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PubMedDate not supplied

Does the use of methylmethacrylate cement in total shoulder replacement induce hemodynamic or pulmonary instability?

STUDY OBJECTIVE: To investigate whether the use of methylmethacrylate cement causes hemodynamic or pulmonary instability during total shoulder replacement surgery. DESIGN: Prospective, nonrandomized study. SETTING: Operating room. PATIENTS: 9 ASA physical status I and II patients. INTERVENTIONS: A 20-gauge radial artery catheter was placed in the wrist opposite the surgical site. Sedation with midazolam was provided, and a pulmonary artery catheter was placed through an 8.5-Fr introducer into the patient's right internal jugular vein. MEASUREMENTS AND MAIN RESULTS: Before induction of anesthesia, systolic, diastolic, and mean arterial blood pressures; heart rate; central venous pressure; systolic, diastolic, and mean pulmonary artery pressures; pulmonary capillary wedge pressure; and thermodilution cardiac output measurements were obtained. Arterial and mixed venous blood gas samples also were collected and analyzed for calculation of Qs/Qt. These hemodynamic and pulmonary parameters were measured again just before cementing of each prosthesis with methylmethacrylate cement and at 1, 5, 10, and 20 minutes after cementing. There were no statistically significant changes in any of the measured hemodynamic parameters at any time. There was no statistically significant difference in the calculated intrapulmonary shunt fraction. CONCLUSION: In this study population, the use of methylmethacrylate for total shoulder replacement was not associated with adverse hemodynamic events or increased intrapulmonary shunting.

Aged↗
PubMed1991

High-dose alfentanil for myocardial revascularization: a hemodynamic and pharmacokinetic study.

It has been suggested that high plasma levels of alfentanil are required in order to control hemodynamic responses to noxious stimuli in patients undergoing myocardial revascularization. The present study was designed to determine the hemodynamic profile in 10 patients and the time course of alfentanil plasma concentrations and pharmacokinetics (7 patients) during and following coronary artery surgery using alfentanil administration based on an overdosage principle. Premedication consisted of lorazepam, 0.07 mg/kg, given 2 hours before surgery. Ten milligrams of alfentanil was given over 5 minutes for anesthesia induction, followed by an infusion of 60 mg/h until sternotomy and 30 mg/h up to skin closure. Additional 5-mg boluses were given prior to noxious intraoperative events. Hemodynamic measurements were performed prior to cardiopulmonary bypass. Blood was sampled simultaneously prebypass and then during the postbypass period for determination of alfentanil plasma levels. The very high alfentanil plasma concentrations achieved provided satisfactory intraoperative conditions in most, but not all, patients. Recovery time was short, despite the large amounts of narcotic used. It is concluded that very high doses of alfentanil associated with lorazepam premedication resulted in hemodynamic stability and markedly elevated narcotic plasma concentrations in most patients. Such plasma levels seem to provide satisfactory anesthetic conditions.

Alfentanil↗
PubMed1991

Hemodynamic effects of muscle relaxant drugs during anesthetic induction in patients with mitral or aortic valvular heart disease.

The hemodynamic effects of three nondepolarizing skeletal muscle relaxant drug regimens were compared during the induction of general anesthesia in 64 patients with valvular heart disease using a double-blind protocol. Patients were first stratified according to primary valvular defect (aortic stenosis, aortic regurgitation, mitral stenosis, or mitral regurgitation). Next, patients were randomly allocated to a drug group, either group A (atracurium), group V (vecuronium), or group MP (metocurine plus pancuronium). Data were collected during three periods: awake, postanesthetic induction, and posttracheal intubation. Four cardiovascular variables were designated a priori as primary variables of interest. These were heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), and systemic vascular resistance index (SVRI). Patients with mitral stenosis showed two significant hemodynamic differences among muscle relaxant drug groups: (1) CI increased in group A but decreased in group MP between the awake and postinduction measurements (P = 0.032); and (2) SVRI decreased in group A but increased in group MP between the awake and postintubation periods (P = 0.034). In contrast, patients with aortic stenosis, aortic regurgitation, or mitral regurgitation demonstrated no statistically significant difference in cardiovascular responses among drug groups. Further analysis was performed using the following data: (1) other hemodynamic variables; (2) incidence of deviations from cardiovascular stability; and (3) the frequency of cardiovascular drug use. This examination showed no important differences among the muscle relaxant drug groups. The small but significant hemodynamic changes observed in mitral stenosis patients in drug groups A and MP were not noted with vecuronium.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Intravenous↗
PubMed1993

Isoflurane versus fentanyl: hemodynamic effects in cancer patients treated with anthracyclines.

