Relapse of minimal change disease following the third mRNA COVID-19 vaccination: a case report and literature review

Mass vaccination is the most important strategy to terminate the coronavirus disease 2019 (COVID-19) pandemic. Reports suggest the potential risk of the development of new-onset or relapse of minimal change disease (MCD) following COVID-19 vaccination; however, details on vaccine-associated MCD remain unclear. A 43-year-old man with MCD, who had been in remission for 29 years, developed nephrotic syndrome 4 days after receiving the third dose of the Pfizer-BioNTech vaccine. His kidney biopsy revealed relapsing MCD. Intravenous methylprednisolone pulse therapy followed by oral prednisolone therapy was administered, and his proteinuria resolved within 3 weeks. This report highlights the importance of careful monitoring of proteinuria after COVID-19 vaccination in patients with MCD, even if the disease is stable and no adverse events occurred during previous vaccinations. Our case report and literature review of COVID-19 vaccine-associated MCD indicated that MCD relapse tends to occur later after vaccination and slightly more often following the second and subsequent vaccine doses than new-onset MCD.

Hypereosinophilia-associated acute intradialytic hypotension: a report of three cases and literature review

Occasionally, patients undergoing dialysis develop acute severe hypotension that requires interruption of dialysis within minutes of initiating every dialysis session. Although the underlying causes of recurrent intradialytic hypotension are evaluated extensively, including dialysis-associated allergic reactions or other possible causes, the definitive cause is sometimes missed. Dialysis is a life-sustaining procedure; therefore, prompt identification and management of the underlying cause of dialysis intolerance are crucial. Herein, we report three cases of patients undergoing dialysis who presented with hypereosinophilia-associated acute intradialytic hypotension. All three patients developed acute severe hypotension within minutes after the start of every dialysis session. The prescriptions for dialysis were changed, but episodes of intradialytic hypotension persisted. Pretreatment with methylprednisolone given intravenously before the dialysis session was also ineffective. All patients had hypereosinophilia (> 1500/μL) of different etiology. Eosinophil-lowering therapy with 0.5 mg/kg of prednisolone given orally daily was initiated, and all of them could restart dialysis without any hypotensive episodes within a few days. Our case report and literature review indicated that hypereosinophilia, regardless of its etiology, could result in severe acute hypotension shortly after the start of dialysis session. The oral administration of prednisolone daily was highly effective on hypereosinophilia-associated intradialytic hypotension, while pretreatment with intravenous corticosteroid therapy just before dialysis had no effect. Hypereosinophilia-associated acute intradialytic hypotension is an under-recognized condition; therefore, clinicians need to be aware of this clinical entity and initiate effective treatment strategies. We also provide a brief summary of previously published cases.

PRDM9 activity depends on HELLS and promotes local 5-hydroxymethylcytosine enrichment

Meiotic recombination starts with the formation of DNA double-strand breaks (DSBs) at specific genomic locations that correspond to PRDM9-binding sites. The molecular steps occurring from PRDM9 binding to DSB formation are unknown. Using proteomic approaches to find PRDM9 partners, we identified HELLS, a member of the SNF2-like family of chromatin remodelers. Upon functional analyses during mouse male meiosis, we demonstrated that HELLS is required for PRDM9 binding and DSB activity at PRDM9 sites. However, HELLS is not required for DSB activity at PRDM9-independent sites. HELLS is also essential for 5-hydroxymethylcytosine (5hmC) enrichment at PRDM9 sites. Analyses of 5hmC in mice deficient for SPO11, which catalyzes DSB formation, and in PRDM9 methyltransferase deficient mice reveal that 5hmC is triggered at DSB-prone sites upon PRDM9 binding and histone modification, but independent of DSB activity. These findings highlight the complex regulation of the chromatin and epigenetic environments at PRDM9-specified hotspots.

A case of septic pulmonary embolism caused by P. aeruginosa in a hemodialysis patient and review of the literature

Background

Septic pulmonary embolism (SPE) is an uncommon but serious complication resulting from infection of the blood. Gram-positive cocci, including methicillin-susceptible Staphylococcus aureus and methicillin-resistant Staphylococcus aureus, are the most common causative organisms of SPE. Few case reports have been published on SPE caused by Pseudomonas aeruginosa (P. aeruginosa), and thus, the consensus treatment of SPE caused by P. aeruginosa infections remains undetermined. Management of P. aeruginosa infection can be challenging due to its poor prognosis and antimicrobial resistance. Here, we report a case of successful combination antibiotic therapy for SPE associated with infective endocarditis (IE) caused by P. aeruginosa in a hemodialysis patient, with a review of the literature.

Case presentation

A 62-year-old man receiving maintenance hemodialysis as treatment for end-stage renal disease due to IgA nephropathy was admitted to our hospital with high fever and chills lasting 10 days. Chest computed tomography revealed multiple nodular shadows, and gram-negative rods were confirmed by blood culture obtained on admission. We suspected SPE and initiated meropenem (MEPM) treatment. P. aeruginosa was identified in blood cultures, and transesophageal echocardiography demonstrated vegetation on the tricuspid valve. Therefore, a diagnosis of SPE associated with IE caused by P. aeruginosa was made. P. aeruginosa isolates showed good susceptibility to MEPM, but no symptomatic improvement was observed. Thus, antibiotics were changed from MEPM to a combination of ceftazidime and tobramycin (TOB). The patient exhibited a favorable response to the combination therapy, although we discontinued TOB on day 23 because of tinnitus symptoms.

Conclusions

We report a rare case of SPE associated with IE caused by P. aeruginosa in a hemodialysis patient. Combination antibiotic therapy may be effective in this situation.

Real time quantification of low temperature radiofrequency ablation lesion size using phased array intracardiac echocardiography in the canine model: comparison of two dimensional images with pathological lesion characteristics

OBJECTIVE

To evaluate the feasibility of quantifying low temperature radiofrequency catheter ablation (RFCA) lesions using a phased array intracardiac echocardiography (ICE) catheter--with better tissue penetration and in a deflectable device-in the canine model.

INTERVENTION

Low temperature radiofrequency (RF) energy (50-60 degrees C at up to 40 W) was delivered to the left ventricle in 11 beagles for 60 seconds, using an 8 French catheter with a deflectable tip and a 4 mm distal electrode.

MAIN OUTCOME MEASURES

Comparison of the width and depth of RFCA lesions measured by ICE with pathological findings.

RESULTS

33 RF energies were delivered in 11 dogs. 31 lesions (94%) were confirmed at necropsy. 27 of 31 ablation lesions (87%) were detected by ICE. The mean (SD) width and depth of the ICE detected lesions were 10.4 (2.6) mm and 5.7 (1.9) mm, respectively. Pathological findings showed that RFCA lesions consisted of inner and outer layers. Macroscopically, the mean (SD) width and depth of the inner layers were 7.6 (2.3) mm and 3.6 (1.2) mm and those for the whole layers were 10.0 (2.8) mm and 5.3 (1.5) mm, respectively. Microscopically, the inner and outer layers corresponded to necrotic and oedematous areas, respectively. The ICE detected lesion size had better correlation with the pathological measurements of the whole layers in width (r = 0.911) and in depth (r = 0.756).

CONCLUSION

The real time evaluation of RFCA lesion size using the phased array ICE is feasible, even with a low temperature RF application. However, ICE slightly overestimates RFCA lesion size compared with pathological necrotic lesion size.

New applications of intracardiac echocardiography: assessment of coronary blood flow by colour and pulsed Doppler imaging in dogs

OBJECTIVE

To explore the application of a new 10 French intracardiac echocardiography (ICE) catheter with phased array and Doppler capable transducer for the assessment of epicardial and intramyocardial coronary blood flow.

