Dynamic change in collateral flow associated with myocardial ischemia in humans

BACKGROUND

This study sought to investigate how collateral flow changes during myocardial ischemia in patients.

METHODS

Myocardial contrast echocardiography (MCE) and rapid atrial pacing were performed in 20 patients with angiographically evidenced coronary collaterals from the right coronary artery (RCA) to the occluded left anterior descending coronary artery. Sonicated contrast medium was injected into the RCA before and immediately after atrial pacing to determine the peak background-subtracted contrast intensity (PI) in the collateral territory (PIA) and its ratio to PI in the control territory (PI ratio) as parameters of collateral blood flow. Lactate production in the coronary circulation during pacing was determined to assess myocardial ischemia in the collateral territory.

RESULTS

PIA showed a significant correlation with regional wall motion either before (r(squared)=-0.64, P<0.01) or after pacing (r(squared)=-0.65, P<0.01). Similarly, PI ratio was significantly correlated with regional wall motion either before (r(squared)=-0.54, P<0.05) or after pacing (r(squared)=-0.64, P<0.01). Rapid atrial pacing decreased both PIA and PI ratio significantly greater in patients with lactate production than in those without (PIA: -67+/-53 vs. -15+/-34%, P<0.05; PI ratio: -68+/-49 vs. -8.2+/-32%, P<0.05, respectively), while neither PIA nor PI ratio differ between the two groups of patients before pacing (PIA: 13.8+/-19. vs. 16.2+/-13.3U, P=0.75; PI ratio: 0.70+/-0.71 vs. 0.87+/-0.65, P=0.58, respectively).

CONCLUSIONS

We concluded that (1) collateral flow determined by MCE was closely associated with regional cardiac function, and (2) not the amount of collateral flow at rest, but pacing-induced change of collateral flow seemed to be a determinant of regional ischemia in patients with coronary collaterals.

[Effect of oxygen inhalation on myocardial opacification using levovist: an animal experimental study]

OBJECTIVES

Levovist can opacify the myocardium via venous injection, and is widely used in the clinical field. However, left ventricular opacification deteriorates during oxygen inhalation using Albunex, one of the first generation of contrast agents. This study examines the effect of blood oxygen pressure on the myocardial opacification by Levovist.

METHODS

Myocardial contrast echocardiography (Toshiba Power Vision 6000) was performed using second harmonic imaging, intermittent exposure of ultrasound (every 4 cardiac beats) and acoustic power of 1.4 mechanical index. The video intensity of the ventricular septum after venous injection of Levovist (0.5 ml of 300 mg/ml) was measured under various respiratory conditions by manipulating the respirator and oxygen inhalation. Arterial blood gas was measured and correlated with the myocardial video intensity.

RESULTS

The video intensity of myocardial opacification was lower with higher oxygen pressure in the arterial blood. Visual recognition of myocardial opacification was only 14% under high oxygen pressure over 200 mmHg. Microbubbles of Levovist form from normal air, and are easily affected by the gas concentration of the surrounding blood.

CONCLUSIONS

Myocardial opacification using Levovist is deteriorated under high oxygen pressure at examination.

[Optimal setting of focus points for myocardial contrast echocardiography with intravenous Optison (FS-69): an experimental study]

OBJECTIVES

Myocardial contrast echocardiography is useful to assess myocardil perfusion, but myocardial opacification is affected by the setup of the ultrasonic equipment. The optimal setting of focus points for adequate opacification of the myocardium was examined in myocardial contrast echocardiography.

METHODS

Myocardial contrast echocardiography was performed in six dogs using triggered second harmonic technology following intravenous administration of Optison(FS-69). The short-axis view was recorded and baseline subtracted video intensity(peak intensity: PI) was calculated at three regions of the left ventricular wall, the anterior, septum, and posterior walls, to evaluate myocardial opacification. The focus point was set at near(2 cm), middle(4 cm) and far(6 cm)points. The myocardial opacification was evaluated at each focus setting. The effect of the acoustic power was also examined by changing the mechanical index to 1.6, 1.2 or 0.8.

RESULTS

Myocardial opacification was recognized at all focus points, and segments near the focus points had high PI. However, the PI of the posterior wall was lowest at near focus, whereas the PI of the anterior wall was lowest at far focus. The difference of PI between the anterior and posterior walls was significant (p < 0.05, p < 0.01, respectively) at either focus point. Adequate myocardial opacification of all segments was observed when the focus was set at the middle point. The PI of the whole left ventricle increased relative to mechanical index.

CONCLUSIONS

Setting up of focus points at the middle of the left ventricle provides more homogeneous myocardial opacification of the whole left ventricle in myocardial contrast echocardiography, and high acoustic power possibly improves myocardial opacification. Inadequate setting of focus points leads to inadequate estimation of myocardial perfusion by myocardial contrast echocardiography.

[Usefulness of intravenous myocardial contrast echocardiography in rats]

OBJECTIVES

Few intravenous myocardial contrast echocardiography trials have evaluated myocardial perfusion in small animals. The feasibility of using intravenous myocardial contrast echocardiography to assess the ischemic area in rats was investigated.

METHODS

Fourteen open chest Wister male rats were examined. Intravenous myocardial contrast echocardiography was performed by fundamental and intermittent mode using a high frequency (5-12 MHz) transducer (SONOS 5500) with injection of NC100100 (20% dilution) into the femoral vein. The mechanical index was set to 1.6. Baseline-subtracted video intensity (256 level) was measured in the anterior, posterior, septal and lateral walls of the left ventricle. The left anterior descending artery was ligated in 16 rats. The area at risk was evaluated by myocardial contrast echocardiography and compared to the area of defect by Evans Blue staining.

RESULTS

All wall segments were clearly opacified (anterior 63.8 +/- 24.7, posterior 27.0 +/- 11.0, septal 44.5 +/- 11.6, lateral 52.3 +/- 19.1), although the baseline-subtracted video intensity of the posterior wall was low. The area at risk was clearly observed, and there was a good correlation with the nonperfused area by Evans Blue staining (y = 1.13x-3.54, r = 0.98).

CONCLUSIONS

Intravenous myocardial contrast echocardiography can detect the perfusion defect even in rats using a high frequency transducer and suitable setup of equipment.

