Association of QRS-T angle and Late Gadolinium Enhancement in patients with a Clinical Suspicion of Myocarditis.

Objective: To investigate the association of a wide QRS-T angle on the surface ECG and late gadolinium enhancement on contrast-enhanced cardiovascular magnetic (CMR) imaging in patients with clinically suspected myocarditis. Background: Diagnosis and risk stratification in patients with suspected myocarditis is particularly challenging due to a great spectrum of clinical presentations. Late gadolinium enhancement (LGE) visualizes myocardial necrosis and fibrosis in patients with biopsy-proven myocarditis. The presence or absence of late gadolinium enhancements in these patients is prognostically meaningful. The QRS-T angle from the surface ECG, on the other hand, may serve as a simple and easily available risk marker in suspected myocarditis. Methods: We enrolled 97 consecutive patients that were referred to CMR imaging for a clinical suspicion of myocarditis. All patients obtained a standardized digital 12-lead ECG for the calculation of the QRS-T angle and underwent contrast-enhanced CMR imaging. Patients were divided into two groups according to the absence or presence of LGE on CMR. Results: 78 of 97 patients with suspected myocarditis had LGE on CMR. Patients with LGE had wider QRS-T angles as compared to the patient group without LGE (53.95-47.5 vs. 26.2-21.2; p<0.001). The sensivity, specificity, negative predictive value and positive predictive value for a QRS-T angle above 90 degrees for LGE positive myocarditis were 16.5%, 100%, 24.7%, and 100%, respectively. Conclusion: A wide QRS-T angle of 90 degrees or more is linked to myocardial fibrosis or necrosis (late gadolinium enhancement) in patients with suspected myocarditis.

QRS-T-angle in Patients with ST-Segment Elevation Myocardial Infarction (STEMI) - a Comparison with Cardiac Magnetic Resonance Imaging.

Background: The QRS-T angle from the surface EKG is a promising prognostic marker in patients with coronary artery disease. Cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) offers high resolution imaging of myocardial damage. We investigated the association of the QRS-T angle and the extent of myocardial damage as assessed by LGE in patients with acute ST-segment myocardial infarction (STEMI) Methods: 169 patients with STEMI obtained a standardized digital 12-lead EKG on admission for the calculation of the QRS-T angle and underwent CMR imaging for analysis of infarct size by LGE within the first week. Patients were divided into groups: (1) abnormal QRS-T angle ≥ 90 degree and (2) QRS-T angle < 90 degree. Results: Patients with a QRS-T angle of 90 degree or more had larger infarcts (36.5±12.4 vs. 13.3±9.5; p<0.001) and lower ejection fraction (42.9±12.1% vs. 50.6±10.6%; p<0.001). Conclusion: The extent of myocardial damage as measured by the gold standard LGE is associated with a larger QRS-T angle calculated from the surface EKG.

Stable silencing of IGF1R using Lentiviral-mediated shRNA in HEK293T cells.

Insulin-like growth factors are among the peptide mitogens that regulate cell proliferation and differentiation as well as mediator of antiapoptotic signals. The imbalance between the expression and activities of these molecules may lead to malignancy in cells. Evidences have suggested the insulin-like growth factor 1 receptor (IGF-1R) signaling pathway as a therapeutic target in the management and treatment of cancer. In this present study, we have generated silencing stable clones of HEK cells using six different pGIPZ (lentiviral vector) shRNAs targeted to human IGF-1R gene and a pGIPZ non-silencing shRNAmir lentiviral vector (as negative control). The recombinant lentiviral vectors were separately transduced into human embryonic kidney 293 T (HEK293T) cell lines. The knockdown of IGF-1R was confirmed by reverse transcription polymerase chain reaction (RT-PCR) and the relative IGF-1R mRNA levels were expressed as a ratio of IGF-1R to ß-actin by REST software. The results showed significant reduction in the expression of IGF-1R mRNAs in cells transduced with all six pGIPZ-IGF-1R recombinant lentivirals compared to non-silencing negative control. No significant difference was observed among the six cassettes. Results indicated that recombinant lentiviral vectors provided an efficient and stable knockdown of IGF-1R providing useful tool for IGF-1R pathway studies.

Treatment with desmopressin acetate in routine coronary artery bypass surgery to improve postoperative hemostasis.

Desmopressin acetate (DDAVP) has been shown to decrease blood loss and transfusions in complex cardiac operations with long extracorporeal times. Its use in routine cardiac valve operations has been shown not to be beneficial, but its role in routine coronary artery bypass grafting operations has not been defined. We examined the effect of DDAVP in a prospective study of 60 patients undergoing uncomplicated primary coronary artery bypass grafting operations. Thirty consecutive patients received DDAVP (0.3 micrograms/kg) after cardiopulmonary bypass and were compared with 30 consecutive patients who did not receive DDAVP. No significant differences were seen in 12-hour mediastinal blood loss (465 +/- 207 ml with DDAVP versus 511 +/- 221 ml without DDAVP) or 12-24-hour mediastinal blood loss (236 +/- 127 ml with DDAVP versus 260 +/- 112 ml without DDAVP). Transfusion of blood products were similar for both groups. Platelet aggregometry at intraoperative and postoperative time points using ADP, collagen, and ristocetin was not significantly different from baseline values in either group. In a subgroup of patients with poor initial ristocetin-induced platelet aggregometry, a significant increase (p less than 0.05) in ristocetin-induced platelet aggregometry was seen postoperatively only in those patients who had received DDAVP. A decrease in blood loss and transfusions, however, was not demonstrable. In those patients who had been on aspirin or nonsteroidal anti-inflammatory drugs preoperatively, DDAVP did not improve mediastinal blood loss or transfusion needs.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of hypothermia on cellular membrane function during low-flow extracorporeal circulation.

