Initial clinical experience with the novel POLARx FIT cryoballoon system for pulmonary vein isolation in patients with atrial fibrillation

Background

The POLARx FIT system (Boston Scientific, MA, USA) is a novel cryoballoon (CB) ablation technology in which the balloon diameter can be expanded from 28 to 31 mm. The aim of this study was to compare the benefits and safety of the new POLARx FIT system to those of the existing POLARx system currently in use for pulmonary vein (PV) isolation (PVI) in patients with atrial fibrillation.

Methods

The first 70 consecutive patients who underwent CB-based PVI with the POLARx FIT system were retrospectively compared with 200 consecutive patients treated with the POLARx system at Sakakibara Heart Institute from October 2021 to May 2023.

Results

The POLARx FIT system yielded a higher mean ± standard deviation nadir temperature in the right inferior PV (-59.2 ± 5.29 °C vs. - 62.0 ± 5.08 °C, p = 0.006), but this required a balloon size reduction to 28 mm in 30 % of cases. No significant differences were detected in the time to isolation and thaw time of any PV between the two groups. After the CB-based PVI procedure, no residual PV carina potentials were observed with the POLARx FIT system, whereas 4/20 were with the POLARx system (p = 0.04).

Conclusions

The POLARx FIT system had comparable effectiveness and safety to the basic POLARx system. This technology may improve the ablation area, including the PV carina. However, the 31-mm balloon alone was not sufficient to isolate certain PVs.

Impact of monitoring surface temperature during pulmonary vein isolation in a second-generation hot balloon system

Background

Methods

Results

Conclusions

Evaluation of linear lesion formation and thermodynamics by dragging ablation with the third-generation laser balloon

Background

The lesion formation properties of a motorized rotational delivery (RAPID) mode, third-generation laser balloon (LB3) ablation compared to point-by-point laser ablation in patients with atrial fibrillation remain unclear.

Objective

The purpose of this study was to assess lesion characteristics and thermodynamics in LB3 ablation with a RAPID mode in vitro model.

Methods

Chicken muscles were cauterized using LB3 in RAPID mode with 13 W and 15 W and 50% overlapped point-by-point fashion with 7 W/30 seconds, 8.5 W/20 seconds, 10 W/20 seconds, and 12 W/20 seconds. Lesion depth, width, and continuity were compared. Lesion continuity was classified by the visible gap degree categorized from 1 (perfect) to 3 (poor). Thermodynamics and maximum tissue temperatures were assessed under infrared thermographic monitoring. Fifteen and 5 lesions were evaluated per ablation protocol for measurement of lesion size and continuity and for thermographic assessment, respectively.

Results

Lesion depth and width were smaller in RAPID mode laser ablation than point-by-point laser ablation (P <.001). However, RAPID mode laser ablation revealed sufficient mean lesion depth of 5 mm or more. Lesion continuity was 1 (perfect) in all samples in RAPID mode laser ablation and point-by-point laser ablation (P = 1). Infrared thermographic observation demonstrated fast and gapless linear lesion formation with thermal stacking in RAPID mode laser ablation. Maximum tissue temperature was lower in RAPID mode laser ablation than point-by-point laser ablation (P <.001).

Conclusion

RAPID mode LB3 ablation could provide fast, gapless, and acceptable lesion formation with thermal stacking and moderate tissue temperature rise.

Prediction of Serious Adverse Events of Patients with Hypertrophic Cardiomyopathy by Magnetic Resonance

