Search

Background: The role of vaccine hesitancy on influenza vaccination is not clearly understood. Low influenza vaccination coverage in U.S. adults suggests that a multitude of factors may be responsible for under-vaccination or non-vaccination including vaccine hesitancy. Understanding the role of influenza vaccination hesitancy is important for targeted messaging and intervention to increase influenza vaccine confidence and uptake. The objective of this study was to quantify the prevalence of adult influenza vaccination hesitancy (IVH) and examine association of IVH beliefs with sociodemographic factors and early-season influenza vaccination., Methods: A four-question validated IVH module was included in the 2018 National Internet Flu Survey. Weighted proportions and multivariable logistic regression models were used to identify correlates of IVH beliefs., Results: Overall, 36.9% of adults were hesitant to receive an influenza vaccination; 18.6% expressed concerns about vaccination side effects; 14.8% personally knew someone with serious side effects; and 35.6% reported that their healthcare provider was not the most trusted source of information about influenza vaccinations. Influenza vaccination ranged from 15.3 to 45.2 percentage points lower among adults self-reporting any of the four IVH beliefs. Being female, age 18-49 years, non-Hispanic Black, having high school or lower education, being employed, and not having primary care medical home were associated with hesitancy., Conclusions: Among the four IVH beliefs studied, being hesitant to receiving influenza vaccination followed by mistrust of healthcare providers were identified as the most influential hesitancy beliefs. Two in five adults in the United States were hesitant to receive an influenza vaccination, and hesitancy was negatively associated with vaccination. This information may assist with targeted interventions, personalized to the individual, to reduce hesitancy and thus improve influenza vaccination acceptance., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The National Center for Health Statistics' (NCHS) Research and Development Survey (RANDS) is a series of commercial panel surveys collected for methodological research purposes. In response to the COVID-19 pandemic, NCHS expanded the use of RANDS to rapidly monitor aspects of the public health emergency. The RANDS during COVID-19 survey was designed to include COVID-19 related health outcome and cognitive probe questions. Rounds 1 and 2 were fielded June 9-July 6, 2020 and August 3-20, 2020 using the AmeriSpeak® Panel. Existing and new approaches were used to: 1) evaluate question interpretation and performance to improve future COVID-19 data collections and 2) to produce a set of experimental estimates for public release using weights which were calibrated to NCHS' National Health Interview Survey (NHIS) to adjust for potential bias in the panel. Through the expansion of the RANDS platform and ongoing methodological research, NCHS reported timely information about COVID-19 in the United States and demonstrated the use of recruited panels for reporting national health statistics. This report describes the use of RANDS for reporting on the pandemic and the associated methodological survey design decisions including the adaptation of question evaluation approaches and calibration of panel weights.

Challenges in measuring early childhood development (ECD) at scale have been documented, yet little is known about the specific difficulties related to questionnaire design and question interpretation. The purpose of this paper is to discuss the challenges of measuring ECD at scale in the context of household surveys and to show how to overcome them. The paper uses examples from the cognitive interviewing exercises that were conducted as part of the methodological work to develop a measure of ECD outcomes, the ECDI2030. It describes the methodological work carried out to inform the selection and improvement of question items and survey implementation tools as a fundamental step to reduce and mitigate systematic measurement error and improve data quality. The project consisted of a total of five rounds of testing, comprising 191 one-on-one, in-depth cognitive interviews across six countries (Bulgaria, India, Jamaica, Mexico, Uganda, and the USA). Qualitative data analysis methods were used to determine matches and mismatches between intention of items and false positives or false negative answers among subgroups of respondents. Key themes emerged that could potentially lead to systematic measurement error in population-based surveys on ECD: (1) willingness of child to perform task versus ability of child to perform task; (2) performing task versus performing task correctly; (3) identifying letters or numbers versus recognizing letters or numbers; (4) consistently performing task versus correctly performing task; (5) applicability of skills being asked versus observability of skills being asked; and (6) language production versus language comprehension. Through an iterative process of testing and subsequent revision, improvements were made to item wording, response options, and interviewer training instructions. Given the difficulties inherent in population-level data collection in the context of global monitoring, this study's findings confirm the importance of cognitive testing as a crucial step in careful, culturally relevant, and sensitive questionnaire design and as a means to reduce response bias in cross-cultural contexts.

Web, or online, probing has the potential to supplement existing questionnaire design processes by providing structured cognitive data on a wider sample than typical qualitative-only question evaluation methods can achieve. One of the practical impediments to the further integration of web probing is the concern of survey managers about how the probes themselves may affect response to other items and to a questionnaire as a whole. This study explores the effects web probes had on response to a self-administered web survey by comparing two rounds of this survey-one without web probes and one with web probes-that were administered to a probability-based panel of approximately 100,000 American adults. While the item response to the probes themselves appears to be related to the way they are formatted, the findings indicate that web probes do not have an overall negative effect on a questionnaire in which they are embedded., Competing Interests: Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objectives: This study compared left atrial and left atrial appendage contraction velocities in sinus rhythm before and after a brief period of atrial fibrillation in a canine model., Background: In patients, left atrial appendage contraction velocities measured during sinus rhythm after cardioversion from atrial fibrillation are depressed relative to left atrial appendage emptying velocities measured during atrial fibrillation, suggesting that the left atrial appendage is mechanically "stunned.", Methods: This phenomenon was studied in a canine model of acute (60 min) pacing-induced atrial fibrillation followed by spontaneous reversion to sinus rhythm using epicardial and transesophageal pulsed wave Doppler. Unique features of the model include: 1) comparison of left atrial function postconversion to baseline sinus rhythm rather than to measurements during atrial fibrillation, 2) control of the duration of atrial fibrillation and 3) elimination of the extraneous influences of direct current shock and antiarrhythmic agents, which may independently depress left atrial function., Results: Hemodynamic conditions (heart rate, mean arterial pressure, cardiac output, mean pulmonary artery pressure, mean right atrial pressure and mean left atrial pressure) at baseline, during 60 min of atrial fibrillation and after reversion to sinus rhythm were constant throughout the study period. Peak left atrial contraction velocities (measured from the transmitral flow velocity profile) were significantly (p < 0.02) reduced to 64+/-22% of baseline values upon spontaneous conversion of atrial fibrillation to sinus rhythm and recovered to basal values by 20 min after resumption of sinus rhythm. Peak left atrial appendage contraction velocities were significantly (p < 0.001) reduced to 49+/-24% of baseline values upon spontaneous conversion of atrial fibrillation to sinus rhythm and recovered to basal values by 40 min after reversion to sinus rhythm., Conclusions: Even brief (60 min) periods of atrial fibrillation in normal canine hearts result in marked depression of global left atrial systolic function and regional left atrial (left atrial appendage) systolic function upon resumption of sinus rhythm. This "mechanical stunning" of left atrial systolic function appears to be more profound and of longer duration for the left atrial appendage compared with the left atrium as a whole, which may predispose the appendage to blood stasis and thrombus formation. Chronic models of atrial fibrillation need to be developed to examine the impact of longer periods of atrial fibrillation upon the magnitude and duration of postconversion left atrial "stunning."