Myocardial ischemia activates the JAK-STAT pathway through angiotensin II signaling in in vivo myocardium of rats

There have been many studies concerning the hemodynamics and physiological mechanisms in ischemic heart disease, little is known about molecular mechanisms during myocardial ischemia in in vivo study. As the signal transduction pathway responsible for myocardial hypertrophy and apoptosis, janus kinase (JAK) and signal transducers and activators of transcription (STAT) are suggested to play an important role. However, whether in vivo activation of JAK-STAT pathway occurs during myocardial ischemia is still unknown. The purpose of this study was to determine whether myocardial JAK or STAT is activated in ischemic heart, and to evaluate the angiotensin blockade on the pathway. Myocardial infarction was produced by ligation of the coronary artery in Wistar rats. After myocardial ischemia, we analysed both activated levels and total amounts of JAK1, JAK2, STAT1 and STAT3 by Western blot analyses at 0, 5, 15, 30, 60, 120 and 240 min. Compared with JAK activities at 0 min, JAK1 activities were significantly increased at 60 and 120 min (3.0- and 3.7-fold, respectively, P<0.01). JAK2 and STAT1 activities of ischemic myocardium were unchanged through the time course. STAT3 activities were increased at 5 min (3.3-fold, P<0.01) and markedly enhanced at 30, 60 and 120 min (4.6-, 7.7- and 8.7-fold, respectively, P<0.01). Pretreatment with imidapril (ACE inhibitor) and candesartan cilexitil (AT1 receptor antagonist) significantly prevented the increase in the phosphorylation of JAK1 at 120 min and STAT3 at 30 and 120 min. Sis-inducing factor (SIF) DNA complex was supershifted by specific anti-STAT3 antibody, indicating that increased SIF complex at least contained activated STAT3 proteins in ischemic myocardium. Imidapril and candesartan cilexitil inhibited the activation of SIF DNA binding at 1 day after coronary ligation. In conclusion, we showed that JAK1 and STAT3 were activated by ischemia from the basal activities in in vivo rat myocardial ischemia model. Imidapril and candesartan cilexitil prevented the increase in phosphorylated JAK1 and STAT3, thereby suggesting that angiotensin II, especially angiotensin II type I receptor, partially mediates activation of myocardial JAK-STAT pathway in acute myocardial ischemia.

Effects of sildenafil citrate (Viagra) combined with nitrate on the heart

BACKGROUND

Sildenafil citrate (Viagra) is indicated for the treatment of erectile dysfunction. Large and sudden decreases in systemic blood pressure were reported in a substantial number of patients taking sildenafil citrate combined with nitroglycerin. We studied the effect of sildenafil citrate on the relationship between changes in systemic blood pressure and coronary blood flow.

METHODS AND RESULTS

Healthy male beagles were used to assess systemic blood pressure, pulmonary arterial pressure, and flow in the left circumflex artery (in which a critical stenosis was established) and left anterior descending coronary artery. After measurement of the hemodynamic variables, 2 mg/kg sildenafil citrate was administered via a nasogastric tube. Hemodynamic changes were monitored for 1 hour. Subsequently, the acute effect of nitrate combined with sildenafil citrate was studied by the bolus injection of 0.2 mg isosorbide dinitrate before and after sildenafil citrate. Systemic blood and pulmonary arterial pressures and circumflex flow did not change during this study; however, left anterior descending coronary arterial flow increased from 16.0+/-5.8 to 24.6+/-8.7 mL/min 1 hour after administration of sildenafil citrate. The prolongation of systemic blood pressure decrease and the circumflex flow decrement induced by isosorbide dinitrate after sildenafil citrate were significantly larger and longer than those before sildenafil citrate.

CONCLUSIONS

Sildenafil citrate had the effect of vasodilation in a normal coronary artery; however, a combined effect with nitrate resulted in large and protracted decreases in systemic blood pressure and coronary blood flow in vessels with critical stenosis.

The role of coenzyme Q10 in the pathophysiology and therapy of experimental congestive heart failure in the dog

BACKGROUND

Coenzyme Q10 (CoQ10) is essential for ATP generation and has antioxidant properties. Decreased CoQ10 levels have been reported in human heart failure (CHF), but it remains unclear if this is a conserved feature of CHF. The objective of the study was to determine if tachycardia-induced CHF in the dog is associated with reduced CoQ10 levels. Furthermore, it was hypothesized that CoQ10 supplementation may improve CHF severity by preventing CoQ10 deficiency (if present) or via antioxidant effects.

METHODS AND RESULTS

Serum and myocardial levels of CoQ10 were examined in normal dogs (n = 6), dogs with CHF (control, n = 5), and dogs with CHF treated with CoQ10 (CoQ10; 10 mg/kg/day, n = 5). Serum CoQ10 levels did not change with CHF in control dogs, and myocardial levels were similar to those of normal dogs. CoQ10 therapy increased serum but not myocardial levels of CoQ10. In early CHF, CoQ10-treated dogs had lower filling pressures, and, in severe CHF, CoQ10-treated dogs had less hypertrophy as compared with untreated dogs. Other indices of CHF severity were similar in control and CoQ10-treated dogs.

CONCLUSION

These data indicate that CoQ10 deficiency is not present in this model of CHF. Although dramatic effects on hemodynamics were not observed, CoQ10 supplementation did appear to attenuate the hypertrophic response associated with CHF. Key words: enzymes, cardiomyopathy, hormones, antioxidant.

Mechanism for abnormal thallium-201 myocardial scintigraphy in patients with left bundle branch block in the absence of angiographic coronary artery disease

Patients with left bundle branch block (LBBB) often show abnormal images on exercise thallium (T1)-201 scintigraphy without evidence of significant coronary stenosis. We investigated the mechanism for this phenomenon. Six patients with LBBB and without significant coronary stenosis underwent T1-201 SPECT, ECG-gated SPECT imaging with Tc-99m-methoxyisobutyl-isonitrile (MIBI), and atrial pacing stress test. The % count amplitude in Tc-99m-MIBI images was calculated as [(maximal counts) - (minimal counts)]/(minimal counts) x 100. Though all patients had a low count in the septal and inferior wall in T1-201 SPECT images, there was no ischemic production of lactate during an atrial pacing stress test. Nevertheless, gated SPECT images showed attenuated septal activity during systole. In patients with LBBB, the ratios of % count amplitude at the septum to that at the lateral wall at rest (0.47 +/- 0.05, mean +/- SE) were significantly less than the controls (n = 5, 0.83 +/- 0.12, p = 0.014). In conclusion, these results suggest that abnormal T1-201 SPECT images of the septum in patients with LBBB are partially caused by impaired septal wall thickening during systole. Such an abnormal wall motion may reduce blood flow demands to the septum, resulting in reduction of coronary blood flow with little ischemia.