METHODS

The coronary arteries were detected by cross sectional imaging in seven closed chest dogs, and coronary blood flow visualised by colour Doppler. Blood flow velocities were recorded by pulsed Doppler at baseline for reproducibility of repeated measurements, and during hyperaemia for coronary flow reserve measurements. Comparisons were made with Doppler guide wire data obtained simultaneously. Intramyocardial coronary artery blood flow was assessed by colour flow mapping, and the blood flow velocities recorded using pulsed Doppler at baseline and during hyperaemia.

RESULTS

Seven left main, six left anterior descending, seven left circumflex, and five right coronary arteries were visualised in the seven animals by cross sectional or colour Doppler imaging. Repeated measurements of coronary flow velocity showed a good correlation (mean diastolic velocity, r = 0.93, n = 22, p < 0.0001; peak diastolic velocity, r = 0.96, n = 22, p < 0.0001, respectively). Intraobserver/interobserver variability was satisfactorily low. Coronary flow reserve from ICE correlated highly with the value obtained from the Doppler guide wire (r = 0.90, n = 26, p < 0.0001). Intramyocardial coronary blood flow was identified in all seven dogs, and flow velocities were recorded at baseline and during hyperaemia in four animals.

CONCLUSIONS

This new ICE catheter provides high quality diagnostic resolution. It is useful for coronary blood flow assessment.

Effects of smoking on myocardial injury in patients with conservatively treated acute myocardial infarction: a study with resting 123I-15-iodophenyl 3-methyl pentadecanoic acid/201Tl myocardial single photon emission computed tomography

Many reports have demonstrated that smokers who have suffered an acute myocardial infarction (AMI) have a better prognosis than nonsmokers. The present study investigated the effects of current smoking on myocardial injury with resting 123I-15-iodophenyl 3-methyl pentadecanoic acid (BMIPP)/201Tl myocardial single photon emission computed tomography in 103 patients with conservatively treated AMI. The left ventricular myocardium was divided into 9 segments and BMIPP and 201Tl defects were scored using a 5-point grading system (0 = normal and 4 = no uptake). The sum of the defect scores was defined as the total defect score. There was no significant difference in either the baseline severity of the coronary artery disease or the total defect scores for BMIPP and 201Tl between the current smoker and nonsmoker groups. The difference between the total defect scores for BMIPP and 201Tl tended to be larger in the current smoker group than in the nonsmoker group (2.0 +/- 1.9 vs 1.3 +/- 1.6, p = 0.056). Forty-one (53%) of 77 patients in the current smoker group exhibited a BMIPP/201Tl mismatch, whereas only 8 (31%) of 26 patients in the nonsmoker group did (p = 0.047). In conclusion, current smokers had more likelihood of salvageable myocardium in areas at risk, as demonstrated by BMIPP/201Tl mismatch, in AMI than nonsmokers.

Point mutations in mitochondrial DNA of patients with alcoholic cardiomyopathy

The pathogenesis of alcoholic cardiomyopathy (ACM) is not well understood. However, recent reports have shown that mutations in mitochondrial DNA (mtDNA) were associated with mitochondrial encephalomyopathy and cardiomyopathy. Our objective was to explore point mutations in mtDNA and the pathogenesis of ACM. We obtained heart biopsy specimens from ten male habitual drinkers with congestive heart failure. We amplified the total mtDNA obtained from these specimens using a two-step polymerase chain reaction method and analyzed the products using automated fluorescence-based direct sequencing. The sequences were compared with those of controls. MtDNA from the ACM patients contained multiple point mutations. Specifically, four of the ten patients carried five point mutations that had been detected previously in several other mitochondrial diseases. These point mutations were not observed in controls. These results suggest that mtDNA abnormalities are involved in the pathogenesis of ACM.

Angiotensin blockade inhibits increased JNKs, AP-1 and NF- kappa B DNA-binding activities in myocardial infarcted rats

Inhibition of the renin-angiotensin system has been shown to prevent left ventricular remodeling after myocardial infarction. However, the effect of angiotensin on the signal transduction pathway of left ventricular remodeling after myocardial infarction is as yet unknown. The purpose of this study was to measure myocardial MAPKs and AP-1, NF- kappa B, and Sp-1 DNA-binding activities after myocardial infarction. Moreover, we evaluated the effects of angiotensin converting enzyme (ACE) inhibitor and angiotensin receptor blocker (ARB) on signal transduction pathway. Myocardial infarction was produced by ligation of the coronary artery in Wistar rats. Temocapril (ACE inhibitor) (3 and 30 mg/kg/day) and candesartan cilexitil (ARB) (1 and 10 mg/kg/day) were orally administered once a day. After ligation of the left descending coronary artery, JNKs (p46JNK and p55JNK) increased to 2.0- (P<0.01) and 2.8-fold (P<0.01) at 7 days, respectively. ERKs (p44ERK and p42ERK) and p38 activities did not increase significantly. AP-1 and NF- kappa B binding activities increased at 5 days, reached their peak 2.2- and 2.0-fold at 7 days. Sp-1 did not change. ACE inhibitor and ARB inhibited JNKs, NF- kappa B and AP-1 activities. Increased JNKs, AP-1, NF- kappa B, and Sp-1 DNA-binding activities were suppressed by both drugs in the infarcted region. Doppler-echocardiography showed that ACE inhibitor and ARB prevented the dilatation of left ventricular cavity at 14 days and improved diastolic filling pattern. JNKs, AP-1 and NF- kappa B activation in myocardial infarcted rats could be responsible for left ventricular remodeling after myocardial infarction and angiotensin may be related to the activation of these signals.

Prediction of functional recovery in patients with myocardial infarction after revascularization--comparison of low-dose dobutamine stress echocardiography with fluorine-18 fluorodeoxyglucose positron emission tomography

The present study investigated the agreement between low-dose dobutamine stress echocardiography (LDDSE) and fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and compared each technique's ability to detect myocardial viability and predict functional recovery in 30 patients. All patients underwent revascularization, followed by echocardiography 5+/-3 months. Of the 390 segments analyzed by echocardiography before revascularization, 110 (28%) had abnormal wall motion. LDDSE showed viability in 66 sites of the 110 dyssynergic segments and 58 of these viable segments recovered their wall motion. With FDG-PET, 78 of the 110 dyssynergic segments were diagnosed as viable and 62 of these showed improvement of the wall motion. The sensitivities for LDDSE and FDG-PET to assess functional recovery were 84% and 90%, respectively; specificities were 80% and 64%, respectively. Positive predictive values for LDDSE and FDG-PET were 88% and 79%; negative predictive values were 75% and 78%, respectively. Both methods had good sensitivity for detecting improvement in regional function after revascularization, but LDDSE had a higher specificity for detecting viability and a better positive predictive value for left ventricular functional recovery.

Prediction of contractile reserve by cyclic variation of integrated backscatter of the myocardium in patients with chronic left ventricular dysfunction

OBJECTIVE

To clarify whether assessment of the acoustic properties of the myocardium at rest can predict contractile reserve in patients with chronic left ventricular dysfunction.

METHODS

23 patients (mean (SD) age 63 (12) years) with chronic left ventricular dysfunction were studied. The magnitude of cardiac cycle dependent variation of integrated backscatter (CVIB) of the myocardium was measured at rest in the basal and mid segment of the septum and posterior wall of the left ventricle, using a real time two dimensional integrated backscatter imaging system. The results were compared with the percentage wall thickening and the wall motion at rest and during low dose dobutamine infusion. The wall motion was graded as normal, hypokinetic, or akinetic and contractile reserve was considered present when an akinetic or hypokinetic segment improved during dobutamine infusion.