The use of systemic hypothermia is known to allow recovery from potentially lethal states of profound hypoperfusion or total circulatory arrest. While the cellular alterations accompanying states of decreased perfusion in skeletal muscle are well defined, little is known regarding the impact of coexistent hypothermia. To investigate this issue, nine dogs were placed on total cardiopulmonary bypass (CPB) and perfused in nonpulsatile fashion. The following flow and temperature parameters were used in three different perfusion models: 3.5 L/min/m2 at 23 degrees C (group A, n = 3), 1.6 L/min/m2 at 37 degrees C (group B, n = 3), and 1.6 L/min/m2 at 23 degrees C (group C, n = 3). Assessment of cellular function in a hind limb adductor muscle by measurement of resting transmembrane potential difference (Em) and determination of tissue electrolyte distribution in a biopsy specimen was performed in the control state and again after 60 minutes of total CPB. Low-flow/hypothermic CPB (group C) was associated with depolarization of resting Em to -63.3 +/- 3.2 mV from a control value of -87.0 +/- 1.3 mV (p less than 0.05), an increase in the calculated intracellular Na ([Na]i) to 16.4 +/- 4.0 mEq/L from a control value of 7.6 +/- 1.4 mEq/L (p less than 0.05), and an increase in the ratio of the selective membrane permeabilities of Na+ to K+ (pNa/pK), to 0.067 +/- 0.013 from a control value of 0.013 +/- 0.002 (p less than 0.05). In contrast, resting Em was maintained at -86.4 +/- 6.1 mv during normal-flow/hypothermic CPB (group A), while low-flow/normothermic CPB (group B) produced an intermediate depolarization to -75.2 +/- 3.0 mV (p less than 0.05). Neither [Na]i or pNa/pK was altered significantly in group A or group B dogs. These data characterize a physiologic alteration in the cellular membrane function of skeletal muscle during low-flow/hypothermic CPB, which is similar in many respects to that accompanying hemorrhagic shock. This suggests that during periods of profound hypothermia certain flow-related derangements in skeletal muscle are not obviated and may be exacerbated.

Myosin heavy chain expression in embryonic cardiac cell cultures.

Chick embryonic heart cell isolates and monolayer cultures were prepared from atria and ventricles at selected stages of cardiac development. The cardiac myocytes were assayed for myosin heavy chain (MHC) content using monoclonal antibodies (McAbs) specific in the heart for atrial (B-1), ventricular (ALD-19), or conductive system (ALD-58) isoforms. Using immunofluorescence microscopy or radioimmunoassay, MHC accumulation was measured before plating and at 48 hr or 7 days in culture. Reproducible changes in MHC antigenicity were observed by 7 days in both atrial and ventricular cultures. The changes were stage dependent and tissue specific but generally resulted in a decreased reactivity with the tissue specific MHC McAbs. In addition, the isoform recognized by ALD-58, characteristic of the conductive system cells in vivo, was never present in cultured myocytes. These results indicate that MHC isoforms produced in vivo may be replaced in monolayer cultures by an isoform(s) not recognized by our tissue specific MHC McAbs. This suggests that the intrinsic program of cardiac myogenesis, within cardiac myocytes, may not be sufficient to establish and maintain differential expression of tissue specific MHC in monolayer cell culture.

Small bowel obstruction in the elderly.

Hospital records were reviewed for all patients 70 years or older who were treated for small bowel obstruction (SBO) at The New York Hospital-Cornell Medical Center from January 1975 through December 1980. There were 87 patients treated surgically and 20 patients treated nonoperatively. When the clinical evidence of strangulation was evaluated for preoperative reliability, 35 per cent of the patients had none of the accepted criteria for strangulation. Complications occurred in 60.9 per cent of patients following operative intervention. Wound infection was the most common postoperative complication and was related to wound management and to the number of enterotomies made at the time of surgery. Using delayed 1 degree closure, the infection rate was 6.2 per cent compared to 21.1 per cent when wounds were closed at surgery. The overall operative mortality was 18 per cent; advanced carcinoma accounted for 60 per cent of these fatalities. The mortality for patients with nonmalignant obstruction was 10.0 per cent as compared with 40.7 per cent in patients with cancer. From these data the authors conclude: that age alone should not be a deterrent to operative intervention in small bowel obstruction; the presence of a 1 degree or 2 degrees malignant process in the elderly patient is a significant risk factor for mortality; any patient operated on for SBO having an enterotomy should have their wound managed by delayed 1 degree closure; and because of the lack of reliability of the clinical criteria for strangulation, operative intervention in the elderly should be undertaken as soon as the diagnosis of mechanical obstruction is made.