Intraoperative application of power Doppler imaging: visualization of myocardial perfusion after anastomosis of left internal thoracic artery to left anterior descending coronary artery

The purpose of this study was to determine the role of power Doppler imaging in assessing patency of coronary artery bypass graft (CABG) anastomosis. Twelve consecutive patients referred for CABG with the use of anastomosis of the internal thoracic artery to the left anterior descending coronary artery (LAD) were studied. A linear 6.5-MHz wide-band transducer was used during cardioplegic administration and reperfusion. Baseline power Doppler signals were obtained in the LAD in 11 patients, and post-CABG signals were obtained in 11 patients. In one patient the LAD was poorly visualized because of extensive calcification. In another patient the flow after bypass worsened and the graft was revised. Visualization of the LAD and internal thoracic artery grafts by epicardial intraoperative power Doppler imaging is feasible in almost all patients and allows rapid and simple intraoperative assessment of graft patency. In addition, myocardial perfusion is limited by heavily calcified coronaries.

Estimation of shunt flow in coronary-pulmonary fistula by lung perfusion scintigraphy with technetium-99m macroaggregated albumin

The shunt flow from the coronary artery to pulmonary arteries was evaluated in 6 patients with coronary-pulmonary fistula by lung perfusion scintigraphy with technetium-99m macroaggregated albumin. In 2 patients, whose degree of visualization of pulmonary arteries by coronary angiography was relatively high, lung perfusion scintigrams demonstrated the defects at the distal of coronary-pulmonary fistulas.

Clinical application of power Doppler imaging to visualize coronary arteries in human beings

Supplementation of angiographic information during bypass procedures is an attractive goal for the echocardiographic researcher. Compared with color flow mapping, power Doppler imaging is superior in terms of identifying small vessels and noise suppression because of the use of Doppler signal strength for imaging. Although power Doppler imaging does not provide information about flow velocity or its direction, it does show detailed vessel flow in a static organ. Our study was designed to obtain angiographic images of the coronary artery by the use of power Doppler imaging in 31 patients during open heart surgery. During cold cardioplegic infusion, the epicardial coronary artery and the coronary artery within myocardium, such as the septal perforator, could be well visualized by power Doppler imaging. There was good correlation between the diameters of coronary arteries measured from power Doppler imaging and those from quantitative coronary angiography (r = 0.964, p < 0.0001). We obtained clear and accurate images of the coronary artery by using power Doppler imaging during cardiac standstill. These images might provide meaningful supplemental information to the operator, such as confirming the target coronary artery during the cardioplegia and choosing the appropriate arterial portion for a bypass operation.

Different mechanisms of ischemic adaptation to repeated coronary occlusion in patients with and without recruitable collateral circulation

OBJECTIVES

The aim of this study was to investigate the interaction between ischemic preconditioning (IP) and collateral recruitment (CR) during ischemic adaptation in patients.

BACKGROUND

The mechanism of ischemic adaptation still remains controversial in humans.

METHODS

The clinical, electrocardiographic, hemodynamic and echocardiographic responses to three 150-s occlusions of the left anterior descending coronary artery were assessed in relation to CR in 18 patients with effort angina undergoing elective percutaneous transluminal coronary angioplasty.

RESULTS

During the first occlusion, recruitable collateral circulation (RCC) to the occluded myocardium was detected by myocardial contrast echocardiography in 6 patients (Group C) and was not seen in 12 (Group N). In Group N, all patients manifested signs of severe ischemia during each inflation. However, their symptoms and ST segment shift significantly decreased from the first to the third occlusions, suggesting the occurrence of IP. The elevation of mean pulmonary artery pressure and deterioration of anterior wall motion were comparable between the first and the third occlusions in Group N. In contrast, myocardial ischemia was significantly less marked during occlusion in Group C than in Group N, and no preconditioning effect was observed. The extent of RCC did not differ between the first and the third occlusions in each group.

CONCLUSIONS

Both IP and CR may play independent roles in ischemic adaptation in humans. With RCC, myocardial ischemia was greatly reduced. Without RCC, preconditioning clinically and electrocardiographically lessened myocardial ischemia but failed to preserve left ventricular function.

[Drug induced impotence]

Medication induced impotence has been reported in the some papers. However, it is unusual to talk about the sexual history in a general clinical interview and there are few reports to show the possible mechanisms of induced sexual dysfunction in Japan. Recently, the average life span of the Japanese population has gradually increased, so now we have a chance to evaluate the sexual history from older people. Some drugs, such as diuretics, antiarrtythmic and antihypertensive drugs, were reported to induce impotence, however, there was not a detailed study in Japan. We studied the effect of cardiovascular medicine to sexual dysfunction in 1,000 patients. Almost all medication did not always reduce sexual activities, however, sexual activities in old people might decrease because of medications or sickness. It is important for the general physician to ask the patients about general conditions including sexual history while on medications.

Salutary effect of adjunctive intracoronary nicorandil administration on restoration of myocardial blood flow and functional improvement in patients with acute myocardial infarction

Salutary effect of nicorandil, a K+ adenosine triphosphate channel opener, on restoration of myocardial blood flow and functional improvement after coronary revascularization was investigated in 20 patients with first anterior acute myocardial infarction. Ten patients received intracoronary administration of nicorandil (2 mg) after coronary revascularization; the other 10 patients received coronary revascularization only and served as control subjects. Myocardial contrast echocardiography and two-dimensional echocardiography were performed to assess microvascular integrity and regional function in the infarcted area. Nicorandil improved peak contrast intensity ratio (p < 0.001), calculated as the ratio of peak contrast intensity in the infarcted and noninfarcted areas, indicating the restoration of myocardial blood flow to the infarcted myocardium. Regional wall motion improved more significantly in 1 month in patients who received nicorandil (p < 0.01). Thus our results suggested the usefulness of intracoronary nicorandil administration after coronary revascularization for restoring blood flow and functional improvement in patients with acute myocardial infarction.