Although it is well known that patients with hypertrophic cardiomyopathy (HCM) have serious adverse events, such as life-threatening arrhythmia and heart failure, the prediction of such evens is still difficult. Recently, it has been reported that one of the causes of these serious adverse events is microvascular dysfunction, which can be noninvasively evaluated by employing cardiac magnetic resonance (CMR) imaging.We analyzed 32 consecutive HCM patients via CMR imaging and myocardial scintigraphy and divided them into two groups: ventricular tachycardia (VT) group and non-VT group. Myocardial perfusion studies were conducted quantitatively using the QMass^® software, and each slice image was divided into six segments. The time-intensity curve derived from the perfusion image by CMR imaging was evaluated, and the time to 50% of the peak intensity (time 50% max) was automatically calculated for each segment.Although no difference was observed in various parameters of myocardial scintigraphy between the two groups, the VT group exhibited a higher mean of time 50% max and wider standard deviation (SD) of time 50% max in each segment than the non-VT group. The cutoff values were obtained by the receiver operating characteristic curves derived from the mean of time 50% max and SD of time 50% max. The two groups divided by the cutoff values exhibited significant differences in the occurrence of serious adverse events.CMR imaging may be useful for predicting serious adverse events of patients with HCM.

A case of hypertrophic obstructive cardiomyopathy with aortic stenosis

A 78-year-old woman complained of experiencing dyspnea (New York Heart Association II) and faintness. Echocardiography revealed she had asymmetric left ventricular hypertrophy, and a dynamic left ventricular outflow tract (LVOT) obstruction due to systolic anterior motion of the mitral valve. It also revealed calcification of the noncoronary cusp and a high-flow velocity in the LVOT (6.3 m/s). The planimetry measurement with transesophageal echocardiography was 0.89 cm² (aortic valve area/body surface area: 0.69 cm²/m²). Later, she was diagnosed with hypertrophic obstructive cardiomyopathy (HOCM) and aortic stenosis (AS). However, during the catheterization, the transvalvular pressure gradient (PG) was only 25 mmHg. In order to solve this, we performed a percutaneous transluminal septal myocardial ablation. As a result, the PG of the LVOT decreased from 152 mmHg to 25 mmHg. We first thought that the LVOT obstruction had reduced the flow passing through the aortic valve, and restricted the motion of the aortic valve leaflets. We also considered the possibility that the aortic valve area had been underestimated. The hemodynamic study played an important role in the decision for the treatment plan. The present case was a combination of HOCM and "mild" AS. <Learning objective: We know that we can distinguish between a left ventricular outflow tract obstruction and aortic stenosis using continuous-wave Doppler according to the phase of the peak gradient. However, if both are present, it is uncertain whether we can distinguish between them. It is necessary to measure the subaortic pressure and flow passing through the aortic valve accurately by catheterization in order to know which is the chief pathology.>.

A case of prosthetic valve endocarditis caused by Streptococcus constellatus as a rare agent of endocarditis

We present a case of prosthetic valve endocarditis, which was caused by a rare etiological agent, Streptococcus constellatus. In our case, transesophageal echocardiography showed a large and broad abscess formation throughout the patient's aortic prosthetic valve ring and left atrium. Despite specific intravenous antibiotic therapy, the infection was uncontrollable, and the patient underwent surgical treatment. The pathogen rarely causes endocarditis, but it is known to have a strong potential to form abscess, and therefore its infection may be more serious than other Streptococcus species. Our case seems to be the first report of surgical treatment of PVE caused by S. constellatus. As in our case, transesophageal echocardiography is useful for the detection of vegetation and abscess, and early cardiac surgery may be a more appropriate therapeutic approach for endocarditis caused by S. constellatus.

Outcome of implantable cardioverter defibrillator therapy for congenital heart disease

BACKGROUND

The use of implantable cardioverter defibrillator (ICD) therapy for congenital heart disease (CHD) has been increasing, but few studies have reported on the efficacy of ICD therapy in Japanese CHD patients.

METHOD

Twelve CHD patients (median age, 35 years) with first ICD implantation were examined. Median follow-up duration was 2.9 years. Demographic information, implant electrical parameters, appropriate and inappropriate discharge data and complications were recorded for all implants from 2003 to 2010.

RESULTS

Implant indication was primary prevention in two patients and secondary prevention in 10. Overall four patients received one or more discharges; three patients (25%) with secondary prevention received nine appropriate discharges. Inappropriate discharge attributed to sinus tachycardia occurred in two patients (16.7%). Only one patient experienced the late complication of skin erosion at the generator implantation site.

