The efficacy of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) has improved dramatically due to the development of new devices. Severe calcification of coronary lesions may be encountered even when the guidewire crosses the CTO, preventing the balloon from penetrating the lesion. A new “Tornus” penetration catheter has been developed for CTO recanalization. The purpose of this study was to evaluate the feasibility and safety of the Tornus catheter compared with traditional rotational atherectomy for CTO lesions.
From August 2002 to July 2009, 77 patients with CTO of the coronary artery were selected to undergo PCI. Forty-one patients were treated with rotational atherectomy before the availability of the Tornus catheter when the smallest balloon failed to pass the CTO lesion. Later, 36 patients were treated with a Tornus catheter. Device and angiographic success rates as well as procedural complications were assessed. Device success was defined when the Tornus or Rota burr passed through the lesion. Major complications included death, Q-myocardial infarction, or emergency bypass surgery. Minor complications included perforation, cardiac tamponade, no reflow phenomenon, or long spiral dissection.
The mean procedural time was significantly longer in the Tornus group (144 minutes versus 115 minutes, P = 0.01), while the device success rate was significantly lower (77% versus 95%, P = 0.024). Rotational atherectomy was subsequently performed in 3 of 8 Tornus failure cases. There were no between group differences in major complication rate (6% Tornus versus 5% rotational atherectomy). There was an insignificant trend for lower minor complication rates in the Tornus group (17% versus 20%).
Use of the Tornus catheter was associated with significantly longer procedural duration and lower device success rates compared to rotational atherectomy. Major and minor complications were not different between the groups. Our findings suggest that Tornus catheter penetration is not superior to conventional rotational atherectomy for CTO recanalization.

View full abstract

Myocardial tissue fluid flow (MTFF) directly represents the oxygen supply to the cardiomyocytes. Therefore, imaging of MTFF is carried out by fluorescence cardioscopy (FC).
Sixty-six patients with coronary artery disease underwent FC using fluorescein as an indicator of MTFF because this dye exhibits fluorescence in tissue fluid but not in the blood. Three mL of 10% fluorescein was injected intravenously and fluorescence images of the left ventricular endocardial surface were obtained by FC at 30 seconds and 1, 3 and 6 minutes later to evaluate the MTFF.
The CF images were classified as follows: diffuse with high intensity indicating normal MTFF; diffuse but with low intensity indicating decreased MTFF, no fluorescence indicating absent MTFF, and patchy fluorescence indicating patchy preservation of MTFF. MTFF was normal in all 18 patients with chest pain syndrome, patchy fluorescence was decreased or absent in 16 of 20 patients with angina and/or old myocardial infarction due to organic coronary artery disease, and was patchy in 21 of 28 patients with vasospastic angina. Ten of these 20 patients underwent coronary stenting with successful angiographic results in all. However, MTFF disturbance frequently remained.
FC is clinically feasible for evaluation of MTFF disturbance, for evaluation of even emergency coronary interventions, and for guidance of transendocardial angiogenic and myogenic therapies in patients with coronary artery disease.

View full abstract

Brugada syndrome is often accompanied by atrial tachyarrhythmia, such as atrial fibrillation (AF). The aim of this study was to examine atrial vulnerability in patients with Brugada syndrome. Two groups of patients were compared: 18 patients with Brugada syndrome (Brugada syndrome group) and 11 age-matched patients with neither organic heart disease nor AF episodes (control group). Programmed electrical stimulation was performed from the right atrium (RA), and the effective refractory period of the right atrium (ERP-RA), interatrial conduction time (IACT), monophasic action potentials (MAPs) at the high RA, and the inducibility of AF lasting > 30 seconds were studied. MAP duration at 80% repolarization (MAPD₈₀) was calculated. AF was induced with a single extrastimulus or double extrastimuli in all patients with Brugada syndrome but in none of the control patients. The ERP-RA did not differ between the groups. IACT at the shortest diastolic interval was significantly increased in the Brugada syndrome group compared to that in the control group. The maximum slope of the MAPD₈₀ restitution curve was significantly steeper in the Brugada syndrome group than in the control group (2.4 ± 2.0 versus 0.82 ± 0.36, P < 0.02). Ventricular fibrillation was induced with ventricular programmed stimulation in all Brugada syndrome patients. Both abnormal interatrial conduction and steep restitution of action potential duration may contribute to the atrial arrhythmogenicity in Brugada syndrome.