Though qualitative transthoracic echocardiographic criteria for abnormal systolic leaflet motion are widely accepted as diagnostic characteristics of mitral valve prolapse, transesophageal echocardiographic criteria have not been evaluated against such a standard. Because transesophageal imaging planes are not identical to transthoracic imaging planes, validation of transesophageal echocardiographic criteria for mitral valve prolapse is needed. Eleven patients with mitral valve prolapse (based on physical findings and transthoracic echocardiographic criteria) and 11 healthy persons underwent prospective transesophageal echocardiography in two orthogonal imaging planes. Measurements of maximal leaflet displacement superior to the annular hinge points and mitral prolapse area subtended by the displaced mitral leaflets and the chord connecting the annular hinge points were performed in triplicate and averaged by a blinded observer. Though maximal systolic leaflet displacement was greater among patients with mitral valve prolapse than healthy subjects for both the transesophageal four-chamber (0.66+/-0.39 cm versus 0.05+/-0.11 cm, p < 0.001) and two chamber views (0.57+/-0.44 cm versus 0.20+/-0.25 cm, p < 0.04), no unique value differentiated patients with from those without mitral valve prolapse. Mitral prolapse area was greater for patients with mitral valve prolapse than for healthy subjects in both transesophageal four-chamber (1.23+/-1.18 cm2 versus 0.03+/-0.06 cm2, p < 0.02) and two-chamber views (1.73+/-1.65 cm2 versus 0.21+/-0.31 cm2, p < 0.02). Whereas a mitral prolapse area of 0.20 cm2 uniquely differentiated patients with from those without mitral valve prolapse in the four-chamber view, data overlap prevented determination of a similar diagnostic criterion for the two-chamber view. The difficulty in defining quantitative transesophageal echocardiographic criteria for mitral valve prolapse based on leaflet displacement alone suggested that the simple qualitative observation of leaflet displacement above the annular hinge points should not be used as a defining morphologic criterion for mitral valve prolapse.

Objectives: This prospective, blinded transesophageal echocardiographic study was performed to determine the relative contributions of leaflet redundancy and overlap versus intrinsic tissue thickening as mechanisms for the apparent increase in diastolic thickness of the mitral valve., Background: Increased diastolic thickness of the mitral valve has been identified as an echocardiographic feature that predicts subsequent adverse sequelae in patients with mitral valve prolapse (MVP)., Methods: Eleven patients with clinical and transthoracic echocardiographic evidence of MVP and 11 age-matched control subjects underwent protocol transesophageal echocardiography to image the mitral valve in two orthogonal planes and to measure its thickness in systole and diastole., Results: Maximal diastolic width of the slack, unloaded anterior leaflet was significantly greater in patients with MVP than in control subjects (mean +/- SD: 0.64 +/- 0.20 cm vs. 0.30 +/- 0.04 cm, p < 0.001). Similarly, diastolic posterior leaflet width was greater in patients with MVP (0.67 +/- 0.39 cm vs. 0.31 +/- 0.06 cm, p < 0.01). In contrast, minimal systolic width of the distended pressure-loaded mitral valve was not significantly different between patients with MVP and control subjects for either the anterior (0.22 +/- 0.05 cm vs. 0.20 +/- 0.04 cm, p = NS) or the posterior (0.25 +/- 0.07 cm vs. 0.24 +/- 0.05 cm, p = NS) leaflets. The percent change in leaflet width from diastole to systole (% delta W), an index of the contribution of dynamic factors (e.g., leaflet redundancy and overlap) to the apparent increase in diastolic leaflet thickness, was significantly greater in patients with MVP than in control subjects for both the anterior (% delta W 62 +/- 13% vs. 34 +/- 16%, p < 0.001) and the posterior (% delta W 54 +/- 19% vs. 22 +/- 21%, p < 0.005) leaflets., Conclusions: The apparent increase in diastolic mitral leaflet thickness in patients with MVP versus control subjects is largely attributable to dynamic factors such as leaflet redundancy, overlap and deformation. During diastole, when the mitral leaflets are slack and unstressed, the leaflets appear markedly thickened in patients with MVP. In contrast, during systole, when developed intraventricular pressure distends the leaflets, causing them to stretch and balloon into the left atrium, the intrinsic tissue thickness is much less than that measured in diastole. These findings have important implications for the morphologic criteria used to diagnose MVP and the potential pathophysiologic mechanisms for adverse sequelae in this syndrome.

Registry data suggests that bifurcation lesions are associated with reduced success during percutaneous revascularization. We studied 1012 CAVEAT patients to compare procedural outcomes in patients with and without bifurcation lesions whose target vessel was treated with either atherectomy or angioplasty. Bifurcation lesions have increased angiographic complexity and interventions on them are associated with lower acute procedural success rates compared to non-bifurcation lesions. Subgroup analysis suggests that atherectomy treatment of bifurcation lesions improves acute procedural success rates and lowers restenosis rates compared to angioplasty treatment of bifurcation lesions but atherectomy of bifurcation lesions is associated with higher acute complication rates than angioplasty of bifurcation lesions.

