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PubMed1996

Negative inotropic actions of nitric oxide require high doses in rat cardiac muscle.

Initial experiments were designed to determine if vasoactive concentrations of nitric oxide (NO) alter contractility in rat heart. Contractile function was monitored in left atrial and papillary muscles (30 degrees C; paced at 0.5 Hz) during cumulative addition of 3-morpholino-sydnonimine-HCl(SIN-1), an agent that releases NO. At concentrations between 10(-7) and 10(-4) M (NO concentrations of approximately 10(-8)- 3 x 10(-7) M), SIN-1 did not affect contractility in either tissue. Similarly, 10(-4) M SIN-1 did not alter the positive inotropic responses to isoproterenol or increasing extracellular [Ca+2] ([Ca+2]o). To obtain higher concentrations of NO, additional studies were conducted using authentic NO. NO-saturated stock solutions and a corresponding control solvent were adjusted to pH 1.6 with HCl. Dose-dependent effects of NO were examined by adding aliquots of the stock solutions (or control solvent) to the bathing solution. At final concentrations of 1 x 10(-5)- 5 x 10(-4) M, NO produced transient, concentration-dependent decreases in contractility that were paralleled by reductions in buffer pH. Control solvent elicited similar reductions in pHo and transient decreases in contractility; however, the negative inotropic action elicited by the NO-containing solution was approximately 20% greater than that observed in control conditions. These data demonstrate that only high concentrations of NO depress contractility in isolated rat cardiac muscle, and suggest that this effect is mediated by both acidosis and a pHo-independent mechanism.

Animals↗
PubMed1975

Hemodynamic changes after valve replacement with Starr-Edwards prostheses.

A brief review of the pathophysiology of aortic and mitral valve disease and the hemodynamic results of valve replacement with caged ball prostheses are described. In most patients intracardiac pressures and restored to normal at rest, although there are small pressure gradients across mechanical valves. Severe pulmonary hypertension, if present, usually will regress. With exercise, abnormalities of left atrial pressure or left ventricular function may be found after valve replacement. The causes of failure to achieve hemodynamic improvement with surgery and the late return of congestive failure are discussed.

Aortic Valve Insufficiency↗
PubMed1998

Optimal Frequency of Patient Monitoring and Intensity of Oral Anticoagulation Therapy in Valvular Heart Disease.

The antithrombotic effect of oral anticoagulation therapy and the incidence of anticoagulant-related bleeding complications are both closely correlated with the intensity of treatment. The optimal intensity of oral anticoagulation for an individual patient is the target INR that results in the lowest incidence of thromboembolic plus bleeding complications. For patients with native valve lesions, one must consider the cardiac morphology and pathophysiology, for example, the etiology of the disease, left atrial diameters, loss of active atrial contraction (atrial fibrillation), left ventricular pump function, and left ventricular diameters, to determine an optimal INR target. In patients with prosthetic devices, the "thrombogenicity" of the heart valve prosthesis is an additional risk factor for intracardiac thrombus formation and thromboembolic episodes. This "thrombogenicity" may vary significantly from device to device. INR self-testing improves the overall prognosis of patients on lifelong oral anticoagulation therapy because patients remain more precisely within that target therapeutic INR range. For most patients under phenprocoumon, one to two INR measurements per week are a sufficient frequency to provide a stable intensity of anticoagulation.

Journal Article↗
PubMed2000

Management of postoperative arrhythmias.

