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PubMed1992

Right latissimus dorsi cardiomyoplasty for left ventricular failure.

Recent experimental studies have shown that cardiomyoplasty using the right latissimus dorsi provides excellent hemodynamic augmentation. Based on these experimental findings, this procedure was performed in a 40-year-old man with a dilated cardiomyopathy after a large myocardial infarction. The patient tolerated the procedure well and has had marked functional improvement. Examination 6 months after operation demonstrated decreases in right atrial pressure, pulmonary capillary wedge pressure, and left ventricular end-diastolic volume. In addition, increases were noted in cardiac output, stroke volume, left ventricular stroke-work, right ventricular ejection fraction, and left ventricular ejection fraction. Because of this promising clinical result, we have started a series of right latissimus dorsi cardiomyoplasties for left ventricular failure.

Adult↗
PubMed1991

The human atrial trabecula: effects of calcium and temperature.

The human atrial trabecular preparation is an in vitro model which has been used to evaluate drugs and conditions to which cardiac muscle is exposed perioperatively. During its development, modifications have been made to this preparation. Two important components affecting myocardial muscle contraction are temperature and calcium concentration of the muscle bath medium. Previously, these parameters were determined independently of one another and found to be 34 degrees C and 2.5 mM calcium in a minimal Tyrode's buffer with glucose. This study was undertaken to define the optimal temperature and calcium concentration which would result in the highest yield of muscles that satisfied rigorous criteria for acceptability: developed force (DF) greater than 0.8 g, resting force (RF) less than 0.7 g, cross-sectional area less than or equal to 1.0 mm2). A total of 134 trabeculae were tested using a modified Krebs-Henseleit buffer, enriched with Eagles' medium and containing either 1.25 or 2.5 mM calcium at 34 or 37 degrees C. The trabeculae contracting in 2.5 mM calcium at 37 degrees C resulted in the highest yield of 26% while those maintained at 34 degrees C in either 1.25 or 2.5 mM calcium led to 20 and 15% useful preparations respectively (P = N.S.). Trabeculae contracting at 37 degrees C in 1.25 mM calcium resulted in the poorest yield of 8% (P = 0.002). There is a small (5 to 7%), but significant (P = 0.02), decrease in DF in 1 h when all groups were analyzed together. The exclusion criteria which are applied eliminate variability due to disease and/or treatment, therefore only 20 to 25% are acceptable for study. In summary, with well-defined and stringently applied criteria, the human right atrial trabecular preparation can be a reliable and reproducible model functioning at 37 degrees C and 2.5 mM calcium for a variety of studies.

Calcium↗
PubMed1997

Assessment of the appropriateness of the decision of heart transplantation in idiopathic-dilated cardiomyopathy.

One hundred thirty patients with idiopathic-dilated cardiomyopathy were referred for heart transplantation to our center and followed for 18 months. Heart transplantation was performed on 63 patients, 17 patients died before transplantation due to heart failure, and 50 patients never had transplantation. Clinical, electrocardiographic, echocardiographic, and hemodynamic data of the 50 nontransplanted survivors and the 17 patients who died were used to identify independent risk variables with discriminant analysis. Using a statistical model based on the results of discriminant analysis, each of the remaining 63 transplanted patients were predicted as being alive or dead in absence of transplantation. The discriminant analysis identified right atrial pressure, cardiac index, and the New York Heart Association functional class as the strongest predictors of 18-month outcome. The accuracy of the model in predicting survival without transplantation in the nontransplanted group of patients, based on the concordance between actual and predicted outcome, was 85% (kappa = 0.62). Subsequent application of this model to the transplanted group of patients suggested that the decision for transplantation was appropriate in 41 of the 63 patients, and could have been premature in the remaining 22 patients predicted as alive. These results suggest that two-thirds of patients receiving transplants would have died without intervention, but the decision to transplant could have been premature in the remaining patients.

Adult↗
PubMed1996

Differential effects of changes in local myocardial refractoriness on atrial and ventricular latency.