View full abstract

It has previously been reported that cardiac troponin I (cTnI) is useful in predicting the postoperative course after cardiac surgery, and that elevated serum cTnI levels are associated with increased in-hospital mortality. However, these findings have been reported in heterogeneous groups of cardiac surgical procedures. In the current study, the usefulness of postoperative cTnI measurements for the prediction of patient outcomes in a specific group of cardiac surgical procedures was determined, with the analysis limited to patients undergoing mitral valve surgery. The results of cTnI measurements were compared with postoperative creatine kinase-myocardial band fraction (CK-MB) levels.
A total of 24 patients who underwent mitral valve surgery from July 2004 to April 2009 were retrospectively studied. Serum cTnI and CK-MB levels were measured on postoperative day (POD) 0 (immediately after surgery), and on POD 1, 2, and 3. The relationship between serum cTnI and CK-MB levels, cardiopulmonary bypass (CPB) time, aorta cross-clamping (AoC) time, and the length of ICU stay and postoperative hospital stay (POHS) were evaluated.
CPB and AoC time influenced postoperative cTnI and CK-MB levels. Values of cTnI on POD 1 and POD 2 were significantly correlated with the length of ICU stay, whereas only the CK-MB level on POD 2 was significantly correlated with the length of ICU stay. In addition, the cTnI levels on POD 1 and POD 2 were significantly correlated with POHS, however, there was no relationship between postoperative CK-MB levels and POHS.
Postoperative cTnI measurements are more useful than CK-MB measurements in predicting the postoperative course of a patient following mitral valve surgery.

View full abstract

It has been unclear how acute hypoxia at moderate altitude affects stroke volume (SV), an index of cardiac function, during exercise. The present study was conducted to reveal whether acute normobaric hypoxia might alter SV during exercise.
Nine healthy male subjects performed maximal exercise testing under normobaric normoxic, and normobaric hypoxic conditions (O₂: 14.4%) in a randomized order. A novel thoracic impedance method was used to continuously measure SV and cardiac output (CO) during exercise.
Acute hypoxia decreased maximal work rate (hypoxia; 247 ± 6 [SE] versus normoxia; 267 ± 8 W, P < 0.005) and VO₂ max (hypoxia; 2761 ± 99 versus normoxia; 3039 ± 133 mL/min, P < 0.005). Under hypoxic conditions, SV and CO at maximal exercise decreased (SV: hypoxia; 145 ± 11 versus normoxia; 163 ± 11 mL, P < 0.05, CO: hypoxia; 26.7 ± 2.1 versus normoxia; 30.2 ± 1.8 L/min, P < 0.05). In acute hypoxia, SV during submaximal exercise at identical work rate decreased. Furthermore, in hypoxia, 4 of 9 subjects attained their highest SV at maximal exercise, while in normoxia, 8 of 9 subjects did.
Acute normobaric hypoxia attenuated the increment of SV and CO during exercise, and SV reached a plateau earlier under hypoxia than in normoxia. Cardiac function during exercise at this level of acute normobaric hypoxia might be attenuated.

View full abstract

Chronic kidney disease (CKD) is a major and serious risk factor for cardiovascular disease (CVD). Continuous hypoxia due to hypoperfusion in peritubular capillaries is one of the factors aggravating CKD, but evaluation of perfusion in this region is difficult using clinically available imaging methods. Since the second-generation ultrasound contrast agent Sonazoid^TM has a stable shell, it enables visualization of the renal vasculature for a long period of time. We therefore evaluated changes in contrast-enhanced ultrasound (CEUS) imaging with Sonazoid^TM in CKD patients.
Sonazoid^TM was used in 85 CKD patients and 5 control subjects, and images were recorded for 10 minutes. Time-intensity curves were generated from the images of 62 time points in both cortex and medulla.
In control samples, contrast enhancement spread from the hilar portion to the periphery along the direction of arterial flow, and renal cortex and medulla were then enhanced in sequence. Enhancement was maximal soon after, then gradually decreased, but was still visible at 600 seconds. In CKD patients, renal contrast enhancement was attenuated in both cortex and medulla. On time-intensity curves, the attenuation of enhancement was composed of delayed rising, reduction of peak, and acceleration of decay in both cortex and medulla with progression of renal dysfunction. No side effects of the contrast agent were observed in any subjects.
The attenuation of renal contrast enhancement observed in CKD patients appears to reflect disturbance of perfusion in peritubular capillaries. CEUS with Sonazoid^TM is a useful and safe means of visualizing the renal microvasculature.