RESULTS

The CVIB at rest correlated with per cent wall thickening at rest and during dobutamine infusion (at rest, r = 0.61, p < 0.0001, during dobutamine, r = 0.76, p < 0.0001). Of the 76 segments examined, 27 showed contractile reserve. The mean CVIB at rest was significantly greater in segments with contractile reserve than in those without (p < 0.0001). CVIB above 3 dB at rest predicted segments with contractile reserve with a sensitivity and specificity of 81% and 60%, respectively (p < 0.0001).

CONCLUSIONS

CVIB reflected not only myocardial contractility but also the functional capacity of the myocardium. It predicted segmental contractile reserve in patients with chronic left ventricular dysfunction.

Dobutamine stress electrocardiography-gated Tc-99m tetrofosmin SPECT for detection of viable but dysfunctional myocardium

BACKGROUND

Technetium-99m-labeled myocardial perfusion tracers allow simultaneous assessment of myocardial perfusion and left ventricular function by electrocardiography-gated scan. This study was performed to determine whether dobutamine stress electrocardiography-gated tetrofosmin single photon emission computed tomography (SPECT) can identify viable (as defined by positron emission tomography [PET]) but dysfunctional myocardium with contractile reserve.

METHODS AND RESULTS

Thirty-five patients with myocardial infarction underwent resting electrocardiography-gated SPECT and fluorodeoxyglucose (FDG) PET. The relative uptakes of tetrofosmin (%tetrofosmin) and FDG (%FDG) were calculated. Wall motion in 9 left ventricular segments was assessed at rest and during dobutamine stress on a 3-dimensional cine-mode display created with automatic left ventricular function analysis software. A total of 129 dysfunctional segments were analyzed. Forty-five (48.9%) of 92 segments with %tetrofosmin of 50% or greater and only 4 (10.8%) of 37 segments with %tetrofosmin less than 50% had contractile reserves (P <.0001). The sensitivity, specificity, and predictive accuracy of %tetrofosmin of 50% or greater for detecting %FDG of 50% or greater were 85.7%, 74%, and 82.9%, respectively. The incidence of the presence of contractile reserve rose with increasing magnitude of %FDG. The sensitivity, specificity, and predictive accuracy of the presence of contractile reserve for detecting %FDG of 50% or greater were 43.9%, 80.6%, and 52.7%, respectively.

CONCLUSIONS

Dobutamine stress electrocardiography-gated SPECT can identify viable (as defined by PET) but dysfunctional myocardium with contractile reserve.

Novel method for assessing myocardial perfusion: visualization and measurement of intramyocardial coronary blood flow in the entire left ventricular wall using contrast enhanced, high frequency Doppler echocardiography

Using a high frequency ultrasonic transducer, intramyocardial coronary blood flow (IM-CBF) can be visualized and evaluated during hemodynamic changes in the anterior wall and septum of the left ventricle (LV). We tested the hypothesis that detection and quantitative measurement of IM-CBF of entire LV segments are feasible using a high frequency ultrasonic transducer in conjunction with intravenous contrast injection in vivo. A 3 - 8 MHz transducer was used to image and measure IM-CBF in 10 anesthetized dogs. We obtained a color Doppler image of IM-CBF in the LV short-axis view after intravenous Levovist injection (25 mg/ml). The IM-CBF velocity was recorded using spectral Doppler in the antero-septal and infero-posterior wall of closed chest dogs and in the entire LV after opening the chest. A significant increase in IM-CBF velocity was observed in all LV regions after adenosine 5'- triphosphate (ATP) administration. After Levovist(TM) injection, the visualization of IM-CBF was improved and the spectral Doppler pattern of coronary flow velocity was clarified compared to baseline. IM-CBF was assessed in the antero-septal region of the LV before and after left anterior descending coronary artery occlusion. A high frequency ultrasonic transducer in conjunction with intravenous contrast injection improved IM-CBF visualization, enabling quantitative evaluation of the intramyocardial coronary circulation in the entire LV after coronary occlusion and hyperemia. This study may represent a step towards noninvasive assessment of myocardial perfusion before and after coronary reperfusion.

A reverse flow-metabolism mismatch pattern: a new marker of viable myocardium with greater contractility during dobutamine stress than myocardium with a flow-metabolism mismatch pattern

Few studies have investigated the contractility of myocardium with a reverse flow-metabolism pattern; that is, greater uptake of nitrogen- 13-ammonia (NH3) than fluorine- 18-fluorodeoxyglucose (FDG) on positron emission tomography (PET). This study examined the contraction thickening represented by count increase in ECG-gated FDG-PET of myocardium with a reverse flow-metabolism pattern during low-dose dobutamine stress. Fifty-four patients with myocardial infarction were studied. Relative NH3 and FDG uptake (%NH3, %FDG) and %count increase were measured in 216 apical and 216 lateral segments on ECG-gated FDG-PET. The %count increase during low-dose dobutamine stress was greater in myocardium with a reverse flow-metabolism mismatch pattern than in myocardium with a flow-metabolism mismatch pattern (35.9+/-25.7% vs 24.6+/-15.9%, p=0.0221 in apical segments, and 38.4+/-22.6% vs 27.6+/-18.4%, p=0.0040 in lateral segments) despite smaller %FDG. A reverse flow-metabolism mismatch pattern should be noted as a new marker of viable myocardium with greater contractility during dobutamine stress than myocardium with a flow-metabolism mismatch pattern.

Effects of metabolically ischemic, but viable, myocardium on QT dispersion in patients with acute myocardial infarction: a study with resting I-123-BMIPP/thallium-201 myocardial single-photon emission computed tomography

In chronic Q-wave myocardial infarction, QT dispersion is closely correlated with infarct size, but this correlation has not been evaluated for acute myocardial infarction (AMI). The effects of abnormal fatty acid metabolism on QT dispersion were examined in 123 patients with AMI who underwent resting iodine-123-15-iodophenyl 3-methyl pentadecanoic acid (BMIPP)/thallium-201(201Tl) myocardial single photon emission computed tomography (SPECT) and electrocardiographic analysis in the subacute phase. The relationship between BMIPP and 201Tl was defined as match when the total defect score for BMIPP was equal to or smaller than that for 201Tl, and as mismatch when the total defect score for BMIPP was larger than that for 201Tl. Twenty-six patients (21%) demonstrated BMIPP-201Tl match and 97 (79%) demonstrated mismatch. Infarct size was closely correlated with QT dispersion (r=0.67, p<0.001) in patients with BMIPP-201Tl match, but weakly correlated (r=0.30, p<0.005) in patients with BMIPP-201Tl mismatch. For small infarctions, QT dispersion was significantly larger in patients with BMIPP-201Tl mismatch than in those with BMIPP-201Tl match (62+/-24 ms vs 41+/-18 ms, p=0.03), but did not differ between the 2 groups for large infarctions. This study shows that QT dispersion is influenced by infarct size and by the presence of metabolically ischemic but viable myocardium in patients with AMI.

[Clinical usefulness of intracoronary Doppler for prediction of coronary restenosis]

The Doppler guide wire is widely used in the diagnosis of heart diseases, and in particular including ischemic heart disease. It offers various advantages for application in tortuous and peripheral arteries, and in the detection of functional coronary stenosis that coronary angiography cannot detect. A number of multicenter trials have also shown that the Doppler guide wire is of value in predicting coronary restenosis after coronary intervention. On the other hand, the Doppler guide wire is influenced not only by the stenosis in the epicardial coronary artery, but also by stenosis in the vascular beds of coronary microcirculation. An appreciation of both the advantages and disadvantages of the Doppler guide wire and its usefulness is of considerable importance.