CONCLUSIONS

Patients with CHD experienced significant rates of appropriate discharges and lower complications. But given that the indications of ICD implantation were mostly for secondary prevention, the ratio of appropriate shocks might be lower than in previous studies. In the primary prevention patients, the benefit of ICD was not clear because no appropriate discharges were seen during follow up. Although ICD implantation for CHD is beneficial for preventing sudden cardiac death, careful decision making and a large, long-term prospective study is required for the determination of the efficacy of ICD therapy in Japanese patients with CHD.

Impact of ejection fraction on long-term outcome after elective aortic valve replacement in octogenarians with aortic stenosis

BACKGROUND

Aortic stenosis (AS) is increasingly common in the elderly population. A recent invention of transcatheter aortic valve implantation tends to tilt the risk-benefit balance to favor earlier elective intervention for AS. Hence, decision making for elective intervention in octogenarians gradually becomes important. However, the outcome after elective aortic valve replacement (eAVR) has not been evaluated adequately. This study aimed to identify risk factors after eAVR in octogenarians and investigate their influence on long-term outcome.

METHODS AND RESULTS

One hundred and thirty-seven consecutive Japanese octogenarians with AS who underwent eAVR were studied. The mean follow-up period was 35±22 (range, 0-88) months. Long-term overall survival rates after eAVR were 92.0%, 85.2% and 75.5% at 1, 3 and 5 years, respectively. Cox proportional hazards model identified age [hazard ratio (HR) 1.23; 95% confidence interval (CI) 1.07-1.43; P<0.01)] and ejection fraction (EF) <50% (HR 3.38; 95%CI 1.34-8.52; P<0.01) as the risk factors of mortality. Post-eAVR survival rates in octogenarians with an EF ≥50% and <50% were 97.3% and 70.4% at 1 year, 90.1% and 65.3% at 3 years, and 84.3% and 39.2% at 5 years, respectively (P<0.0001).

CONCLUSIONS

Octogenarians with preserved LV systolic function before surgery have favorable long-term survival after eAVR. However, an EF <50% influences the mortality in octogenarian patients. Therefore, eAVR should be considered for octogenarians with AS before the progression of LV impairment.

Aortic regurgitation caused by cusp bending of aortic valve leaflet

Pure aortic regurgitation (AR) is caused by primary disease of the aortic leaflet and/or the aortic root. However, there are many patients with AR with unclear etiology and mechanism. The assessment of mechanism is critical to the decision of surgical modality for AR. Echocardiography, particularly a detailed analysis of the aortic leaflets and root by transesophageal echocardiography (TEE), could be an important diagnostic step to assess its mechanism. In this report, we present a case of AR in which the TEE images led to diagnosis of cusp bending of aortic leaflet without specific findings indicating this pathology.

Left atrial thrombus and prognosis after anticoagulation therapy in patients with atrial fibrillation

BACKGROUND

Anticoagulation therapy reduces the risk of thromboembolic events by two-thirds in patients with atrial fibrillation (AF). The prevalence of left atrial thrombus (LAT) in AF patients with anticoagulation therapy has not been fully investigated.

PURPOSE

To investigate the prevalence of LAT and its impact on the outcomes in patients with nonvalvular AF after anticoagulation therapy.

METHODS

This study consisted of 231 patients with nonvalvular AF who had transthoracic (TTE) and transesophageal echocardiographic (TEE) examinations more than 3 weeks after anticoagulation therapy. The clinical and echocardiographic characteristics were evaluated.

RESULTS

LAT was observed in 13 (8.8%) of 148 patients with sub-therapeutic anticoagulation, and in 3 (3.6%) of 83 patients with sufficient anticoagulation. The presence of LAT was associated with higher CHADS(2) score, decreased LA volume changes and the presence of spontaneous echocardiographic contrast (SEC) in patients with sub-therapeutic anticoagulation. Patients with LAT after sufficient anticoagulation were male with permanent AF who had decreased left ventricular systolic and diastolic function and dilated LA on TTE and SEC, and reduced appendage flow velocity on TEE. Patients with LAT had worse cardiovascular outcomes compared with those without LAT (p=0.02).