View full abstract

Smoking is associated with increased plasma homocysteine levels, and both are associated with an increased risk of cardiovascular disease. However, little information is available on the effects of passive smoking on the level of homocysteine in nonsmokers. We analyzed the data of self-reported never-smokers (aged ≥ 20 years, n = 3,232), who were from the Third National Health and Nutrition Examination Survey. We quantified the passive nicotine exposure by dividing the never-smokers into quartiles as based on the serum cotinine values. Multiple linear and logistic regression models were used to determine any independent relationships between serum cotinine concentration and levels of homocysteine, vitamin B12, and folate. An elevated homocysteine level was defined as a concentration greater than the 80th percentile. A reduced folate or vitamin B12 level was defined as a concentration less than the 20th percentile.
After adjusting for age, gender, body mass index, race, folate and vitamin B12 levels, increased cotinine levels (quartile III and IV) were found to be associated with hyperhomocysteinemia. There was a strong nonlinear increase in the serum homocysteine levels across the quartiles of cotinine. Multivariate analysis showed that age, male gender, non-Caucasian, low levels of folate and vitamin B12, and increased serum cotinine (quartile II-IV) were independently associated with elevated homocysteine levels. In conclusion, these findings indicate that passive smoke exposure in never-smokers is positively and independently associated with plasma homocysteine levels in a dose-dependent manner. These findings may help further determine the link between passive smoking and cardiovascular events.

View full abstract

Components of the renin-angiotensin-aldosterone system such as angiotensin II and aldosterone are believed to contribute to the development and progression of cardiovascular tissue and organ injuries. We compared the effects of two calcium channel blockers, efonidipine and amlodipine, on the renin-angiotensin-aldosterone system in patients with end-stage renal diseases on maintenance hemodialysis. Twenty hypertensive patients on chronic hemodialysis were given efonidipine 20-60 mg twice daily and amlodipine 2.5-7.5 mg once daily for 12 weeks each in a random crossover manner. The average blood pressure was comparable between the efonidipine and amlodipine periods (151 ± 15/77 ± 8 versus 153 ± 15/76 ± 8 mmHg). The pulse rate did not change significantly during the administration periods. Although the plasma renin activity and plasma angiotensin II were not significantly different between the efonidipine and amlodipine periods, plasma aldosterone was significantly lower in the efonidipine period than in the amlodipine period (123 ± 118 versus 146 ± 150 pg/mL, P = 0.027). The findings suggest that efonidipine reduces plasma aldosterone levels in patients on maintenance hemodialysis, and this seems to be an additional benefit to the cardiovascular protection by antihypertensive therapy with efonidipine in patients with end-stage renal disease.

View full abstract

Steam pop and intramural charring have been reported during cooled-tip radiofrequency catheter ablation (RFCA). We studied the feasibility of temperature-controlled cooled-tip RFCA in the canine heart.
An internally cooled ablation catheter was inserted into the left ventricle. A custom-made radiofrequency (RF) generator capable of controlling the tip-temperature at the preset level by slow increases in the power was used. Temperature-controlled cooled-tip RF applications were performed at a target temperature of 40°C for 90 seconds. Acute study: Intramyocardial temperature was measured at the ablation site in 10 dogs by inserting a fluoroptic probe. Chronic study: Lesion depth and volume were measured in 5 dogs after 3 weeks of survival. In the acute study, no pop or abrupt impedance rise was observed. Maximum intramyocardial temperature was 72.4 ± 14.4°C at 2-4 mm above the endocardium. No coagulum formation, craters, or intramural charring were observed. Maximum lesion depth was 6.7 ± 1.5 mm, and lesion volume was 404 ± 219 mm3. In the chronic study, maximum lesion depth was 5.9 ± 1.1 mm, and lesion volume was 281 ± 210 mm³.
Temperature controlled RFCA is feasible with a cooled-tip catheter and an RF generator that slowly increases the RF power until the preset catheter-tip temperature is reached.