The effect of acute pericardial tamponade on pulmonary venous return was assessed by transesophageal pulsed Doppler echocardiography. In 14 open-chest anesthetized dogs peak pulmonary venous flow velocities in systole (VJ) and in diastole (VK) were measured during apnea and atrial pacing while acute tamponade was induced by intrapericardial instillation of 0.9% sodium chloride solution. Before intravascular volume expansion, induction of acute tamponade resulted in a significant decline in VK (43 +/- 17 to 19 +/- 8 cm/sec; p < 0.05) but no change in VJ or the ratio VJ/VK. After intravascular volume expansion, induction of acute tamponade resulted in significant reductions in VJ (43 +/- 9 to 29 +/- 10 cm/sec; p < 0.001) and VK (37 +/- 19 to 15 +/- 11 cm/sec; p < 0.001). The effect was disproportionately greater on VK, however, resulting in a significant increase in VJ/VK (1.51 +/- 0.84 to 2.58 +/- 1.41; p < 0.001). The disproportionate effect of acute tamponade on VK suggests that increased pericardial pressure directly constrains diastolic filling of the left atrium as a conduit to the left ventricle and that it does not decrease the systolic and diastolic phases of pulmonary venous return uniformly. Intravascular volume expansion increases cardiac output before acute tamponade, but during acute tamponade it amplifies the disproportionate impact of increased pericardial pressure on left ventricular diastolic filling as the left ventricle is constrained within the fluid-filled pericardial sac.

Coronary vascular responses after brief periods of myocardial ischemia are impaired. Whereas some studies suggest that the ischemic insult selectively depresses endothelium-dependent vasodilator mechanisms, other studies indicate that even responses to direct vascular smooth-muscle relaxants such as adenosine may be decreased. This study was undertaken to measure regional myocardial blood flow (RMBF) responses to adenosine (a direct coronary vasodilator) and serotonin (an indirect, endothelium-dependent vasodilator) in myocardium subjected to regional ischemia followed by reperfusion. Temporary regional ischemia was achieved by 20 minutes of occlusion of the left anterior descending coronary artery (LAD) followed by 20 minutes of reflow in 10 open-chest anesthetized dogs. In the left circumflex coronary artery (LCX) territory, which served as a nonischemic control, RMBF (measured with radioactive microspheres) increased significantly in response to left atrial infusions of adenosine (1.29 +/- 0.27 to 3.89 +/- 3.89 +/- 2.15 ml/min/gm; p < 0.001) and serotonin (1.29 +/- 0.27 to 3.29 +/- 1.49 ml/min/gm; p < 0.001) and the percent reduction in coronary vascular resistance (% delta CVR) was comparable for these two pharmacologic probes (65% +/- 26% vs 62% +/- 19%; difference not significant [NS]). In contrast, in the myocardium supplied by the LAD, which was subjected to ischemia followed by reperfusion, the augmentation of RMBF by adenosine (1.07 +/- 0.29 to 1.82 +/- 1.35 ml/min/gm; p < 0.001) and serotonin (1.07 +/- 0.29 to 2.37 +/- 1.21 ml/min/gm; p < 0.001) was blunted.(ABSTRACT TRUNCATED AT 250 WORDS)

Ten patients with severe aortic regurgitation (AR) and early diastolic mitral closure demonstrated by M-mode echocardiography (group I) were compared to 10 age-matched patients with severe AR and normal timing of mitral closure to quantify the accompanying alterations in transmitral flow dynamics assessed by pulsed Doppler echocardiography. Transmitral filling period expressed as a fraction of the time available for diastolic filling was significantly shortened in group I patients relative to group II patients (0.50 +/- 0.10 vs 1.04 +/- 0.09, p < 0.001) because early mitral closure truncated transmitral filling and obliterated the atrial contribution to left ventricular filling. The rapid diastolic filling period normalized for the time available for diastolic filling was also shortened for group I patients relative to group II patients (0.49 +/- 0.11 vs 0.64 +/- 0.19; p < 0.05). Early mitral closure in group I patients was functionally incomplete because 9 of the 10 patients had diastolic mitral regurgitation, which was not detected in any patients in group II (p < 0.001). Thus the group I patients with early mitral closure and severe aortic regurgitation had truncated transmitral inflow and diastolic mitral regurgitation. These patients had higher pulmonary capillary wedge pressures (32 +/- 6 vs 11 +/- 9 mm Hg; p < 0.001) and more severe functional limitation (p < 0.001) than group II patients.

Eighteen patients with severe renal artery atherosclerosis underwent conventional percutaneous transluminal renal angioplasty (PTRA) followed immediately by implantation of an endovascular stent. Hemodynamic measurements showed a baseline trans-stenotic pressure gradient of 78.3 mmHg that was reduced to 14.8 mmHg after PTRA. The post PTRA trans-stenotic pressure gradient was further reduced to 0.86 mmHg after stent placement. The average baseline diameter stenosis of 81.3% was reduced to 43.7% after PTRA and 6.1% after stent placement. Six month angiographic follow-up revealed restenosis in 6/16 patients. In patients treated for chronic renal insufficiency without restenosis the 6 month creatinine was 1.46 mg/dl compared to a pre-procedure creatinine of 2.4 mg/dl. Therefore those patients with renal insufficiency and renal artery stenosis who had long term patency after successful stent implantation showed significant improvement in renal function at six months. Stent implantation also significantly improved acute hemodynamic results and acute angiographic results compared to conventional renal artery angioplasty.

We report a case of ergotamine tartrate induced severe vasospasm in the renal arteries and the arteries of the lower extremities. Classic features seen on peripheral angiography make the diagnosis. Anticoagulation, thrombolysis, vasodilation, steroids, and prostaglandin inhibitors all have been successfully used to treat symptomatic ergot induced arterial vasospasm. Although balloon angioplasty of ergot induced vasospasm has been described in case reports, ergot vasospasm is a self limited and medically treatable condition that does not require peripheral mechanical intervention, unless the immediate threat of necrosis and gangrene exists.