Comparison of myocardial contrast echocardiography and coronary angiography for assessing the acute protective effects of collateral recruitment during occlusion of the left anterior descending coronary artery at the time of elective angioplasty

To assess the immediate change in collateral flow distribution within the occluded myocardium and the acute protective effects on myocardial ischemia after coronary occlusion, myocardial contrast echocardiography (MCE) was performed in 15 patients with normal left ventricular function undergoing elective coronary angioplasty of the left anterior descending artery, and the results were compared with those obtained from coronary angiography (CA). The sonicated or nonsonicated contrast material was injected into the right coronary artery before and during coronary occlusion and collaterals were graded on a 4-point scale (none = 0 to good = 3). Development of subjective anginal symptoms, ST-segment shift and wall motion abnormality during coronary occlusion were graded on a 4-point scale (none = 0 to severe = 3). Both MCE and CA detected a significant development in collateral flow during coronary occlusion. There was no significant correlation between MCE and CA collateral grades before or during coronary occlusion. The collateral flow assessed with MCE was inversely but significantly correlated with development of subjective anginal symptoms (r(s) = -0.70, p <0.01), ST-segment shift (r(s) = -0.78, p < 0.005) or wall motion abnormality (r(s) = -0.91, p < 0.001) during coronary occlusion. In contrast, the angiographic collateral flow was not correlated with development of anginal symptoms (r(s) = -0.46, p = 0.10), ST-segment shift (r(s) = -0.41, p = 0.14), or wall motion abnormality (r(s) = -0.26, p = 0.35). The present study suggested that the acute protective effects of coronary collaterals during coronary occlusion were closely associated with myocardial perfusion rather than the angiographic epicardial collateral vessel filling, and thus MCE was useful in assessing the acute protective effects of coronary collaterals during coronary occlusion.

Disappearance of the 'no-reflow' phenomenon after adjunctive intracoronary administration of nicorandil in a patient with acute myocardial infarction

Adjunctive intracoronary administration of nicorandil, an ATP-sensitive potassium channel opener, after successful coronary revascularization was performed in a 54-year-old patient with acute myocardial infarction. The 'no-reflow' phenomenon disappeared after nicorandil administration and significant functional recovery of the infarcted myocardium was achieved. This suggests that nicorandil could eliminate the 'no-reflow' phenomenon after successful coronary revascularization.

Changes of plasma atrial and brain natriuretic peptide levels during hemodialysis

OBJECTIVES

The purpose of this study was to evaluate the effect of hemodialysis on the plasma concentration of atrial and brain natriuretic peptides, and to determine the two-dimensional echocardiographic parameters affecting the changes of plasma atrial and brain natriuretic peptide levels in patients with chronic renal failure.

BACKGROUND

Brain natriuretic peptide has been found in human cardiac tissue and increases in patients with congestive heart failure. However, the factors that stimulate the secretion of plasma brain natriuretic peptide have not yet been fully clarified.

METHODS

In 15 patients with chronic renal failure, plasma atrial and brain natriuretic peptide levels and two-dimensional echocardiographic parameters were measured before and after each session of hemodialysis.

RESULTS

Plasma atrial natriuretic peptide levels significantly decreased from 367 +/- 537 pg/mL to 138 +/- 167 pg/mL after hemodialysis (p < 0.01). However, plasma brain natriuretic peptide levels did not significantly change after hemodialysis. Left atrial dimension significantly decreased (41.1 +/- 6.6 vs. 36.3 +/- 6.2 mm, p < 0.01) and left ventricular end-diastolic dimension slightly decreased after hemodialysis (57.0 +/- 10.3 vs. 55.7 +/- 9.9 mm, p < 0.05). The decrease of left atrial dimension was greater than that of left ventricular end-diastolic dimension (4.9 +/- 1.6 vs. 1.3 +/- 0.6 mm, p < 0.05). Plasma brain natriuretic peptide levels significantly correlated with fractional shortening both before and after hemodialysis (r = 0.65, p < 0.05).

CONCLUSION

Plasma atrial natriuretic peptide levels significantly decreased as the right and left atrial overloads decreased, and plasma brain natriuretic peptide levels did not significantly decrease after hemodialysis. Plasma brain natriuretic peptide levels were not significantly influenced by acute hemodynamic change, such as hemodialysis. However, plasma brain natriuretic peptide levels were significantly correlated with basic cardiac function.

Salutary effect of disopyramide on left ventricular diastolic function in hypertrophic obstructive cardiomyopathy

OBJECTIVES

The purpose of this study was to estimate the effect of disopyramide on left ventricular diastolic function in patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND

Although disopyramide has been reported to lessen clinical symptoms in patients with hypertrophic obstructive cardiomyopathy, few data exist regarding its effect on diastolic function in these patients.

METHODS

Thirteen patients with hypertrophic cardiomyopathy (six with and seven without left ventricular outflow obstruction) were examined. Before and after intravenous disopyramide, hemodynamic and angiographic studies were performed.

RESULTS

In patients with outflow obstruction, pressure gradient at the outflow tract decreased from a mean +/- SD of 100 +/- 45 to 26 +/- 33 mm Hg (p < 0.01). Although systolic function was similarly impaired in both groups, the time constant of left ventricular pressure decay (tau) shortened from 56 +/- 10 to 44 +/- 8 ms (p < 0.01) and the constant of left ventricular chamber stiffness (kc) decreased from 0.049 +/- 0.017 to 0.038 +/- 0.014 m2/ml (p < 0.01) only in patients with outflow obstruction. Shortening in tau correlated best with decrease in left ventricular systolic pressure (r = 0.84, p < 0.01). In contrast, tau was prolonged from 52 +/- 10 to 64 +/- 11 ms (p < 0.01) and kc was unchanged in patients without outflow obstruction.

CONCLUSIONS

The primary effects of disopyramide on the hypertrophied left ventricle were negative inotropic and negative lusitropic. However, left ventricular diastolic properties in patients with outflow obstruction were improved with a decrease in outflow pressure gradient. Relief of clinical symptoms in hypertrophic obstructive cardiomyopathy with disopyramide might be due in part to improvement of diastolic function, which appears secondary to the reduction in ventricular afterload.