Cancer patients treated with anthracycline derivatives are at risk for perioperative cardiovascular decompensation. The authors studied hemodynamic performance before, during, and after laparotomy in 14 anthracycline-treated patients with ovarian carcinoma. General anesthesia was maintained with 70% N2O in O2, and patients were randomized to receive supplementation with either isoflurane, 0.59% end-tidal +/- 0.04 (mean +/- SE), or fentanyl, 2.67 micrograms/kg +/- 0.49 as a loading dose, and a total dose of 7.16 micrograms/kg +/- 0.71. The degree of hemodynamic stability relative to the baseline was assessed. There was no obvious superiority of either technique prior to the skin incision. However, during and immediately after surgery, a clearer tendency for isoflurane-N2O to result in better hemodynamic stability was found. Isoflurane-N2O demonstrated significantly smaller change scores in systemic vascular resistance (SVR) and cardiac index (CI). At the start of surgery, the isoflurane-N2O change in SVR was 228.08 dyne.sec.cm-5 compared to 479.58 for the fentanyl patients, (P = 0.002); at the end of surgery the corresponding means were -12.09 and 703.14 dyne.sec.cm-5, respectively, (P = 0.002). Isoflurane-N2O was associated with significantly greater CI stability in the early postoperative period: the isoflurane-N2O mean change was -0.081 L/min/m2, versus -0.993 for the fentanyl-N2O patients, (P = 0.005). The authors conclude that anthracycline-treated patients who do not have overt evidence of cardiomyopathy can be safely anesthetized with either anesthetic technique. However, during surgery and in the early postoperative period, an isoflurane-N2O technique appears to offer better hemodynamic stability.

Acid-Base Imbalance↗
PubMed1994

Comparative hemodynamic effects of OPC-18790 and dobutamine in patients with advanced heart failure.

OPC-18790 (Otsuka America Pharmaceutical, Rockville, MD), a novel positive inotropic agent, produces titratable hemodynamic benefits in patients with advanced heart failure. In such patients, OPC-18790 has been shown to acutely increase the cardiac index, while reducing systemic vascular resistance and left ventricular filling pressure, without an associated increase in heart rate. This study was performed to compare the acute hemodynamic effects of OPC-18790 and the beta-adrenergic receptor agonist, dobutamine, in patients with advanced heart failure. OPC-18790 and dobutamine were compared on successive days in 13 patients with worsening New York Heart Association class III or IV heart failure. The mean (+/- SEM) left ventricular ejection fraction was 15 +/- 2% (range, 6-29%). Pretreatment hemodynamics were: heart rate, 96 +/- 2 beats/min; mean arterial pressure, 77 +/- 3 mmHg; cardiac index, 1.80 +/- 0.10 L/min/m2; pulmonary capillary wedge pressure, 27 +/- 1 mmHg; mean pulmonary arterial pressure, 41 +/- 2 mmHg; and systemic vascular resistance, 1,732 +/- 152 dynes.s/cm5. At infusion rates yielding comparable increases in the cardiac index (5 micrograms/kg/min for 2 hours for each drug), OPC-18790 produced significantly more favorable effects on heart rate (-2 +/- 3% vs 11 +/- 4%; P = .01), pulmonary capillary wedge pressure (-32 +/- 4% vs -17 +/- 8%; P = .04), mean pulmonary arterial pressure (-14 +/- 3% vs 6 +/- 11%; P = .06), stroke volume index (48 +/- 8% vs 29 +/- 7%; P = .02), stroke work index (70 +/- 11 vs 42% +/- 12%; P = .03), and rate pressure product (2 +/- 4% vs 14 +/- 4%; P = .05). The hemodynamic profile for OPC-18790 differs from dobutamine, with OPC-18790 exhibiting no increase in heart rate, greater preload reduction, and an increase in cardiac performance at a lower estimated metabolic cost.