Effects of preinfarction angina on myocardial injury in patients with acute myocardial infarction: a study with resting 123I-BMIPP and 201T1 myocardial SPECT

METHODS

Recent studies have suggested that patients with preinfarction angina have smaller infarcts and a better in-hospital outcome than those without angina. The mechanisms responsible for limitation of infarct size in the presence of preinfarction angina are unclear. We examined the effects of preinfarction angina on myocardial injury in patients with the first acute myocardial infarction with resting 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) 201TI myocardial scanning performed within 1 mo of infarction.

RESULTS

Of 136 patients tested, 48 (35%) had preinfarction angina within 72 h before infarction, whereas 88 (65%) did not. BMIPP and 201TI defects were scored in 9 segments of the left ventricle (0 = normal, 1 = mild defect, 2 = moderate defect, 3 = severe defect, and 4 = no uptake). The total defect score was defined as the sum of the defect scores. There was no significant difference in percentage diameters of stenoses of infarct-related arteries, collateral circulation, total defect scores for BMIPP, or 201TI between the groups with and without preinfarction angina. However, the ratio of total defect score for 201TI to that for BMIPP was significantly smaller for patients with than for those without preinfarction angina (0.64 +/- 0.21 versus 0.74 +/- 0.25, respectively; P = 0.007).

CONCLUSION

Preinfarction angina did not affect the areas at risk in acute myocardial infarction, as shown by BMIPP defect, but decreased necrotic myocardium in the areas at risk, as shown by 201TI defect, and increased metabolically damaged but viable myocardium, as shown by BMIPP and 201TI mismatch through unidentified mechanisms other than collateral circulation (e.g., ischemic preconditioning).

Endomyocardial biopsy findings in patients with atrioventricular block in the absence of apparent heart disease

The purpose of this study was to examine the histopathological findings of right ventricular endomyocardial biopsies from ten patients less than 60 years of age (47 +/- 9.8 (mean +/- SD) years) with documented atrioventricular block but without apparent heart disease. They underwent electrophysiological testing, echocardiography, coronary angiography, and right ventricular endomyocardial biopsy. Biopsy specimens were assessed for morphologic changes in myocyte diameter, fibrosis, disarray, and degeneration. Electrophysiological testing demonstrated atrioventricular nodal block in 2, intra-His bundle block in 2, and infra-His bundle block in 6 patients. Histology revealed evidence of myocardial fibrosis with either myocyte hypertrophy or disarray in 7 of the 10 patients. The results of electrophysiological testing did not correlate with the histopathological findings or severity. In one patient, heart failure appeared during the follow-up period. We conclude that patients with atrioventricular block of unknown etiology have histological abnormalities of the ventricular endomyocardium in addition to the conduction system disturbances. We consider such cases as constituting one of the disease groups of cardiomyopathy, and suggest that it is necessary to follow up the clinical course in these patients.

[Prediction of restenosis after percutaneous transluminal coronary angioplasty using coronary flow reserve. Kansai Doppler Guide Wire Study Group]

This multi-center prospective study attempted to predict restenosis after percutaneous transluminal coronary angioplasty(PTCA) using coronary flow reserve. Intracoronary blood flow velocity was measured in 47 patients(37 males, 10 females, mean age 66 +/- 9 years) with a Doppler guide wire, following successful PTCA. Twenty-four patients had prior myocardial infarction. After successful PTCA, a Doppler guide wire was placed at the distal portion of the target lesion, and coronary blood flow velocity was measured before and during intravenous administration of adenosine triphosphate. Follow-up coronary angiography was performed 154 +/- 69 days after PTCA, and the diameter stenosis of the target lesion was measured using quantitative coronary angiography. Follow-up angiography showed restenosis in 13 patients(28%). Sensitivity and specificity for predicting restenosis were low(50%, 45%, respectively) with a post-PTCA% diameter stenosis cut-off point of 27%. Sensitivity and specificity were 67% and 61% with a minimal lumen diameter cut-off of 1.8 mm. The reference coronary artery diameter(cut-off point 2.5 mm) was better for predicting restenosis(sensitivity 78% and specificity 76%). Sensitivity and specificity were 62% and 67%, respectively, using coronary flow reserve(cut-off point 2.0). The restenosis rate of patients with a reference diameter of more than 2.5 mm was 10%, but 54% for those with less than 2.5 mm(p < 0.05). In patients with a reference diameter of less than 2.5 mm, coronary flow reserve was useful for predicting restenosis(cut-off point 1.9, sensitivity 71% and specificity 83%). Coronary flow reserve is useful for predicting restenosis after PTCA, when combined with reference coronary artery diameter.

Angiotensin blockade inhibits SIF DNA binding activities via STAT3 after myocardial infarction

The in vivo activation of transcription factors, which is important for cell regulation by gene expression, has not been well examined in myocardial infarcted heart. The purpose of this study was to determine whether myocardial signal transducer and activator of transcription (STAT) pathway is activated as sis-inducing factor (SIF) in infarcted heart, and to assess the angiotensin blockade on SIF activity in ischemic and non-ischemic myocardium of rat. Myocardial infarction was made by ligation of the coronary artery in Wistar rats. In electrophoretic mobility shift assay, myocardial SIF DNA binding activities gradually increased and reached to peak at 1 week in infarcted and non-infarcted regions after myocardial infarction. Imidapril and candesartan cilexitil significantly prevented the increase in SIF DNA binding activity in infarcted and non-infarcted regions. This increased SIF DNA complex was supershifted by specific anti-STAT3 antibody, indicating that increased SIF complex at least contained activated STAT3 proteins in myocardial infarcted heart. Furthermore, immunoprecipitation-Western blot analysis revealed that STAT3 of infarcted and non-infarcted regions were tyrosine-phosphorylated at 1 week after myocardial infarction. Imidapril and candesartan cilexitil prevented the increase in phosphorylated STAT3. Thus, the transcriptional activation of STAT3 through AT1 receptor may be partially involved in cardiac remodeling after myocardial infarction.

Dobutamine-stress electrocardiographically gated positron emission tomography for detection of viable but dysfunctional myocardium

PURPOSE

This study was performed to determine whether low-dose dobutamine stress electrocardiography (ECG)-gated fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) can assess wall motion and identify myocardium without contractile reserve despite preserved FDG uptake.

METHODS

Fifty-three patients with myocardial infarction and normal sinus rhythm underwent ECG-gated FDG-PET and transthoracic echocardiography. Wall motion of 10 segments of the left ventricle was graded as normal, hypokinetic, or akinetic/dyskinetic.

RESULTS

In 365 (76%) of 480 segments, assessment of wall motion was concordant between the 2 modalities. In 30 patients dobutamine-stress ECG-gated FDG-PET was performed. In 13 (50%) of 26 dysfunctional segments with normal FDG uptake, 16 (36%) of 44 dysfunctional segments with mildly reduced FDG uptake and 12 (25%) of 48 dysfunctional segments with moderately reduced FDG uptake, wall motion was improved by dobutamine infusion.

CONCLUSION

Assessment of left ventricular wall motion with ECG-gated FDG-PET is feasible, and dobutamine stress ECG-gated FDG-PET can simultaneously identify metabolic viability and contractile reserve.

