, 79% (192 of 242 patients ). The odds ratio (OR) for CAD with either IgG or IgA was 1.4 (95% confidence interval [CI] 0.7 to 2.7, p = 0.31). After adjusting for the known CAD risk factors, the OR decreased to 0.8 (95% CI 0.3 to 2.1, p = 0.60). The OR for unstable angina or acute myocardial infarction with the presence of either IgG or IgA was 0.5 (95% CI 0.2 to 1.1, p = 0.08) and 0.4 ( 95% CI 0.1 to 1.0, p = 0.049) after adjusting for other risk factors. These results suggest a high prevalence of C. pneumoniae infection in Taiwan. However, C. pneumoniae infection is not associated with angiographically documented CAD, and, in contrast, is a negative predictor for the development of acute coronary syndromes.

Differential lipogenic effects of cilostazol and pentoxifylline in patients with intermittent claudication: potential role for interleukin-6

Cilostazol, a novel oral phosphodiesterase inhibitor, has shown consistent improvement in exercise tolerance in patients with intermittent claudication (IC). In addition to this effect, cilostazol has previously been shown to have beneficial effects on the dyslipidemia, i.e., combination of high triglycerides with low high-density-lipoprotein cholesterol (HDL-C) levels. Interleukin-6 (IL-6) suppresses the activity of lipoprotein lipase, which modulates the metabolism of triglycerides and HDL-C. To determine whether a reduction of IL-6 contributes to the improvement of lipid profiles, we prospectively investigated the effect of cilostazol (n=16, 100 mg, twice daily) on the changes of lipid profiles and on the association with the changes of IL-6 compared with those of pentoxifylline (n=16, 400 mg, bid) in patients with IC. After eight weeks of administration of cilostazol to patients with IC, walking distances were increased, associated with a 29% decrease in plasma triglycerides and a 13% increase in HDL-C. No significant changes of lipid profiles in the pentoxifylline and placebo groups were observed although a similar improvement in walking distances was achieved in the pentoxifylline group. IL-6 levels were significantly reduced in patients receiving cilostazol as compared with those receiving placebo or pentoxifylline. The cilostazol-induced changes in the IL-6 were positively related to those of triglycerides in the cilostazol group (r=0.63, P<0.05) and negatively related to those of HDL-C (r=-0.55, P<0.05). These findings suggest that in addition to consistent improvement of exercise tolerance, cilostazol may improve lipid profiles by reducing IL-6 release. However, pentoxifylline did not affect lipid profiles although a similar improvement of maximal walking distance (MWD) was achieved.

Expression pattern in a modified equalized kidney cDNA library of hypertensive rat

BACKGROUND

Genes with important functions and rarely expressed would probably more easily be cloned from a modified equalized kidney cDNA library for further investigation.

METHODS

A kidney cDNA library of a spontaneously hypertensive rat was synthesized by a modified equalization method. Inserts of random clones were amplified by PCR and sequenced. Sequences were compared against a nonredundant database in GenBank. The cDNA profile was compared with an expression profile of a mouse renal proximal tubule cDNA library. Seven clones were analyzed by Northern blot analysis. The cDNA ends of two novel genes were amplified by PCR, sequenced and analyzed.

RESULTS

336 cDNA clones were analyzed and grouped into 323 species of transcript with 77 species similar to previously reported genes. Northern blot analysis identified one kidney-specific, one rarely expressed and lung-specific, and another relatively testis-specific gene. Two novel genes were cloned. One was 4.1 kb in length and encoded a 390-amino acid zinc-finger protein. Another was 2.5 kb and encoded a 474-amino acid protein of unknown function. Compared with the expression profile of a mouse renal proximal tubule cDNA library, this kidney library had a lower proportion of ribosomal genes and had a greater proportion of genes for signal transduction and DNA or RNA binding.

CONCLUSIONS

Rare or novel genes could be more easily isolated from this library for molecular study of hypertension and renal pathophysiology.

Ultrasonic tissue characterization evaluates myocardial viability and ischemia in patients with coronary artery disease

To evaluate whether or not ultrasonic tissue characterization (UTC) can detect jeopardized or salvageable myocardium in patients having chronic coronary artery disease, we studied 103 patients with sequential UTC, dobutamine stress echocardiography (DSE) and (201)thallium stress-reinjection single-photon emission computed tomography (T1-SPECT). This revealed that the weighted amplitude of the cyclic modulation of integrated backscatter was larger for the myocardium with less ischemia burden or greater viability (p<0.001). The segments with larger ischemia burden or the nonviable myocardium demonstrated the contrary result. Using the receiver-operating characteristic curve analyses to determine the cutoff value of weighted amplitude for various predictions, UTC can detect ischemia in normokinetic myocardium (kappa = 0.34 compared to DSE or T1-SPECT) and viability in dyssynergic myocardium (kappa = 0.57 compared to DSE and 0.45, to T1-SPECT). These observations show that UTC may prove useful in the identification and pathophysiological understanding of myocardial ischemia and viability.

Cloning a novel metallophosphoesterase gene from a kidney cDNA library of hypertensive rat

BACKGROUND AND PURPOSE

Genetic and environmental factors may contribute to the pathogenesis of essential hypertension. To facilitate genetic studies of hypertension and renal disorders, we sought to clone novel genes from a modified, equalized kidney (MEK) cDNA library of a spontaneously hypertensive rat (SHR).

METHODS

A kidney cDNA library of an SHR was synthesized using the modified equalization method. Inserts of 350 random clones were amplified by polymerase chain reaction (PCR) and sequenced, of which 246 were presumably unknown after being compared against a nonredundant database in the GenBank. The cDNA ends of clone 38S were obtained by rapid amplification of cDNA ends, sequenced, and then analyzed with Translate, Prosite, Profile, SignalP, and TMpred programs.

RESULTS

The full-length cDNA was 938 bp, and translated into a 182-amino acid protein. The deduced protein had a metallophosphoesterase domain, a signal peptide at its amino end, a protein kinase C phosphorylation site, and a transmembrane domain. Northern blot analysis revealed that this gene was expressed in the heart, brain, spleen, lungs, liver, skeletal muscles, kidneys and testes of Sprague-Dawley rats. A putative protein of Arabidopsis thaliana shares 62% homology with protein 38S, but the two proteins differ in terms of function and structure.

CONCLUSIONS

Our results support that protein 38S is a novel membrane metallophosphoesterase, although its function in the kidneys remains to be elucidated. This study also demonstrates the feasibility of using PCR to clone novel genes from our MEK cDNA library.

A novel effect of cyclic AMP on capacitative Ca2+ entry in cultured rat cerebellar astrocytes

One of the most important intracellular Ca2+ regulatory mechanisms in nonexcitable cells, "capacitative Ca2+ entry" (CCE), has not been adequately studied in astrocytes. We therefore investigated whether CCE exists in cultured rat cerebellar astrocytes and studied the roles of cyclic AMP (cAMP) and protein kinase C (PKC) in CCE. We found that (1) at least two different intracellular Ca2+ stores, the endoplasmic reticulum and mitochondria, are present in cerebellar astrocytes; (2) CCE does exist in these cells and can be inhibited by Ni2+, miconazole, and SKF 96365; (3) CCE can be directly enhanced by an increase in intracellular cAMP, as 8-bromoadenosine 3',5'-cyclic monophosphate (8-brcAMP), forskolin, and isobutylmethylxanthine have stimulatory effects on CCE; and (4) neither of the two potent protein kinase A (PKA) inhibitors, H8 and H89, nor a specific PKA agonist, Sp-adenosine 3',5'-cyclic monophosphothioate, had a significant effect on cAMP-enhanced Ca2+ entry. The [Ca2+]i increase was not due to a release from calcium stores, hyperpolarization of the membrane potential, inhibition of calcium extrusion, or a change in pHi, suggesting that cAMP itself probably acts as a novel messenger to modulate CCE. We also conclude that activation of PKC results in an increase in CCE. cAMP and PKC seem to modulate CCE by different pathways.