Perfusion lung scanning before and after percutaneous transvenous mitral commissurotomy--early estimation of lung congestion relief

Percutaneous transvenous mitral commissurotomy (PTMC) has recently been used to treat mitral stenosis. The aim of this study was to evaluate the usefulness of radionuclide perfusion lung scanning in assessing the effect of PTMC on the relief of lung congestion. We studied 30 patients (7 males and 23 females, mean age 55 years). Perfusion lung scannings were performed within 1 week before and after PTMC. We calculated the ratio of activity in the upper quarter to that in the lower quarter of the right lung (U/L) as an index of lung congestion. After PTMC, the mean mitral valve area increased from 1.1 +/- 0.3 to 1.9 +/- 0.4 cm2, the mean left atrial pressure decreased from 14.8 +/- 6.3 to 9.1 +/- 3.5 mmHg, the mean pulmonary artery pressure decreased from 22.7 +/- 8.6 to 17.4 +/- 6.3 mmHg, and the U/L ratio decreased significantly from 0.89 +/- 0.40 to 0.68 +/- 0.24 (p < 0.0001). The U/L ratio showed greater improvement (4.5%) in patients whose NYHA class improved (n = 19) than in those whose NYHA class did not improve after PTMC. The U/L ratio was closely related to mitral valve area, and left atrial and pulmonary artery pressures. The change in the U/L ration before and after PTMC also reflected symptomatic improvement. In conclusion, U/L ratios obtained from perfusion lung scannings before and after PTMC reflect mitral valve area and pressures, and can be used to assess lung congestion relief after PTMC.

[Diagnosis of coronary artery dehiscence and pseudoaneurysm after modified Bentall operation by Doppler color flow imaging: a case report]

This 48-year-old man presented with anterior chest and back pain in 1981. He was treated with replacement of the ascending aorta and aortic valve under a diagnosis of dissection of the ascending aorta with severe aortic regurgitation. He underwent modified Bentall reoperation for the dilation of the aortic root in 1991. Postoperative two-dimensional echocardiography was performed because of sustained atrial flutter. An echo-free space was detected between the aorta graft and aorta wrapping on the short-axis view. Doppler color flow imaging revealed blood flow from the left coronary artery graft into the echo-free space. This leakage was suspected to be the cause of the echo-free space. Transesophageal echocardiography was performed to conform this hypothesis, which revealed blood flow from the left coronary artery graft into the echo-free space in systole and flow into the left coronary artery graft from the echo-free space in diastole.

Early diagnosis of stuck Starr-Edwards disc valve in mitral position: inconstant and interrupted mitral regurgitation

The patient was a 40-year-old man with Starr-Edwards disc valve for 21 years without symptoms. Newly developed systolic murmur at the apex was noticed at the monthly medical examination. Doppler color flow mapping indicated severe mitral regurgitation. However, the appearance of mitral regurgitation was not constant. Continuous wave Doppler recording indicated that some of the mitral regurgitations were abruptly terminated at early or mid systole with the disc closing signal. Mitral regurgitation was observed only at bradycardia and on the left lateral position. Cardiac surgery demonstrated no abnormality on the disc valve except small sulci on the rim of the disc. When the disc was tilted in the cage, it was stuck and did not move. Echocardiography was useful in detecting the early stage of stuck artificial valve that might be fatal in the mitral position.

Influence of intraballoon pressure on development of severe mitral regurgitation after percutaneous transvenous mitral commissurotomy

To evaluate the influence of intra-balloon pressure on the development of severe mitral regurgitation (> or = grade 3+), we measured intraballoon pressure during percutaneous transvenous mitral commissurotomy (PTMC) in 62 patients using the Inoue balloon catheter. The peak intraballoon pressure was 2.29 +/- 0.55 kg/cm2. Severe mitral regurgitation as a result of leaflet tear occurred in 7 patients (11%). Patients were divided into two groups those with (n = 7) and those without (n = 55) severe mitral regurgitation. Intraballoon pressure had been significantly higher in those with vs. those without severe mitral regurgitation (2.76 +/- 0.31 kg/cm2 vs. 2.23 +/- 0.55 kg/cm2, P < 0.01). Multiple logistic regression analysis revealed that the occurrence of severe mitral regurgitation was related to only the peak intraballoon pressure. These data suggest that a high intraballoon pressure is a risk factor for severe mitral regurgitation as a result of leaflet tear.

Diastolic suction in the human ventricle: observation during balloon mitral valvuloplasty with a single balloon

Diastolic suction has been demonstrated experimentally as a ventricular negative pressure when the ventricle is allowed to relax completely in the absence of filling, but it has not been extensively studied in the in vivo human heart. In balloon mitral valvuloplasty with a single balloon, the mitral orifice is occluded and inflow is considered to be completely obstructed during a balloon inflation. To demonstrate diastolic suction in the human ventricle, we measured left ventricular pressure during valvuloplasty with a high-fidelity catheter tip manometer in 17 patients. Left ventricular pressure fell below zero during a balloon inflation in all patients (-2 to -12 mm Hg). The peak negative diastolic pressure showed significant correlations with end-systolic volume index (r = 0.53, p = 0.03) and with the ejection fraction (r = 0.80, p = 0.0001). Thus diastolic suction was demonstrated in the human beating heart, and the sucking effect was potent in the heart with small end-systolic volume and high-ejection fraction.

Increase in peak oxygen uptake by restoration of atrial contraction in patients after percutaneous transvenous mitral commissurotomy

The aim of the present study was to determine the effect of sinus conversion after mitral commissurotomy on the exercise performance of patients with mitral stenosis (MS) and atrial fibrillation (Af). Electric cardioversion was attempted 10 days after successful balloon mitral commissurotomy in 32 patients with MS and Af. Both symptom-limited exercise tests with respiratory gas analysis and constant workload exercise tests with echo-Doppler examinations were performed before, five days and three months after mitral commissurotomy, and five days after successful sinus conversion. The balloon commissurotomy attenuated the increase in transmitral pressure gradient during exercise. However, no significant increase either in peak oxygen uptake (PVO2) or stroke volume were observed even three months after commissurotomy in patients with persistent Af. Sinus conversion was successful in 17 patients and PVO2 increased from 21.4 +/- 4.1 to 23.4 +/- 4.0 ml/min/kg (p < 0.01). The extent of the increase in PVO2 was related to the atrial contribution in transmitral flow (R2 = 0.39, y = 0.81x + 1.2). Sinus rhythm was maintained for three months in 14 of 17 patients. Increased PVO2 was also preserved in these patients. These results suggest that the sinus conversion after mitral commissurotomy has an effect on the exercise performance of patients with MS and Af.

Plasma atrial natriuretic peptide response to direct current cardioversion of atrial fibrillation in patients with mitral stenosis

OBJECTIVES

The purpose of this study was to evaluate the effect of direct current cardioversion therapy on the plasma concentration of atrial natriuretic peptide and to determine the main factors that influence the change in plasma atrial natriuretic peptide levels in patients with atrial fibrillation.