Detection of a biphasic response of hibernating myocardium by dobutamine-stress electrocardiography-gated technetium-99m-tetrofosmin single photon emission computed tomography--a case report

A woman with coronary artery disease underwent a new imaging technique: dobutamine-stress electrocardiography (ECG)-gated tetrofosmin-single photon emission computed tomography (SPECT). Dobutamine-stress ECG-gated tetrofosmin-SPECT with automatic left ventricular function analysis software programs detected improvement and a biphasic response of dysfunctional myocardium during dobutamine infusion, which suggested viable but hibernating myocardium. Dobutamine-stress ECG-gated tetrofosmin-SPECT with automatic left ventricular function analysis software programs has the potential to detect viable but dysfunctional myocardium with contractile reserve.

A case of diffuse pulmonary arteriovenous fistula

A 30-year-old Japanese woman was admitted to hospital for dyspnea. She had a history of corrective surgery for a large atrial septal defect and partial anomalous pulmonary venous drainage, which had produced cyanosis in her infancy. However, her cyanosis continued postoperatively. Angiography revealed a double inferior vena cava (IVC), with the left IVC connected with the hemiazygos vein and the right IVC with the left atrium through a very small orifice. Most of the blood from the 2 IVCs flowed into the superior vena cava via the distended azygos and hemiazygos veins. Pulmonary arteriography revealed no abnormal structures. Pulmonary arterial pressure was normal. There was marked pulmonary venous oxygen desaturation. Perfusion lung scintigraphy revealed multiple segmental perfusion defects. These findings suggested the presence of diffuse microscopic pulmonary arteriovenous fistulas bilaterally in the lungs. The patient appears to be the first reported adult case of microscopic and diffuse arteriovenous fistulas. Neither resection of the arteriovenous fistulas nor corrective surgery for the diversion was indicated, and heart-lung transplantation might be the only treatment able to relieve her dyspnea.

Potential applications of intracardiac echocardiography in the assessment of the aortic valve from the right ventricular outflow tract

Intracardiac echocardiography (ICE) is a developing technology and a promising method for visualizing intracardiac structures. However, its applications are currently limited to guidance during mitral valvuloplasty, catheter ablation, or electrophysiologic examination. The goal of this study was to observe the aortic valve, measure the annular diameter of the valve by ICE through a right-sided approach, and compare the results by ICE with those by transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE). We studied 18 patients (9 men, 9 women, aged 19 to 72 years) with various heart diseases, including 15 patients with mitral or aortic valvular disease. An imaging catheter was advanced through a long sheath into the outflow tract of the right ventricle. We obtained good longitudinal views of the aortic valve in all patients. Two of the 18 patients had poor image quality by TTE. The annular diameter by ICE correlated more closely with TEE than with TTE. In conclusion, right-sided ICE is a safe, simple, and useful procedure for observing the aortic valve during cardiac catheterization without additional discomfort in the patients. Right-sided ICE is superior to TTE in observing the aortic valve and measuring the annular diameter of the valve. The annular diameter can be measured by ICE as precisely as by TEE.

Assessment of transmural coronary blood flow with intraoperative transesophageal color Doppler echocardiography during coronary revascularization

Intraoperative color Doppler transesophageal echocardiography with a 4- to 7-MHz transducer was performed on 28 consecutive patients who underwent coronary artery bypass grafting to image and evaluate the transmural coronary blood flow before and after cardiopulmonary bypass. The transmural coronary flow was visualized in 26 (92.8%) of 28 patients in the inferior wall and in 13 (46.4%) of 28 patients in the lateral wall. The peak diastolic flow velocity of the transmural coronary artery in the inferior and lateral wall was significantly increased after coronary revascularization in patients with a successful bypass graft to the right coronary artery (from 34.0 +/- 19.7 to 64.9 +/- 30.9 cm/s, P <.001, n = 10) and to the left circumflex coronary artery (from 35.1 +/- 18.6 to 62.1 +/- 21.1 cm/s, P <.001, n = 10). No significant changes were observed in patients with no bypass graft to the right or left circumflex coronary artery. Coronary blood flow can be mapped and the velocity measured with Doppler transesophageal echocardiography with a high-frequency (4- to 7-MHz) transducer. Assessment of the transmural coronary flow may provide valuable information and aid in decision making during surgical revascularization.

Effects of candesartan and cilazapril on rats with myocardial infarction assessed by echocardiography

The purpose of this study was to compare the angiotensin II type 1 receptor antagonist candesartan cilexitil (candesartan) and the angiotensin-converting enzyme inhibitor cilazapril on cardiac function, assessed by Doppler echocardiography and cardiac gene expression associated with cardiac remodeling, in rats with myocardial infarction. Candesartan or cilazapril was administered after myocardial infarction. At 1 and 4 weeks after myocardial infarction, cardiac function and mRNA expression in noninfarcted myocardium were analyzed. Candesartan and cilazapril equally prevented increases in hypertrophy in noninfarcted myocardium, left ventricular dilatation, and ejection fraction at 4 weeks. The E-wave/A-wave velocity ratio and the rate of E-wave deceleration, measures of diastolic function, increased to 9.2+/-0.6 and 26.3+/-2. 6 m/s2 at 1 week after myocardial infarction. Candesartan and cilazapril, administered at a dose of 1 mg/kg per day, prevented increases in E-wave/A-wave velocity ratio and E-wave deceleration at 1 and 4 weeks. Candesartan and cilazapril significantly suppressed increased mRNA expression of beta-myosin heavy chain, alpha-skeletal actin, and atrial natriuretic peptide in noninfarcted ventricle at 1 and 4 weeks and expression of collagen I and III at 4 weeks to a similar extent. When given at a dose of 10 mg/kg per day, both candesartan and cilazapril prevented cardiac dysfunction and gene expression to the same extent as when given at 1 mg/kg per day. In conclusion, Doppler echocardiography showed that candesartan and cilazapril equally improved systolic and diastolic function and that ventricular remodeling accompanied modulation of cardiac gene expression.

A case of dobutamine-induced coronary arterial spasm with ST-segment elevation

A 55-year-old Japanese woman demonstrated ST-segment elevation in leads I, aVL, and V3-V6 with chest pain both in an ergometer exercise test and on dobutamine stress echocardiography. Although the baseline coronary arteriogram revealed no organic stenosis, total occlusion of the distal portion of the posterolateral branch of the left circumflex artery was observed during dobutamine infusion with ST-segment elevation and chest pain. This is a rare case of documented dobutamine-induced coronary arterial spasm.

Effect of manidipine hydrochloride, a calcium antagonist, on isoproterenol-induced left ventricular hypertrophy

We examined the effect of a calcium antagonist, manidipine hydrochloride, on cardiac hypertrophy and the expression of the atrial natriuretic peptide (ANP), transforming growth factor beta 1 (TGF-beta 1), and extracellular matrix protein genes in rats with isoproterenol-induced cardiac hypertrophy. Rats were continuously infused with saline or isoproterenol (0.5 mg/kg per day) for 7 days using an osmotic minipump. Treatment with manidipine hydrochloride (once a day at 3 mg/kg) began 1 day before minipump implantation and continued until the end of the experiments (each group; n = 6). After treatment, left ventricular weight was measured and mRNA was extracted and analyzed by Northern blot hybridization. Isoproterenol increased left ventricular weight (2.40 +/- 0.04 g/kg; p < 0.01) without increasing blood pressure. ANP, collagen type I and type III, and fibronectin mRNAs were increased 1.5-(p < 0.01), 1.9- (p < 0.01), 2.7- (p < 0.01), and 3.2-fold (p < 0.01), respectively, by isoproterenol infusion. However, TGF-beta 1, collagen type IV, and laminin B1 and B2 mRNA levels were unchanged by isoproterenol. Manidipine hydrochloride prevented isoproterenol-induced left ventricular hypertrophy (2.26 +/- 0.02 g/kg; p < 0.01) and expression of mRNA of ANP (0.9-fold of the control value; p < 0.01), collagen types I (1.1-fold; p < 0.01) and type III (1.6-fold; p < 0.01), and fibronectin (1.1-fold; p < 0.01). Thus, manidipine hydrochloride prevented cardiac hypertrophy and changes in the expression of genes for ANP and interstitial components of extracellular matrix induced by isoproterenol.