Characteristic findings of body surface potential map during ventricular repolarization in patients with coronary heart disease

The objective of the present study was to investigate the characteristics of body surface potential map (BSPM) findings during ventricular repolarization in patients with coronary artery disease (CAD). A total of 108 consecutive patients, 99 men and 9 women with angina pectoris and positive treadmill exercise test results as well as angiographically documented CAD underwent BSPM study in a fasting state. Their ages ranged from 30 to 70 years. There were 13 patients with right coronary artery (RCA) lesions, 37 with left anterior descending artery (LAD) lesions, 5 with left circumflex artery (LCX) lesions, 17 with both RCA and LAD lesions, 12 with both LCX and LAD lesions, and 24 with 3-vessel disease. The BSPMs were obtained by using the heart potential map system designed by Toyama et al. There were 59 lead points on the anterior chest wall and 28 on the back. The BSPMs in isopotential distribution were made every one msec throughout the ventricular activation period. The distribution of positive and negative potentials, potential maximum and potential minimum, polarity of potential distribution, and the reversal of potential distribution during ventricular repolarization were analyzed. The following information on BSPMs was obtained: (1) In early ventricular repolarization, the negative potential and the potential minimum appeared abnormally on the anterior thorax. The potential abnormality displayed on the right portion or the inferior portion in patients with RCA lesions, on the middle portion or the left portion in patients with LAD lesions, and on the left-superior portion or the left-middle portion in patients with LCX lesions. In patients with multi-vessel disease, the abnormal potential distribution showed a combined pattern of individual vessel lesions. (2) In some cases, the multipolar potential distribution appeared abnormally during the initial stage and the peak of the T wave. (3) The reversal of potential distribution was observed in about half of the patients. The characteristic findings of the BSPM during ventricular repolarization, including abnormal potential distribution, multipolar potential distribution and reversal of potential distribution, will be of clinical value in patients with CAD.

Electrophysiologic study and radiofrequency catheter ablation of isthmus-independent atrial flutter

INTRODUCTION

We report the electrophysiologic study and radiofrequency catheter ablation of isthmus-independent atrial flutter in 2 patients. The isthmus-independent atrial flutter in these 2 patients had similar ECG and electrophysiologic findings. Both were reproducibly induced by rapid atrial pacing. The atrial activation sequence and entrainment study proved that these atrial flutters were not isthmus-dependent. A high-right atrial site was identified as the critical site of the slow conduction zone of the tachycardia in both. This site showed double potentials and mid-diastolic potentials. Radiofrequency catheter ablation at this site successfully eliminated the isthmus-independent atrial flutter in both patients.

Implications of an early reversal pattern of body surface potential maps in coronary artery disease

During early ventricular depolarization, the normal body surface potential map (BSPM) has a maximal potential that is greater than the absolute value of the minimal potential; this reverses in late depolarization, so that the absolute value of the minimal potential is greater. Nevertheless, an abnormal "early reversal" BSPM pattern has been observed in some patients with cardiovascular disease. To investigate the implications of this abnormal pattern, BSPMs were studied in 100 patients with angiographically proven coronary artery disease (CAD). There were 57 patients (57%; group A) with an abnormal early reversal pattern and 43 (43%; group B) without this early reversal pattern. A significant (> 70% narrowing) CAD lesion was observed in a significantly higher proportion of group A (97%) than group B (77%) patients, although the number of involved coronary arteries was not significantly different between the two groups. The maximal extent of the abnormal negative potential was significantly greater in group A (21.2 +/- 9.6 cm2) than in group B (12.2 +/- 7.5 cm2). The abnormal negative potential lasted significantly longer in group A (22.1 +/- 12.1 msec) than in group B (14.4 +/- 9.2 msec). Similarly, the minimal potential lasted significantly longer in group A (20.1 +/- 11.3 msec) than in group B (11.8 +/- 7.1 msec). These findings suggest that the abnormal early reversal BSPM pattern is a valuable indicator of extensive myocardial lesions and the severity of CAD.

Impaired cardiac performance relating to delayed left atrial activation after atrial compartment operation for chronic atrial fibrillation

In the presence of a normal atrial systole and optimal AV delay, atrial kick contributes to a significant fraction of the stroke volume. This atrial contribution may be lost during atrial asystole or mismatch in the timing of atrial and ventricular contraction. A patient received atrial compartment operation for his chronic AF. Although the AF was successfully converted to sinus rhythm, the conduction from the right to left atrium was markedly delayed so that the left atrial and ventricular activations occurred almost simultaneously. This delay in left atrial activation resulted in impaired cardiac performance.

Q-T interval prolongation and pleomorphic ventricular tachyarrhythmia ('Torsade de pointes') in organophosphate poisoning: report of a case

1. A 63-year-old woman presented with drowsy consciousness and dyspnea, followed by respiratory failure, after taking a bottle of parathion for suicide. 2. Sinus tachycardia was noted initially by ECG and Q-T interval prolongation with pleomorphic ventricular tachyarrhythmia ('Torsade de pointes') occurred on the third day of admission. 3. Torsade de pointes was relieved by magnesium sulfate and atropine sulfate intravenously. Q-T interval returned to normal on the fifth day of admission. 4. Practicing physicians should be aware of this uncommon type of cardiac toxicity caused by organophosphate poisoning, Q-T interval prolongation and pleomorphic ventricular tachyarrhythmia.

The use of body surface potential map for identifying sites of accessory pathway in patients with Wolff-Parkinson-White syndrome

The body surface potential map (BSPM) may reflect regional myocardial electrical activity. This technique can thus provide information regarding the excitation of ventricles. This study is an attempt to evaluate the usefulness of BSPM in determining the sites of the atrioventricular (AV) accessory pathway (AP) in patients with Wolff-Parkinson-White (W-P-W) syndrome. The BSPMs were obtained from 40 consecutive patients with W-P-W syndrome in a fasting state, using the heart potential map system designed by Toyama et al. Unipolar electrocardiograms were recorded simultaneously from 87 lead points on the chest surface, including 59 lead points on the anterior chest and 28 on the back. Wilson's central terminal was used as a voltage reference and BSPMs in an isopotential distribution pattern were made every millisecond throughout ventricular activation from these unipolar ECGs with the use of a microcomputer system. All patients underwent an electrophysiologic study (EPS) at cardiac catheterization. We analyzed the potential distribution during ventricular depolarization and compared the results between EPS and BSPM findings. The following results were obtained: (1) seven types of BSPM pattern were identified in accordance with the sites of the AV AP confirmed by EPS; (2) the location of the potential minimum of ventricular depolarization and the direction of the excitation wavefront during early ventricular depolarization, the reversal pattern of ventricular potential distribution, the epicardial right ventricular breakthrough and the dynamic change of ventricular potential distribution were useful for the detection of the ventricular pre-excitation site; (3) epicardial right ventricular breakthrough occurred in nearly all patients with left ventricular free wall accessory AV connections; (4) the abnormal early reversal pattern of ventricular potential distribution did not occur in patients with left ventricular AV connections but did appear in most patients with right ventricular free wall AV connections. Accordingly, BSPM is a reliable non-invasive procedure to determine the ventricular pre-excitation sites of patients with W-P-W syndrome.