Infants undergoing open-heart surgery with hypothermic cardiopulmonary bypass experience markedly elevated lactate and glucose levels. Reports in infants less than 10 kg show the elevated lactate to be progressive during the operative period. The pathogenesis of the hyperglycemia is not clear but may be caused by excess glucose administration, inadequate insulin response, or glucose regulatory hormone levels of glucagon, cortisol, and growth hormone. The purpose of this study is to confirm these findings and to investigate their pathogenesis. Serial blood samples were taken preoperatively, intraoperatively, and postoperatively during hypothermic cardiopulmonary bypass in nine infants of less than 10 kg. Samples were analyzed for levels of lactate, glucose, and regulatory hormones insulin, growth hormone, glucagon, and cortisol. Our study did not show a progressive accumulation of lactate. The elevated lactate level appears to come from the pump prime solution. The hyperglycemia is also from the pump prime solution, and there do not appear to be elevated levels of regulatory hormones intraoperatively. Insulin response during hypothermia is blunted; however, on rewarming the patient in the immediate postoperative period, a brisk insulin response is seen. The changes in levels of lactate and glucose and the regulatory hormones return to baseline at 24 hours with no further significant changes in the next 48 hours.

Objectives: The purpose of this study was to estimate the prevalence of potential right to left interatrial shunting and to quantify the morphologic characteristics of the fossa ovalis in adults without a prior history of stroke or systemic embolism., Background: Paradoxic embolization through a patent foramen ovale is an important cardiac mechanism for embolic stroke. Although anatomic and physiologic data obtained by transesophageal echocardiography increase the frequency of demonstration of potential cardiac sources of systemic embolism and occasionally can conclusively demonstrate the mechanism for embolic stroke, the prevalence and prognostic implications of these findings in neurologically healthy persons are still being actively investigated., Methods: Intraoperative transesophageal saline contrast echocardiography was performed on 50 adult patients without prior history of stroke or systemic embolism who were undergoing elective cardiovascular surgery., Results: No patient had a manifest atrial septal defect by right heart oximetric measurements or transesophageal Doppler echocardiographic examination. Eleven of the 50 patients demonstrated right to left atrial passage of saline contrast medium during apnea or after release of 20-cm H2O positive airway pressure, signifying patency of the foramen ovale. These 11 patients with a patent foramen ovale had increased total excursion of the flap valve (septum primum) of the fossa ovalis (1.3 +/- 0.7 cm) compared with findings in the 39 patients without a patent foramen ovale (0.3 +/- 0.5 cm, p < 0.001). All patients with a patent foramen ovale exhibited some mobility of the septum primum and 73% of these patients had > or = 1 cm total excursion of the septum primum. In contrast, 56% of patients without a patent foramen ovale exhibited no motion of the septum primum out of the plane of the atrial septum. The maximal diameter of the fossa ovalis was greater in patients with (1.4 +/- 0.4 cm) than in patients without (1.0 +/- 0.3 cm, p < 0.003) a patent foramen ovale., Conclusions: Hypermobility of the septum primum and enlargement of the fossa ovalis are morphologic findings that occur in the presence of a patent foramen ovale.

Exercise-induced bundle branch block is an uncommon electrocardiographic entity said to be associated with coronary heart disease. Thirty-seven patients were studied to determine if exercise hemodynamics and stress/rest thallium scans could identify those patients with coronary heart disease. Eighteen patients of the study group also had coronary angiography. Group I (n = 17) with normal thallium scans and group II (n = 20) with abnormal thallium scans had significantly different maximal heart rate, maximal blood pressure, and double product in exercise as well as duration of exercise. Clinical evaluation of the patient study group permitted a division of the patients into two subgroups: group A, atypical chest pain or abnormal exercise electrocardiogram (n = 12), and group B, definite or probable angina (n = 25). Group B patients had significantly more abnormal thallium scans (17/25) than group A patients (3/12) (p less than 0.04). When compared to coronary angiography, stress/rest thallium scans had a predictive accuracy of 85% for coronary heart disease. While exercise-induced ST-segment depression and R wave amplitude increases are not specific in exercise-induced bundle branch block, exercise hemodynamics and stress/rest thallium scans can help diagnose patients with coronary heart disease. These test findings added to a clinical evaluation permit a more accurate stratification of the patients and indicate which patients need further study.

Myocardial ATP, ADP, and AMP were measured from cardiac biopsy in 11 dogs after intracoronary injection of 6 mL of sodium-meglumine diatrizoate (SMD), iohexol (IOH), or 0.9% sodium chloride (NaCl), and in three of the dogs at baseline before any injection. The ATP at baseline and after SMD, IOH, and 0.9% NaCl were 5.39 +/- 0.41, 3.72 +/- 0.70, 5.52 +/- 0.82, and 5.44 +/- 1.40 mumol/g wet weight, respectively. There were significant differences between SMD and IOH (P less than .02), and between SMD and 0.9% NaCl (P less than .05). The energy charge of SMD was 0.82 +/- 0.08, which differed from 0.89 +/- 0.02 for NaCl or 0.9 +/- 0.05 for baseline (P less than .05), but not from 0.85 +/- 0.04 for IOH. In conclusion, diatrizoate caused significant depletions in ATP stores in comparison with iohexol, but there was no significant difference with respect to energy charge. Nonionic contrast media would be preferable for coronary arteriography in patients whose high-energy stores might be depleted from severe ischemia.

The impact of pericardial constraint on patterns of left ventricular filling was measured by transesophageal pulsed Doppler echocardiography in 30 patients undergoing elective nonvalvular cardiac surgery. Peak early left ventricular filling velocity increased from 0.52 +/- 0.11 to 0.56 +/- 0.15 m/s (p less than 0.05) and early left ventricular filling fraction increased from 60 +/- 9% to 65 +/- 9% (p less than 0.005) after pericardiotomy. The study group was retrospectively subdivided into two groups based on the prepericardiotomy mean right atrial pressure, an index of intrapericardial pressure and hence pericardial constraint. In 13 patients with a mean right atrial pressure less than 6 mm Hg, no significant changes in early left ventricular filling were evident after pericardiotomy. In 17 patients with a mean right atrial pressure greater than or equal to 6 mm Hg indicative of a greater degree of pericardial constraint before pericardiotomy, significant increases in peak early filling velocity (0.52 +/- 0.13 to 0.57 +/- 0.19 m/s, p less than 0.05), peak early filling rate (4.29 +/- 0.67 to 4.66 +/- 0.86 stroke volumes/s, p less than 0.05) and early left ventricular filling fraction (57 +/- 7% to 63 +/- 8%, p less than 0.001) were measured after pericardiotomy. Thus, the pericardium does constrain early left ventricular filling and its effects are more pronounced in patients with an elevated right atrial pressure.

