Two cases of hemodynamic improvement by modulation of atrioventricular delay in cardiac operations.

BACKGROUND: Symptomatic sick sinus syndrome is one of the indications for pacemaker implantation, and we have to consider to program the pacemaker to an asynchronous pacing mode during an operation. CASE PRESENTATION: We reported two cases with a pacemaker implanted for sick sinus syndrome undergoing cardiac operation. We changed programming of the pacemaker to an asynchronous pacing mode (DOO) and modulated the programmed atrioventricular delay to avoid ventricular pacing, resulting in better hemodynamic condition. Although we observed premature ventricular contraction, no lethal arrhythmias induced by the R-on-T phenomenon were noted. CONCLUSION: Programming of the pacemaker to an asynchronous pacing mode and modulation of the programmed atrioventricular delay to avoid ventricular pacing may be an option for pacemaker management during an operation.

Anesthetic management of a patient with severe aortic regurgitation undergoing reoperation for ascending aorta false aneurysm using hypothermia: prevention of ventricular fibrillation by nifekalant.

BACKGROUND: To prevent cardiac collapse and to protect cerebral function, hypothermic cardiopulmonary bypass is established before resternotomy. However, ventricular fibrillation under hypothermia facilitates left ventricular distension, which causes irreversible myocardial damage when the patient has aortic regurgitation. We report a case of successful management in preventing ventricular fibrillation under hypothermia by using nifekalant. CASE PRESENTATION: A 56-year-old male, who had been performed a David operation, was scheduled for a Bentall operation for a pseudo aortic aneurysm with severe aortic regurgitation. After inducing anesthesia, we administered intravenous nifekalant and a vent tube was inserted into the left ventricle under one-lung ventilation. Extracorporeal circulation was established and resternotomy started after cooling to 27 °C. Although severe bradycardia and QT prolongation were observed, ventricular fibrillation did not occur until aortic cross-clamping. CONCLUSION: Combining maintaining cerebral perfusion and avoiding left ventricle distension during hypothermia was successfully managed with nifekalant in our redo cardiac patient with aortic regurgitation.

Analysis of difficulty in placement of pulmonary artery catheter through the left internal jugular vein.

PURPOSE: The left internal jugular vein may be an alternative route for the placement of a pulmonary artery catheter when the right jugular vein is not available. Although the placement through the left internal jugular vein is expected to be more difficult, little has been written regarding difficulties in achieving proper placement of the catheter through the left internal jugular vein. METHODS: This prospective and observational study includes patients undergoing cardiac surgery with the catheter placement by monitoring the pressure waveform for 2 years. We measured the time required for the catheter to pass through the tricuspid and pulmonary valves, respectively. The data were analyzed by Mann-Whitney. P < 0.05 was considered significant. RESULTS: The catheter placement through the right and left internal jugular vein was done in 285 (group R) and 10 patients (group L), respectively. The time duration through the tricuspid valve in group L was significantly longer than that in group P (8 [5-14] s vs 70 [19.8-138] s, median [range], P < 0.01), whereas the time duration through the pulmonary valve was comparable between the two groups (15 [10-27.75] s vs 15 [10.25-19] s, median [range], P = 0.62). CONCLUSION: These results indicate that the difficulty in the catheter placement through the left jugular vein may be to pass through the tricuspid valve, not the pulmonary valve.

An analysis of factors influencing pulmonary artery catheter passage through the tricuspid and pulmonary valves.

PURPOSE: A pulmonary artery catheter (PAC) has to pass the tricuspid and pulmonary valves for its proper placement. Although several factors were reported to hinder the placement, there have been no reports to identify the factors that prolong the individual time for passing through each valve. METHOD: We individually measured the time required for a PAC to pass through the tricuspid and pulmonary valves. We examined the effect of the following factors on those times: the patient's age, sex, height, weight, cardiothoracic ratio, tricuspid regurgitation, left ventricular ejection fraction, and the diameters of the sinus of Valsalva and of the sinotubular junction divided by the body surface area which represent the diameter of the aorta. Data were analyzed by multiple linear regression analysis after univariate analysis. RESULTS: The placement of a PAC was successful in all of 100 patients. The time required to pass through the pulmonary valve was significantly longer than that through the tricuspid valve (15 [10-28] s vs 9 [5-16] s, median [range], P < 0.01). The incidence of ventricular arrhythmias during passage through the pulmonary valve was significantly higher than that through the tricuspid valve (17% vs 0%, P < 0.01). Tricuspid regurgitation and the diameter of sinotubular junction had a significant positive association with the time required to advance a PAC through the pulmonary valve, although there was no significant factors that increased the time required to advance a PAC through the tricuspid valve. CONCLUSION: The time required to advance a PAC through the pulmonary valve is much longer than that to pass through the tricuspid valve. The diameter of aortic root and tricuspid regurgitation are significant factors that increased the time required to advance a PAC through the pulmonary valve.

Relationship between findings of mandibular cortical bone in inferior border and bone mineral densities of lumbar vertebrae in postmenopausal women.

It is important to assess the general bone condition in dental implant treatment. The relationships between the bone mineral densities (BMDs) of lumbar vertebrae and mandibular cortical bone condition in the inferior border using multi-slice computed tomography (CT) were assessed in postmenopausal women. If a strong correlation between them is obtained, the mandibular cortical bone condition may be useful to evaluate the general bone condition. Twenty-two postmenopausal women were enrolled in this investigation. The maximum CT value and width of the mandibular cortical bone (MCW-MSCT) were measured, and the mandibular cortical bone index (MCI-MSCT) was classified using multi-slice CT. BMDs of lumbar vertebrae were measured using dual energy X-ray absorptiometry (DXA), and then the percentage of the young adult mean (YAM) was analyzed. The correlations were investigated between the mandibular cortical bone condition and values of lumbar vertebrae. Weak correlations were observed between MCW-MSCT and the percentage of YAM. Also, significant differences in the percentage of YAM were noted between types of MCI-MSCT. The mandibular cortical bone index (MCI-MSCT) in the inferior border using multi-slice CT may be applicable to evaluate the influence of the general bone condition.