Adrenergic beta-Antagonists↗
PubMed2005

B-type natriuretic peptide levels are not a surrogate marker for invasive hemodynamics during management of patients with severe heart failure.

BACKGROUND: We sought to assess the utility of serial BNP measurements in patients with severe heart failure and attempted to correlate values with invasively derived data. METHODS: In a retrospective study, we analyzed serial BNP levels in patients receiving hemodynamically guided therapy for severe heart failure and sought correlation with invasively derived data. RESULTS: Thirty-nine patients with New York Heart Association Class III-IV, with an ejection fraction of 35% or less, who had a pulmonary artery catheter inserted for hemodynamically tailored heart failure therapy, were identified and serial BNP measurements reviewed. BNP was estimated on admission, at 12 and 36 hours. Normally distributed variables are expressed as mean +/- SD and otherwise as median +/- interquartile range. Mean ejection fraction was 16% +/- 6%. Mean pulmonary artery occlusion pressures (PAOP) fell with therapy and were 25 +/- 7 mmHg, 18 +/- 7 mmHg and 19 +/- 7 mmHg at admission, 12 hours and 36 hours respectively ( P < 0.05). Median BNP levels fell from 1200 +/- 641 to 771 +/- 803 at 12 hours and to 805 +/- 771 at 36 hours (P < .001). There was no correlation between BNP and any hemodynamically derived variable. A change in BNP was not associated with a change in PAOP in any individual patient. Only 42% remained alive on medical therapy at 30 days. CONCLUSIONS: In patients with severe heart failure, BNP levels do not accurately predict serial hemodynamic changes and do not obviate the need for pulmonary artery catheterization.

Adult↗
PubMed2005

Levosimendan improves hemodynamics and coronary flow reserve after percutaneous coronary intervention in patients with acute myocardial infarction and left ventricular dysfunction.

BACKGROUND: Positive inotropic agents may be associated with increasing myocardial ischemia or malignant arrhythmias. Levosimendan, a new calcium sensitizer, with its little effect on myocardial oxygen demand is better tolerated by patients with acute coronary syndromes. We evaluated the acute effects of levosimendan on hemodynamics and coronary flow velocities in patients with left ventricular (LV) dysfunction undergoing percutaneous coronary interventions (PCIs) for an acute myocardial infarction (AMI). METHODS: Patients with AMI and LV dysfunction undergoing primary PCI were randomized to intravenous infusion of levosimendan (10 minutes bolus with 12 microg/kg followed by 0.1 microg/kg per minute for 24 hours) or placebo, 10 minutes after a primary PCI. Evaluation of hemodynamics and of coronary flow reserve (CFR) were performed at baseline and after bolus. RESULTS: Twenty-six consecutive patients (mean age 57 +/- 5.4 years, 18 males) were included into the study. At baseline, mean values of hemodynamics and coronary flow velocities were comparable between groups. After bolus, patients with levosimendan (n = 12) showed a significant decrease of pulmonary capillary wedge pressure (from 24 to 19 mm Hg) and a significant increase of cardiac index (from 1.8 to 2.4 L/m2 per minute) resulting in a significant decrease of systemic vascular resistance (from 1366 to 1075 [dyne . s]/cm2). Moreover, CFR on infarct-related artery and on reference vessel significantly improved in patients treated with levosimendan (from 1.6 to 2.0 and from 2.1 to 2.4, respectively). On the other hand, no statistically significant changes have been observed in the placebo group (n = 14). CONCLUSIONS: Levosimendan, given intravenously after a PCI procedure in patients with AMI and LV dysfunction, significantly improves hemodynamics and CFR, compared with placebo.

Angioplasty, Balloon, Coronary↗
PubMed2003

Hemodynamic response to intensive unloading therapy (furosemide and nitroprusside) in patients >70 years of age with left ventricular systolic dysfunction and decompensated chronic heart failure.