Arrhythmias occur commonly in patients after cardiac surgery. Atrial fibrillation is the most common arrhythmia in the postoperative period; it accounts for significant morbidity to the patient and prolonged hospital stays, and it contributes significantly to the cost of hospitalization. It occurs more commonly in elderly men and in patients undergoing valvular procedures. Beta blockers are effective agents that keep patients from developing postoperative atrial fibrillation and help maintain ventricular rate control. Prophylaxis with antiarrhythmic agents such as amiodarone and sotalol and recently with atrial pacing have shown promise in recent randomized trials. Patients with atrial fibrillation that persists for longer than 48 hours appear to be at a greater risk for cerebroembolic events and should receive anticoagulation unless a contraindication exists. Although frequent premature ventricular contractions and nonsustained ventricular tachycardia (NSVT) occur frequently in patients after cardiac surgery, sustained ventricular tachycardia and ventricular fibrillation are rare and are associated with a poor prognosis. Polymorphic ventricular tachycardia may occur in the setting of myocardial ischemia, metabolic disturbances, and drug toxicities (including antiarrhythmic agents used to treat atrial fibrillation). Poor left ventricular function is a potent risk factor for sudden death in patients with NSVT. Patients with persistent NSVT and ischemic cardiomyopathy with left ventricular ejection fractions of less than 40% should undergo electrophysiologic testing. Conduction abnormalities that may be encountered in patients after cardiac surgery are rarely life threatening. Patients who have undergone valve replacement or repair are at higher risk of developing significant bradyarrhythmias that may require temporary pacing.

Arrhythmias, Cardiac↗
PubMed1988

Demonstration of a widely distributed atrial pacemaker complex in the human heart.

Atrial depolarization was analyzed in 14 patients with the Wolff-Parkinson-White syndrome undergoing surgery to ablate accessory atrioventricular pathways associated with tachyarrhythmias. Bipolar potentials were recorded simultaneously from 156 atrial epicardial electrodes arranged in three templates to fit the anterior and posterior aspects of both atria. Spontaneous or sinus rhythms were recorded, as were atrial escape rhythms after overdrive pacing at rates of 150 and 200 beats/min. Atrial activation maps revealed different patterns of impulse initiation varying from typical unifocal sinus node impulse origin, unifocal extranodal impulse origin, and multicentric impulse origin from two to four widely distributed atrial pacemaker sites. In subjects demonstrating only unifocal impulse origin during control or sinus rhythm, other widely divergent pacemaker sites were recorded in other maps during subsequent rhythms. In addition to sites located at the upper superior vena cava-right atrium junction, pacemakers also dominated at sites anterior and inferior to the sinus node region during both control and escape depolarizations. Most of the subjects were found to have two or more pacemaker sites when maps of all control and postpacing conditions were analyzed. The right atrial pacemaker region encompassed a zone of 7.5 X 1.5 cm centered about the long axis of the sulcus terminalis posteriorly and the precaval band anteriorly. An unexpected finding was the participation of left atrial escape pacemakers. The functional behavior of both the control and escape pacemakers, as assessed by sinus node recovery time, was normal, indicating physiologic operation of the extranodal sites as part of an overall system of distributed pacemakers involved in the control of rate. Although functional assessment was limited in these initial patient studies, correspondence with similar observations in extensive previous canine studies supports the concept of a widely distributed atrial pacemaker complex in man.

Adolescent↗
PubMed1987

Echocardiographic assessment of left ventricular diastolic performance in hypertensive subjects. Correlation with changes in left ventricular mass.

Left ventricular hypertrophy resulting from hypertension is accompanied by significant morbidity and mortality and in advanced stages may be irreversible. Hence, early detection of cardiac changes in hypertensive patients remains an important diagnostic goal. When the hypertrophy is mild or moderate, parameters of left ventricular diastolic function and measurements of left atrial size may facilitate the distinction between normal variation and pathologic increases in left ventricular mass. We measured left ventricular isovolumic relaxation time (IVRT, the time from aortic valve closure to mitral valve opening) and left atrial dimensions and correlated them to left ventricular mass index measured by M-mode echocardiography and rapid left ventricular filling by radionuclide ventriculography. In 20 subjects with untreated mild essential hypertension, IVRT was prolonged compared to a normotensive age-matched control group (91 +/- 23 vs 65 +/- 13 msec, p less than 0.0001). Left atrial dimension index was increased in patients compared to controls (1.9 +/- 0.4 vs 1.4 +/- 0.5 cm/m2, p less than 0.001), and this increase was related to prolonged IVRT (r = 0.46, p less than 0.001). Abnormal IVRT correlated with both increased left ventricular mass and decreased rapid ventricular filling in the hypertensive subjects. Thus, prolonged IVRT and borderline left atrial dimension may help identify subtle pathologic left ventricular mass increases in hypertensive subjects.