BACKGROUND: Assessment of myocardial refractoriness and conduction properties, critical to development and propagation of reentrant arrhythmias, is an integral part of the investigation of atrial and ventricular tachycardias through the use of programmed electrical stimulation. Local conduction itself, however, may be affected by myocardial refractoriness. METHODS AND RESULTS: We studied the effects of changes in myocardial refractoriness on local conduction in right atrial and ventricular myocardium in 19 patients. Changes in effective, functional, and relative refractoriness were accomplished with the use of four pacing protocols, including drive train pacing cycle lengths (PCLs) of 600 and 400 milliseconds (ms) and drive train durations (DTDs) of 8 and 50 stimuli. Unipolar cathodal stimulation was performed from the distal electrode, and unipolar electrograms were recorded from the proximal three poles of quadripolar catheters with 5-mm interelectrode spaces. Atrial and ventricular effective and relative refractory periods (ERPs and RRPs) were significantly shortened by both the reduction in PCL and the increase in DTD. The reduction in the PCL shortened atrial and ventricular refractory periods significantly more than did the increase in the DTD. Changes in ventricular refractory periods were significantly greater compared with atrial refractory periods. The ratio of RRP to ERP was reduced in the atrium but significantly increased in the ventricle with reduction in PCL and increase in DTD. For all premature intervals, the conduction interval from stimulus to the first recording electrode pole was significantly greater than conduction intervals measured between subsequent electrode poles. The greatest increase in conduction interval with closely coupled premature complexes occurred between the stimulus artifact and the first recording electrode pole. Reduction in ventricular but not atrial ERP was associated with significantly increased local conduction interval. CONCLUSIONS: First, most of the conduction delay after the stimulus artifact occurs within 5 mm from the pacing site. Second, closely coupled premature complexes delay conduction primarily by prolonging latency in the first 5 mm from the pacing site. Third, fundamental differences occur between the atrium and ventricle regarding changes in local conduction as a function of changes in ERP, suggesting that factors involved in sudden changes in refractoriness (eg, heart rate acceleration) could produce divergent effects on atrial and ventricular arrhythmogenesis.

Adult↗
PubMed1992

The perioperative management of pheochromocytoma in children.

The perioperative experiences of 15 children and adolescents who underwent a total of 18 surgical procedures for resection of a pheochromocytoma were analyzed to determine clinical or hemodynamic events associated with intraoperative or postoperative complications. Of the pre- and intraoperative factors assessed, only preoperative resolution of symptoms and normalization of blood pressure were predictive of uncomplicated outcome. No intraoperative factors were statistically associated with outcome, but the four patients with complicated outcomes had had aggressively administered intraoperative fluids. Noninvasive measures of cardiac function did not help predict outcome; however, echocardiography results were available only for six patients. Two of the patients with complicated outcomes had cardiac dysfunction, suggesting undiagnosed catecholamine-induced cardiomyopathy in the other two with complicated outcomes. Intraoperative fluids should be given based on intraoperative blood pressures, the presence or absence of prior adrenergic blockade, and assessment of preoperative myocardial function. If preoperative myocardial dysfunction is revealed, intraoperative measurement of right atrial and pulmonary capillary wedge pressures may be indicated.

Adolescent↗
PubMed2004

Pulmonary hypertension in systemic lupus.

Pulmonary arterial hypertension (PAH) has devastating consequences in the rheumatic diseases; however, the prevalence in lupus is not well delineated. We searched the University of Toronto lupus database to ascertain the first echocardiogram ordered at their physician's discretion between 1995 and 2002. We reviewed the echocardiogram reports for right ventricular systolic pressure (RVSP), valvular disease, and atrial and ventricular function. The PAH was defined as RVSP > or = 40 mmHg. Patients were divided into three groups: RVSP > or = 40 mmHg, RVSP = 30-39 mmHg and RVSP < 30 mmHg. We analysed potential associations between presence of PAH and lupus including disease activity, organ involvement and anticardiolipin antibodies, both at the time of and any time prior to echocardiography. In total, 129 patients underwent echocardiography. Nine patients' echocardiograms were not obtainable, and three patients were excluded from analysis, as their visit was more than six months from the date of echocardiography. Sixteen patients (14%) had RVSP > or = 40 mmHg, 43 (37%) patients had RVSP of 30-39, and 60 (51%) patients had RVSP < 30 mmHg. There was no statistical difference in disease activity, organ involvement or serology among all three groups. In conclusion, the prevalence of PAH (RVSP > or = 40 mmHg) on first echocardiogram ordered at physician discretion in our cohort was 14%. An RVSP of 30-39 mmHg was found in 37% of patients. Although abnormal, the clinical significance of this finding is unknown. Disease activity, organ involvement and anticardiolipin antibodies were not associated with PAH. Further research is needed to identify the mechanism, response to immunosuppression and impact on quality of life in these patients.