Percutaneous balloon pericardiotomy for patients with recurrent pericardial effusion: using a novel double-balloon technique with one long and one short balloon

Percutaneous balloon pericardiotomy is effective and less invasive for the treatment of recurrent pericardial effusion. This study suggests that the double-balloon method with 1 longer and 1 shorter balloon is the procedure of choice for percutaneous balloon pericardiotomy.

Electrophysiological properties in patients undergoing atrial compartment operation for chronic atrial fibrillation with mitral valve disease

AIMS

Surgical treatment for atrial fibrillation is now feasible in selective cases. The aim of this study was to assess the electrophysiological properties of patients undergoing atrial compartment operation for chronic atrial fibrillation.

METHODS AND RESULTS

Electrophysiological studies were performed in 20 mitral valve patients with atrial fibrillation who had been maintained in sinus rhythm for more than 1 year after atrial compartment operation. Intra-cardiac recording and programmed electrical stimulation were performed in various atrial compartments. The parameters studied included sinus node function, atrial conduction and refractoriness, atrioventricular conduction function and inducible arrhythmias if any. Intra-cardiac recordings showed that the rhythm was of sinus origin in all cases, with the earliest atrial activity located in the high right atrium. The mean sinus cycle length was 750 +/- 110 ms, AH time 106 +/- 29 ms, and HV time 53 +/- 7 ms. The sinus node function was normal in 18 patients (90%), and only two patients had prolonged sinus node recovery and sino-atrial conduction. The right atrial appendage compartment was driven by the sinus node in all patients. However, the conduction time from the high right atrium to the right atrial appendage compartment was markedly prolonged in 12 of 15 patients (80%) undergoing the three-compartment operation in which an incision was placed between the high right atrium and right atrial appendage compartments. On the other hand, the electrical activities in the left atrial compartment were much more varied. In 13 of 20 patients (65%), the left atrial compartment was driven by the sinus node; 11 of the 13 patients had a normal or mildly prolonged conduction time (ranged 75 to 146 ms), whereas two patients had a marked delay in conduction (200 ms and 266 ms, respectively). In the remaining seven patients, the left atrial compartments were dissociated from the rest of the heart; five of them had a quiescent left atrium, one a fluttering left atrial rhythm, and one a slow left atrial rhythm. The effective refractory period was longer in the left atrial compartment (242 +/- 47 ms) as compared to that of the high right atrium (224 +/- 26 ms, P < 0.01) and right atrial appendage compartments (219 +/- 25 ms, P < 0.01). Programmed electrical stimulation could not induce atrial fibrillation in any patient, whereas two patients had inducible atrial flutter and three repetitive atrial responses.

CONCLUSIONS

(1) Atrial compartment operation does not impair sinus node function in most cases. (2) Elimination of atrial fibrillation while maintaining the electrical connection between different atrial compartments is feasible.

Abnormal circadian blood pressure changes in patients with acute cerebrovascular disorders

The central neural mechanisms of circadian rhythm are well known in animal models but less so in humans. In this study we looked for correlations between abnormalities of circadian rhythm and the sites of stroke, with the aim of identifying the location regulating the circadian rhythm in humans. We investigated the circadian profiles of arterial pressure in 100 stroke patients by ambulatory blood pressure monitoring within 2 days after their first stroke. Patients also underwent brain computed tomography and measurements of plasma norepinephrine and adrenal hormones. A total of 52 patients (group A) had abnormal patterns of circadian blood pressure rhythm while 48 patients had normal patterns (group N). The risk of an abnormal 24-hour blood pressure pattern was strongly inversely correlated with the distance between the lesion and the hypothalamus. There was also a close positive correlation between the distance from the lesion to the hypothalamus and the circadian indices of arterial blood pressure (systolic and diastolic pressure) in both groups. Abnormal circadian changes in adrenal hormones were found in 30 of 52 patients in group A, and in nine of 48 patients in group N. Apparently, the circadian rhythm of blood pressure is modulated mainly by direct neural effects and partly by the hormonal effects of the hypothalamus and its associated neural pathways. Individualized antihypertensive treatment and additional monitoring for possible cardiac events should be performed for those at a high risk of autonomic dysfunction.

Myocardial mechanics and titin in experimental insulin-resistant rats

We investigated the intrinsic cardiac mechanics of myocardium and changes in titin in insulin-resistant rats. Microsonometry and micromanometry were used to evaluate the maximal elastance (Emax) and myocardial stiffness constant (Km) of the left ventricle, in addition to the traditional systolic and diastolic cardiac function, with an isolated working heart preparation. Thirty 150 g Wistar rats were divided into three groups of 10. Group A was fed rat chow, while groups B and C were fed a 66% fructose diet for 7-8 months. Group C also received clonidine. Group B rats developed insulin resistance, as well as elevated plasma glucose and blood pressure. Group C rats also had insulin resistance and elevated plasma glucose, but not higher blood pressure. Group B rats had decreased Emax, decreased peak-dp/dt, prolonged Tau and increased Km compared to normal control rats. Group C rats, which mimicked the clinical condition of diabetic cardiomyopathy, maintained normal global left ventricular function as revealed by cardiac output, peak + dp/dt, peak-dp/dt and Tau of relaxation. However, they had a lower Emax slope (355 +/- 51 vs 535 +/- 56 mmHg.mm than group A rats, p < 0.05) and increased Km (81.6 +/- 9.9 vs 25.5 +/- 4.8 in group A, p < 0.001), even though the extent of elevation of plasma glucose was only mild (71.3 +/- 2.0 to 108.9 +/- 4.4 mg/dl, p < 0.001). Their left ventricular mass, myocyte size, interstitial fibrosis and vascular picture did not change. However, the content of myocardial titin decreased significantly (intensity ratio of titin/actin was 0.23 +/- 0.01 and 0.29 +/- 0.02 in group C and group A rats respectively, p < 0.05). These findings suggest that changes in titin play a role in the change in myocardial functional characteristics and may be one of the causes of diabetic cardiomyopathy.