The optimal visualization of the atrial septum and fossa ovalis by transesophageal echocardiography was utilized to demonstrate saline contrast transit across the atrial septum and to relate it to the motion of the flap valve (septum primum) of the fossa ovalis. In three cases, three distinct mechanisms of right to left interatrial shunting in the absence of right ventricular systolic hypertension were identified: 1) transient spontaneous reversal of the left to right atrial pressure differential with each cardiac cycle; 2) sustained elevation of right atrial pressure above left atrial pressure induced by respiratory maneuvers; and 3) aberrant flow redirection across the foramen ovale due to a large right atrial mass. Any of these three mechanisms may be operative during paradoxic embolism in the absence of elevation of right ventricular pressures.

Although the efficacy of long-term administration of antithrombotic agents in unstable angina has been established, short-term effects on myocardial ischemia are unknown. A retrospective analysis was performed in 47 patients undergoing three-channel continuous ST segment monitoring as part of a multicenter trial using esmolol in unstable angina, in which 20 patients received a continuous heparin infusion during the initial assessment of chest pain. Concomitant medications included calcium channel blockers, beta-adrenergic blockers, nitrates, and aspirin in the majority of patients. Clinical variables between the heparin and no heparin groups were similar, except for fewer males and fewer total artery occlusions in the heparin group. No significant differences in the incidence or duration of ischemia were found in a 36 +/- 16 hour monitoring period. Forty percent of the heparin group had 35 episodes of ischemia with a mean of 11 +/- 10 minutes per episode and a total ischemic time of 48 +/- 39 minutes per patient with ischemia. Forty-four percent of the no heparin group had 47 episodes of ischemia with a mean of 13 +/- 13 minutes per episode and a total ischemic time of 58 +/- 47 minutes per patient with ischemia. Multiple linear regression analysis to adjust for intergroup differences did not alter the results. Eighty-five percent of all episodes were asymptomatic. Clinical events, such as episodes of chest pain, emergency coronary arteriography, or coronary revascularization, were also similar between groups. Thus the short-term administration of heparin did not alter the incidence or duration of ischemia in patients with unstable angina.(ABSTRACT TRUNCATED AT 250 WORDS)

The ability of extracorporeal cardiopulmonary support (CPS) to unload the left ventricle and reduce ischemic dysfunction during transient coronary occlusion was studied in 10 anesthetized dogs. Three serial 60-second circumflex coronary artery occlusions were performed with CPS initiated only during the second occlusion. CPS significantly reduced preocclusion systolic blood pressure, blood pressure x heart rate double-product, circumflex blood flow, left ventricular end-diastolic pressure (LVEDP), peak negative dP/dt, and left ventricular systolic thickening. Circumflex occlusion caused changes in LVEDP and left ventricular wall thickening that were similar regardless of the presence or absence of CPS. These data suggest that CPS unloads the left ventricle during myocardial ischemia but does not prevent regional or global myocardial dysfunction.

Hemodynamic changes due to intracoronary injections of nonionic contrast medium Omnipaque-350 (OM), ionic dimer Hexabrix (HB), and ionic contrast medium Renografin-76 (R76) were compared at baseline and during reperfusion after a 30-minute left anterior descending coronary artery (LAD) occlusion. In 11 open chest, anesthetized, and atrially paced dogs, 4 ml of either OM, HB, R76, or 0.9% NaCl were injected into the carotid-LAD bypass system. Coronary blood flow (CBF) and coronary vascular resistance (CVR) were measured before, during and after the intracoronary injection. The maximal hyperemic change (in percentage) from the preinjection value of CBF and CVR were calculated. The results at baseline and during reperfusion for CBF were: 104 +/- 14% vs. 85 +/- 10% for OM (NS); 76 +/- 11% vs. 39 +/- 9% for R76 (p less than 0.05); 57 +/- 8% vs. 33 +/- 5% for HB (P less than 0.05); and 30 +/- 7% vs. 9 +/- 4% for 0.9% NaCl (p less than 0.05). Consequently, the hyperemic changes of CVR at baseline and during reperfusion were: -49 +/- 3 vs. -42 +/- 4% for OM (NS); -44 +/- 3% vs. -24 +/- 6% for R76 (p less than 0.01); -36 +/- 3% vs. -24 +/- 4% for HB (p less than 0.05); and -18 +/- 4% vs. -7 +/- 3% for 0.9% NaCl (p less than 0.05). Thus, ischemia and reperfusion significantly dampened the coronary hemodynamic and vascular response to R76, HB, and 0.9% NaCl but not to OM. The preserved coronary vascular reserve with high flow in this canine post-ischemic reperfusion model may explain the advantage of nonionic over ionic contrast media used in emergency coronary angiography following thrombolysis.