In patients with decompensated chronic congestive heart failure (CHF), intensive unloading therapy allows an acute decrease in ventricular filling pressures and improves long-term prognosis. Because elderly patients do not routinely undergo invasive hemodynamic evaluation, they are generally denied such a pharmacologic approach. We prospectively characterized the acute hemodynamic response to intensive unloading and its prognostic significance in a elderly population with CHF who were hospitalized for cardiac decompensation. Fifty-nine patients aged >70 years with left ventricular systolic dysfunction underwent intensive unloading therapy (furosemide and nitroprusside) tailored to reduce ventricular filling pressures to near-normal levels. The hemodynamic parameters were monitored by Doppler echocardiography. At baseline, left and right ventricular filling pressures were 21 +/- 3 and 10 +/- 3 mm Hg, respectively. Although all patients experienced a relevant improvement in clinical status during hospital stay, a significant reduction of ventricular filling pressures was detected at discharge in only 40 of them (68%) (responders), whereas 19 patients (32%) had a deficient response to therapy (nonresponders). This unfavorable behavior was predicted by the presence of renal dysfunction at admission. During 19-month follow-up, death due to cardiovascular causes occurred in 8 of 40 responders (20%) and in 9 of 19 nonresponders (47%) (p <0.005). Hospitalizations for cardiovascular causes were more frequent in the nonresponders (58% vs 8%, p <0.0001). Thus, a deficient hemodynamic response to intensive unloading treatment is not infrequent in elderly patients with decompensated CHF. This behavior is predicted by renal dysfunction at admission and is associated with poorer outcome.

Age Factors↗
PubMed2005

Hypertension as a hemodynamic disease: the role of impedance cardiography in diagnostic, prognostic, and therapeutic decision making.

Hypertension is the most common cardiovascular disease, affecting approximately 60 million Americans. Despite the importance of this condition, only the minority of patients are appropriately identified and treated to reach recommended blood pressure (BP) goals. Although historically defined as an elevation of BP alone, hypertension is characterized by abnormalities of cardiac output, systemic vascular resistance, and arterial compliance. These hemodynamic aspects of hypertension have implications for diagnosis, risk stratification, and treatment. Impedance cardiography (ICG) has emerged as a unique and highly accurate noninvasive tool that is used to assess hemodynamic parameters. Measurement of the various hemodynamic components using ICG in those with hypertension allows more complete characterization of the condition, a greater ability to identify those at highest risk, and allows more effectively targeted drug management. This article reviews the importance of hemodynamic factors in hypertension and the evolving role of ICG technology in the assessment and management of this important cardiovascular condition.

Cardiography, Impedance↗
PubMed2005

Use of noninvasive hemodynamics in hypertension management.

Hypertension is a chronic disease that is controlled in the United States in only 34% of those taking antihypertensive medications. Because hypertension is a hemodynamic disorder, the patient's hemodynamic profile before and after medical intervention may assist in the decision and evaluation of ongoing antihypertensive therapy. There are several medication classes used in the management of hypertension and it is challenging at best for the clinician to determine the optimal therapeutic combination of medications for each patient. Physician perceptions and patient symptoms are examples of barriers affecting the management and control of hypertension. Impedance cardiography is a noninvasive monitoring technique that provides reliable and reproducible hemodynamic measurements. Three case studies are presented that illustrate how hemodynamic parameters were used to achieve hypertension control in the outpatient setting.

Aged↗
PubMed2005

Hemodynamics in off-pump surgery: normal versus compromised preoperative left ventricular function.

OBJECTIVE: Off-pump coronary surgery (OPCABG), avoiding cardiopulmonary bypass and cardioplegic arrest, seems to be a better choice in patients with poor baseline cardiac function. Since cardiocirculatory collapse could be induced by heart displacement in this group of patients at high risk, a greater pathophysiologic understanding of the hemodynamic derangements occurring in such patients is needed. METHODS: Twenty-eight elective OPCABG patients were evaluated for hemodynamic changes induced by heart displacement, using arterial thermodilution to measure cardiac output and global end-diastolic volume. Hemodynamic parameters were recorded: at baseline; during proper exposure and stabilization of each vessel; and at the end of surgery. Patients were divided into two groups, according to baseline ejection fraction (EF): group A (EF>30%; N=16), group B (EF< or =30%; N=12). RESULTS: Heart displacement induced a significant drop in the cardiac and stroke index, with a lesser decrease of mean arterial pressure because of raised systemic vascular resistance. Preload, measured as global end diastolic volume, significantly decreased in group A, while it remained unchanged or increased in group B. Linear regression between the preload index and left ventricular stroke work was significant only in group A. CONCLUSIONS: Patients with poor baseline cardiac function can well tolerate OPCABG. However, the pathophysiologic modifications underlying the hemodynamic changes are different compared to those in patients with good preoperative cardiac performance.