Atrial Function↗
PubMedDate not supplied

Cerebral microembolization during pediatric scoliosis surgery: a transcranial doppler study.

SUMMARY: The goal of this study was to identify cerebral microemboli during scoliosis surgery and their potential relationship with visual alterations. Transcranial Doppler identified high-intensity transient signals (HITS) during surgery in both middle cerebral arteries, and ophthalmologic examination assessed their potential effects on the visual system. Thirteen children (age 13-17 years) undergoing surgery for scoliosis or kyphosis with spine curvature >45 degrees were studied. HITS were identified in 92%. Eleven patients had a total count of <15 HITS, but in the remaining two the count was unexpectedly high (63 and 265 HITS). Echocardiography in these two patients indicated the presence of an atrial right-to-left shunt. Uneventful preoperative and postoperative visual function was found in 11 patients. One patient had preoperative blindness and in another ophthalmologic complications developed not related to microembolization. Scoliosis surgery is frequently associated with low counts of cerebral microemboli. It appears that such low embolic counts have no effects on postoperative visual function as determined clinically. Some patients may show high rates of microemboli, which may be related to the presence of right-to-left cardiac shunts. The impact of these signals on brain function remains to be investigated.

Adolescent↗
PubMed1992

[Analysis of natural history and long-term follow-up of 59 patients with obliterative pulmonary hypertension (OPH)].

The diagnosis of OPH was made by clinical and hemodynamic data in 59 patients, including 30 cases of unexplained pulmonary hypertension, 26 cases of pulmonary embolism and 3 others. The survival curve showed that the two-year survival rate of the patients was 76.72%, and the five-year rate was 63.37%. The single correlation factors influencing prognosis were the interval from onset of symptoms to diagnosis (course), cardiac function, PaO2, SaO2, cause of disease, pulmonary artery pressure and right atrial pressure. The outcome of long-term treatment (mean 4.2 years) in 15 patients with OPH was as follows: remarkable improvement in 8 cases, amelioration in 3, no change in 2 and deterioration in 2. The total effective rate was 73.33%. The importance of anticoagulant therapy and the use of nifedipine are discussed.

Adolescent↗
PubMed1989

In vitro study on mechanisms of bupivacaine-induced depression of myocardial contractility.

Although several mechanisms have been proposed to explain bupivacaine cardiotoxicity, the predominant effect remains to be determined. In this study, we used an isolated rabbit right atrial model that reproduces the effects on inotropic and chronotropic functions induced by 0.5 micrograms/mL bupivacaine; then we tried to counteract these events by electrical stimulation or by addition of CaCl2 or adenosine triphosphate (ATP) to the bathing solution. Contractile force was dramatically depressed by bupivacaine alone (-68%), even when the preparation was paced (-59%). CaCl2 partially counteracted this decrease (-37%). Inotropic function was almost completely restored (-9%) when ATP was added before administration of bupivacaine. Inhibition of energy metabolism seems to be a major explanation for bupivacaine cardiotoxicity.

Adenosine Triphosphate↗
PubMed1988

Comparison of cardiac function in surgically corrected and congenitally corrected transposition of the great arteries.