To investigate the effect of sodium on cardiac hemodynamics, sodium chloride was added to nonionic contrast media to a 0.9% concentration and was compared with the standard media iohexol, iopamidol, and ioversol. Left coronary angiography was performed in 10 closed-chest, atrial-paced dogs with 10 ml injections of each preparation in a randomized and blinded fashion. The maximum changes in left ventricular systolic pressure, mean aortic pressure, left ventricular and diastolic pressure, and maximal rise of left ventricular pressure were measured. The left ventricular systolic pressure and mean aortic pressure decreased by 17 +/- 7 mm Hg and by 12 +/- 5 mm Hg with iohexol plus 0.9% NaCl, but only by 5 +/- 4 mm Hg and by 4 +/- 3 mm Hg with iohexol alone (p less than 0.001). The left ventricular and end diastolic pressure increased by 2.2 +/- 0.6 mm Hg with iohexol plus 0.9% NaCl, but did not change with iohexol alone (p less than 0.001). Left ventricular dp/dt decreased by 204 +/- 161 mm Hg/sec with iohexol plus 0.9% NaCl but increased by 392 +/- 122 mm Hg/sec with iohexol alone (p less than 0.001). Similar results were obtained from experiments with iopamidol versus iopamidol plus 0.9% NaCl and ioversol versus ioversol plus 0.9% NaCl. Ioversol plus 5% dextrose or ioversol plus 2.1% choline chloride (isomolar to ioversol plus 0.9% NaCl) produced a significant increase in left ventricular systolic pressure and left ventricular dp/dt (versus ioversol plus 0.9% NaCl, p less than 0.001). Thus, sodium, but not the osmolality or chloride, contributed to the negative inotropic effect of the contrast media.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous contrast in the left ventricle is an unusual entity. We retrospectively studied 16 patients who were found to have spontaneous contrast present on two-dimensional echocardiograms, specifically noting their clinical characteristics, the reproducibility of this phenomenon, the presence of thrombi and embolic events, and prognostic implications. Diagnoses included ischemic heart disease in nine patients, dilated cardiomyopathy in six patients, and hypertensive cardiomyopathy in one patient. The mean ejection fraction was 17.6%. There were six thromboembolic events in four patients. The spontaneous contrast was reproducible for periods of time up to 39 months. Patients who had improvement in their left ventricular dysfunction or who underwent aneurysmectomy had disappearance of the spontaneous contrast. Those patients who had spontaneous contrast reproduced on subsequent echocardiograms did not seem to have a worse prognosis than patients with similarly depressed ventricular function, but a larger study is necessary to verify this.

We reviewed the transpulmonary gradient, pulmonary arterial systolic pressure, pulmonary vascular resistance (Wood units), and pulmonary vascular resistance index (Wood units X Body surface area), recorded preoperatively in 109 recipients aged 44.6 +/- 13.5 (mean +/- SD) years who underwent orthotopic heart transplantation between March 1984 and March 1988, to identify which measure of pulmonary hypertension most accurately predicts poor outcome after orthotopic heart transplantation. These recipients were followed up as many as 57 (24.7 +/- 14.5) months after their transplant procedure. Preoperative hemodynamic values were as follows: transpulmonary gradient, 10.4 +/- 4.7 mm Hg; pulmonary artery systolic pressure, 53.6 +/- 14.8 mm Hg; pulmonary vascular resistance, 2.7 +/- 1.8 Wood units; pulmonary vascular resistance index, 4.9 +/- 2.7. Nineteen recipients died within 1 year after orthotopic heart transplantation. Causes of death were acute rejection (8), chronic rejection (1), infection (2), nonspecific orthotopic heart transplant failure (4), bowel ischemia (1), pancreatitis (1), lymphoma (1), and liver failure (1). Preoperative pulmonary arterial systolic pressure, pulmonary vascular resistance, and pulmonary vascular resistance index were not predictive of 1-month, 6-month, or 1-year mortality. One-month mortality rates of orthotopic heart transplant recipients with transpulmonary gradient greater than or equal to 12 mm Hg and of those with transpulmonary gradient less than 12 mm Hg were not significantly different (11% vs 3%; p = 0.12). The 6-month mortality rate of orthotopic heart transplant recipients with transpulmonary gradient greater than or equal to 12 mm Hg, however, was five times greater than that of orthotopic heart transplant recipients with transpulmonary gradient less than 12 mm Hg (24% vs 5%; p = 0.003), and 12-month mortality of orthotopic heart transplant recipients with transpulmonary gradient greater than or equal to 12 mm Hg was increased sevenfold when compared with that of orthotopic heart transplant recipients with transpulmonary gradient less than 12 mm Hg (36% vs 5%; p = 0.0005). These results suggest that presently used measures of pulmonary hypertension do not predict mortality in the first month after orthotopic heart transplantation, but that elevated preoperative transpulmonary gradient is associated with a significant increase in mortality at 6 and 12 months after orthotopic heart transplantation. Prospective randomized trials are needed to determined whether extended preload and afterload reduction before and/or after transplant will favorably influence long-term prognosis of orthotopic heart transplant recipients with elevated preoperative transpulmonary gradient.

Electrophysiological testing was performed in 100 consecutive patients with spontaneous asymptomatic nonsustained ventricular tachycardia, chronic coronary artery disease, and ejection fraction of less than 40%. Fifty-seven patients without inducible sustained ventricular arrhythmias were discharged on no antiarrhythmic therapy. Sustained monomorphic ventricular tachycardia was induced in 37 patients, and polymorphic ventricular tachycardia or ventricular fibrillation was induced in six patients. Of the 43 patients with inducible sustained ventricular arrhythmias, three had spontaneous cardiac arrest during serial drug testing and were excluded from further analysis. Twenty patients were discharged on drug therapy, resulting in suppression of inducible sustained ventricular arrhythmias. The remaining 20 patients with persistently inducible sustained arrhythmias were discharged on drug therapy, resulting in maximal rate slowing of the induced tachycardia. During a mean follow-up of 16.7 months, there were 10 recurrent cardiac arrests or sudden deaths. The 1- and 2-year actuarial incidence of these events was 2% and 6%, respectively, in patients without inducible sustained ventricular arrhythmias; 0% and 11%, respectively, in patients in whom inducible arrhythmias were suppressed; and 34% and 50%, respectively, in patients with persistently inducible sustained ventricular arrhythmias. Multivariate Cox analysis identified only the persistence of inducible sustained ventricular arrhythmias as a significant independent predictor of sudden death or recurrent sustained arrhythmias (p less than 0.001; relative risk, 3.5; 95% confidence intervals, 2.1-4.9). In this population, therapeutic intervention to prevent sudden death is unnecessary in patients without inducible sustained ventricular arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)

