Fumihiko Miyake

Left Ventricular Rupture Associated With Takotsubo Cardiomyopathy

A 70-year-old woman was admitted to the hospital with chest discomfort after quarreling with her neighbors. Electrocardiography revealed ST-segment elevation in leads I, II, III, aVL, aVF, and V2 through V6. Coronary angiography demonstrated normal arteries, but left ventriculography showed apical akinesis and basal hyperkinesis. Takotsubo cardiomyopathy was diagnosed on the basis of these characteristic findings. The creatine kinase and creatine kinase-MB concentrations were elevated at admission and reached maximum levels 6 hours after admission. The plasma level of brain natriuretic peptide was 10.7 pg/mL (reference range, <18.4 pg/mL) on the first hospital day. ST-segment elevation in leads I, II, III, aVL, aVF, and V2 through V6 persisted at 72 hours after admission. On the third hospital day, sudden rupture of the left ventricle occurred, and despite extensive resuscitation efforts, the patient died. Takotsubo cardiomyopathy presents in a manner similar to that of acute myocardial infarction, but ventricular systolic function usually returns to normal within a few weeks. To our knowledge, this is the first reported case of fatal left ventricular rupture associated with takotsubo cardiomyopathy. We suggest that takotsubo cardiomyopathy may be a newly recognized cause of sudden cardiac death.

Reversible ventricular dysfunction takotsubo cardiomyopathy

Recently, many cardiologists have recognized the existence of a rapidly reversible form of heart failure of unknown origin characterized by a takotsubo‐shaped, dyskinetic left ventricle on left ventriculography.

Reversible left ventricular dysfunction “takotsubo” cardiomyopathy associated with pneumothorax

An 83 year old woman presented to the emergency department with chest pain and dyspnoea. Chest radiography showed pneumothorax of the left lung. Arteries were normal on coronary angiography. Left ventriculography showed asynergy of apical akinesis and basal hyperkinesis. Within 18 days, the asynergy improved without any specific treatment. In the present case the left ventricular dysfunction may have been induced by altered catecholamine dynamics as a result of pneumothorax.

Acute Myocardial Infarction Induced by Alternating Exposure to Heat in a Sauna and Rapid Cooling in Cold Water

We describe a patient with acute myocardial infarction, which was thought to result from plaque rupture or thrombosis because of coronary artery spasm. The vasospasm was most likely induced by stimulation of the α-adrenergic receptors during alternating heat exposure during sauna bathing and rapid cooling during cold water bathing. This report emphasizes the dangers of rapid cooling after sauna bathing in patients with coronary risk factors.

Impact of Contrast-Induced Nephropathy and Cardiovascular Events by Serum Cystatin C in Renal Insufficiency Patients Undergoing Cardiac Catheterization

We assessed the usefulness of serum cystatin C for predicting contrast-induced nephropathy (CIN) in patients (n = 100) undergoing coronary catheterization. After a 12-month follow-up, the incidence of CIN was 8.3% (n = 5) in patients with mild renal insufficiency (estimated glomerular filtration rate [eGFR] 60-89 mL/min per 1.73 m2), 34.4% (n = 10) in those with moderate renal insufficiency (eGFR 30-59 mL/min per 1.73 m2), and 100% (n = 3) in those with severe renal insufficiency (eGFR 15-29 mL/min per 1.73 m2). The sensitivity was 81.8% and specificity was 90.9% at the cutoff level of serum cystatin C >1.18 mg/L. Serum cystatin C levels were significantly (P < .001) higher in the patients with moderate renal insufficiency in the CIN group than those in the non-CIN group. Multivariate logistic regression analysis demonstrated that baseline serum cystatin C independently predicted short-term mortality (odds ratio [OR], 0.311; 95% confidence interval [CI] 0.058-0.538; P = .026). Baseline serum cystatin C significantly predicted the occurrence of CIN in the patients with moderate renal insufficiency.

Intramural Purkinje Cell Network of Sheep Ventricles as the Terminal Pathway of Conduction System

To identify the anatomical basis for cardiac electrical signal conduction, particularly seeking the intramural terminals of conduction pathway within the ventricles, sheep hearts were examined compared with human hearts utilizing the characteristic morphology of Purkinje cells as a histological marker. In 15 sheep and five human autopsies of noncardiac death, prevalence of Purkinje or Purkinje‐type cells were histologically examined in the atrioventricular node, its distal conduction pathway, the interventricular septum, and the right‐ and left‐ventricular free walls. Myocardial tissue cleavages were examined in the transmural sections (along cardiac base‐to‐apex axis) obtained from the septum and ventricular free walls. Serial histological sections through virtually the entirety of the septum in selected sheep were used as the basis of a three‐dimensional reconstruction of the conduction pathway, particularly of the intramural Purkinje cell network. Purkinje cells were found within the mural myocardium of sheep ventricles whereas no intramural Purkinje‐type cell was detected within the human ventricles. In the sheep septum, every intramural Purkinje cell composed a three‐dimensional network throughout the mural myocardium, which proximally connected to the subendocardial extension of the bundle branches and distally formed an occasional junction with ordinary working myocytes. The Purkinje‐cell network may participate in the ventricular excitation as the terminal conduction pathway. Individual connections among the Purkinje cells contain the links of through‐wall orientation which would benefit the signal conduction crossing the architectural barriers by cleavages in sheep hearts. The myocardial architectural changes found in diseased hearts could disrupt the network links including those with transmural orientation. Anat Rec, 2009.

Relationship between left ventricular ejection fraction and mitral annular displacement derived by speckle tracking echocardiography in patients with different heart diseases.