BACKGROUND

In atrial arrythmias, whether the fast atrial rate itself or the associated elevation of atrial pressure, or both, contributes to the increase in atrial natriuretic peptide is a subject of debate.

METHODS

In 15 patients with mild mitral stenosis, plasma atrial natriuretic peptide levels were measured and transmitral flow pattern was obtained by continuous wave Doppler echocardiography immediately before cardioversion and at 5 min, 4 h, 24 h and 5 days after direct current cardioversion. Mean mitral pressure gradient and atrial filling fraction were calculated on the basis of transmitral flow.

RESULTS

In three patients who did not have a successful return to sinus rhythm, plasma atrial natriuretic peptide levels remained elevated after cardioversion. In 12 patients who maintained sinus rhythm, plasma atrial natriuretic peptide levels were significantly reduced from 79 +/- 29 to 36 +/- 11 pg/ml 4 h after cardioversion to sinus rhythm. However, the mitral pressure gradient did not change significantly during the observation period. There were progressive increases in atrial filling fraction throughout the observation period. From 4 h to 5 days after direct current cardioversion, plasma atrial natriuretic peptide levels gradually increased concomitantly with the recovery of atrial mechanical function.

CONCLUSION

The reduction of plasma atrial natriuretic peptide levels after direct current cardioversion might be due to recovery from the high rate of atrial firing and not to an alteration in the mitral pressure gradient. Direct current cardioversion itself does not seem to influence atrial natriuretic peptide secretion. The increase in atrial natriuretic peptide levels from 4 h to 5 days after cardioversion concomitantly with an increase in atrial filling fraction may be due to recovery of atrial mechanical function.

Left ventricular diastolic pressure-volume response immediately after successful percutaneous transvenous mitral commissurotomy

The left ventricular (LV) diastolic pressure-volume response after percutaneous transvenous mitral commissurotomy (PTMC) was investigated to determine whether it was related to the baseline conditions of the left ventricle. Left ventriculography was performed, and the measurements of LV pressure were obtained in 32 patients before and after PTMC. Mitral valve area increased from 1.0 +/- 0.3 to 1.9 +/- 0.4 cm2 (p < 0.005) after PTMC, which caused a decrease in left atrial mean pressure (14.8 +/- 5.9 to 7.4 +/- 2.7 mm Hg; p < 0.005). LV end-diastolic pressure increased in all patients 5 minutes after PTMC. However, patients could be divided into 2 groups according to the following changes in LV end-diastolic pressure 20 minutes after PTMC: In 22 patients, LV end-diastolic pressure returned to the near-baseline level 20 minutes after PTMC (before 5.0 +/- 2.2, 5 minutes after 8.6 +/- 3.1, and 20 minutes after 6.3 +/- 2.5 mm Hg) with a significant increase in LV end-diastolic volume index (64 +/- 12 to 74 +/- 14 ml/m2; p < 0.001) and augmentation of LV stroke volume index (39 +/- 9 to 47 +/- 11 ml/m2; p < 0.001). However, in the remaining 10 patients with a larger LV volume (> 80 ml/m2) and reduced ejection fraction (< 50%) at baseline, LV end-diastolic pressure further increased 20 minutes after PTMC (before 5.5 +/- 2.8, 5 minutes after 7.8 +/- 2.7, and 20 minutes after 11.0 +/- 2.9 mm Hg) without significant changes in LV volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid increase in plasma endothelin concentrations during percutaneous balloon dilatation of the mitral valve in patients with mitral stenosis

OBJECTIVE

To investigate the relation between plasma concentrations of immunoreactive endothelin and haemodynamic variables before and after percutaneous transvenous balloon dilatation of the mitral valve.

DESIGN

Prospective study.

SETTING

National cardiovascular centre.

PATIENTS

25 patients with mitral stenosis and 26 healthy volunteers.

MAIN OUTCOME MEASURES

Plasma concentrations of immunoreactive endothelin were measured in the pulmonary artery, left atrium, ascending aorta, and femoral vein before and after balloon dilatation of the mitral valve.

RESULTS

Peripheral venous concentrations (mean (SD)) of endothelin were higher in the patients with mitral stenosis than in the healthy volunteers (1.76 (0.51) v 1.37 (0.45) pg/ml, p < 0.05) and they correlated with the mean left atrial pressure (r = 0.74, p < 0.01). Balloon dilatation of the mitral valve reduced the mean left atrial pressure without changing the mean right atrial pressure, systemic arterial pressure, heart rate, or cardiac index. Concentrations of plasma endothelin in the femoral vein increased from 1.76 (0.51) to 3.39 (2.46) (p < 0.01), 4.82 (2.34) (p < 0.001), and 2.43 (0.52) pg/ml (p < 0.05) at 15 and 30 minutes and 24 hours after the procedure. The concentration of endothelin in the pulmonary artery also increased from 1.85 (0.85) to 4.32 (1.58) pg/ml (p < 0.01) 30 minutes after the dilatation, whereas there were no appreciable changes in endothelin concentration in the left atrium or ascending aorta.

CONCLUSIONS

Plasma endothelin concentrations were higher in patients with mitral stenosis than in healthy volunteers and the increase was proportional to left atrial pressure. After balloon dilatation of the mitral valve there was an abrupt rise in endothelin in the femoral vein and pulmonary artery but no change in left atrial or aortic blood samples. These findings suggest that endothelin may be another vasoactive substance involved in congestive heart failure.

[Initial and follow-up results of PTCA and PTMC]

On the bases of the initial and follow-up results of patients who underwent percutaneous transluminal coronary angioplasty (PTCA) and percutaneous transvenous mitral commissurotomy (PTMC), the proper applications of these interventional therapies were discussed. The efficacy of PTMC on valvotomy was comparable to open mitral commissurotomy and the procedural safety was noticed. Our results supported the use of PTMC for patients with plicable mitral valve. Despite the good and acceptable results of elective PTCA, low initial success rate and high incidence of major cardiac events including mortality was noted in the group of urgent PTCA for patients with multivessel lesions. The urgent use of PTCA for refractory unstable angina should be restricted to selected patients without high-risk multivessel lesions.