CONCLUSIONS

We demonstrated that LAT was a univariate risk factor associated with worse cardiovascular outcomes, which was observed in 8.8% of patients with sub-therapeutic anticoagulation and 3.6% of patients with sufficient anticoagulation.

Delayed enhancement cardiovascular magnetic resonance as a novel technique to predict cardiac events in dilated cardiomyopathy patients

PURPOSE

Delayed enhancement cardiovascular magnetic resonance (DE-CMR) can detect cardiac scarring and has the potential to visualize the progression of myocardial remodeling. We determined whether DE-CMR can predict cardiac events in dilated cardiomyopathy patients.

MATERIALS AND METHODS

Transthoracic echocardiography, coronary arteriography, and DE-CMR studies were performed in 60 consecutive dilated cardiomyopathy (DCM) patients. Percent delayed enhancement (%DE) was determined as the ratio of the area showing delayed enhancement to the total myocardial area in three short-axis views. Patients were classified as advanced group (Group A) when %DE was 10% or higher, and as non-advanced group (Group NA) when %DE was less than 10%. The incidence of cardiac events and the clinical history were compared between Group A and Group NA.

RESULTS

There were 11 patients in Group A and 49 patients in Group NA. The incidence of cardiac events was significantly higher in Group A (36%; 4/11 patients) than in Group NA (2.0%; 1/49 patients) (log rank, p=0.0001).

CONCLUSION

DE-CMR is a useful tool to predict cardiac events in DCM patients.

Preventive effect of N-acetylcysteine on contrast-induced nephropathy following coronary angiography and angioplasty

Contrast-induced nephropathy (CIN) is one of the serious side effects of contrast media. A few studies have suggested that N-acetylcysteine (NAC) is effective to prevent CIN, but the efficacy remains unclear in Japanese. Therefore, we retrospectively studied the preventive effect of NAC on CIN in Sakakibara Heart Institute. Patients who had been administered NAC for the purpose of preventing CIN before coronary intervention between February 2005 and November 2006 were included in the NAC group. In addition, age- and rate of diabetes mellitus-matched controls were randomly extracted. We retrieved and analyzed patient data including demographics, NAC dosage, and serum creatinine concentrations (Scr). NAC group (n=16) showed significantly higher baseline Scr (p<0.01) and a tendency toward a lower dose of contrast media (p=0.068) compared with controls (n=48). Since the occurrence of CIN was low, there was no significant difference in the proportion of CIN between the groups (NAC: 6%, controls: 4%). NAC group trended toward a decrease in Scr after the use of contrast media, while controls increased (-0.04+/-0.25 versus +0.03+/-0.36 mg/dl, p=0.096). The multivariate analysis showed that the dosage of NAC is inversely correlated with Scr independent of baseline Scr and dosage of contrast media. Despite higher baseline Scr (i.e., high-risk with CIN) in the NAC group, the real Scr value reflected a lower trend on average. In addition, this finding suggests that a larger dose of NAC results in a lower Scr value, we consider that the NAC dosage more likely prevented CIN.

Long-Term Outcome of First-Generation Metallic Coronary Stent Implantation in Patients With Coronary Artery Disease Observational Study Over a Decade

BACKGROUND

In the era of drug-eluting stents, percutaneous coronary intervention (PCI) has been considered an established therapeutic modality for patients with coronary artery disease (CAD). However, little is known about the long-term prognosis.