Aged↗
PubMed2004

The hemodynamic and neurohormonal effects of low doses of tezosentan (an endothelin A/B receptor antagonist) in patients with acute heart failure.

BACKGROUND: In previous studies (the RITZ project), tezosentan, an intravenous (i.v.)-balanced dual endothelin (ET-A/B) antagonist, in doses of 50 and 100 mg/h, improved the hemodynamics but not the clinical outcome of patients with acute heart failure (AHF). OBJECTIVE: To evaluate the effect of lower doses of tezosentan in patients with AHF. SUBJECTS AND METHODS: Included were 130 patients hospitalized due to AHF with dyspnea at rest, despite initial treatment, and were in need of hemodynamic monitoring with cardiac index (CI)<2.5 l/min/m(2) and wedge pressure > or = 20 mm Hg. Patients were randomized in a double-blind fashion to receive placebo or tezosentan: 0.2, 1, 5, or 25 mg/h for 24 h. RESULTS: The primary endpoint of the study, CI increase at 6 h of treatment, was significant in the 5 and 25 mg/h groups. Tezosentan induced a dose-dependent increase in CI and a decrease in wedge pressure, peaking after 3 h in the 5 and 25 mg/h groups. In the 1 mg/h group, this effect was smaller during the first 6 h and increased gradually, becoming significant at 24 h and beyond treatment discontinuation. There was no hemodynamic effect in the 0.2 mg/h arm. Type-B natriuretic peptide (BNP) decreased in the 1, 5, and 25 mg/h groups but not on placebo. Endothelin levels were significantly increased by the 5 and 25 mg/h groups but not in the lower (< or = 1 mg/h) tezosentan doses. Urine output decreased on the 25 mg/h dose. There was a trend towards improvement in patients' subjective dyspnea score and worsening heart failure events, mainly in the 1 mg/h group. CONCLUSIONS: In patients admitted with AHF, tezosentan doses of 1-25 mg/h are efficacious in improving the hemodynamics and reducing BNP. Tezosentan doses beyond 1 mg/h increased plasma endothelin levels and reduced urine output, probably limiting their clinical efficacy, as compared to tezosentan 1 mg/h.

Aged↗
PubMed2005

Echocardiographic ejection fraction in patients with acute heart failure: correlations with hemodynamic, clinical, and neurohormonal measures and short-term outcome.

BACKGROUND: Although echocardiographic ejection fraction (EF) is frequently used for the estimation of left ventricular contractility in patients with acute heart failure, its exact role and correlations with clinical, hemodynamic, and neurohormonal variables of cardiac contractility is not known. METHODS: Patients (343) with acute heart failure, enrolled into two prospective placebo-controlled hemodynamic studies of tezosentan, and in whom EF was available at baseline, were included. Outcome was evaluated in a subset of 94 patients who were enrolled in the placebo arms of the studies. RESULTS: Higher echocardiographic EF was correlated with older age, increased incidence of hypertension and atrial fibrillation, and female gender. We observed weak correlation between EF and cardiac output or cardiac power and no correlation with wedge pressure, and the change in hemodynamic variables over time. Higher EF was correlated with more baseline leukocytosis and higher plasma levels of endothelin-1 and blood urea nitrogen, while lower EF was related to higher baseline B-type natriuretic peptide (BNP). We observed no overall correlations between EF and outcome. CONCLUSIONS: In patients with acute heart failure, echocardiographic EF is weakly correlated with hemodynamic measures of left ventricular contractility and outcome; hence, it should be interpreted cautiously when evaluating patients admitted due to acute heart failure.

Aged↗
PubMed2004

Predicting pregnancy-induced hypertension with dynamic hemodynamics.