BACKGROUND Speckle tracking echocardiography (STE)-derived mitral annular displacement (MAD) utilizes the speckle tracking technique to measure strain vectors, which provides accurate estimates of left ventricular ejection fraction (LVEF). Here, we investigated a link between STE-derived MAD and LVEF in patients with different heart diseases and evaluated its clinical usefulness. METHODS This study included 266 outpatients and 84 controls. Of the study patients, 52 patients had ischemic heart disease (IHD), 37 patients had dilated cardiomyopathy (DCM), 34 patients had hypertrophic cardiomyopathy (HCM), 74 patients had valvular heart disease (VHD), and 69 patients had hypertensive heart disease (HHD). STE continuously tracked annular motion throughout the cardiac cycle in the apical 4- and 2-chamber views. RESULTS In all participants, the curvilinear relationship was found between STE-derived MAD and LVEF (R(2)=0.642). The strong correlation between STE-derived MAD and LVEF was also found in the patients with IHD (R(2)=0.733, p=0.001) and in those with DCM (R(2)=0.614, p=0.008). However, such a correlation was not found in the patients with HCM, VHD, or HHD. CONCLUSION The specificity in the correlation between STE-derived MAD and LVEF was found in patients with each heart disease, which should be taken into account when assessing these parameters.

Three-dimensional echocardiographic assessments of exercise-induced changes in left ventricular shape and dyssynchrony in patients with dynamic functional mitral regurgitation

AIMS Left ventricular (LV) shape and LV dyssynchrony are two cofactors associated with functional mitral regurgitation (MR) in patients with heart failure. Both can be accurately examined by real-time three-dimensional echocardiography (3DE). We examined the relationship between dynamic MR and exercise-induced changes in LV shape and synchronicity using 3DE. METHODS AND RESULTS Fifty patients with systolic LV dysfunction underwent 2D and 3D quantitative assessment of LV function, shape, and synchronicity at rest and during symptom-limited exercise test. According to the magnitude of change in MR, patients were divided into EMR group (15 patients, 30%), if the degree of MR increased during test, and NEMR group. During exercise, the changes in LV volumes and ejection fraction were similar in both groups, whereas changes in mitral valvular deformation parameters, in LV sphericity index, and in the extent of LV dyssynchrony were more pronounced in the EMR group. At rest, only the 3D sphericity index could distinguish the two groups. By stepwise multiple regression model, dynamic changes in the systolic dyssynchrony index, sphericity index, and coaptation distance were associated with dynamic MR (r(2) = 0.45, P = 0.012). CONCLUSION Dynamic MR during exercise is related to the 3D changes in LV shape and in LV synchronicity.

Changes in mitral regurgitation and left ventricular geometry during exercise affect exercise capacity in patients with systolic heart failure.

AIMS exercise may dramatically change the extent of functional mitral regurgitation (MR) and left ventricular (LV) geometry in patients with chronic heart failure (CHF). We hypothesized that dynamic changes in MR and LV geometry would affect exercise capacity. METHODS AND RESULTS this study included 30 CHF patients with functional MR who underwent symptom-limited bicycle exercise stress echocardiography and cardiopulmonary exercise testing for quantitative assessment of MR (effective regurgitant orifice; ERO), and pulmonary artery systolic pressure (PASP). LV sphericity index was obtained from real-time three-dimensional echocardiograms. The patients were stratified into exercised-induced MR (EMR; n = 10, an increase in ERO by ≥13 mm(2)) or non-EMR (NEMR; n = 20, an increase in ERO by <13 mm(2)) group. At rest, no differences in LV volume and function, ERO, and PASP were found between the two groups. At peak exercise, PASP and sphericity index were significantly greater (all P < 0.01) in the EMR group. The EMR group revealed lower peak oxygen uptake (peak VO(2); P = 0.018) and greater minute ventilation/carbon dioxide production slope (VE/VCO(2) slope; P = 0.042) than the NEMR group. Peak VO(2) negatively correlated with changes in ERO (r = -0.628) and LV sphericity index (r = -0.437); meanwhile, VE/VCO(2) slope was well correlated with these changes (r = 0.414 and 0.364, respectively). A multivariate analysis identified that the change in ERO was the strongest predictor of peak VO(2) (P = 0.001). CONCLUSION dynamic changes in MR and LV geometry contributed to the limitation of exercise capacity in patients with CHF.

The exercise training effects of skeletal muscle strength and muscle volume to improve functional capacity in patients with myocardial infarction

BACKGROUND No previous studies have fully investigated the exercise training effect on the skeletal muscle strength and volume to improve the exercise capacity in patients with myocardial infarction (MI). The present study was performed based on a hypothesis that the relationship between exercise capacity, skeletal muscle strength and volume might be changed by the amount of skeletal muscle volume in MI patients up to 3 months after the onset. METHODS Seventy patients with MI underwent symptom-limited cardiopulmonary exercise testing using a treadmill. The lower limb muscle volume (MV) was evaluated according to electrical impedance analysis and the maximal knee extension strength (Peak torque: PT) was measured by a Biodex. All patients participated in 12-week exercise training program. The subjects were divided into 2 groups on the basis of MV: Group H, MV>==22 kg; Group L, MV<22 kg. Delta values were calculated as follows: the value at 3 months minus the value at 1 month. RESULTS A positive and significant correlation was observed between the delta PT and delta peak VO(2) (r=0.50, p<0.005) only in the L group. No significant correlation was observed between the delta peak VO(2) and the delta lower limb MV or between the delta lower limb MV and the delta PT in the 2 groups. CONCLUSIONS Cardiac rehabilitation program combined with resistance and aerobic training improved exercise capacity and increased not the skeletal muscle volume but the skeletal muscle strength in patients with MI in their recovery phase. It was presumed that the improvement of exercise capacity was determined by the skeletal muscle strength not by the muscle volume especially in MI patients with low muscle volume.