METHODS AND RESULTS

Using data obtained from a single-center registry for cases of first-generation bare metallic stent (BMS) implantation, a 10-year follow-up study in patients with CAD was performed. Data for 125 serial patients (aged 62+/-9 years, 104 males) in whom a BMS was successfully implanted was analyzed. Cardiac death (n=16 [12.8%]), including sudden cardiac death (n=9 [7.2%]), non-cardiac death (n=17 [13.6%]) and non-fatal acute myocardial infarction (n=16 [12.8%]) were documented. At 10 years, cumulative probabilities of target and non-target lesion revascularization were 20.5% and 41.5%, respectively, and only 39.2% of the patients were free from cardiac events (cardiac death/myocardial infarction/unplanned revascularization). Age and left ventricular ejection fraction (LVEF) were significant predictors of total death, and LVEF and the use of diuretics were predictors of cardiac events.

CONCLUSIONS

Stabilization of the initial stented site was relatively good and the majority of cardiac events might have originated in non-target lesions. Prevention of systemic arteriosclerosis progression is important for patients with CAD, even after successful PCI.

Impact of a preoperative mitral regurgitation scoring system on outcome of surgical repair for mitral valve prolapse

The optimal timing of surgical correction of severe mitral regurgitation (MR) is important for improved morbidity and mortality. We utilized a scoring system to decide the timing of procedures. Based on clinical features and echocardiographic data, we hypothesized that preoperative semi-quantitation of MR using this scoring system may be useful for predicting prognosis after repair. The MR score was composed of 6 parameters associated with disease severity (i.e., history of heart failure, atrial fibrillation, pulmonary hypertension, left ventricular end-systolic dimension, fractional shortening, and left atrial dimension). The maximum score was 6. Of 267 patients who underwent mitral valve repair in the last 10 years, 191 patients with mitral valve prolapse were studied. Patients were categorized into 2 groups according to MR score (group low [L] : 0 to 2.5 and group high [H]: >/=3.0) irrespective of New York Heart Association functional class. A significant difference in postoperative event-free survival was observed between both groups (p = 0.0014); the adjusted risk ratio was 3.4 (95% confidence interval 1.6 to 7.2). Postoperative echocardiography showed larger left ventricular systolic dimensions (p <0.0001), lower fractional shortening (p = 0.0016), and larger left atrial dimensions (p <0.0001) in group H than group L. Thus, an MR score is a simple way to predict the prognosis of severe MR independently of subjective symptoms in patients undergoing mitral valve repair.

Cor triatriatum with unroofed coronary sinus and persistent left superior vena cava associated with atrial tachycardia

A 2-year-old girl with cor triatriatum with unroofed coronary sinus and persistent left superior vena cava underwent preoperative radiofrequency catheter ablation for atrial tachycardia attack that developed after admission to our hospital. The procedure was not successful. Cryoablation was successfully performed during corrective surgery. Cutting back from the coronary sinus orifice, resection of the fibrous tissue above the mitral valvular orifice, closure of the excised fossa ovalis and coronary sinus orifice with a Gore-Tex patch, and ligation of the persistent left superior vena cava resulted in an excellent hemodynamic outcome. At 2-year follow-up, the patient was free from tachycardia attack.

Echocardiographic prediction of left ventricular dysfunction after mitral valve repair for mitral regurgitation as an indicator to decide the optimal timing of repair

OBJECTIVES

This study sought to determine whether echocardiography before mitral valve repair (MVR) for mitral regurgitation (MR) was predictive of postoperative left ventricular (LV) dysfunction and useful for deciding the optimal timing of repair.

BACKGROUND

Some reports have shown that the preoperative echocardiographic data of left ventricular ejection fraction (LVEF) and left ventricular end-systolic diameter (LVDs) were good predictors of postoperative LV dysfunction. However, few reports were based on long-term follow-up data of large numbers of patients who underwent MVR in the last decade.