Differences in expression of sarcoplasmic reticulum Ca2+-ATPase and Na+-Ca2+ exchanger genes between adjacent and remote noninfarcted myocardium after myocardial infarction

Although cardiac failure can develop over time after myocardial infarction, the mechanism responsible for this is still unknown. The change of intracellular Ca2+ transport protein, such as sarcoplasmic reticulum (SR) Ca2+-ATPase (SR-Ca2+), Na+-Ca2+ exchanger (Na+-Ca2+), or cardiac phenotypic modulation of contractile protein in noninfarcted myocardium may have a important role. However, the time course in gene expression of sarcoplasmic reticulum (SR) Ca2+-ATPase (SR-Ca2+), Na+-Ca2+ exchanger (Na+-Ca2+), and contractile protein in the adjacent and remote noninfarcted myocardium after myocardial infarction has not been examined. At 1, 3 weeks and 3 months after myocardial infarction, hemodynamics were measured and mRNA of the left ventricle was analyzed. Left ventricular end-diastolic volume and weight increased both with time. Ascites became apparent at 3 months after infarction. SR-Ca2+ mRNA levels in the adjacent noninfarcted myocardium were 0.7- (P<0.01), 0.9- (N.S.), and 0.7-fold (P<0.01) of control, and Na+-Ca2+ mRNA levels were 2.1- (P<0.01), 1.4- (P<0.01), and 0.8-fold (P<0.01) of control, at 1, 3 weeks and 3 months after infarction, respectively. beta-Myosin heavy chain (MHC) mRNA was increased to 2.1- (P<0.01), 1.5- (P<0.01), and 1.4-fold (P<0.01), and alpha-skeletal actin was increased to 2.4- (P<0.01), 3.8- (P<0.01), and 1.6-fold (P<0.01) control levels, at 1 week, 3 weeks and 3 months, respectively. In contrast, alpha-MHC mRNA level was decreased at 1 week and 3 months after infarction. alpha-cardiac actin mRNA level did not change over time after infarction. In the remote non-infarcted myocardium, beta-MHC, alpha-skeletal actin, and Na+-Ca2+ mRNA levels were increased, but SR-Ca2+, alpha-MHC, and alpha-cardiac actin mRNA did not change after infarction. These findings suggest that: (1) intracellular Ca2+ handling system after myocardial infarction may be different between adjacent and remote non-infarcted myocardium: and that (2) both decreased gene expression of SR Ca2+-ATPase and Na+-Ca2+ exchanger in the adjacent non-infarcted myocardium may progress cardiac dysfunction.

Angiotensin II type-1 receptor antagonist as well as angiotensin converying enzyme inhibitor attenuates the development of heart failure in aortocaval fistula rats

OBJECTIVES

We investigated the effect of chronic administration of an angiotensin II type-1 receptor antagonist in the development of heart failure due to volume overload in rats.

METHODS

Aortocaval fistula (AVF), a model of volume overloaded heart failure, was induced in rats by our newly developed technique using a simple and rapid 18-gauge needle multipuncture. After 3 weeks of oral administration of an angiotensin II receptor antagonist TCV-116, 1 mg/kg per day, we evaluated the hemodynamics, heart weight, and degree of left ventricular dilatation. We also compared the effect of TCV-116 with that of an angiotensin-converting enzyme inhibitor delapril, 1 g/L in drinking water.

RESULTS

AVF heart failure produced by our technique exhibited significant increases in the left ventricular end-diastolic pressure (LVEDP) (12 = 1 vs 4 +/- 1 mmHg, p < 0.05), right atrial pressure (RAP) (5.0 +/- 0.6 vs 1.0 +/- 0.4 mmHg, p < 0.05), right ventricular systolic pressure (RVSP) (58 +/- 6 vs 33 +/- 1 mmHg, p < 0.05), left ventricular weight (LVW) (3.00 +/- 0.13 vs 2.09 +/- 0.04 g/kg BW, p < 0.05), right ventricular weight (RVW) (0.93 +/- 0.05 vs 0.59 +/- 0.01 g/kg BW, p < 0.05), and left ventricular end-diastolic volume index (LVEDVI) (2.55 +/- 0.14 vs 0.80 +/- 0.12 ml/kg BW, p < 0.05) as compared with these values in sham-operated rats. There were no differences in shunt ratio between untreated and TCV-116- and delapril-treated AVF groups. TCV-116 improved these hemodynamics, as did delapril (TCV-116 vs delapril: LVEDP 8 +/- 1 vs 8 +/- 1, RAP: 3.8 +/- 0.6 vs 2.3 +/- 1.4, RASP: 50 +/- 2 vs 46 +/- 3, LVW: 2.53 +/- 0.11 vs 2.52 +/- 0.15, RVW: 0.80 +/- 0.04 vs 0.77 +/- 0.06, LVEDVI: 1.67 +/- 0.15 vs 1.70 +/- 0.17).

CONCLUSION

These results suggest that AVF rats with volume overload produced by a new multipuncture method exhibit both right- and left-side heart failure. Angiotensin II type-1 receptor antagonist as well as angiotensin converting enzyme inhibitor attenuate the development of this type of heart failure in rats.

Inhibition by angiotensin II type 1 receptor antagonist of cardiac phenotypic modulation after myocardial infarction

The purpose of this study was to examine the cardiac phenotype and remodeling after myocardial infarction and the effect of the angiotensin II type 1 (AT1) receptor antagonist (TCV-116) on the gene expression. Myocardial infarction in rats was produced by ligation of the coronary artery. TCV-116 (10 mg/kg/day) was administered orally to rats from 1 day after myocardial infarction. At 1, 2 and 3 weeks after myocardial infarction, blood pressure and heart rate were measured, and the heart was removed. The left ventricle was measured for infarct size and weight, and then the total RNA from the non-ischemic left ventricle was extracted. mRNAs in the non-ischemic left ventricle were measured by Northern blot analysis. The weight of the non-ischemic left ventricle was significantly increased 3 weeks after infarction. This was completely prevented by TCV-116 treatment. mRNA levels for beta-myosin heavy chain (beta-MHC), atrial natriuretic polypeptide (ANP), collagen types I and III and transforming growth factor-beta 1 (TGF-beta 1) in the non-ischemic left ventricle were increased by a factor of 3.0, 6.7, 7.9, 4.0 and 1.4 (P < 0.01), respectively, 1 week after infarction. There was no increase in alpha-skeletal actin mRNA at 1 and 2 weeks, but it was increased by a factor of 2.9 (P < 0.05) at 3 weeks. On the other hand, there was no change in alpha-MHC mRNA during the 3 weeks. TCV-116 significantly suppressed the increased gene expression of beta-MHC and alpha-skeletal actin in the non-ischemic myocardium at all time points, and also suppressed the expression of ANP at 2 and 3 weeks. However, TCV-116 failed to inhibit the expression of collagen I and III mRNAs at 1 and 3 weeks. These results show that myocardial infarction causes a rapid shift of myocytes to fetal phenotype and a rapid activation of collagen genes in the non-ischemic myocardium. AT1 receptor may be responsible for the phenotypic modulation of myocytes following myocardial infarction.

