We evaluated the effects of disopyramide in terms of the balance between myocardial oxygen supply and demand in patients with hypertrophic obstructive cardiomyopathy (HOCM). The myocardial oxygen supply was evaluated by measuring coronary flow velocity and the myocardial oxygen demand was assessed by the pressure-volume area (PVA). The time velocity integral of coronary flow did not change significantly (20 +/- 6 to 21 +/- 8 cm), but the peak left ventricular pressure and left ventricular external work decreased significantly (206 +/- 44 to 157 +/- 37 mmHg, P < 0.001; 1.09 +/- 0.33 to 0.80 +/- 0.23 J/beat, P < 0.001) after disopyramide administration. From theoretical analysis using these data, we concluded that disopyramide improves the myocardial oxygen supply-demand balance in patients with HOCM.

Introduction Screening of coexistent typical atrial flutter (AFL) in patients with atrial fibrillation (AF) is sometimes challenging. This study investigated whether a prolonged right atrial conduction time (RACT) estimated by tissue Doppler imaging (TDI) predicts patients with concomitant AFL and AF. Methods and Results We retrospectively analyzed 398 patients (mean age: 61.6 years, 73.4% men) undergoing catheter ablation of paroxysmal AF. The patients were classified into two groups according to whether they had evidence of AFL (N = 122, 30.7%) determined by a clinical observation (N = 68), induction during procedures (N = 33), or AFL recurrence after procedures (N = 21) or not (N = 276, 69.3%). The preoperative RACT, defined as a longer duration between the onset of the P‐wave and peak A′‐wave on the right atrial lateral wall or septal wall, and total atrial conduction time (TACT), defined as the same time duration on the left atrial lateral wall, were evaluated in all patients. Patients with evidence of AFL had a significantly longer RACT than those without AFL (p < .001). A multiple logistic regression and receiver operator characteristics curve analysis revealed the ratio of the RACT and TACT (RACT/TACT) was the independent and most superior accurate cofounder for predicting evidence of AFL (area under the curve: 0.867). When adding a discriminator of an RACT/TACT ≧ 93% into the conventional screening, 98.4% of the patients with evidence of AFL were estimated to be treated during the initial procedures. Conclusion The estimated RACT/TACT using the TDI may be useful for predicting patients with concomitant AFL in patients with AF.

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There is considerable interest of the changes in intracellular electrolytes in various pathophysiological states in cardiology. X-ray microanalysis is a useful method to measure the concentration of intracellular elements, and freeze-drying is a required technique for X-ray microanalysis to preserve elements. In this study, we utilized a new technique by which ultrathin sections were evaporated by carbon in an external freeze-dryer after freeze-drying and we were able to obtain clear electron micrographs of papillary muscles and myocytes. Calcium concentrations of mitochondria and cytosol were measured during 120 rain ischemia. We showed that mitochondria played a role in intracellular calcium regulation during 30 min ischemia.

Background Adaptive servo-ventilation (ASV) is reportedly beneficial for the treatment of heart failure in patients with central sleep apnea syndrome. However, the recent SERVE-HF trial reported that ASV treatment increased mortality in these patients. One cause of the negative result was considered to be the low output induced by high expiratory positive airway pressure (EPAP) against the background of low left ventricular ejection fraction (LVEF). Hypothesis We hypothesized that optimized ASV settings can be determined by evaluating outflow by using echocardiography, thereby ensuring benefits for patients with severe heart failure (HF). Methods Between July 2016 and March 2017, we optimized ASV settings by using hemodynamic parameters on echocardiography in hospitalized patients with severe HF treated with catecholamine or who were candidates for heart transplantation. We calculated stroke volume (SV) by using the time-velocity integral in the left ventricular outflow tract and compared the response to ASV with EPAP settings of 2, 4, 6, or 8 mmHg. We determined the optimal setting at which the SV reached the maximum value and compared this with the settings at baseline and discharge. We also compared rehospitalization and all-cause mortality between the patients who used ASV with titration (n=28) and without titration (n=37). Result We evaluated 28 patients with severe HF (mean EF, 32%). ASV treatment improved the SV (from 53.4 to 58.8 ml, P&lt;0.05) when optimal settings were used. However, the SV decreased when ASV was performed with a higher-than-optimal EPAP setting. Moreover, at discharge, the EPAP setting was lower than at baseline (mean EPAP, 4.75 cmH2O decreased to 3.71 cmH2O, P&lt;0.05). During the follow-up (median, 420 days), more hospitalizations and deaths occurred in the patients without ASV titration (48.8% vs 37.8%) than in those with ASV titration (28.6% vs 21.4%, respectively; Figure 1). Conclusion In patients with severe HF, high EPAP decreased the SV and optimal settings were different at baseline and after treatment. The result indicated that the optimal setting for ASV may be beneficial for preventing rehospitalization and death. Whether optimal ASV settings reduce mortality in these patients must be investigated. Figure 1 Funding Acknowledgement Type of funding source: None