The capacity of the anatomic right ventricle to sustain normal function against systemic pressure long after atrial baffle procedures in patients with complete transposition of the great arteries remains unknown. Pulmonary and systemic ventricular function was measured by first-pass radionuclide studies in 11 children 7 +/- 3 years (+/- standard deviation) after baffle procedures. For comparison, similar measurements were made in eight patients with isolated congenitally corrected transposition of the great arteries and in 10 children in a control group. Exercise increased heart rate and cardiac index to similar levels in all three groups. Ventricular volumes were greater than control volumes in both groups with congenital heart disease. Exercise increased pulmonary ventricular ejection fraction in the control and congenitally corrected groups, but not in the surgically corrected group. Systemic ventricular ejection fraction increased during exercise in the control group, but remained unchanged in both transposition groups. These results show that cardiac index during exercise is maintained in patients after baffle procedures for complete transposition of the great arteries. However, pulmonary and systemic ventricular ejection fractions fail to increase with exercise, and ventricular volumes are markedly greater than normal.

Adolescent↗
PubMed1995

[Body surface isopotential T map and ventricular volume characteristics in secundum atrial septal defect].

Body surface isopotential T map was analyzed to detect right ventricular volume and pressure overloads in 25 patients with secundum atrial septal defect. Three patterns were distinguished: the T map resembling normal (type A, n = 9); that with isolated negative area in positive area (type B, n = 11); and that with rightward movement of maximum (type C, n = 5). Right ventricular end-diastolic volumes in type B (161 +/- 19% of normal; %N) and C (175 +/- 40% N) were significantly (p < 0.01) greater than those in control (100 +/- 9% N) and type A (113 +/- 18% N). Right ventricular systolic pressure in type C (48 +/- 11 mmHg) was significantly (p < 0.01) higher than those in control (30 +/- 5 mmHg), type A (31 +/- 4 mmHg) and type B (34 +/- 5 mmHg). These results suggest that the cases with type B have right ventricular volume overload, and those with type C have both volume and pressure overloads.

Body Surface Potential Mapping↗
PubMed2005

Detection of right to left shunting through a patent foramen ovale in Japanese patients with ischemic stroke by transesophageal echocardiography using a standardized Valsalva maneuver.

We attempted to clarify the usefulness of transesophageal echocardiography performed using a standardized Valsalva maneuver to detect the presence of a patent foramen ovale in Japanese patients with ischemic stroke. Four hundred ninety six patients with ischemic stroke who were admitted to the Yokohama City Brain and Stroke Center between September 1999 and February 2002 were enrolled for the study. All the enrolled patients underwent transesophageal echocardiography with contrast injection and color Doppler imaging. During the procedure, a standardized Valsalva maneuver was performed to induce right to left shunting through a patent foramen ovale. Other related structural abnormalities, such as atrial septal aneurysm and the Chiari network anomaly, were also detected by the test. Transesophageal echocardiography without the Valsalva maneuver revealed a functional right to left communication in only 8.2% of the ischemic stroke patients, whereas the procedure conducted using a standardized Valsalva maneuver to provoke shunting revealed a patent foramen ovale in 15.3% of the patients. The presence of an atrial septal aneurysm or the Chiari network anomaly was not sensitive or specific enough to predict the presence of a patent foramen ovale as diagnosed by transesophageal echocardiography using the standardized Valsalva maneuver. Our results suggest that the standardized Valsalva maneuver is a safe and useful technique to detect the presence of a patent foramen ovale, which is potentially known to be associated with paradoxical embolism.

Aged↗
PubMed1984

Alterations in subsidiary pacemaker function after prolonged subsidiary pacemaker dominance in the canine right atrium.

In vivo and in vitro techniques were used to study the functional characteristics of subsidiary atrial pacemaker activity 4 to 11 months after surgical excision of the sinoatrial node region of the dog heart. Characteristics of this long-term subsidiary atrial pacemaker activity were compared with those of sinoatrial node and short-term subsidiary atrial pacemaker activities. Extracellular bipolar electrodes were used to estimate the site of earliest activation and monitor spontaneous rate. Under both in vivo and in vitro conditions, long-term pacemaker activity was located in the same region of the inferior right atrium as was short-term pacemaker activity. Under in vitro conditions, long-term activity was characterized by a reduced sensitivity to acetylcholine and overdrive pacing and by a lack of dependence on beta-adrenergic stimulation compared with short-term activity. Furthermore, long-term pacemaker activity was more sensitive to acetylcholine and less sensitive to norepinephrine (greater than 10(-7) M) compared with sinoatrial node activity. It is concluded that the subsidiary atrial pacemakers that emerge soon after removal of the sinoatrial node are the same as those pacemakers that ultimately assume long-term control of the heart. In addition, after subsidiary atrial pacemakers assume dominant pacemaker function, their dependence on norepinephrine and their response to acetylcholine and overdrive pacing are reduced. These changes facilitate a more stable regulation of atrial pacemaker rhythm and, thereby, make subsidiary atrial pacemaker function more like that of the sinoatrial node.

