Biomedical subjects

B L Cmolik

Publications and source records attributed to B L Cmolik.

15 recordsLinked to original sources

PubMed2001

Increased coronary artery blood flow with aortomyoplasty in chronic heart failure.

BACKGROUND: We hypothesized that diastolic counter-pulsation using aortomyoplasty will increase coronary blood flow. METHODS: In dogs (n = 6, 20 to 25 kg), the left latissimus dorsi muscle was isolated, wrapped around the descending thoracic aorta, and conditioned by chronic electrical stimulation. Heart failure was induced by rapid ventricular pacing. In a terminal study, left ventricular and aortic pressures, and blood flow in the left anterior descending coronary artery and descending aorta were measured. The endocardial-viability ratio was calculated. RESULTS: Aortomyoplasty increased mean diastolic aortic pressure (70 +/- 5 to 75 +/- 5 mm Hg, p < 0.05) and reduced peak left ventricular pressure (86 +/- 4 to 84 +/- 4 mm Hg, p < 0.05), leading to a 16% increase in endocardial-viability ratio (1.29 +/- 0.05 to 1.49 +/- 0.05, p < 0.05). Coronary blood flow was increased by 15% (8.2 +/- 1.5 to 9.4 +/- 1.6 mL/min, p < 0.05). During muscle contraction, 2.7 +/- 0.5 mL was ejected from the wrapped aortic segment. CONCLUSIONS: These data demonstrate that aortomyoplasty provides successful diastolic counterpulsation after muscle conditioning and heart failure.

Animals↗

PubMed1998

A versatile microprocessor-based multichannel stimulator for skeletal muscle cardiac assist.

A versatile, microprocessor-based stimulator for skeletal muscle cardiac assist (SMCA) has been designed, constructed, and used in several studies. The stimulator uses multiple bipolar electrodes to deliver arbitrarily specified electrical stimulus sequences to three nerve branches of the latissimus dorsi muscle. The electrodes are electrically isolated to effect regional stimulation of the muscle. The width, amplitude, and interpulse interval of each pulse in the stimulus sequence are independently variable, and the three channels are independently programmable, allowing a wide variety of stimulus patterns. Battery powered units have been used in studies for up to one year. In this paper, the stimulator and sample applications in SMCA are described.

Analog-Digital Conversion↗

PubMed1997

Coronary bypass in vascular patients: a relatively high-risk procedure.

A premise of cardiac risk stratification is that the added risk of coronary artery bypass grafting (CABG) is offset by the improved safety of subsequent vascular reconstruction (VR). We questioned if elective CABG is patients with severe peripheral vascular disease (PVD) is a relatively high-risk procedure. A cohort study of 680 elective CABG patients from January 1993 to December 1994 was performed using three mutually exclusive outcomes of complication-free survival, morbidity, and mortality. Patient characteristic, operative, and outcome data were prospectively collected. Retrospective review determined that 58 patients had either a standard indication for or a history of VR. Overall CABG mortality was 2.5%, with statistically similar but relatively higher rates for PVD as compared to non-PVD patients. In contrast, major morbidity occurred at rates 3.6-fold higher in PVD patients (39.7%) than in disease-free patients (16.7%) after adjustment for the effects of patient and operative variables (odds ratio [OR] 3.67, 95% confidence interval [CI] 1.93-6.99). CABG morbidity in the PVD patient was most likely in those patients with aortoiliac (OR 9.51, CI 3.20-28.27) and aortic aneurysmal (OR 5.24, CI 1.28-21.41) disease types. CABG in PVD patients is associated with significant major morbidity. Such morbidity may preclude or alter the timing of subsequent VR.

Adult↗

PubMed1997

Optimizing muscle-to-cardiac timing for aortomyoplasty.