METHODS

A total of 274 patients with moderate or severe MR underwent MVR between October 1, 1991, and September 30, 2000. Among them, 171 patients who had both an operation for isolated MR due to degenerative pathology and a postoperative echocardiogram were studied. Postoperative echocardiograms were performed 3.9 +/- 2.4 years after the operation. The LVEF decreased from 66 +/- 10% before surgery to 63 +/- 11% after surgery (p < 0.0001). On univariate analysis, preoperative LVEF and LVDs correlated with postoperative LVEF (r = 0.41 and r = -0.39, respectively). Overall, postoperative LV dysfunction (defined as LVEF <50%) was not frequent (12%). However, the incidence of postoperative LV dysfunction was high in patients with preoperative LVEF <55% (38%) or LVDs > or =40 mm (23%).

CONCLUSIONS

In patients with MR, the echocardiographic data of LVEF and LVDs were good predictors of postoperative LV dysfunction. When a decrease in LVEF or an increase in LVDs is detected, MVR should be considered to preserve postoperative LV function.

Etiology of aortic valve disease and recent changes in Japan:a study of 600 valve replacement cases

BACKGROUND

Recent studies on the etiology of aortic valve disease in the US showed a decrease in rheumatic valve disease and an increase in age-related degenerative disease. The purpose of this study was to describe the etiology of aortic valve disease and its temporal changes in Japan, based on a large number of cases.

METHODS

The medical charts of all patients who underwent aortic valve replacement at our institute between 1977 and 1999 were reviewed. Among the 600 patients analyzed, 213 (36%) had pure aortic stenosis, 265 (44%) had pure aortic regurgitation, and 122 (20%) had combined stenosis and regurgitation.

RESULTS

The causes were rheumatic change (49%), degenerative change (19%), bicuspid valves (18%), infective endocarditis (5%) and others (9%). Rheumatic disease continued to be the most common cause of aortic stenosis, but its frequency decreased from 100% in 1977-1979 to 37% in 1995-1999. In contrast, the frequency of degenerative change among stenotic valves increased recently from 11% in 1990-1994 to 30% in 1995-1999. Similarly, rheumatic disease remained to be the leading cause of aortic regurgitation, with a decline in frequency from 46% in 1985-1989 to 27% in 1995-1999. The percentage of degenerative change among regurgitant valves did not change appreciably.

CONCLUSIONS

There was a shift in the causes of aortic valve disease, with a decrease in rheumatic disease and an increase in degenerative disease. This trend was similar to that observed in the US. These findings suggest the increasing importance of aortic valve disease due to degenerative change.

Normalization of left ventricular parameters following combined pimobendan and carvedilol treatment in a case of unclassified cardiomyopathy with longstanding refractory status

A 58-year-old man with a 64-month history of unclassified cardiomyopathy developed congestive heart failure (CHF) and had been dependent on long-term intravenous positive inotropes. Combined pimobendan and carvedilol administration resulted in marked symptomatic improvement from New York Heart Association functional class IV to I. Echocardiograms showed improvement of left ventricular (LV) ejection fraction from 15 to 48%, and LV end-diastolic diameter from 6.7 to 4.9 cm. This mode of therapy not only improved LV contractile function but also normalized LV volume, which was an unusual clinical course compared with the general course of advanced CHF.

Effects of carvedilol on plasma levels of interleukin-6 and tumor necrosis factor-alpha in nine patients with dilated cardiomyopathy

OBJECTIVES

Whether beta-blocker therapy changes the circulating levels of cytokines as congestive heart failure improves remains uncertain.

METHODS

Nine patients with idiopathic dilated cardiomyopathy, who had previously received conventional treatment and were classified as New York Heart Association (NYHA) functional class II, received carvedilol by stepwise dose increase up to 20 mg daily, and the plasma interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) levels were measured.

RESULTS

IL-6 was significantly reduced from 0.80 +/- 0.49 pg/ml before therapy to 0.21 +/- 0.08 pg/ml after carvedilol was increased to 20 mg daily (p < 0.05). Moreover, IL-6 level had already decreased significantly compared to the baseline when the dose of carvedilol had reached 10 mg daily (0.28 +/- 0.12 pg/ml, p < 0.05). TNF-alpha levels did not change significantly.

CONCLUSIONS

These results demonstrate that IL-6 concentration is significantly decreased by beta-blocker therapy. The efficacy for heart failure may be related to the change of IL-6 concentration.