Cardiac contractility in noninsulin dependent diabetes mellitus evaluated using the relation between endsystolic wall stress and velocity of circumferential fiber shortening

The relation between left ventricular (LV) endsystolic wall stress (sigma es) and rate-corrected velocity of circumferential fiber shortening (Vcfc), which is independent of heart rate (HR) and loading conditions has previously been used to assess cardiac contractility in insulin dependent diabetes mellitus (IDDM). This study is the first report in which this relation has been utilized with data obtained by echocardiography in addition to the traditional indices, to evaluate the cardiac function in asymptomatic, middle-aged patients with noninsulin dependent diabetes mellitus (NIDDM) at baseline and during dobutamine stimulation. There were 16 NIDDM patients in our study and these patients were classified into 2 groups. Group 1 consisted of 11 patients without microvascular complications. Group 2 consisted of the remaining 5 patients with microvascular complications. Ten age- and sex-matched normal subjects were enrolled as a control group. At baseline, diabetic patients tended to have a faster HR and a greater LV enddiastolic dimension, though these values were not significantly different from the normal subjects. Ejection fraction (EF) in group 1 was significantly higher than that of the normal controls (73 +/- 2% vs 65 +/- 2%, p < 0.005). Mitral inflow pattern was normal (E/A > 1) in the normal subjects (1.11 +/- 0.06), but reversed in group 1 (0.87 +/- 0.07) and group 2 (0.95 +/- 0.12). Isovolumic relaxation time corrected for HR (IVRTc) and the slope of relation between sigma es and Vcfc were similar among the 3 groups. Comparing Vcfc at 50 g/cm2 of sigma es, it tended to increase from the normal subjects (0.883 +/- 0.057 cir/sec) to 0.969 +/- 0.048 in group 1 and 1.034 +/- 0.101 in group 2, though this result was not statistically significant. During dobutamine stimulation, EF increased and IVRTc shortened significantly only in the normal subjects. E/A became normalized in both diabetic groups. The increment in Vcfc representing cardiac reserve of contractility was significantly lower in the diabetics (0.110 +/- 0.040 in group 1 and 0.057 +/- 0.043 in group 2) than in normal subjects (0.244 +/- 0.044). In conclusion, using the index of relation between sigma es and Vcfc, the cardiac contractility of NIDDM was not impaired at baseline, and even had a tendency to increase. However, during dobutamine stimulation, the inadequate reserve of contractility was exposed, especially in those patients who had microvascular complications. These results indicate the importance of controlling diabetes, not only to prevent the development of microvascular complications but also to preserve cardiac function.

Congenital mitral stenosis: challenge of percutaneous transvenous mitral commissurotomy

A 26-year-old woman with congenital mitral stenosis and embolic stroke was referred to our hospital. The echocardiogram showed a hypoplastic posterior mitral valve leaflet with short, unbalanced chordal attachments to the posteromedial papillary muscle. The mitral valve area was 0.9 cm2 by the pressure half-time method. There was no left atrial thrombus and spontaneous echo contrast. Percutaneous transvenous mitral commissurotomy was performed since the suggestion of surgical management was refused by her family members. A rupture at the chordae tendinae of the hypoplastic posterior papillary muscle developed during the procedure and needed mitral replacement. We advise that percutaneous transvenous mitral commissurotomy be avoided in adult patients with congenital mitral stenosis having an asymmetric and hypoplastic mitral valve.

Association of the renin gene polymorphism with essential hypertension in a Chinese population

To study the association of renin gene polymorphism with essential hypertension in the Chinese population, 86 hypertensive and 107 normotensive subjects were enrolled from an epidemiologic survey. Leukocyte DNA was extracted and digested with Hind III and Bgl I restriction enzymes. Southern hybridization was done with digoxigenin-incorporated renin gene probes generated by polymerase chain reaction. The restriction fragments were detected by anti-digoxigenin antibody and enzyme methods. Two Hind III polymorphysms of the renin gene (8.7 kb and 6.2 kb) were identified. The allele frequences were 129(75%) and 43(25%), respectively, in hypertensives; they were 139(65%) and 75(35%), respectively, in normotensives (chi2 = 4.074, p = 0.044). The genotypes of 8.7/8.7,8.7/6.2 and 6.2/6.2 were significantly different between hypertensives and normotensives, being 45(52%), 39(45%), 2(3%) and 48(45%), 43(40%), and 16(15%), respectively (chi2 = 9.002, p = 0.11). The Bgl I polymorphism did not show a difference between hypertensives and normotensives. Thus, we conclude that the renin gene Hind III polymorphysm is associated with hypertension in this Chinese population.

Molecular variant M235T of the angiotensinogen gene is associated with essential hypertension in Taiwanese

OBJECTIVE

To examine the association of the molecular variants of the angiotensinogen (AGT) gene with essential hypertension in Taiwanese.

METHODS

We conducted a case-control study concerning 151 subjects, 102 hypertensives and 49 normotensives. We created a rapid mini-sequencing method based on dye-terminator cycle sequencing to simultaneously detect the M235T and T174M variants of the AGT gene for each subject.

RESULTS

The genotype and allele distribution of the M235T variant differed significantly in hypertensives and normotensives (chi 2 = 11.106, P = 0.004 and chi 2 = 6.453, P = 0.011, respectively), whereas those of the T174M variant did not differ (chi 2 = 0.004, P = 0.998 and chi 2 = 0.032, P = 0.858, respectively). The odds ratio for hypertension was 3.64 (95% confidence interval 1.56-8.49) for subjects with the C/C genotype of the M235T variant compared with other genotypes of 2.87 (95% confidence interval 1.76-4.68) for those carrying allele C versus those carrying allele T.

CONCLUSION

The molecular variant M235T, but not T174M, of the AGT gene is associated significantly with essential hypertension in this Taiwanese population. The genotype C/C or allele C is a risk factor for hypertension. The underlying mechanism of this association needs to be elucidated further.

Penetration of the interatrial septum: a rare complication of percutaneous transluminal mitral commissurotomy

Interatrial septal dissection and penetration into the aorta by a balloon catheter occurred in a 38-year-old man with mitral stenosis as a complication of percutaneous transluminal mitral commissurotomy during trans-septal puncture. It was speculated that the thickened septum was partially punctured into the potential space between the septa primum and secundum. Then, the balloon catheter went through the interatrial septum dissection into the aortic root. Emergency surgery was performed with the catheter left in situ. The surgical findings confirmed the speculated mechanism of this rare complication. In order to avoid this complication, the location of the tip of the Brockenbrough catheter after transeptal puncture must be confirmed. Checking the left atrial pressure tracing, arterial oxygenation and contrast injection are all important and indispensable procedures.

Lack of association between angiotensin-converting enzyme gene polymorphism and coronary heart disease in a Chinese population

Insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has been postulated as a risk factor for coronary heart disease. We conducted a case-control study of 271 Chinese, including 114 subjects with coronary artery disease (CAD), 42 with non-CAD and 115 apparently normal controls to examine the association of I/D polymorphism and CAD. The genotypes were identified by polymerase chain reaction and the plasma ACE activity was assayed by spectrophotometry. The allele and genotype frequencies were not different among the CAD, non-CAD and apparently normal groups (p = 0.42 and 0.63). Plasma ACE activity was not different among the three groups (p = 0.32). The D-allele and DD genotype were not more prevalent in subjects with low risk CAD (p = 0.07 and 0.16) and subjects with myocardial infarction (p = 0.79 and p = 0.35). No association was found between I/D polymorphism and severity of CAD (p = 0.42 and 0.70). In conclusion, the deletion polymorphism of the ACE gene may not be an independent risk factor in the development of CAD or myocardial infarction in this Chinese population. The unique or synergistic effect of other genes needs further study.