Serial changes of mitral flow pattern after percutaneous transvenous mitral commissurotomy--assessment of Doppler and two-dimensional echocardiography

To evaluate the acute change in the mitral flow pattern, especially pressure half-time after percutaneous transvenous mitral commissurotomy (PTMC) and to investigate the factors influencing the mitral flow pattern, Doppler and two-dimensional echocardiographic studies were performed in 15 patients before and two, six, 10 and 24 hours and seven days after PTMC. Mitral valve area increased and the mean mitral pressure gradient decreased after PTMC (1.0 +/- 0.4 cm2 to 1.8 +/- 0.4 cm2; 11 +/- 6 mmHg, to 3 +/- 2 mmHg, p < 0.01). Pressure half-time also decreased two hours after surgery, from 292 +/- 70 msec to 176 +/- 48 msec (p < 0.01) and then gradually decreased to 140 +/- 47 msec within seven days of the procedure without remarkable changes in mitral valve area and the mean transmitral pressure gradient. Left atrial dimensions decreased and left ventricular end-diastolic dimensions gradually increased after PTMC (51 +/- 6 mm to 46 +/- 5 mm; 47 +/- 4 mm to 50 +/- 3 mm). The time course of this was similar to that of the pressure half-time. Further study, in which the changes in pressure half-time were evaluated within 30 minutes of PTMC in 17 patients, indicated that pressure half-time significantly decreased from 248 +/- 69 msec to 139 +/- 28 msec five minutes after balloon inflation, slightly increasing again after 30 minutes to 153 +/- 31 msec.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct secretion from left atrium and pulmonary extraction of human atrial natriuretic peptide

To evaluate direct secretion from the left atrium and pulmonary extraction of human atrial natriuretic peptide (hANP), we measured plasma hANP levels in the pulmonary artery, pulmonary vein, and left atrium in patients with either mitral stenosis or atrial septal defect. Left atrial pressure in patients with mitral stenosis was significantly higher than that in patients with atrial septal defect (7.5 +/- 1.0 mm Hg vs 3.1 +/- 0.5 mm Hg, p less than 0.01). The significant increase in the hANP level in the left atrium was recognized only in patients with mitral stenosis (149 +/- 33 pg/ml in the left atrium vs 130 +/- 28 pg/ml in the pulmonary vein, p less than 0.05). The plasma hANP level in the pulmonary vein was significantly lower than that in the pulmonary artery in both patients with mitral stenosis and those with atrial septal defect, which suggests that hANP is extracted in the lung. We conclude that hANP is secreted not only through the coronary sinus but also directly from the left atrium, stimulated by high left atrial pressure, and that circulating hANP is partially extracted in the pulmonary circulation.

Balloon diameter of the Inoue balloon catheter during percutaneous transvenous mitral commissurotomy: clinical and experimental study

To determine adequate and effective balloon diameters of the Inoue balloon catheter, we reviewed clinical results and characteristics of the Inoue balloon catheter, especially the relationship between the intra-balloon pressure and the balloon diameter, experimentally and clinically, in 46 patients with mitral stenosis undergoing percutaneous transvenous mitral commissurotomy (PTMC). Mitral valve area increased from 1.1 +/- 0.3 to 2.1 +/- 0.3 cm2 in all patients after PTMC. Based on balloon diameter settings, mitral valve area increased from 1.3 +/- 0.4 to 2.3 +/- 0.5 cm2 in patients treated with a balloon setting greater than 26 mm in diameter, from 1.1 +/- 0.3 to 2.0 +/- 0.5 cm2 in patients with a balloon setting at 26 mm in diameter, and from 1.1 +/- 0.4 to 1.7 +/- 0.4 cm2 in those treated with a balloon setting less than 26 mm in diameter, with an increase in mitral valve area of 1.0 +/- 0.6, 0.9 +/- 0.4, and 0.7 +/- 0.2 cm2, respectively. There was a significant difference between the increase in mitral valve area at a setting of 26 mm in diameter and that observed at a setting less than 26 mm in diameter. We next investigated differences between balloon diameter settings and actual balloon diameters measured from cineangiograms at maximum balloon inflation. The ratio of actual balloon diameter to a setting diameter of less than 26 mm was smaller than that of 26 mm. To evaluate the reason for the difference, we investigated the relationship between intra-balloon pressure and balloon diameter. In the prototype Inoue balloon catheter, intra-balloon pressure increases from 1.0 kg/cm2 at 20 mm in diameter to 2.2 kg/cm2 at 30 mm in diameter at atmospheric pressure. In conclusion, the increase in mitral valve area was inadequate when the balloon was less than 26 mm in diameter because of inadequate intra-balloon pressure. We, therefore, recommend a balloon size set above 26 mm to obtain adequate intra-balloon pressure when using the Inoue balloon catheter.

Acute reduction of mitral valve area after percutaneous balloon mitral valvuloplasty: assessment with Doppler continuity equation method

Mitral valve areas before and after balloon mitral valvuloplasty were serially determined by the Doppler continuity equation method in 16 patients. Ultrasound examinations were performed before and immediately after balloon inflation and 24 hours, 1 week, and 1 month after valvuloplasty. Mitral valve area determined by the Doppler continuity equation method correlated well with that determined at catheterization by the Gorlin formula, not only before but also immediately after balloon inflation (y = 0.87 x + 0.05, standard error of estimate = 0.22 cm2, r = 0.90). Serial calculation of mitral valve area by the Doppler continuity equation method showed a slight but significant decrease in the valve area at 24 hours after balloon mitral valvuloplasty but no change after that. We conclude that the Doppler continuity equation method provides an accurate estimation of mitral valve area before and even after balloon valvuloplasty. Mitral valve area dilated by balloon inflation is decreased slightly within 24 hours after the procedure, which corroborates valve stretch as one mechanism for increasing mitral valve area with balloon valvuloplasty. Estimation of mitral valve area immediately after balloon mitral valvuloplasty may overestimate the long-term efficacy of the procedure.