Metal complexation with Langmuir monolayers of histidyl peptide lipids

Langmuir monolayers made from peptide-lipid molecules represent a novel direction in the research areas of biomimetic interfaces and two-dimensional supramolecular chemistry. Peptide structures and molecular recognition activities toward other guest molecules have been the focus of previous study. This study reports the investigation of metal complexation to histidine-containing peptide lipids in the organized Langmuir, Langmuir-Schaefer, or Langmuir-Blodgett films. Three peptide lipids PEP1-PEP3, with a histidine amino acid incorporated in the middle of the peptide, were designed and synthesized. The monolayer structures and metal-binding activities of each peptide lipid and their 1:1:1 molar ratio mixture were studied by thermodynamic and spectroscopic techniques. It was found that hard Lewis acid type metal cations such as K+ and Mg2+, and borderline or soft metal cations such as Zn2+, Cu2+, and Cd2+ exhibit clearly different binding activity toward peptide-lipid monolayers. The conformational changes of peptides upon binding with Cu2+ and Zn2+ were partially revealed by FT-IR spectroscopic studies. Furthermore, by adding a fluorescent-probe lipid to the peptide monolayer, dramatic fluorescence change was observed when Cu2+ or Zn2+ bound to the Langmuir and Langmuir-Schaefer films of peptide-lipid monolayers. Metal-protein complexation plays a crucial role in the function and activity of proteins and enzymes. Investigation of metal complexation to organized peptide Langmuir monolayers may provide an alternative approach for the development of artificial metalloproteins and novel supramolecular systems or materials.

Cation recognition by self-assembled monolayers of oriented helical peptides having a crown ether unit

Cation recognition of self-assembled monolayers (SAMs) of helical peptides having a crown ether unit was investigated by the impedance spectroscopy and cyclic voltammetry. Lipo-(Ala-Aib)8-Ala-Cr and Boc-Glu(Cr)-(Ala-Aib)8-Lipoa (Lipo, Lipoa, and Cr represent lipoic acid, lipoamide, and amidobenzo-18-crown-6, respectively) were synthesized and the helix SAMs were prepared. The peptides having a crown ether unit formed SAMs oriented nearly vertically to the substrate. The capacitance of the Lipo-(Ala-Aib)(8)-Ala-Cr SAM changed specifically with the addition of cations, and the binding constants of the SAM were larger than those of the crown ether in aqueous solution because of a large dipole moment of the helical peptide. In the case of the Boc-Glu(Cr)-(Ala-Aib)8-Lipoa SAM, the cation binding to the SAM showed a drastic decrease in the peak current of the cyclic voltammetry around 10(-5)M of K+ ion. In either capacitance measurement or cyclic voltammetry, the helical peptide SAM played an important role in the sensitive response to cations.

[Pitfalls in echocardiographic diagnosis of mitral bileaflet prolapse]

Preoperative echocardiography provides good planning information for successful repair of mitral valve regurgitation, but identifying the prolapse of both the anterior and posterior leaflets is sometimes difficult. To clarify the cause of this problem, preoperative echocardiographic findings and intraoperative observations of the prolapse were analyzed in 124 patients with non-rheumatic pure mitral regurgitation. In 48 patients with final diagnoses of bileaflet prolapse, 16 (33%) were considered to have only single leaflet prolapse before the operation. Anterior leaflet prolapse was overlooked in 14, and prolapse of either of its commissural segments was the least detectable by echocardiography. Chordal rupture was seen more in the posterior leaflet than in the anterior leaflet. Movement of the anterior leaflet may be influenced by a prolapsed and hypermobile posterior leaflet and/or regurgitant jet flow caused by the posterior leaflet prolapse.