Acetylcholine↗
PubMed1987

Effects of treadmill and pacing stress testing on peripheral arterial thromboxane, platelet function and catecholamine activities in patients with chronic coronary artery disease.

Two different methods of causing myocardial oxygen demand and supply imbalance; symptom limited treadmill exercise and right atrial pacing stimulation, were used to examine the alteration of hemodynamics and the effects upon sympathetic nerve activities, platelet functions and prostaglandin synthesis in patients with coronary artery disease (CAD). Age and sex distributions, the cardiothoracic ratio, left ventricular end-diastolic pressure, ejection fraction and coronary artery obstructions of the patients did not differ significantly between the two tests. Arterial blood samples were obtained to assay for plasma catecholamine, beta-thromboglobulin (beta TG), platelet factor 4 (PF4), TXB2 (thromboxane B2) and 6 keto-PGF1-alpha (6 ketoprostaglandin F1-alpha) without any difficulties before and immediately after testing. The arterial systolic pressure and pressure rate product (PRP) were changed more significantly by treadmill exercise than pacing, while the DPTI/TTI (diastolic pressure time index/tension time index) ratio and ST segment deviations showed similar changes with both tests. The plasma NE (norepinephrine) level, beta TG, PF4, and TXB2/6 keto-PGF1-alpha were significantly elevated by treadmill exercise, but not by pacing. 6 keto-PGF1-alpha was not markedly affected by either tests. There were no significant differences between the patients with and without anginal pain either in hemodynamics or metabolites. Significant relationships were observed between changes in plasma NE levels and the PRP (r = 0.76, n = 26, p less than 0.01) and also changes in the arterial systolic pressure (r = 0.64, n = 26, p less than 0.01), but there were no significant correlations between any other hemodynamic parameters with plasma NE, platelet function, prostaglandin activity, or between each metabolite.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed2006

Effects of on-pump versus off-pump coronary artery bypass graft surgery on right ventricular function.

OBJECTIVES: Right ventricular dysfunction is a possible cause of cardiac failure after coronary surgery. The use of cardiopulmonary bypass is regarded as a major cause for its occurrence, and it has been postulated that performing coronary surgery without cardiopulmonary bypass might reduce ventricular dysfunction. Therefore, this prospective, randomized, controlled study tested the hypothesis that off-pump coronary surgery would better preserve right ventricular systolic and diastolic function than conventional bypass surgery. METHODS: Fifty patients scheduled for elective coronary artery bypass surgery were randomly assigned to conventional or off-pump surgery. Right ventricular function was assessed by intraoperative transesophageal echocardiography immediately before and after coronary surgery. Right ventricular ejection fraction was used as a marker of global systolic function and tricuspid early/late (atrial) ratio as a marker of the global diastolic function. Peak systolic and early diastolic velocities of the lateral tricuspid annulus were studied to assess systolic and diastolic function in the area of the right ventricular free wall. RESULTS: Surgery was completed according to randomization in 48 of 50 patients. Preoperative characteristics were similar in both groups. Intraoperative differences between the two groups included a higher volume of allogeneic blood transfusion in the conventional surgery group. At the end of surgery, global systolic right ventricular function was similarly maintained and diastolic function similarly impaired in both groups. There were no significant intergroup differences in any of the echocardiographic markers of right ventricular function. CONCLUSIONS: Off-pump surgery did not better preserve right ventricular systolic and diastolic function than did conventional coronary surgery.

Aged↗
PubMed1982

Hemodynamic response to changes in ventilatory patterns in patients with normal and poor left ventricular reserve.