AIM: To study dynamic changes in the hemodynamic parameters in pregnant women during different weeks of gestation and to comprehend changes to the cardiovascular system in normal pregnant women and in patients with pregnancy-induced hypertension (PIH), with the object of finding predictors of pregnancy-induced hypertension. METHODS: Radialis artery pulse waves of 132 pregnant women were examined from 10 weeks of gestation onward, and the subjects' hemodynamics were examined every 4 weeks. RESULTS: In the women with PIH hemodynamic changes occurred earlier than the onset of disease and even presented in early pregnancy; there might be another mode, and there were factors disturbing the blood pressure modulating mechanism. CONCLUSION: The prediction of PIH from the dynamic changes in hemodynamic parameters has significant implications for clinical practice.

Adult↗
PubMed2005

Calpain inhibition reduces infarct size and improves global hemodynamics and left ventricular contractility in a porcine myocardial ischemia/reperfusion model.

Calpains, a family of Ca2+-dependent cysteine proteases, are activated during myocardial ischemia and reperfusion. This study investigates the cardioprotective effects of calpain inhibition on infarct size and global hemodynamics in an ischemia/reperfusion model in pigs, using the calpain inhibitor A-705253. The left anterior descending coronary artery was occluded for 45 min and reperfused for 6 h. A bolus of 1.0 mg/kg A-705253 or distilled water was given intravenously 15 min prior to induction of ischemia and a constant plasma level of A-705253 was maintained by continuous infusion of 1.0 mg/kg A-705253 during reperfusion. Infarct size was assessed histochemically using triphenyltetrazolium chloride staining. Macromorphometric findings were verified by light microscopy on hematoxylin-eosin- and Tunel-stained serial sections. Global hemodynamics, including the first derivate of the left ventricular pressure (dP / dtmax), were measured continuously throughout the experiment. A-705253 reduced the infarct size by 35% compared to controls (P < 0.05). Hemodynamic alterations, including heart rate, aortic blood pressure, central venous pressure and left atrial pressure, were attenuated mainly during ischemia and the first 2 h during reperfusion by A-705253. Cardiac function improved, as determined by dP / dtmax, after 6 h of reperfusion (P < 0.003). Our results demonstrate that myocardial protection can be achieved by calpain inhibition, which decreases infarct size and improves left ventricular contractility and global hemodynamic function. Hence, the calpain-calpastatin system might play an important pathophysiological role in porcine myocardial ischemia and reperfusion damage and A-705253 could be a promising cardioprotective agent.

Animals↗
PubMed2004

Hemodynamic variations during thoracic and abdominal stop-flow regional chemotherapy.

AIMS: The aim of this study was to study hemodynamic modifications during thoracic and abdominal stop-flow regional chemotherapy and to evaluate the need for routine hemodynamic monitoring during such kind of procedures. METHODS: Thirty patients, aged 17-67 years, ASA physical status II-III, scheduled for thoracic (group A, n = 15), and abdominal (group B, n = 15) stop-flow regional chemotherapy were enrolled. Heart rate (HR), electrocardiogram lead I and V(5), end tidal carbon dioxide (ETCO(2)), arterial oxygen saturation (SaO(2)), systolic, diastolic and mean arterial pressure (SBP, DBP, MAP), mean pulmonary arterial pressure (MPAP), pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), cardiac output (CO), stroke volume (SV), stroke index (SI), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), left cardiac work (LCW), right cardiac work (RCW), left cardiac work index (LCWI), right cardiac work index (RCWI), cardiac index (CI), and body O(2) consumption (VO(2)) were recorded. RESULTS: After aortic and inferior vena cava endovascular occlusion (T(1)), a significant reduction of CO and SV, associated with an increase of CVP, MAP, PAPM and PCWP were observed. A concomitant reduction of CI and increase of SVR and PVR were registered. The VO(2) was significantly reduced compared to basal values in both groups. After deflating aortic and vena cava balloons (T(2)), CO, SV and CI increased with respect to basal value p < 0.05) whereas MAP, CVP, PAPM, PCWP and calculated parameters (SVR, PVR) showed a significant reduction compared to T(1). The oxygen consumption was significantly higher than that of basal values p < 0.05. After hemofiltration (T(3)), all hemodynamic variables were comparable with the basal values. Modifications of direct and calculated parameters, during the stop-flow period, showed a similar trend in both study groups, without any statistically significant difference. No ST modifications at ECG were noted during all perioperative period. CONCLUSIONS: The results of this study have confirmed in both groups, the safety of stop-flow regional chemotherapy procedure, despite endovascular occlusion of the aorta and inferior cava vein. The hemodynamic and oxygenation changes are reversible and did not produce any ST modifications at ECG during all perioperative period. Routine pulmonary artery catheterization is thus unnecessary, except in high cardiac risk patients.