Survival following cardiogenic shock caused by acute left main coronary artery total occlusion. A case report and review of the literature

The authors describe a fifty-five-year-old Japanese man with an acute extensive anterior myocardial infarction associated with a total occlusion of the left main coronary artery. The patient suffered cardiogenic shock and was treated successfully with rescue percutaneous transluminal coronary angioplasty and an intraaortic balloon pump (IABP) after unsuccessful intracoronary thrombolysis. Ten days after admission, he was weaned from IABP, and recovery-phase coronary angiography revealed no significant coronary artery stenosis and an ejection fraction of 32% by left ventriculography. The patient was discharged from the hospital without any ischemic findings.

Quantitative analysis of molecular orientation in chlorophyll a Langmuir monolayer: a polarized visible reflection spectroscopic study

Polarized visible reflection spectra of a chlorophyll a (Chl.a) Langmuir monolayer have been measured in situ at various surface pressures. By applying Hansen's optics to the three-phase plane-bounded system (air/Chl.a monolayer/water), the negative reflection absorbances observed were reproduced satisfactorily by the theoretical calculation. Molecular orientation of Chl.a in the monolayer was evaluated quantitatively as a function of surface pressure, from the reflection absorbance of p- and s-polarized spectra of the red (Qy) band. It has been proven that Chl.a molecules in the monolayer form aggregates (islands) even in the low surface pressure region and that during the monolayer compression the molecules are gradually reorganized from inhomogeneous islands to ordered structures, with the chromophores oriented on the average vertically to the water surface.

[Determining factors of successful percutaneous transvenous mitral commissurotomy and eligible indications for the procedure]

The aim of this report is to investigate the factors which influence mean left atrial pressure (LAP) after percutaneous transvenous mitral commissurotomy (PTMC) and the characteristics of patients in whom PTMC is most effective. Fifty one patients with symptomatic mitral stenosis underwent PTMC. The patients included 8 males and 43 females, aged 26-66 years (mean age of 46). These patients were classified into two groups according to LAP after PTMC: 31 cases with LAP after PTMC of 12 mmHg or less (group A) and 20 cases with LAP after PTMC greater than 12 mmHg (group B). The patients of group A were younger (44 +/- 6 vs 48 +/- 6 years, p < 0.05), and had atrial fibrillation (af) less frequently (35 vs 65%, p < 0.05), and had mitral valve calcification less frequently (29 vs 65%, p < 0.01). Before PTMC, LAP (19 +/- 6 vs 23 +/- 5 mmHg, p < 0.01) was lower and mitral valve area (MVA) (0.95 +/- 0.24 vs 0.81 +/- 0.15 cm2, p < 0.05) larger in group A. Symptoms graded according to the New York Heart Association functional classification system were similar in both groups before PTMC. After the procedure, final MVA (1.79 +/- 0.69 vs 1.40 +/- 0.50 cm2, p < 0.05) was larger and systolic pulmonary artery pressure (32 +/- 9 vs 39 +/- 7 mmHg, p < 0.01) lower in group A. Mitral regurgitation > or = 3-grade tended to complicate more frequently (3 vs 20%, NS) in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

[Duration of QRS complexes in arrhythmogenic right ventricular dysplasia. A new non-invasive diagnostic marker]

Arrhythmogenic right ventricular dysplasia (ARVD) may result in sudden death of young and sometimes athletic individuals, while if properly treated it is associated with a good prognosis. It is probably more widespread than currently thought. Comparison of the electrocardiograms of 43 ARVD patients with those of 44 normal individuals provided a new criterion enabling identification of the disease. Measurement of a QRS interval longer than 110 ms in sinus rhythm in lead V1 in an individual with an apparently normal heart enabled identification of the disease with a sensitivity of 55 p. cent and specificity of 100 p. cent if used alone, and a sensitivity of 60 p. cent if used in combination with a prolongation of QRS in lead V3 to greater than 110 ms, but with a specificity of 82 p. cent. After elimination of appearances of right bundle branch block, sensitivity was 50 p. cent for V1. This parameter studied in a hospital population should be validated in minor forms before leading to compulsory ECGs for individuals in high-risk occupations (athletes, public vehicle drivers, etc.).