Lack of association of the angiotensin converting enzyme polymorphism with essential hypertension in a Chinese population

To examine the association between insertion/deletion (I/D) polymorphism of the angiotensin converting enzyme (ACE) gene and essential hypertension in a Chinese population, a case-control study was conducted using 157 hypertensive and 115 normotensive subjects. The I/D polymorphism of the ACE gene was identified by polymerase chain reaction. Plasma ACE activity was determined using spectrophotometry. The difference of allele frequencies between normotensives and hypertensives was statistically significant (chi 2 = 4.467, P = .035), while the genotype distribution was not different between normotensive and hypertensive subjects (chi 2 = 3.954, P = .138). Plasma ACE activity was highest in the DD genotype, followed by the ID genotype, and the lowest in the II genotype (P = .0001 in normotensives and P = .163 in hypertensives, respectively). Thus, we conclude that the ACE gene polymorphism is not associated with essential hypertension in this Chinese population, but plasma ACE activity is genetically determined in the normotensive Chinese.

Left isomerism in a middle-aged woman with early-onset atrial fibrillation

An unusual case of left isomerism in a 52-year-old woman with early-onset atrial fibrillation was presented. Magnetic resonance imaging clearly delineated the morphology of both atrial appendages, the vascular anatomy and all other associated anomalies, obviating further invasive studies. The discovery of left isomerism at advanced age indicates that abnormal atrial situs itself is of less clinical importance, and despite the associated sinus node dysfunction may predispose the heart to atrial fibrillation.

Age- and gender-dependent association of the angiotensin-converting enzyme gene with essential hypertension in a Chinese population

A case-control study was carried out on 272 Chinese subjects over 40 years of age, including 157 hypertensives and 115 normotensives, to examine the association between angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and blood pressure (BP) status. The I/D polymorphism of the ACE gene was identified by polymerase chain reaction. As a whole group, the difference of allele frequencies between normotensives and hypertensives was statistically significant (chi 2 = 4.46, P = 0.03; D/I odds = 1.46), while there was no difference in the genotype distribution (chi 2 = 3.95, P = 0.13). In a subgroup with elderly hypertension (age > 65), the frequencies of D-allele and DD genotype significantly increased (chi 2 = 4.43, P = 0.03 and chi 2 = 4.03, P = 0.08, respectively; D/I odds = 2.28). The association and relative risk increased further in the male gender (chi 2 = 6.65, P = 0.01 and chi 2 = 7.51, P = 0.02 respectively; D/I odds = 4.57 and DD/II odds = 12.00 respectively). The D-allele increased with age in the hypertensives, while the I-allele increased with age in normotensives. Thus, we conclude that the deletion polymorphism of the ACE gene is significantly associated with male elderly hypertension, at least in this Chinese population. This observation, if proved in a larger population, may have some implications for the prevention and treatment strategy for elderly hypertension.

Coronary artery perforation and delayed cardiac tamponade following balloon coronary angioplasty

A 62-year-old woman who had coronary artery disease and hypertrophic cardiomyopathy received percutaneous transluminal coronary angioplasty and endomyocardial biopsy. She withstood the procedure well. However, delayed pericardial tamponade occurred 2 hours after discharge from the cardiac catheterization laboratory. Despite pericardial drainage with a pigtail catheter and blood transfusion, the patient required emergency surgery. An oozing diagonal branch of the left anterior descending coronary artery was found. Ligation of this small branch stabilized the hemodynamics. Avoidance of improper positioning of the guide wire in the small coronary artery branch is important in preventing arterial wall trauma and subsequent perforation.

The cause-effect relationship of sympathovagal activity and the outcome of percutaneous transluminal coronary angioplasty

We studied 25 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) to determine the association of sympathovagal imbalance and the outcome of coronary angioplasty. We examined the profiles of heart rate variability (HRV) using echocardiography, stress thallium scanning and radionuclide angiography before, immediately after and 1 month after the procedure. Coronary angiography was followed up at 6 months or if restenosis was suspected, to determine whether restenosis had occurred. Frequency domain (LF/HF) and time domain (SDNN, SDANN-ind, and r-MSSD) parameters were analyzed. According to the evolution of each parameter, we classified the patients into Group Ax (improved in HRV profile) and Group Bx (deteriorated in HRV profile) [x = 1 for LF/HF, 2 for SDNN, 3 for SDANN-ind, and 4 for r-MSSD]. We found that there was no definite association between Gensini score and HRV profiles at the baseline for each group. No significant changes existed between the HRV profiles before and immediately after PTCA. For the LF/HF ratio, 5 of 11 in Group B1 had restenosis while 0 of 14 in Group B2 and 1 of 19 in Group A2 had restenosis (p < 0.01). There were no significant predictive values for SDANN-ind and r-MSSD (p = 0.12 and 0.07, respectively). We conclude that the sympathovagal imbalance did not reflect the severity in coronary artery disease but was associated with restenosis after successful PTCA.

Ambulatory blood pressure monitoring for evaluation of long-acting beta-blockers in Taiwan

This study attempted to evaluate the efficacy of several "long-acting" antihypertensive agents. One-hundred consecutive hypertensive subjects with normal casual blood pressure after once-daily antihypertensive monotherapy treatment were studied. They were divided into three groups: group A, metoprolol (100 mg, daily); group B, atenolol (100 mg, daily); and group C, nadolol (80 mg, daily). Ambulatory blood pressure monitoring (ABPM) was used to evaluate the efficacy of the antihypertensive agents. The overall average ambulatory blood pressures were within the normal limits for all three groups. However, there were some abnormally high blood pressure (BP) readings shown on ABPM. Patients with an abnormally high systolic blood pressure (SBP) average > 140 mmHg accounted for 16.7% of group A, 19.4% of group B and 20% of group C. Those with an abnormally high diastolic blood pressure (DBP) average > 90 mmHg accounted for 16.7%, 19.4% and 10%, respectively, of the corresponding groups. There were no significant differences in the frequency of abnormally high SBP and DBP among the three groups. These "long-acting" antihypertensive drugs did not effectively control BP throughout the entire day. The duration of antihypertensive effect is not necessarily reflected by the blood half-life of the drug. ABPM is an effective way to ascertain the efficacy of "long-acting" hypertensive agents.

The mechanism of sympathovagal imbalance in patients with myocardial ischemia

To investigate the mechanism of sympathovagal imbalance due to myocardial ischemia, we studied 42 consecutive patients undergoing successful percutaneous transluminal coronary angioplasty by correlating frequency domain and time domain measures of heart rate variability with parameters such as echocardiography, stress thallium scanning and radionuclide angiography before, immediately after and 2 months after the procedure. Of these, 20 patients (Group N) had normal and 22 patients (Group A) had abnormal regional wall motion. A control group of 20 healthy subjects (Group C) underwent echocardiography and examination of heart rate variability twice at 2-month intervals to check for spontaneous variations. At baseline, frequency domain measures such as low and high frequency power and time domain measures such as SDANN index (the mean of the standard deviations of the average of RR intervals) were lower in Group A than in Groups N and C, whereas no differences were detectable in ultra low and very low frequency, total power, SDNN index (the mean of the standard deviations of the mean of normal RR intervals), and r-MSSD (the root mean square of successive RR differences). There was high association between the diastolic wall stress index and both high frequency (r = -0.82) and low frequency power (r = -0.77). There were similar findings for the systolic wall stress index (r = -0.72 for high frequency and r = -0.64 for low frequency power). After successful coronary angioplasty, regional wall motion, left ventricular wall stress indices and all measures of heart rate variability were unchanged in Group N. In Group A the mean summed segment score improved from 15.9 +/- 2.6 to 12.2 +/- 1.7 (p < 0.0001), and mean low frequency, mean high frequency power (logarithmic units), and SDANN index (msec) increased from 6.10 +/- 0.23 to 6.36 +/- 0.28 (p < 0.005), from 5.36 +/- to 0.40 to 5.70 +/- 0.39 (p < 0.01) and from 70 +/- 18 to 83 +/- 18 (p < 0.01) respectively. In addition, low and high frequency power and SDANN index, lower at baseline in Group A than in the other two groups, were comparable in the three groups after coronary angioplasty. The evolution of diastolic and systolic wall stress indices paralleled that of the above three parameters. In conclusion, diastolic and systolic wall stress indices, in addition to segmental left ventricular dysfunction, were synergistically involved in determining sympathovagal imbalance in patients with significant coronary artery disease; the reversal of left ventricular dysfunction and wall stress indices improves the profile of heart rate variability. Alterations in cardiac geometry and wall stress influence mainly the discharge of afferent sympathetic and efferent parasympathetic innervations and also principally the long-term heart rate variations instead of short-term modulation.