Myocardial infarct size by serum troponin T and myosin light chain 1 concentration

The late troponin T (TnT) peak concentration, which is known to be independent of reperfusion of the infarcted zone in acute myocardial infarction (MI), has been suggested to be correlated with clinical estimates of cardiac function and myocardial infarct size. To refine the clinical application of the late TnT peak in infarct sizing, and to examine differences in this estimation in different infarct sites, we measured the serum concentrations of TnT and myosin light chain 1 (MLC1), and compared these values with left ventricular ejection fraction (LVEF) obtained from left ventriculography, and extent score (ES) and severity score (SS) obtained from 201Tl scintigraphy in patients with anterior and inferior myocardial infarction. The late TnT peak concentration was strongly correlated with the MLC1 peak value in patients with anterior MI (r = 0.67, p < 0.05) and in those with inferior MI (r = 0.92, p < 0.0005). Furthermore, there were strong linear correlations between the late TnT peak values and all of the clinical data (LVEF; r = -0.79, p < 0.01, ES; r = 0.75, p < 0.05, SS; r = 0.75, p < 0.05, respectively) in patients with anterior MI. However, these correlations were weak in patients with inferior MI. Similar correlations were observed between MLC1 and the clinical data. Thus, TnT and MLC1 have similar kinetics in the serum at the late phase and can be used to estimate the size of anterior infarct.

Relationship between insufficient redistribution in exercise thallium-201 myocardial single-photon emission computed tomography and reverse redistribution at rest

It is widely accepted that perfusion defects in 3 to 4-h delayed images in exercise thallium-201 (201Tl) myocardial scintigraphy underestimate the viability of myocardium in the infarct region. In the present study, to examine the contribution of the condition of myocardium which demonstrates reverse redistribution in resting scintigraphy to the insufficiency of redistribution in the 4-h delayed image in exercise scintigraphy, we performed exercise and resting 201Tl myocardial single-photon emission computed tomography in 58 patients with acute myocardial infarction and a single diseased coronary artery. Twenty eight patients demonstrated reverse redistribution (group RR) and 28 showed a fixed defect (group FD) in resting scintigraphy. Redistribution in the 4-h delayed image in exercise scintigraphy was significantly more insufficient in group RR than in group FD (p < 0.01), and the degree of the insufficiency of redistribution in exercise scintigraphy closely correlated with the degree of reverse redistribution in resting scintigraphy (r = 0.79, p < 0.001). We conclude that in patients with acute myocardial infarction, the condition of myocardium which demonstrates reverse redistribution in resting myocardial scintigraphy is related to the insufficiency of redistribution in the delayed image in exercise scintigraphy.

Cardioprotective effect of the angiotensin II type 1 receptor antagonist TCV-116 on ischemia-reperfusion injury

We investigated the protective effect of angiotensin II (Ang II) type 1 receptor antagonist on myocardial ischemia-reperfusion injury and the role of exogenous Ang II to this injury in perfused hearts. We orally administered TCV-116 (Ang II type 1 receptor antagonist) and delapril (angiotensin converting enzyme inhibitor) to Wistar rats for 1 week and measured the immunoreactive cardiac Ang II. Immunoreactive cardiac Ang II (pg/gm tissue) was 14.3 +/- 2.0 in control group, 11.8 +/- 0.8 in TCV-116-treated group, and 7.3 +/- 0.6 in delapril-treated group (p < 0.05 compared to TCV-116-treated group; p < 0.01 compared to control group). The 15 hearts (five rats in each group) were perfused by a langendorff method and global ischemia was maintained for 30 min. Both TCV-116 and delapril were found to improve postischemic cardiac function and decrease reperfusion creatine kinase (CK) release. Ang II injection before ischemia worsened postischemic cardiac function and increased reperfusion CK release. Only TCV-116 prevented this injury. These data indicated that TCV-116 Ang II type 1 receptor antagonist was effective against myocardial ischemia-reperfusion injury, and exogenous Ang II accelerated this injury through Ang II type 1 receptor.

The deleterious effects of exogenous angiotensin I and angiotensin II on myocardial ischemia-reperfusion injury

Angiotensin II is well known to have a cardiotoxic effects. However, it is still unclear whether exogenous angiotensin I or angiotensin II has a deleterious effect on myocardial ischemia-reperfusion injury. To examine this deleterious effects, we administered angiotensin I and angiotensin II to perfused hearts before ischemia, and measured creatine kinase (CK) release and cardiac function during subsequent reperfusion. Wistar Kyoto rats were used and the hearts were perfused by the Langendorff technique at a constant flow (10 ml/min). Seven hearts were perfused for 20 min and then subjected to 15 min of global ischemia (Control). In the experimental groups, during the 5 min before ischemia, we administered 100 ng/ml angiotensin I (Ang I; n = 9), 1 microgram/ml enalaprilat (ACEI; n = 5), both agents (ACEI + Ang I) (n = 6), or 10 ng/ml angiotensin II (Ang II; n = 6). The perfusates were then sampled to measure angiotensin II. After 15 min of ischemia, the hearts were reperfused with control perfusate. Throughout the 20 min of reperfusion, the effluent was collected to measure cumulative CK release. Angiotensin I increased coronary perfusion pressure (CPP) by 32 +/- 4 mmHg, however, the angiotension converting enzyme inhibitor inhibited the increase of CPP by angiotension I (11 +/- 1 mmHg) (p < 0.01). The contents of angiotensin II in the effluent in Ang I and Ang I + ACEI were 11.5 +/- 1.9 ng/ml and 4.0 +/- 0.5 ng/ml (p < 0.01). After 20 min of reperfusion, the left ventricular developed pressure was unchanged in all of the groups. CPP was also unchanged by ischemia in all of the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of nitric oxide in the vasodilatory responses to acetylcholine and bradykinin in perfused hearts

The role of nitric oxide in the coronary vasodilation caused by acetylcholine or bradykinin in perfused guinea-pig hearts was investigated by using 1 mM L-NG-nitro arginine (L-NNA), a specific inhibitor of the formation of nitric oxide from L-arginine. L-NNA increased coronary perfusion pressure and inhibited the vasodilator responses to acetylcholine and bradykinin. The extent of vasodilation was evaluated in terms of the reduction of perfusion pressure from the initial baseline that had been induced by U-46619. L-NNA markedly attenuated coronary vasodilation caused by 5 x 10(-11) mol of acetylcholine from 15 +/- 1 to 4 +/- 1 mmHg (p < 0.01), and that caused by 1 x 10(-11) mol bradykinin from 21 +/- 2 to 8 +2- 1 mmHg (p < 0.01). On the other hand, L-NNA only weakly inhibited coronary vasodilation caused by 5 x 10(-7) mol of acetylcholine from 40 +/- 3 to 27 +/- 4 mmHg (p < 0.01), and that caused by 1 x 10(-9) mol of bradykinin (from 39 +/- 2 to 32 +/- 2 mmHg (p < 0.01). L-NNA had no effect on the vasodilation induced by 1 x 10(-8) mol of bradykinin. Ibuprofen, cyclooxygenase inhibitor, did not affect these vasodilatory responses. These results suggest that the formation of nitric oxide from L-arginine in coronary resistance vessels helps to regulate vascular tone, and that prostaglandins are not related to the vasodilatory responses to acetylcholine or bradykinin.(ABSTRACT TRUNCATED AT 250 WORDS)

Estimation of infarct size using serum troponin T concentration in patients with acute myocardial infarction

To estimate the size of myocardial infarction, serum troponin T concentration was measured in 34 patients with acute myocardial infarction. Left ventriculography, 2-dimensional echocardiography and resting 201thallium myocardial single photon emission computed tomography (SPECT) were performed about 4 weeks after the onset of myocardial infarction and used for correlation with the late serum troponin T peak concentration which occurred on the 3rd to 5th day after onset. Both left ventricular ejection fraction (LVEF) obtained from left ventriculography and wall motion index (WMI) obtained from 2-dimensional echocardiography were inversely related to late troponin T peak value (LVEF: r = 0.68, p < 0.001, WMI: r = 0.70, p < 0.001). Extent score (ES) and severity score (SS), which were estimated from the initial resting 201thallium SPECT image, showed excellent linear correlations with late troponin T peak concentrations (ES: r = 0.77, p < 0.001, SS: r = 0.66, p < 0.001). This correlation was present both in patients with an early troponin T peak on day 1 (group A-16 patients) and in those without an early peak (group B-10 patients). Thus, late troponin T peak concentration can be used to predict infarct size regardless of the kinetics of its appearance in serum.