A new surgical approach to support failing hearts is known as aortomyoplasty-a technique in which the latissimus dorsi muscle is wrapped around the aorta and stimulated during cardiac diastole to provide chronic diastolic counterpulsation. We hypothesized that the timing of muscle contraction within the cardiac cycle effects the amount of diastolic augmentation during counterpulsation. In dogs (n = 9, 20-25 kg), the effect of muscle-to-cardiac timing on hemodynamic outcome of aortomyoplasty was measured. Muscle stimulation was initiated at the dicrotic notch and stimulus durations were systematically increased. Mean diastolic aortic pressure was maximized when stimulation terminated at the ensuing R-wave. Peak left-ventricular pressure was minimized when muscle stimulation terminated before the ensuing R-wave. The endocardial-viability ratio (a ratio of aortic diastolic pressure augmentation to left-ventricular pressure reduction) was maximized when stimulus terminated at the ensuing R-wave. Muscle-to-cardiac timing influences the effectiveness of counterpulsation during aortomyoplasty.

Animals↗

PubMed1996

Successful atrial defibrillation with very-low-energy shocks by means of temporary epicardial wire electrodes.

Sustained atrial fibrillation is very common after cardiac surgical procedures. We hypothesized that atrial defibrillation could be accomplished consistently and safely by means of low-energy shocks delivered by temporary stainless steel wire electrodes placed at the time of the operation. Sterile pericarditis was created in five mongrel dogs (20.9 +/- 2.1 kg), and pairs of standard temporary stainless steel wire electrodes were placed on the right atrial appendage, on Bachmann's bundle, and on the right ventricular apex for pacing, sensing, and recording. Temporary stainless steel wire electrodes, insulated except for the distal 6 cm and used to deliver defibrillation shocks, were placed adjacent to both atrial free walls and secured to the pericardium. All electrodes were brought out through the skin, and the sternotomy was closed. Dogs were tested in the conscious state on postoperative day 2. Sustained atrial fibrillation was induced by rapid atrial pacing. A customized software program was used to control the defibrillator, which delivered R wave-synchronous biphasic shocks to the atria through the temporary defibrillation electrodes. The shock intensity began at 50 volts and was increased by 10-volt increments until atrial fibrillation was terminated. Atrial fibrillation was terminated in all dogs at 112 +/- 7 volts, with an energy of 0.42 +/- 0.07 joule and an impedance of 67.8 +/- 4 ohms (all values mean +/- standard error of the mean). The mean percent success for atrial defibrillation at this minimal threshold was 49%. Thus at low-threshold voltages atrial fibrillation could be terminated with every other shock. A 25% increase in the minimal threshold voltage improved the conversion rate to 73% (mean energy 0.66 +/- 0.19 joule and mean impedance of 67 +/- 3.8 ohms). No complications were detected with the use of the electrodes or after their removal on the seventh postoperative day. One instance of electrode migration on the right atrial free wall was detected by roentgenography, but this did not adversely affect atrial defibrillation threshold. No ventricular arrhythmias or hemodynamic complications were noted during shock delivery. We conclude that successful conversion of atrial fibrillation to sinus rhythm can be achieved consistently with shock energies below 0.5 joule delivered with temporary epicardial defibrillation wire electrodes in this canine pericarditis model. These results suggest that this approach to the management of sustained atrial tachyarrhythmias has considerable promise in the management of atrial fibrillation in patients who have had cardiac operations.

Animals↗

PubMed1996

Cost analysis of early extubation after coronary bypass surgery.