Severe aplastic anemia induced by ticlopidine: report of a case

Ticlopidine is a powerful antiplatelet activator that inhibits adenosine diphosphate (ADP)-induced platelet aggregation. Its most common side-effects are skin rashes, diarrhea and neutropenia. Aplastic anemia is rare. This paper reports a patient with severe aplastic anemia that developed after the use of ticlopidine. The 85-year-old woman developed fever, chills and chest pain 5 weeks after starting ticlopidine 250 mg twice daily. Severe aplastic anemia was proved by blood examination, bone marrow aspiration and biopsy. In spite of the recovery of absolute neutrophil count to more than 1,000/mm3, 16 days after ticlopidine was stopped and administration of strong antibiotics, the patient died from candidal sepsis.

The evolution of platelet aggregability in patients undergoing catheter ablation for supraventricular tachycardia with radiofrequency energy: the role of antiplatelet therapy

Forty-two consecutive patients were checked for profiles of platelet aggregability before, during, and 10 and 30 minutes after catheter ablation. They were randomized into Group A (n = 20) who accepted intravenous aspirin (in 0.015 g/kg body weight) and Group P (n = 22) who accepted only placebo treatment. Blood samples were drawn from ascending aorta (Ao) and main pulmonary artery (MPA) simultaneously at each time period. In Group P, the EC50 of substrate induced platelet aggregability decreases significantly during (for ADP, from 1.72 to 0.78 mumol/L for samples from Ao, P < 0.0001; and from 1.68 to 0.69 mumol/L for MPA, P < 0.0001; for collagen, from 2.26 to 1.34 micrograms/mL for Ao, P < 0.005, and from 2.40 to 1.64 micrograms/mL, P < 0.0001) and 10 minutes after successful ablation (for ADP, to 0.70 mumol/L for Ao, P < 0.000, and to 0.61 mumol/L for MPA, P < 0.0001; for collagen, to 1.54 micrograms/mL for Ao, P < 0.01, and to 1.63 micrograms/mL, P < 0.0001), and then returned to baseline levels 30 minutes later (all P = NS) compared with comparative baseline levels. The levels of thromboxane B2 (TXB2) had the similar evolution. The evolution of platelet aggregability profiles was not associated with total energy dose, duration of energy application, duration of procedure, impedance, and ablation site. However, there were moderate positive correlations between the TXB2 levels and tip temperatures (r = 0.56, P < 0.05 for Ao and r = 0.65, P < 0.01 for MPA). These results suggest that increased platelet aggregability can occur during and 10 minutes after radiofrequency current ablation and antiplatelet therapy can maintain "flat" response of platelet aggregability to radiofrequency energy, which may provide possible benefits in preventing the occurrence of the complication.

Perinodal slow potential as a local guide for transcatheter radiofrequency ablation of atrioventricular nodal reentrant tachycardia: therapeutic efficacy and electrophysiological mechanisms of success

BACKGROUND

A specific local indicator in the Koch's triangle could be critical to the complication-free treatment of atrioventricular nodal reentrant tachycardia by transcatheter radiofrequency ablation. Recording of perinodal slow potential reflects a slow conduction area, and probably indicates the location of the slow pathway component of the circuit. Specific ablation of the slow pathway would carry the least risk of atrioventricular block.

METHOD AND RESULTS

Guided by the mapped perinodal slow potential, atrioventricular nodal reentrant tachycardia was successfully eliminated in all of 55 consecutive patients in one session. Fifty two patients (94.5%) had confirmed slow potential at the final success sites. Despite the good result, the underlying electrophysiological mechanisms of early success from slow-potential-guiding catheter ablation were heterogeneous: selective slow pathway eradication in 31 patients (56.4%, group A), selective slow pathway modification in 18 patients (32.7%, group B), inadvertent fast pathway damage in six patients (10.9%, group C). Group B patients had the preservation of dual atrioventricular nodal pathways, adequate atrio-Hisian delay, fast pathway facilitation, and a higher frequency of inducible, single non-conducted nodal echo (15/18, 83.3% v 6/31, 19.4% in group A, P << 0.001). The upper communicating path of the circuit was implicated as another site of radiofrequency destruction. Three recurrences were documented in follow up study. However, reablation by the same approach caused complete atrioventricular block in one patient (1.7%, 1/58 procedures). None of the local characteristics of ablation sites was an independent predictor of procedure outcome.

CONCLUSIONS

Perinodal slow potential is not a specific slow pathway indicator in transcatheter radiofrequency ablation of atrioventricular nodal reentrant tachycardia. Multiple strategic sites of the reentry circuit may be damaged through similar local signals.

Anaerobic metabolism in patients undergoing intra-aortic balloon counterpulsation for cardiogenic shock

To find the best predictors of outcome for patients undergoing intra-aortic balloon counterpulsation (IABP) for cardiogenic shock, we prospectively studied 30 consecutive patients by examining hemodynamic parameters and cardiac lactic acid extraction ratios before the procedure. 1 hour after and then every 6 hours for 3 days. Complete hemodynamic data were obtained from the recordings of Swan-Ganz catheterization. Blood samples were drawn from the peripheral artery, central vein, pulmonary artery wedge position (PAW) and right atrium (RA) to quantify lactic acid levels. The simplified lactic acid extraction ratio was defined as the concentration of lactic acid in RA--the concentration of lactic acid in PAW/the concentration of lactic acid in PAW. The traditional systemic lactic acid production ratio was defined as the concentration of lactic acid in the central vein--the concentration of lactic acid in the peripheral artery/the concentration of lactic acid in the peripheral artery. Of the 30 patients studied, 19 died of cardiogenic shock, (group 1), while the surviving 11 patients formed group 2. The lactic acid extraction ratios at each of the time periods after the procedure were all significantly different, while the differences in the systemic lactic acid production ratio and hemodynamic parameters, including the systemic arterial pressure, cardiac output, cardiac index and PAW pressure, became significant at varying times after IABP. In group 2, the lactic acid extraction ratios 1 hour after IABP and later were all significantly higher than at baseline. This trend was not seen in group 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Vectorcardiography in experimental myocardial infarction. Serial changes and correlation between QRS loop change and the infarction size