To compare monoclonal anti-T3-receptor antibody (OKT3) and horse antithymocyte globulin (HATG) immunoprophylaxis, 23 heart transplant recipients were randomized to OKT3 (N = 12) 5 mg IV x 14 days of HATG (N = 11) 5 mg/kg IV x 10 days and followed up for 216 +/- 137 days receiving triple immunosuppression. Recipient groups were demographically and clinically similar. First rejection occurred later in OKT3 recipients vs HATG recipients (31.7 +/- 18.3 vs 15.1 +/- 2.3 days; p less than 0.01), but the first rejection necessitating intensified immunosuppression occurred at similar times (30.9 +/- 14.6 vs 21.9 +/- 10.2 days; NS). Phenotypic characterization of peripheral blood lymphocytes by flow cytometry revealed that OKT3 and HATG recipients had similar decreases in total T lymphocytes and lymphocyte subpopulations. During the follow-up period rejection rates in the OKT3- and in the HATG-treated patients were 3.4 +/- 2.7 and 5.9 +/- 4.7, respectively (NS). The number of rejection episodes per recipient treated with intensified immunosuppression was 1.4 +/- 1.2 in the OKT3- and 2.0 +/- 3.1 in the HATG-treated patients (NS). Infection rates were 4.9 +/- 5.2 in the OKT3- and 2.7 +/- 1.7 in the HATG-treated patients (NS). The number of infection episodes that necessitated intravenous antimicrobial therapy was 2.7 +/- 2.3 in the OKT3- and 1.6 +/- 1.3 in the HATG-treated recipients (NS). The number and length of hospitalizations were similar in patients given OKT3-based or HATG-based immunoprophylaxis. We conclude that immunosuppressive prophylaxis with OKT3 vs HATG in heart transplant recipients is associated with a slightly lower incidence and severity of rejection and slightly higher infection rates.

A sixty-three-year-old patient with malignant histiocytic lymphoma of the heart presented with both superior vena cava syndrome and cardiac tamponade. A two-dimensional echocardiogram showed a large tumor mass in the right atrium and pericardial effusion with right ventricular compression. Superior and inferior vena cavagrams disclosed a lobulated tumor located in the right atrium that extended into and obstructed the superior vena cava. After the pericardial effusion was drained and the diagnosis was established, the patient was irradiated and given chemotherapy with resolution of the tamponade and superior vena cava obstruction.

To investigate the relationship between clot formation and thromboembolism, canine blood was withdrawn into catheter-syringe or catheter-steerable wire systems containing either contrast medium or normal saline as used in debubbling techniques. The contrast media used were iohexol, iopamidol, ioxaglate, and diatrizoate. Without the use of heparin, after a 30-minute incubation, blood clots were harvested from all catheter-syringe systems except those with diatrizoate and from all catheter-steerable wire systems. Significantly more blood clot was harvested from the catheter-steerable wire system. With use of heparinized blood, no clot was found in any system. Twelve dogs that underwent coronary angiography were divided into two groups; one received heparin (5,000 IU) and the other did not. Thromboembolism occurred in all nonheparinized dogs that underwent angiography with iohexol or iopamidol but not in any other group. The authors found that in a dog model nonionic contrast media are more thrombogenic than ionic contrast media, especially in the catheter-steerable wire system. The blood clot in the catheters is associated with thromboembolism during angiography. The authors maintain that in this setting, blood clotting and thromboembolism with nonionic agents can be eliminated with heparin.

Contrast media occasionally produce bradyarrhythmias defined as a 25% decrease in heart rate and/or developing atrioventricular block during coronary angiography. Twelve left coronary angiographies and seven right coronary angiographies were performed with 10 ml of diatrizoate meglumine and diatrizoate sodium (Renografin-76 [R76] or Hypaque [H76]) or iopamidol (Isovue 370 [ISO]) in a blinded randomized fashion. Heart rate decreased significantly from 135 +/- 5 to 120 +/- 5 beats/min (p less than 0.001) with R76, to 127 +/- 7 beats/min (p less than 0.01) with H76, and to 130 +/- 6 beats/min (p less than 0.05) with ISO in left coronary angiographies; more profound decrease was observed in right coronary angiographies from 134 +/- 4 to 87 +/- 18 beats/min (p less than 0.001) with R76, to 99 +/- 14 beats/min (p less than 0.001) with H76, and to 125 +/- 7 beats/min (p less than 0.01) with ISO. In 12 left coronary angiographies bradyarrhythmia was observed in five cases with R76, two with H76, and none with ISO. In seven right coronary angiographies it occurred in six with R76, three with H76, and none with ISO. The differences in the incidence of bradyarrhythmia between R76 and ISO were significant during left and right coronary angiographies (p less than 0.05 and p less than 0.01, respectively). Thus ionic contrast media produced more marked bradyarrhythmias than nonionic contrast media in coronary angiography, especially R76. Right coronary angiography resulted in more profound bradyarrhythmias than left coronary angiographies. This study suggested that nonionic contrast media (ISO) might be preferable to ionic contrast media (R76 or H76) for coronary arteriography.

The influence of contrast media on coagulation has an important association with thromboembolic complication during coronary angiography. In this study, whole blood was methodically mixed with nonionic contrast medium, Iohexol (IOH), conventional ionic contrast medium, Hypaque-76 (H76), and low osmolar ionic dimer Hexabrix (HB) in vitro. The thrombotic propensity of contrast agents can be evaluated by measuring the clot formation of the mixtures. The experiments were repeated with whole blood after systemic heparinization. In the in vitro study, 5 ml of canine (N = 10) and 3 ml of human (N = 11) whole blood was incubated for 30 min in glass tubes with equal volumes of IOH, H76, HB, and 0.9% NaCl before heparinization. Clot formation with IOH and 0.9% NaCl were seen both in dogs (4.0 +/- 0.7 gm and 5.6 +/- 0.8 gm) and in patients (1.4 +/- 0.9 gm and 2.9 +/- 1.3 gm), whereas no clot was seen with H76 or XB. Following heparinization, no clot was visualized in any mixture of whole blood with contrast media or 0.9% NaCl. Similar results were observed in the catheter-syringe system with canine blood (N = 11) mixed with the contrast agents. Blood clots found in 15 min and 30 min of IOH were 0.07 +/- 0.08 gm and 0.44 +/- 0.20 gm (P less than 0.01) and of NaCl were 0.29 +/- 0.37 gm and 0.69 +/- 0.38 gm (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