BACKGROUND: Although early extubation after coronary bypass surgery has been shown to reduce length of stay, a systematic cost analysis of its economic benefit has not been reported, and previous studies have used hospital charges that are typically confused with actual costs. METHODS: A consecutive series of 690 patients undergoing coronary bypass surgery during a 24-month period were studied to determine the effect of early extubation, defined as removal of the endotracheal tube within 8 hours of arrival to the intensive care unit, on length of stay and hospital costs. Patients in group 2 (n = 362) who underwent coronary bypass surgery in 1995, subsequent to the initiation of an early extubation protocol, were compared with those in group 1 (n = 328) operated on in 1994, before implementation of early extubation. To reflect true hospital resource consumption, only costs (not charges) directly related to patient health core (variable direct cost) were analyzed. RESULTS: Baseline characteristics such as age, gender, previous myocardial infarctions, ejection fraction, reoperations, diabetes, and left main stenosis were similar in both groups. Operative mortality for the entire group was 3.3% and did not differ between the two groups; the incidence of serious morbidity was 10.9% for the entire group. Early extubation was accomplished in 38% of patients in group 2 versus 3% in group 1 (p < 0.001), and postoperative length of stay declined from 9.4 days to 7.7 days (p < 0.01). This was accompanied by a significant (p = 0.001) reduction in variable direct cost per case. CONCLUSIONS: Early extubation after coronary bypass surgery is an effective strategy of reducing length of stay and does not appear to impact on either morbidity or mortality. An additional benefit is significant cost savings realized through accelerated recovery and control of resource use.

Adult↗

PubMed1996

Salvage of infected ICDs: management without removal.

During the 7-year period from August 1986 to December 1993, 242 patients with malignant ventricular arrhythmias underwent 242 ICD implantations and 50 subcutaneous generator changes. Wound infections developed in 5 patients (1.7%): in 3 cases, after primary implantation (3/242 [1.2%]); and in 2 following a generator change (2/50 [4.0%]). This difference was not statistically significant. Infection developed at the generator pocket and became clinically manifest between 6 weeks and 40 months, postoperatively. Our treatment approach with the first patient consisted of simple debridement of the pocket and reimplantation of the existing generator. This led to recurrence, and the generator was safely explanted. In the remaining four patients, our approach has been that of local treatment, with wide debridement of the pocket, and placement of a closed irrigation system with continuous irrigation with a bacitracin, polymyxin, neomycin solution, and culture-specific antibiotic therapy. We have successfully controlled the infection and salvaged the generator with this approach in all four patients, who are all alive and well at a mean follow-up of 25.0 +/- 17.3 months with no recurrence. The good results obtained in these patients suggest that the concept of total explanation of the infected ICD should be reassessed.

Aged↗

PubMed1995

Atrial defibrillation using temporary epicardial defibrillation stainless steel wire electrodes: studies in the canine sterile pericarditis model.

OBJECTIVES: This study sought to determine whether temporary epicardial wire electrodes can be used safely and effectively to defibrillate the atria with low energy shocks in the absence of anesthesia. BACKGROUND: Atrial fibrillation after open heart surgery is a significant clinical problem. METHODS: Twelve dogs with sterile pericarditis were studied. In the first group (6 dogs, bilateral thoracotomy group), a wire electrode, insulated except for the distal 6 cm, was placed on the epicardial free wall of each atrium. Each end of the bare wire was then sutured to the parietal pericardium. In the second group (6 dogs, median sternotomy group), the wire electrodes were kept in place by a double loop of Prolene placed around the distal tip of the bare wire and sewn to the overlying parietal pericardium. In the bilateral thoracotomy group, atrial defibrillation thresholds (defined as < 90% and > 10% successful defibrillation of 20 shocks at a given delivered energy) were obtained in anesthetized dogs using the wire electrodes with the chest closed and open and using two transvenously placed catheters with coil electrodes in the distal 6 cm (one in the coronary sinus and the other in the right atrial appendage) with the chest open. In the median sternotomy group, thresholds were obtained in minimally sedated animals without reopening the chest. A 25% increase above threshold shock was also used to determine a new percent success. After 4 days, the wire electrodes were removed by pulling on the external ends. At the time of removal, blood pressure and heart rate were monitored for 30 min, after which dogs were killed and their hearts sent for histopathologic study. For all dogs, chest radiographs were obtained postoperatively and on study days. RESULTS: Atrial defibrillation using the wire electrodes was successful in all dogs at a mean (+/- SE) voltage of 112 +/- 9 V, with an energy level of 0.46 +/- 0.07 J and an impedance of 59.3 +/- 5 ohms. The mean percent success at the atrial defibrillation threshold was 36 +/- 5%. The 25% increase in defibrillation voltage improved the mean percent success to 73% (mean energy 0.66 +/- 0.19 J). No clinical or hemodynamic complications were observed during shock delivery, and no ventricular arrhythmias were induced during the shocks. No complications followed wire electrode removal. Histopathologic analysis showed no structural damage. CONCLUSIONS: The atrial defibrillation threshold obtained using temporary epicardial wire electrodes for atrial defibrillation is < 1 J in dogs. Atrial defibrillation using temporary epicardial wire electrodes can be performed safely, quickly and reliably without the need for anesthesia or antiarrhythmic agents. The wire electrodes can be removed without adverse hemodynamic or structural consequences. These data provide a basis for testing atrial defibrillation using epicardial wire electrodes in patients after open heart surgery.