The objectives of this study were to examine the serial vectorcardiographic changes following acute myocardial infarct and to assess the relationship between QRS loop changes and infarct size. Fifty adult male Long-Evans rats of 250-350 gm body weight were used to study experimental acute myocardial infarction induced by coronary artery ligation. Vectorcardiograms (VCG) of the Frank lead system were recorded before, and 1 day and 7 days after operation. Animals were sacrificed on the 7th day for histological quantitation of infarct area ratios. We found that (1) before operation, rats have ST elevation, probably due to early repolarization. (2) After coronary artery ligation, ECG showed characteristic dome-shaped ST elevation at 1 hr after ligation which returned to normal during the first day. Abnormal Q waves appeared thereafter. (3) After ligation, maximum QRS vector, ST vector and maximum T vector were reduced in magnitude the first day and recovered by the 7th day. The vectors tended to shift their direction to the right and to the posterior. QRS-T angle, however, widened as time went on. About half of the rats revealed changes in the inscription direction of the QRS loop and abnormal QRS morphology also appeared in about half of the ligated rats. (4) Those in whom abnormal QRS loop morphology and/or biting appeared had significantly larger infarct area ratios (p < 0.01). (5) Change in QRS loop inscription direction seemed not to be related to the infarct size. (6) In the LS plane, the difference in max QRS vector magnitude between the 1st and 7th days significantly correlated with the infarct area ratio (r = 0.533, p < 0.05). In the H plane, the change in the max QRS vector magnitude at the 7th day correlated with the infarct area ratio (r = -0.531, p < 0.05). In the F plane, changes in the direction of the max QRS vector were significantly correlated to the infarct area ratio both on the first (r = 0.431, p < 0.05) and 7th days (r = 0.531, p < 0.05). It is concluded that the VCG, like the ECG, had evolutional changes in AMI and that the QRS loop seen on vectorcardiography has only a slight correlation with the histological myocardial infarct size.

Influence of isolated diastolic hypertension identified by ambulatory blood pressure on target organ damage

Clinical decisions and controlled studies in regard to hypertension have long emphasized the casual diastolic blood pressure (DBP). The influence of superimposition of high systolic blood pressure (SBP) on the target organ damage has been less studied. To assess the role of isolated diastolic hypertension without interference of superimposition of systolic hypertension, 171 subjects with normal blood pressure, isolated diastolic hypertension (SBP < 140 and DBP > or = 90 mmHg) isolated systolic hypertension (SBP > or = 140 and DBP < 90 mmHg) or combined hypertension (SBP > or = 140 and DBP > or = 90 mmHg) determined by mean 24-h ambulatory blood pressure were compared in relation to target organ damage including ECG abnormality related to hypertension, cardiac enlargement by chest X-ray, proteinuria and retinopathy. The incidence of target organ damage was lower in subjects with normal BP than in the other three groups. The incidence of target organ damage was almost significantly higher in patients with isolated systolic hypertension than in those with isolated diastolic hypertension. No significant difference in the incidence of complications existed between patients with isolated systolic and combined hypertension. These findings demonstrate that the severity of hypertensive complications is more closely related to mean ambulatory SBP than mean ambulatory DBP. The level of systolic BP is important for predicting the severity of target organ damage in patients with high diastolic BP, because there is a significant difference in the incidence of target organ damage between isolated diastolic hypertension and combined hypertension.

Value of local electrogram characteristics predicting successful catheter ablation of left-versus right-sided accessory atrioventricular pathways by radiofrequency current

Despite similar guidance by local electrogram criteria, catheter ablation of right-sided accessory atrioventricular (AV) pathways by radiofrequency current has been less effective than that of left-sided ones. In order to elucidate the possible diversities in local electrosignal criteria, we systematically analyzed the morphological and timing characteristics of 215 bipolar local electrograms from catheter ablation sites of 65 left-sided accessory AV pathways and of 356 from those of 37 right-sided ones in 92 consecutive patients with Wolff-Parkinson-White syndrome or AV reentrant tachycardia incorporating concealed accessory AV pathways. After stepwise multivariate analysis, we selected the presence of a possible accessory pathway potential, local ventricular activation preceding QRS complex for 20 ms or more during ventricular insertion mapping, and the local retrograde ventriculoatrial (VA) continuity, local retrograde VA interval < or = 50 ms, electrogram stability (left-sided targets only), retrograde accessory pathway potential (right-sided targets only) during atrial insertion mapping, as independent local electrogram predictors for successful ablation of left- and right-sided accessory AV pathways. Combination of all local electrogram predictors could have moderate chance of success (80 and 51%) for the ventricular and atrial insertion ablation of left-sided accessory AV pathways, but only low probability of success (40% in ventricular insertion ablation) or very low sensitivity (12.5% in atrial insertion ablation) for right-sided ones. In conclusion, with the present approach, successful catheter ablation of right-sided accessory AV pathways, compared to left-sided ones, still necessitate a breakthrough in the precision mapping and the efficiency of energy delivery.

Circadian variations of atrial natriuretic peptide in normal people and its relationship to arterial blood pressure, plasma renin activity and aldosterone level

To investigate the circadian variations of plasma atrial natriuretic peptide (ANP) and its relationship to arterial blood pressure, plasma renin activity and aldosterone level, we determined 24-h blood pressure in 14 healthy volunteers. Plasma ANP concentration, renin activity and aldosterone levels were measured every 3 h by radioimmunoassay. We found no significant circadian variation of plasma ANP level (pg/ml) (daytime level, 62 +/- 24 vs. nighttime level, 57 +/- 19, P = 0.146) and plasma renin level (ng/ml/h) (1.32 +/- 0.78 vs. 1.15 +/- 0.57, P = 0.148), but there was diurnal change of blood pressure (mmHg) (systolic, 122 +/- 7 vs. 116 +/- 11, P < 0.001; diastolic, 80 +/- 11 vs. 72 +/- 11, P = 0.025) and plasma aldosterone level (pg/ml) (86 +/- 42 vs. 62 +/- 37, P < 0.001). The blood pressure and aldosterone levels reached maxima (11:00 h and 08:00 h, respectively) before that of ANP (17:00 h) and then decreased together until the nadir at 02:00 h. This might indicate that elevation of arterial blood pressure and plasma aldosterone level stimulate release of ANP under normal physiological conditions.

Comparison of the pharmacologic action of two isoquinoline alkaloids on rat cardiac tissue

We investigated the action of two synthetic isoquinoline alkaloids, 3,4-dihydroxybenzyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (CSH109) and 2-bromo-3,4-dimethoxybenzyl 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (CSH118) on rat cardiac tissue. In the right atria, CSH109 increased the amplitude of contractions and spontaneous beats dose-dependently. In the driven left atria and right ventricular strips, CSH109 caused a similar increase in contractions. The positive inotropic and chronotropic actions of CSH109 were antagonized by propranolol. CSH118 caused the spontaneous beats in the right atria to slow down. CSH118, however, failed to antagonize the positive inotropic effect and positive chronotropic effect of isoprenaline. Electrophysiologic study revealed that 3 microM CSH118 markedly reduced fast action potential upstroke and prolonged the action potential duration (APD50) of rat ventricular cells from 34 +/- 8 msec to 122 +/- 29 msec (n = 6). CSH109 prolonged APD50 slightly from 24 +/- 4 msec to 38 +/- 7 msec (n = 4). Under voltage clamp conditions, CSH109 significantly increased the L-type calcium inward current (ICa). The TTX-sensitive sodium inward current (INa), transient outward (Ito) and late outward current (I800), however, were unaffected. The increase in ICa by CSH109 was effectively antagonized by propranolol. Contrary to the action of CSH109, CSH118 strongly suppressed INa, ICa, Ito and I400. The inhibition of INa by 1.5 to 9 microM CSH118 was associated with negative shifting of its steady state inactivation curve. It is concluded that CSH109 exerts a cardiac effect by activating the B-adrenoceptor. CSH118, however, is a broad spectrum ionic channel blocker.