View full abstract

Recent studies have confirmed that PPARα agonists have not brought the anticipated benefits to patients with type 2 diabetes and potentially fatal heart disease. We hypothesized that such agonists may have a cardio-suppressive effect in treating such disorders, therefore, we inoculated diabetic KKAy mice with encephalomyocarditis virus (EMCv) to induce a diabetic model with severe myocardial damage. WY14643, a potent PPARα agonist, was administered intraperitoneally either simultaneously (WY14643-late group) or 3 days before viral inoculation (WY14643-early group). WY14643-treated mice, especially those in the WY14643-early group, had higher mortality than those in the vehicle-treated group (vehicle) in the first 5 days after EMCv inoculation. However, the survival rate in the vehicle group decreased rapidly after day 4 and was the lowest of all 3 groups by day 9. The WY14643-treated mice showed reduced body weight and blood glucose, improved myocardial pathological changes, lower cardiac TNF-α expression, and significantly higher adiponectin expression, whereas the LW/LC ratio was lower and cardiac UCP3 mRNA expression higher in the WY14643 treatment groups than in the vehicle group on day 4. WY14643 therefore has cardioprotective and cardio-suppressive effects when used to treat EMCv-induced myocarditis in diabetic mice. The cardioprotective effect may be due to its anti-inflammatory properties and its ability to increase cardiac adiponectin expression, whereas the reduced cardiac efficiency may be due to its enhancement of cardiac UCP3 mRNA expression.

View full abstract

No reflow phenomenon during percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) has an unfavorable outcome. Previously, some investigators have tried to determine the predictors of this phenomenon, but there are still controversies as to whether it is possible to make predictions beforehand. Here we report the first clinical case by intravascular ultrasound (IVUS) with a newly designed pattern recognition algorithm to evaluate the tissue characteristics of the culprit lesion in a 64-year-old patient with ACS who suffered from no reflow phenomenon during PCI. We also reveal the plaque composition of the culprit lesion of another ACS patient without no reflow as well as a stable angina pectoris patient. The percentage of necrotic tissue was higher in the culprit lesion in a patient with no reflow than in the others. In conclusion, a new spectral similarity concept of IVUS is promising in differentiating ambiguous tissue characterization results.

View full abstract

Coronary spasm can usually be controlled by administration of Ca antagonists. However, there are some cases of coronary spasm whose attacks cannot be controlled even with large doses of Ca antagonist and/or its combination with nitrates. Here we describe the case of a 41-year-old man whose attacks of coronary spasm were resistant to the combined administration of nitrates, Ca antagonists, and a statin. The attacks were alleviated and disappeared after withdrawal of nitrates and recurred after readministration of a nitroglycerin patch. The involvement of nitrate tolerance in the pathogenesis of multidrug resistant coronary spasm was revealed and its implication discussed.

View full abstract

Hypertrophic cardiomyopathy (HCM) is associated with gene mutations that encode sarcomeric proteins. However, the relationship between genotype and histopathologic findings is unclear. We report on two autopsy cases with advanced HCM associated with deletion of lysine 183 mutation in the cardiac troponin I gene. One case, a 74-year-old female exhibited dilated cardiomyopathy-like features. Transmural scarring was diffuse and circumferential, involving the whole left ventricle, especially the ventricular septum which was replaced with extensive fibrosis and showed marked wall thinning. The other case, a 92-year-old male revealed typical HCM findings. Patchy scars which corresponded to replacement fibrosis were found extending from the septum to the anterior wall. These two autopsy cases indicate the clinical heterogeneity of HCM even within the same disease-causing mutation and suggest that the degree and extent of fibrosis determine differences in the clinical manifestations of HCM. This is the first autopsy report that demonstrates identical sarcomeric gene mutations causing different clinical manifestations and histologic findings. The findings suggest that additional genetic or environmental factors influence the phenotypic expressions and clinical courses of HCM caused by genetic mutation of sarcomeric proteins.

View full abstract

Fulminant myocarditis is characterised by acute onset with severe haemodynamic deterioration. With intensive and appropriate bridging management, the prognosis is better than classic forms of myocarditis. Here, we report a patient who suffered from fulminant myocarditis 3 times over the last 8 years with recovery each time.

View full abstract