Algorithms↗

PubMed1993

Right latissimus dorsi cardiomyoplasty augments left ventricular systolic performance.

We hypothesized that the right latissimus dorsi cardiomyoplasty augments left ventricular performance. Five dogs underwent staged right latissimus dorsi cardiomyoplasty. Ventricular function was studied 1 to 3 weeks later. Left ventricular pressure was measured with a micromanometer and left ventricular dimensions with piezoelectric crystals. Inferior vena caval occlusion was used to vary preload. Pressure-volume data were collected with the muscle unstimulated and stimulated at 1:2 and 1:1 muscle/heart ratios. The end-systolic pressure-volume relation (mm Hg/mL), stroke work, preload recruitable stroke work, left ventricular end-diastolic volume, and the diastolic relaxation constant were calculated and expressed as mean +/- standard deviation. Stimulated beats at a 1:2 ratio showed an increase in stroke work of 42.1% (978 +/- 381 to 1,390 +/- 449 g.cm; p < 0.01) and preload recruitable stroke work of 28.8% (59.4 +/- 20.7 to 76.6 +/- 11.0 g.cm/cm3; p = 0.05) compared with the unstimulated beats. With the stimulator on at 1:1, smaller changes occurred: stroke work increased 9% (1,167 +/- 390 to 1,273 +/- 363 g.cm; not significant) and preload recruitable stroke work increased 27% (63.9 +/- 22.7 to 80.9 +/- 23.1 g.cm/cm3; p = 0.05). There were no significant changes in the end-systolic pressure-volume relation. The diastolic relaxation constant did not change at 1:1 (36 +/- 9.7 to 37 +/- 6.4 ms; not significant) or 1:2 (36 +/- 9.3 to 39 +/- 8.2 ms; not significant). Left ventricular end-diastolic volume was unchanged at 1:1 (34 +/- 10.7 to 32 +/- 10.3 mL) and at 1:2 (31 +/- 9.0 to 32 +/- 8.7 mL).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Early effects of right latissimus dorsi cardiomyoplasty on left ventricular function.

BACKGROUND: We hypothesized that left ventricular function could be improved with cardiomyoplasty using the right latissimus dorsi. METHODS AND RESULTS: Five dogs underwent cardiomyoplasty using the right latissimus dorsi. Left ventricular volume and pressure were measured using sonomicrometry and a micromanometer catheter, respectively. Pressure volume loops were recorded with the muscle stimulated at 1:2 and with transient caval occlusion. During stimulated beats, there were significant increases in stroke work (13.90 +/- 4.49 vs 9.78 +/- 3.81 g/m, P < .01), preload recruitable stroke work (0.766 +/- 0.110 vs 0.594 +/- 0.207 g.m-1 x m-3, P < .05), and stroke volume (15 +/- 4 vs 10 +/- 3 mL, P < .05) when compared with unstimulated beats. There were no changes in diastolic filling. This operation was done in 11 patients, with no operative deaths. Six weeks after surgery, resting left ventricular ejection fraction (LVEF) increased from 25 +/- 1.6% to 35 +/- 3% (P < .05), and left ventricular end-diastolic volume (LVEDV) decreased from 365 +/- 18 to 307 +/- 24 mL, (P < .05). Nine patients were alive at 6 months. Preoperative and 6-month LVEF and LVEDV for those 9 patients were 26 +/- 2% and 29 +/- 2% (P = NS) and 316 +/- 23 and 261 +/- 22 mL (P < .05), respectively. CONCLUSIONS: Long-term studies are needed to determine if these changes will improve patient survival.