Characteristic abnormal findings of ambulatory blood pressure indicative of hypertensive target organ complications

To study the correlation between ambulatory blood pressure and target organ complications of hypertension, ambulatory blood pressure monitoring was performed on 290 patients with mild to moderate essential hypertension before treatment. Their target organ complications of hypertension were assessed by ECG, chest X-ray, urinalysis and an eye-fundus examination. An average ambulatory diastolic blood pressure value greater than the casual diastolic blood pressure was found in 35% of subjects with ECG evidence of left ventricular hypertrophy (LVH) and 5.2% of subjects without (P < 0.001); in 36.5% of patients with chest roentgenographic evidence of LVH and 8.4% of patients without (P < 0.0001); in 38.5% of patients with proteinuria and 11% of patients without (P < 0.0001); and in 27.1% of subjects with retinopathy and 10.7% of subjects without (P < 0.01). A similar result was observed for the systolic blood pressure. A reversed circadian pattern of ambulatory diastolic blood pressure was observed in 32.5% of patients with ECG evidence of LVH and 12.9% without (P < 0.0001); in 28.8% of patients with chest roentgenographic evidence of LVH and 16% without (P < 0.05); in 26.9% of subjects with proteinuria and 17.4% without (P < 0.05); in 37.5% of patients with retinopathy and 14.5% without (P < 0.0001). A similar result was also demonstrated for ambulatory systolic blood pressure. There was a close relationship between the blood pressure load and hypertensive target organ complications in terms of LVH and proteinuria, and between significant nocturnal reduction of ambulatory systolic blood pressure and LVH.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of EGb 761, a ginkgo biloba extract, on early arrhythmia induced by coronary occlusion and reperfusion in dogs

EGb 761 is a preparation of Ginkgo biloba extract, which has complex biologic actions including free radical scavenging activity. To examine the anti-arrhythmic effect of EGb 761, a canine preparation of coronary artery occlusion-reperfusion was tested. Under intravenous anesthesia and open chest conditions, 32 dogs were subjected to 30 min of coronary occlusion, followed by reperfusion. Twelve received EGb 761 by intravenous injection, 1 mg/kg five minutes before coronary occlusion, followed by a continuous infusion of 0.1 mg/kg/min until five minutes after reperfusion. Immediately prior to reperfusion, an additional bolus dose of EGb 761 (1 mg/kg) was again injected (group A). The remaining 20 dogs received saline injection, and served as the control (group B). The electrocardiographic changes were recorded during the whole experimental course. The results showed that, during coronary occlusion, group A dogs had a lower count of ventricular premature beats than group B dogs. However, there was no difference in the incidence of ventricular tachycardia (VT) between the two groups. The duration of VT of the treated dogs was similar to that of the control dogs. The incidence of ventricular fibrillation (VF) was also similar. Upon reperfusion, the treated dogs were shown to be protected from VF. The duration of VT was also shorter in the treated group, although the incidence of VT was not different between the two groups. EGb 761 is effective in preventing early VF induced by coronary reperfusion while ineffective in protecting the ischemic VT and VF.

Infundibular pulmonic stenosis with intact ventricular septum: a report of 15 surgically corrected patients

Infundibular pulmonic stenosis with intact ventricular septum of primary origin is an uncommon condition. We report 15 such patients (nine males and six females, aged 7-36 years) who had undergone surgical correction for the anomaly during the period between 1975 and 1992. The occurrence of this clinical setting represents 0.19% (15/7826) of all cardiac operations and 0.46% (15/3222) of congenital heart diseases undergoing surgical correction during that period of time. The lesion was of discrete fibromuscular hypertrophy of the infundibulum in all 15 patients. The presenting symptoms of most patients were exertional dyspnea and syncope; however, five patients with severe obstruction were asymptomatic. The peak systolic pressure gradient across the infundibulum ranged from 71 to 230 mmHg. There was only one operative death; the remainder had remained well following the surgery over a mean follow-up period of 35 months. Surgical correction for infundibular pulmonic stenosis is rewarding in the absence of heart failure.

Influence of age on ambulatory blood pressure in treated hypertensive patients with normal casual pressure

To investigate the influence of age on ambulatory blood pressure monitoring (ABPM) in hypertensive patients whose controlled casual blood pressure was normal, we studied the ABPM in 225 patients, including 122 men and 103 women, aged from 45-74 years. They were classified into three groups: Group A included 93 patients aged 45 to 54 years; Group B included 99 patients, aged 55-64 years; and Group C included 33 patients, aged 65 years and over. The various ABPM data were analyzed and compared among the three groups. The following results were found. The blood pressure (BP) averages for the whole day were normal in all three groups. There was no difference in the systolic BP average among the three groups, but the diastolic BP average declined as age increased. The variability in the systolic BP measurements increased with age. The variability in diastolic BP did not seem to change as conspicuously with age, except for the group C patients who showed a larger variability at nighttime than the other two groups. There were 123 patients (54.7%) with evidence of diurnal change in BP, and the incidence of diurnal change in BP decreased with age. The frequency of abnormally high systolic BP was similar among the three groups, but the frequency of an abnormally high diastolic BP decreased significantly with age. As for the maximal BP levels recorded in the ABPM, group C patients had a higher maximal systolic BP than the other two groups. Therefore, age has a great influence on ABPM in controlled hypertensive patients with normal casual BP.

Superior vena cava syndrome as a complication of permanent transvenous endocardial pacing: report of a case

Superior vena cava syndrome as a complication of permanent transvenous endocardial pacing is unusual. We herein report on a 71-year-old woman who presented with progressive swelling of the face, neck, thorax and upper limbs two months after implantation of a permanent transvenous endocardial pacing device for sinus node dysfunction. Superior vena cava syndrome was diagnosed by venography. Acute heart failure and respiratory failure developed before her scheduled operation. She expired despite vigorous cardiopulmonary resuscitation.

Cardiac amyloidosis presenting as sick sinus syndrome and intractable heart failure: report of a case

Cardiac amyloidosis, an uncommon disease, has been reported to manifest as congestive heart failure (CHF) and/or various arrhythmias. Herein, we report a case of CHF and sick sinus syndrome. The patient, a 66-year-old man, was admitted to the National Taiwan University Hospital because of dizzy spells and recurrent syncope. Electrocardiogram showed a sinoatrial block, first degree atrioventricular block, right bundle branch block and low-voltage Q wave, R wave and S wave (QRS) complex. Prolonged corrected sinus node recovery time was documented by an atrial pacing study. A permanent pacemaker was implanted for the patient's bradyarrhythmia, but he developed progressive heart failure. Echocardiography revealed a normal-sized ventricular chamber, concentric left ventricular hypertrophy with a "granular sparkling" appearance of the myocardium, and impaired diastolic and systolic function of the left ventricle. Despite aggressive treatment, the patient expired due to intractable heart failure. Postmortem needle aspiration revealed amyloidosis involving the heart, lung and skin. We conclude that cardiac amyloidosis should be considered in elderly patients with conduction disturbance and unexplained congestive heart failure.