Adolescent↗
PubMed2005

Comparison of stimulation sites within left ventricular veins on the acute hemodynamic effects of cardiac resynchronization therapy.

OBJECTIVES: The purpose of this study was to study the acute hemodynamic effect of left ventricular (LV) stimulation sites within a coronary vein. BACKGROUND: Access to LV stimulation sites for resynchronization therapy is achieved using specialized lead systems navigated through a coronary vein. The effects of stimulation in different coronary veins have been evaluated previously, but less is known about stimulation sites within a coronary vein. METHODS: Twenty-four patients (New York Heart Association functional class II-IV, age 59 +/- 10 years, ejection fraction 21 +/- 7%, QRS 166 +/- 30 ms) were enrolled in the study. A novel over-the-wire lead system was used to access an anterior or lateral coronary vein. At each lead location, a randomized stimulation protocol was executed. Hemodynamic responses were evaluated using LV dP/dtmax. RESULTS: The mean time to cannulate the coronary sinus and position the LV lead was 19 +/- 30 minutes and 17 +/- 18 minutes, respectively. Data from stimulation at two sites within a coronary vein were obtained in 19 patients (anterior vein 11; lateral vein 8). Of these patients, 14 (anterior vein 9; lateral vein 5) showed large improvement in dP/dtmax (22%-25% in anterior vein, 37%-40% in lateral vein). Overall, there were no group differences in hemodynamic effects among different stimulation sites within a coronary vein, although significant variability among sites was observed in individuals. CONCLUSIONS: Resynchronization therapy through a coronary vein improves acute hemodynamic function of heart failure patients with LV conduction disorder. There were no significant differences between basal and apical pacing sites for this group.

Aged↗
PubMed2004

Effects of cocaine and caffeine alone and in combination on cardiovascular performance: an experimental hemodynamic and coronary flow reserve study in a canine model.

BACKGROUND: With the proliferation of cocaine abuse, increased incidence of catastrophic cardiovascular events like angina pectoris, myocardial infarction, ventricular arrhythmias or sudden death are reported. Cocaine-dependent subjects commonly abuse multiple substances. Many of them drink coffee before and after cocaine use. The high frequency of simultaneous exposure to both the drugs may influence outcome of the cocaine's treatment. Cocaine and caffeine's independent effects on cardiodynamics are documented but to our knowledge combined effects of both on complete cardiovascular hemodynamics remains to be examined. METHODS: Eighteen dogs were instrumented to pass cardiac catheters into right and left heart. The experiments were performed after they recovered from the effects of anesthesia. In phase I (30 experiments on 8 dogs), the doses were established by dose-response curve. In phases II and III, another 10 dogs were subjected to 28 experiments. They were given i.v. cocaine followed by caffeine and vice versa to study their effects on hemodynamics and coronary flow reserve. RESULTS: Phase 1: The doses of cocaine (2 mg/kg) and caffeine (5 mg/kg) were established. Phase II: Cocaine increased heart rate, blood pressure and dP/dt but CFR decreased significantly. Caffeine administered after cocaine attenuated these effects (dP/dt decreased to 4910+/-104 from 5066+/-110 mm Hg s; p<NS). Phase III: Caffeine mildly increased hemodynamic parameters but reduced dP/dt. Cocaine's administration as the second drug had synergistic excitatory effects (dP/dt increased to 6166+/-160 from 5055+/-142 mm Hg/s; p<0.04). CFR decreased significantly. CONCLUSION: Cocaine increased heart rate, blood pressure and dP/dt but reduced CFR. Caffeine mildly increased the hemodynamic variables but decreased CFR. Combined cocaine+caffeine attenuated the excitatory effects of cocaine significantly. A reversed drug combination i.e., caffeine+cocaine generated synergistic excitatory effects on the cardiovascular system of the dogs. CFR showed significant decrease.

Animals↗