Animals↗

PubMed1993

Redo cardiac surgery: late bleeding complications from topical thrombin-induced factor V deficiency.

Bovine thrombin-induced factor V deficiency was though to be a very rare acquired coagulopathy, with only three documented cases. We report a series of nine patients seen during a period of 32 months; these patients had normal preoperative coagulation profiles, and this unique coagulopathy developed 1 to 2 weeks after cardiovascular operations. The coagulopathy was characterized by a markedly elevated prothrombin time (40.9 +/- 5.8 seconds), an elevated activated partial thromboplastin time (96.3 +/- 12.2 seconds), a study positive for lupus anticoagulation (9/9), and markedly decreased levels of factor V (0.09 +/- 0.03 U/ml) and factor XI (0.04 +/- 0.02 U/ml), respectively. All patients had been exposed to commercially available bovine thrombin during prior cardiovascular or vascular operations and received a second bovine thrombin challenge during the latest procedure. Coagulopathic bleeding developed in four of the nine patients. Bleeding was unrelated to absolute fall in factor V level, but cessation of hemorrhage appeared to correlate with improvement in factor V level. Treatment with vitamin K, fresh frozen plasma, and platelet infusion were all unsuccessful in altering prothrombin time or factor V levels. Intravenous gamma globulin was used in three patients, two of whom were bleeding. All three patients showed a transient increase in factor V levels. Bleeding stopped in one of the two patients; the other continued to bleed and subsequently died. The third patient was treated prophylactically to increase factor V levels in preparation for flap reconstruction of his sternum. His factor V level increased from 0.26 to 0.49 U/ml, and he underwent the procedure without incident. Bovine thrombin-induced factor V deficiency may have been previously unrecognized. This deficiency should be suspected in patients who have undergone redo cardiovascular operations and in whom marked elevations in their prothrombin time occur 7 to 10 days after exposure to bovine thrombin. The resulting coagulopathy, although usually self-limited, has the potential to produce devastating bleeding complications. Intravenous gamma globulin (1 gm/kg during each of 2 days) has been used to increase factor V levels transiently but its role in therapy of this coagulopathy requires further investigation.

Administration, Topical↗

PubMed1992

Benefits and limitations of database analysis for outcome prediction in cardiac surgery.

Large databases are being used for outcome prediction analysis with increasing frequency. This review examines four separate databases used to provide risk analysis in the cardiac surgery population. Populations in the databases range in size from 3500 to over 116,000 patients. All of the databases were applied on the clinical, and in one instance, institutional level. Outcome prediction from databases is not without its limitations. Data collection, model bias, and methodologic variation all contribute to weaknesses in the application of databases for outcome prediction.

Cardiac Surgical Procedures↗

PubMed1991

Transesophageal echocardiographic examination of a patient with traumatic aortic transection from blunt chest trauma: a case report.

Traumatic aortic disruption is an injury associated with high mortality. Early recognition, diagnosis, and surgical repair are important in order to salvage patients with this injury. We report a case in which transesophageal echocardiography, a rapid, minimally invasive diagnostic technique, was used to identify an acute disruption of the proximal descending aorta in a patient with blunt chest trauma.

Adult↗

PubMedDate not supplied

Heterotopic lung transplantation: temporary biologic support for reversible pulmonary insufficiency.