Effects of percutaneous transvenous mitral commissurotomy on levels of plasma atrial natriuretic peptide during exercise

To clarify the factors that influenced the secretion of human atrial natriuretic peptide (ANP) during exercise, we studied the relations between the changes in ANP, transmitral pressure gradient, heart rate and blood pressure at exercise in 16 patients with mitral stenosis before and after percutaneous transvenous mitral commissurotomy (PTMC). Before PTMC, ANP levels increased from 107 +/- 70 to 183 +/- 96 pg/ml during exercise testing (p less than 0.01), concomitant with the increment in mean transmitral pressure gradient, heart rate and systolic blood pressure. After PTMC, ANP levels also increased from 78 +/- 43 to 117 +/- 64 pg/ml, concomitant with the increment of those parameters. However, increments of ANP, mean transmitral pressure gradient and heart rate after PTMC were lower than those before PTMC. Because the most important factor influencing the secretion of ANP was unclear, the differences between these parameters were calculated at submaximal exercise before and after PTMC. There was a significant relation only between the change in ANP and mean transmitral pressure gradient (r = 0.70, p less than 0.01). These results suggest that the most important factor influencing the secretion of ANP during exercise is the change in transmitral pressure gradient in patients with mitral stenosis.

Residual atrial septal perforation after percutaneous transvenous mitral commissurotomy with Inoue balloon catheter

To estimate the incidence of residual atrial septal perforation (ASP) following percutaneous transvenous mitral commissurotomy (PTMC) with the Inoue balloon catheter and to examine the factors contributing to ASP, we studied 46 patients with mitral stenosis undergoing PTMC. Residual ASP was evaluated by Doppler color flow imaging 1 day after PTMC, and was detected in 7 out of 46 patients (15.2%). We examined the relationship between the development of ASP (ASP+) and the age of the patient, the left atrial dimension before PTMC, the mean pressure difference between left and right atrium after PTMC, and the duration of the procedure from atrial septal puncture by the Brockenbrough method to balloon inflation. There was a good correlation between the development of residual ASP and the duration of the procedure (ASP+, 51.0 +/- 34.0 minutes; without ASP, 24.6 +/- 16.2 minutes; p less than 0.01). However, there was no significant correlation between the development of ASP and other factors. In the follow-up study, ASP disappeared in four patients within 3 months. ASP persisted in two patients for 1 year after PTMC. However, the shunt in these two patients was clinically insignificant. These data suggest that residual ASP may depend on the duration of the procedure, and that most cases of ASP disappear within 1 year after PTMC.

Improvement in pulmonary function in mitral stenosis after percutaneous transvenous mitral commissurotomy

Before and after percutaneous transvenous mitral commissurotomy (PTMC), pulmonary function studies were performed in 25 patients with mitral stenosis, in order to determine the effects of pulmonary hemodynamics on pulmonary function in patients with mitral stenosis. After PTMC, dramatic improvements in pulmonary hemodynamics were seen in all patients. With regard to pulmonary function data, the VC as percent predicted value increased from 87.6 +/- 16.1 percent to 94.7 +/- 14.4 percent (p less than 0.001). Although the ratio of FEV1/FVC was unchanged, the MVV as percent predicted value increased, and the ratio of RV/TLC, CV, and the difference in nitrogen concentration between 750 ml and 1,250 ml of expired volume decreased significantly. According to the maximum expiratory flow-volume curves, V ax 50% and Vmax 25% improved. Despite marked improvements in pulmonary ventilatory function soon after PTMC, the percent predicted diffusing capacity of the lung for carbon monoxide decreased significantly after PTMC. Arterial blood gas data, such as the partial pressure of oxygen and carbon dioxide in arterial blood and the alveolar-arterial differences in partial pressure of oxygen, did not improve within one or two weeks after PTMC. We conclude that in mitral stenosis, the majority of ventilatory function impairments are caused by hemodynamic alterations that are mainly reversible.

Improvement in mitral flow dynamics during exercise after percutaneous transvenous mitral commissurotomy. Noninvasive evaluation using continuous wave Doppler technique

Evaluation of mitral flow dynamics during exercise is critically important in patients who receive percutaneous transvenous mitral commissurotomy (PTMC) because limited mitral flow during exercise provokes hemodynamic deterioration and involves cardiogenic symptoms in patients with mitral stenosis. To examine mitral flow dynamics during exercise, we applied continuous wave Doppler technique in 20 patients with mitral stenosis. Exercise Doppler study was performed 2 days before and 5 days after PTMC. PTMC increased mitral valve area from 1.0 +/- 0.3 (mean +/- SD) to 1.9 +/- 0.5 cm2 and decreased mean transmitral pressure gradient from 8 +/- 2 to 4 +/- 1 mm Hg at rest. Moreover, PTMC decreased mean transmitral pressure gradient from 21 +/- 6 to 11 +/- 4 mm Hg at submaximal exercise. The extent of an increase in mitral valve area by PTMC correlated with a decrease in the mean transmitral pressure gradient at the submaximal exercise (r = -0.76, p less than 0.01) and that at rest (r = -0.52, p less than 0.05). Heart rate after PTMC during exercise was significantly lower than that before PTMC, indicating that the compensatory mechanism (tachycardia) to increase cardiac output during exercise is less necessary after PTMC. Thus, we conclude that the mitral flow dynamics during exercise is improved, as well as the resting mitral flow dynamics 5 days after PTMC, and that exercise Doppler study enabled us to make a noninvasive evaluation of the mitral flow dynamics in patients who receive PTMC.

Rapid reduction of plasma atrial natriuretic peptide levels during percutaneous transvenous mitral commissurotomy in patients with mitral stenosis

To clarify the direct contribution of the left atrial pressure to secretion of human atrial natriuretic peptide (hANP), we have attempted to study the relations between plasma hANP levels, neurohumoral factors, and hemodynamic changes in 13 patients with mitral stenosis undergoing percutaneous transvenous mitral commissurotomy (PTMC). After PTMC, the left atrial pressure fell from 14.7 +/- 1.9 (mean +/- SEM) to 6.5 +/- 0.7 mm Hg in all patients studied (p less than 0.0005), whereas there were no remarkable changes in either the right atrial pressure, mean arterial pressure, or heart rate. Plasma immunoreactive hANP levels obtained from the pulmonary artery decreased from 278 +/- 51 to 137 +/- 31 pg/ml after PTMC (p less than 0.0005). There was a significant correlation between the decrement of hANP levels and that of left atrial pressure (r = 0.72, p less than 0.005). Neither plasma renin activity nor norepinephrine levels changed. In contrast, plasma aldosterone concentrations significantly increased from 11.3 +/- 1.5 to 16.4 +/- 2.7 pg/ml after PTMC (p less than 0.01), although there was no casual relation between plasma concentrations of aldosterone and hANP. The present result with PTMC-induced rapid fall of the left atrial pressure with a concomitant reduction in hANP secretion strongly suggests the importance of the left atrial pressure on hANP secretion in humans.