We compared the hemodynamic effects during coronary angiography of three nonionic contrast media, iopamidol, iohexol, and ioversol, with each other as well as with the standard ionic contrast medium containing 66% diatrizoate meglumine and 10% diatrizoate sodium (Hypaque-76) in the presence of a left anterior descending coronary artery occlusion in dogs. In 13 opened-chest anesthetized dogs, we recorded the maximal change in left ventricular systolic pressure (LVSP), mean aortic pressure (MAP), left ventricular diastolic pressure (LVDP) and rate of rise in left ventricular pressure (LV dp/dt) during left main coronary artery injections of 10 ml each of Hypaque-76, iopamidol, iohexol, and loversal 1 hour after left anterior descending coronary artery occlusion. The changes in LVSP and MAP were, respectively, -29 +/- 12 mm Hg and -21 +/- 11 mm Hg with Hypaque-76, 3 +/- 6.6 mm Hg and -0.2 +/- 3.6 mm Hg with iopamidol, 4.8 +/- 8.6 mm Hg and 0.5 +/- 4 mm Hg with iohexol, and -0.8 +/- 6 mm Hg and -1.5 +/- 33 mm Hg with ioversal (p less than 0.001). The change in LVDP was 5.4 +/- 4.4 mm Hg with Hypaque-76 but -1.5 +/- 3.1 mm Hg with iopamidol, -1.7 +/- 2.4 mm Hg with iohexol, and -0.5 +/- 2.5 mm Hg with ioversol (p less than 0.001). The LV dp/dt decreased 682 +/- 318 mm Hg/sec with Hypaque-76, but increased 412 +/- 297 mm Hg/sec with iopamidol, 350 +/- 214 mm Hg/sec with iohexol, and 293 +/- 191 mm Hg/sec with ioversol (p less than 0.001). Thus, each nonionic agent produced significantly fewer hemodynamic abnormalities than Hypaque-76. There was no significant difference between any of the nonionic agents on any hemodynamic parameter. These agents may be preferable in patients with acute myocardial infarction or significantly impaired myocardial function.

Coronary angiography with Renografin 76 (RG76) occasionally results in ventricular fibrillation (VF). Angiovist 370 (AV370) is a contrast medium similar to RG76 except the calcium-sequestering agents, sodium citrate and EDTA in RG76 have been replaced by calcium EDTA. To determine whether these sequestering agents contribute to contrast medium-induced VF, a comparison was made of the effects of intracoronary injections of RG76, AV370, and saline solutions containing sodium citrate and EDTA (CIT/EDTA) and calcium EDTA (CA EDTA) on myocardial conduction, local QT intervals, and incidence of spontaneous and induced VF in 32 dogs. Four milliliters of RG76 produced a 111 +/- 12-ms increase in local QT intervals, compared with a 73 +/- 8-ms increase with AV370 (p less than 0.001). Spontaneous VF occurred in 12 of 16 six-milliliter injections of RG76, compared with 4 of 16 injections of AV370 (p less than 0.02) An early-cycle premature impulse applied after every fourth beat induced VF in 15 of 16 four-milliliter injections of RG76 compared with 5 of 16 injections of AV370 (p less than 0.01). As the premature beat conducted through the left anterior descending region, conduction slowing and fractionation occurred, which was less with AV370 than with RG76. The CIT/EDTA solution produced a greater increase in QT intervals (77 +/- 5 ms) than the CA EDTA solution (29 +/- 3 ms) or 0.9% saline solution alone (28 +/- 2 ms) (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate the mechanisms of ventricular fibrillation (VF) during coronary angiography, we assessed ventricular automaticity, local QT intervals, local conduction characteristics, and the ability to induce arrhythmias with premature ventricular stimulation in 30 dogs after intracoronary injections of 4 to 6 cc of Renografin 76 (RG 76). Ventricular automaticity was measured in six dogs as the idioventricular escape rate following intense vagal stimulation and was unchanged (51 +/- 6 vs 52 +/- 6 bpm, p greater than 0.05) with 6 cc of RG 76. In addition, 8 of 10 injections of 6 cc of RG 76 produced VF at a heart rate of 200 bpm compared to only 2 of 10 injections at a heart rate of 80 bpm (p less than 0.05). Composite and bipolar plunge electrodes were placed in the region perfused by the left anterior descending coronary artery (LAD) and circumflex coronary artery to assess QT intervals and conduction characteristics. RG 76, 4cc, produced a 116 +/- 18 msec increase in the QT intervals recorded from the region perfused by the LAD, resulting in a marked dispersion in repolarization. Both local bipolar and composite electrograms showed minimal conduction delay, which rarely extended beyond the QRS of a lead II ECG during atrial paced rhythm. As premature beats (spontaneous or induced) conducted through the region of QT prolongation, marked conduction delay was recorded from bipolar electrograms, while composite electrograms recorded continuous fractionated electrical activity spanning the diastolic interval at the onset of VF.(ABSTRACT TRUNCATED AT 250 WORDS)

Sixty-two (1.10%) of 5719 patients undergoing cardiac surgery between 1976 and 1982 required postoperative gastro-intestinal consultation, and 24 (0.4%) required operation. The major complications were gastrointestinal bleeding due to gastritis in 15, peptic ulcer in ten, and acute cholecystitis in 12. Acute diverticulitis was diagnosed in eight patients. Three patients had massive bowel necrosis, while eight patients had painless jaundice. Six patients had miscellaneous problems requiring consultation. Operative mortality was 10/25 (40%). Most complications occurred within 7 days of cardiac surgery. Seventeen of 62 patients required an intra-aortic balloon pump, and 29/62 had a hypotensive episode during cardiac surgery. Gastro-intestinal complications following cardiac surgery are rare but carry significant mortality. Patients with circulatory compromise and those requiring intra-aortic balloon pump are most likely to develop gastrointestinal complications. Careful monitoring and physical examination of these high-risk patients following cardiac surgery is required for early detection and effective treatment.

In this case report, pacemaker malfunction is simulated by prolonged pauses after each pacemaker discharge. The pauses were due to saturation of the input of the telemetry monitor amplifier by the discharge voltage of the pacemaker. It is important to recognize amplifier saturation as a form of artifact that can mimic pacemaker malfunction.