BACKGROUND: The mortality rate resulting from adult respiratory distress syndrome in patients awaiting orthotopic lung transplantation remains high. Providing an "extra" lung may provide a potential solution to support a failing pulmonary system. We hypothesized that using a heterotopic lung transplant can correct hypoxemia and hypercarbia in both the short term and the long term. METHODS: Seven mongrel dogs underwent transplantation of a left lung into the abdomen. Anastomosis between the left atrial cuff and the pulmonary artery of the donor lungs was accomplished to systemic venous and arterial circulations, respectively. The main stem bronchus was exteriorized, intubated, and ventilated. Immunosuppression consisted of prednisone and azathioprine both preoperatively and postoperatively. Progressive levels of systemic hypoxemia and hypercarbia were induced. The heterotopic lung transplant augmented oxygenation with a tidal volume of 300 cc, a fraction of inspired oxygen of 50%, and a respiratory rate of 10 and then 20 breaths/min. Four animals were studied again at 48 hours. Flow through the heterotopic lung transplant ranged from 25% to 33% of the cardiac output. RESULTS: Statistically significant improvements were seen in both systemic oxygenation and ventilation in the short-term experiment. The systemic oxygen pressure improved from 37 +/- 3 mm Hg to 67 +/- 5 mm Hg after ventilation of the heterotopic lung transplant, and the carbon dioxide pressure improved from 56 +/- 1 mm Hg to 43 +/- 2 mm Hg. At 48 hours an improvement in oxygen pressure was noted after ventilation of the heterotopic lung transplant, from 42 +/- 3 mm Hg to 56 +/- 2 mm Hg and an improvement in systemic carbon dioxide pressure was noted after ventilation of the heterotopic lung transplant from 57 +/- 7 mm Hg to 46 +/- 4 mm Hg. CONCLUSIONS: The heterotopic lung transplant was able to provide effective gas exchange and support both oxygenation and ventilation after the induction of acute hypoxemia or hypercarbia, both immediately and at 48 hours after implantation. The heterotopic lung transplant may serve as an alternative mode of temporary support for those with acute respiratory insufficiency or as a bridge for those awaiting orthotopic lung transplantation.

Abdomen↗

PubMedDate not supplied

Static left latissimus dorsi cardiomyoplasty: effect on left ventricular function.

When the latissimus dorsi is used for ventricular augmentation in cardiomyoplasty, a delay of several weeks occurs before the muscle revascularizes, adheres to the heart, and is transformed to fatigue-resistant status. This study analyzes the effect of static (unstimulated) cardiomyoplasty on left ventricular function. Four mongrel dogs underwent staged left latissimus dorsi cardiomyoplasty. Left ventricular pressure was measured with a micromanometer catheter. Left ventricular volume was measured by sonomicrometry. Cardiac output, heart rate, preload recruitable stroke work, maximum elastance, left ventricular end-diastolic volume, left ventricular end-diastolic pressure, stroke work, and the diastolic relaxation constant were measured before and immediately after cardiomyoplasty with the myoplasty static. Results, expressed as mean +/- standard error of the mean, showed no significant differences in indexes of systolic function (stroke work, 1017 +/- 223 gm.cm to 984 +/- 403 gm.cm; preload recruitable stroke work, 110 +/- 13 gm.cm/cm3 to 115 +/- 19.8 gm.cm/cm3; maximum elastance, 10.38 +/- 5.6 mm Hg/ml to 13.59 +/- 6.5 mm Hg/ml; cardiac output 4.51 +/- 0.43 L/min to 4.21 +/- 0.34 L/min) or diastolic function (left ventricular end-diastolic volume, 21 +/- 5.2 ml to 20 +/- 5.3 ml; left ventricular end-diastolic pressure, 13 +/- 3.5 mm Hg to 15 +/- 3 mm Hg; diastolic relaxation constant 42.8 +/- 5.2 msec to 42.5 +/- 4.5 msec). Heart rate also remained unchanged (131 +/- 8.9 beats/min to 140 +/- 9.8 beats/min). The static (unstimulated) left latissimus dorsi cardioplasty can be done with little effect on left ventricular systolic or diastolic function in the normal canine heart.

Animals↗