Angiographic-pathologic correlations after elective percutaneous transluminal coronary angioplasty

BACKGROUND

The local effect of coronary angioplasty is evaluated on the basis of postangioplasty angiograms. Smooth-walled dilation is considered to represent minimal or no injury, whereas intraluminal haziness corresponds with wall laceration. This study correlates the preangioplasty and postangioplasty angiograms with the histopathology of the target sites.

METHODS AND RESULTS

The study includes 12 patients, each undergoing an elective procedure, and covers 19 angioplasty sites. Smooth-walled dilation and intraluminal haziness were not mutually exclusive. The angiograms were interpreted as smooth-walled dilation (n = 3), smooth-walled dilation with intraluminal haziness (n = 4), intraluminal and extraluminal haziness (n = 5), extraluminal dissection (n = 5), spiraltype dissection (n = 1), and aneurysm (n = 1). The histology of the arterial segments revealed wall laceration in all. Smooth-walled dilation without intraluminal haziness correlated with laceration limited to the intima in two, but with medial injury in one. Smooth-walled dilation with intraluminal haziness correlated with laceration limited to the intima in two and with medial injury in two. Intraluminal and extraluminal haziness corresponded with extensive laceration with deep involvement of the media in each. Extraluminal dissection correlated with a dissection along the shoulder area of the plaque, creating a broad-based flap. The spiral-type dissection corresponded with a true dissection into the plaque-free media. The aneurysm correlated with partial washout of an atherosclerotic plaque.

CONCLUSIONS

The angiographic image of intraluminal and extraluminal haziness indicates extensive medial laceration. Smooth-walled dilation, with or without intraluminal haziness, is not a reliable indicator. The study emphasizes the need to reconsider the interpretations of postangioplasty coronary angiograms.

Clinical and histologic features of alcohol drinkers with congestive heart failure

To clarify the difference between alcoholic cardiomyopathy and dilated cardiomyopathy and to investigate the characteristics of alcoholic cardiomyopathy, right ventricular endomyocardial biopsy was performed, and the two diseases were compared clinically and histologically. Changes in the cardiothoracic ratio, cardiac index, and systolic blood pressure/end-systolic volume index were greater after treatment in patients with alcoholic cardiomyopathy than in patients with dilated cardiomyopathy. Histologically, myocytic hypertrophy, fibrosis, and nuclear change were less significant in the former than in the latter. Among patients with alcoholic cardiomyopathy, the cardiac index in those with less fibrosis was greater than in those with more fibrosis. Thus patients with alcoholic cardiomyopathy had more preserved and reversible cardiac function and fewer histologic changes than the patients with dilated cardiomyopathy. Reversibility of cardiac function in patients with alcoholic cardiomyopathy correlated inversely with the severity of histologic changes.

Clinical significance of reverse redistribution on thallium-201 single-photon emission computed tomography in patients with acute myocardial infarction

To determine the clinical significance of reverse redistribution (RR), resting thallium-201 myocardial single-photon emission computed tomography was performed once or twice in 80 patients in subacute phase (1 week to 2 months) of myocardial infarction. Thirty eight patients demonstrated RR on at least one study (group RR) and 32 a fixed defect only (group FD). Group RR had significantly smaller defects than group FD. Standardizing the relation of the severity of wall motion abnormality of left ventricle on echocardiogram with that of perfusion defect, in group RR wall motion abnormality in the acute and subacute phase reflected the defect of delayed image, while that in chronic phase, which was thought to reflect the viability of myocardium in the infarct region, reflected the defect of initial image. In serial thallium-201 studies, only the defect of delayed image of group RR improved on the second study, while the defect of initial image of group RR and defect of group FD did not improve. Wall motion of group RR improved with the disappearance of RR, and when RR remained, wall motion did not improve so much. We concluded that RR was thought to be demonstrated in viable myocardium with severe wall motion abnormality.

Extensive specifically localized myocardial calcium deposition in a hemodialysis patient

A 51-year-old female who was hospitalized for evaluation of frequent episodes of hypotension, died unexpectedly. At autopsy, there were many fine, white granular deposits in the myocardium, which were more prominent in the subepicardium of the left ventricle than in the subendocardium. Pathologic calcification is sometimes seen in chronic hemodialysis patients and in some organs the sites of calcium deposition are quite specific. There have been few reports concerning the pattern of calcium deposition in the myocardium and, to our knowledge, the reason for this characteristic distribution is unknown. However it may relate to hydrogen ion concentration in the myocardium.

Circulating immunoreactive endothelin in patients undergoing percutaneous transluminal coronary angioplasty

Circulating immunoreactive endothelin (ir-ET) in the coronary sinus (CS) and the femoral artery (Ao) was measured in patients who underwent percutaneous transluminal coronary angioplasty (PTCA). Plasma ir-ET level in the CS was significantly increased from 1.6 +/- 0.8 pg/mL to 2.0 +/- 1.0 pg/mL after PTCA (P less than .05). Plasma ir-ET level in the Ao tended to increase after PTCA, but it was not significant. Plasma ir-ET level in the CS was not related to the plasma thromboglobulin level, plasma thrombin-antithrombin complex level, mean blood pressure, or heart rate. These results suggest that the increase of plasma ir-ET level in the CS may be associated with the coronary endothelial injury by PTCA.

Two-dimensional and Doppler echocardiographic findings in a case of subaortic "fibrous sac"

We described a 37-year-old man with a subaortic "fibrous sac", admitted for congestive heart failure. On 2-dimensional echocardiography a saccular structure was seen to extend from the left coronary cusp of the aortic valve to the outflow tract of the left ventricle. By color Doppler imaging, a grade 3 aortic regurgitation was recognized. Aortic regurgitant flow was recorded from the left coronary cusp to the saccular lesion. When congestive heart failure became exacerbated, the repeat examination showed the regurgitant flow passing through the perforated bottom of this lesion and reaching the left ventricular cavity. On microscopic examination of the excised valve, capillary proliferation and inflammatory changes were recognized near the annular region of the left coronary cusp. The edge of the valve leaflet and the other 2 cusps were intact. It is likely that our patient had a mycotic aneurysm near the aortic ring. We speculate that aortic regurgitation followed inflammation. It dilated the left ventricular cavity and contributed to congestive heart failure. Inflammation also weakened the tissue near the annulus, causing it to protrude into the subaortic region thus forming a small aneurysm. It may have grown to become a large saccular structure under high aortic pressure. That is, it became a "giant" endocardial pocket with inflammatory process. Finally, the rupture of this sac caused a massive aortic regurgitation, exacerbating congestive heart failure.