Hemodynamic effects of controlled mechanical ventilation (CMV), intermittent mandatory ventilation (IMV), and intermittent mandatory ventilation with 5 cm H20 PEEP (IMV 5 peep) were studied in 20 patients after aortocoronary bypass surgery. Significant increases in cardiac index (CI) and stroke volume index (SI) (p less than 0.01) resulted in patients with normal left ventricular end-diastolic pressure (LVEDP) and ejection fraction (EF) changing from CMV to IMV. With a change from IMV to IMV 5 peep, the CI and SI returned to CMV values. However, in patients with increased LVEDP with an EF of less than 0.6, suggesting poor ventricular function and reserve, when the mode of ventilation was changed from CMV to IMV, right atrial pressure (RAP) and pulmonary artery occlusion pressure (PAOP) significantly increased (p less than 0.01) with an associated significant decrease in mean arterial pressure (MAP), CI, SI (p less than 0.01). When these patients were placed on IMV 5 peep, the hemodynamic variables returned to the values obtained during CMV. We conclude that changing from CMV to IMV has salutory effects on the patient's hemodynamic values with normal left ventricular function. But in patients with failing left ventricle, volume overload of right ventricle which occurs with the institution of spontaneous respiration during IMV has deleterious effects on the hemodynamic variables. These deleterious effects can be effectively negated by the application of IMV 5 peep.

Blood Pressure↗
PubMed1989

The effect of acute hypoxaemia on ventricular function during beta-adrenergic and cholinergic blockade in the fetal sheep.

The effect of acute hypoxaemia on right and left ventricular function was investigated in 8 fetal sheep (137-140 days gestation). Fetuses were instrumented with electromagnetic flow sensors on the ascending aorta and the main pulmonary artery. After 8 days recovery, hypoxaemia was achieved by reducing the maternal ewe's inspired O2 concentration to 13.1 +/- 1.5%. Control and hypoxaemic arterial blood values were pH 7.37 +/- 0.04 (SD) and 7.35 +/- 0.06, PCO2 48.0 +/- 2.8 and 47.6 +/- 5.1 mmHg, PO2 19.9 +/- 2.2 and 11.4 +/- 1.5 mmHg, haematocrit 37.5 +/- 1.2 and 39.5 +/- 2.2, respectively. Arterial pressure increased insignificantly with acute hypoxaemia (50.2 +/- 3.9 to 53.6 +/- 8.1 mmHg). Left and right ventricular performance was assessed by generating biventricular function curves relating stroke volume to mean atrial pressure. All function curves were composed of steep ascending and plateau limbs that intersected at a breakpoint. Comparing control and hypoxaemia function curves, the left ventricular stroke volume breakpoints were 0.79 +/- 0.20 and 0.78 +/- 0.21 ml/kg, respectively, while the right ventricular stroke volume breakpoints were 0.99 +/- 0.11 and 0.88 +/- 0.21 ml/kg (n.s.). In 4 fetuses, acute hypoxaemia was associated with significant increases in arterial blood pressure (P less than 0.05). In these fetuses, the right ventricular function curve was shifted significantly downward compared to the control right ventricular curve. When nitroprusside was given to these hypertensive fetuses to return blood pressure to control levels, the right ventricular function curve returned to baseline. We conclude that even under conditions of extreme hypoxaemia, ventricular function is well preserved in the normotensive fetal sheep. However, when increases in arterial pressure also accompany hypoxaemia, detectable changes in right ventricular function can be accounted for by changes in arterial pressure.

Animals↗
PubMed2000

Dramatic improvement of LV function after coronary sinus thromboembolectomy.

We present the case of a 79-year-old man suffering from chronic atrial fibrillation, severe left ventricular dysfunction, massive right atrial thrombosis, and pulmonary hypertension. Complete coronary sinus thrombosis was found incidentally during preoperative screening. Successful coronary sinus, right atrial, and pulmonary operative embolectomy was followed soon after by a dramatic improvement of cardiac performance; the patient's left ventricular function recovery, in particular, suggests that cardiac venous system played an important role in the genesis of myocardial impairment.

Aged↗