Aging↗
PubMed1999

[A case of arteriovenous fistula of the lung].

A 29-year-old male was admitted to our hospital for further evaluation of left sided paresis, cyanosis, clubbing finger. The laboratory data revealed polycythemia and hypoxemia. Cerebralarteriogram showed right middle cerebral artery occulusion. Cardiofunctional test showed atrial fibrillation, lower left ventricular function. Cardiac catheterization, pulmonary arteriography and three dimensions CT were performed. Right to left shunt rate was 20.4%. A single large pulmonary arteriovenous fistura with a feeding artery (A10) and a draining vein (V10) was found clearly. In this cases, arteriovenous fistula was large, blood flow was thought to be rapid. We thought transcatheter embolization was not useful. And we performed right lower lobectomy. Postoperative course was not eventful. Cyanosis disappeared, clubbing finger was cured.

Adult↗
PubMed2004

[Successful management of a patient for cardiac surgery with difficulty in weaning from cardiopulmonary bypass by using both isosorbide dinitrate and olprinone hydrochloride].

A 57-year-old man with mitral stenosis underwent mitral valve plasty under general anesthesia. He had a history of cerebral infarction. Although he was with atrial fibrillation, his left ventricular function was good. Preoperative coronary angiography revealed no significant coronary stenosis. Induction of anesthesia and the surgical procedure had been uneventful, but the patient had difficulty to wean the patient from cardiopulmonary bypass because of unexpected low cardiac output syndrome. O1-prinone hydrochloride, a newly developed phosphodiesterase III inhibitor, was initiated in addition to high doses of dopamine and dobutamine. This increased the amplitude of the electrocardiogram and caused ST elevation of the lead II. A full dose of isosorbide dinitrate was administered intravenously to differentiate coronary artery spasm from coronary air embolism. This drastically improved the ventricular function and mixed venous oxygen saturation, and weaning from CPB was finally accomplished. The heart showed hypercontraction and inotropes were tapered gradually without further cardiac events. Although there are various etiologies for low cardiac output syndrome after CPB, the possibility of myocardial ischemia must be the first consideration. Full pharmacological support must be tried before initiating a mechanical assist modality. Coronary dilators, nitrates in particular, and phosphodiesterase III inhibitors are promising agents in such cases.

Anesthesia, General↗
PubMed1991

[Induction of arrhythmia by licorice abuse].

We report two cases of licorice-induced arrhythmias. In both cases the ingestion of large amounts of licorice caused a marked hypokalemia. The importance of licorice-induced hypokalemia for the development of arrhythmias is underestimated from the small number of published cases. We conclude that patients with a predisposition for arrhythmias should avoid licorice candies.

Adult↗
PubMed1996

Plasma brain natriuretic peptide as an indicator of left ventricular systolic function and long-term survival after acute myocardial infarction. Comparison with plasma atrial natriuretic peptide and N-terminal proatrial natriuretic peptide.

BACKGROUND: Elevated plasma levels of atrial natriuretic peptide (ANP) and the N-terminal fragment of the ANP prohormone (N-ANP) are associated with decreased left ventricular function and decreased long-term survival after acute myocardial infarction (AMI). Previous data suggest that plasma brain natriuretic peptide (BNP) may increase proportionally more than plasma ANP after AMI and in chronic heart failure. The diagnostic and prognostic value of plasma BNP as an indicator of left ventricular dysfunction and long-term survival after AMI, relative to that of ANP and N-ANP, remain to be established. METHODS AND RESULTS: Venous blood samples for analysis of ANP, N-ANP, and BNP were obtained on day 3 after symptom onset from 131 patients with documented AMI. Left ventricular ejection fraction was determined by echocardiography in a subsample of 79 patients. Twenty-eight cardiovascular and 3 noncardiovascular deaths occurred during the follow-up period (median, 1293 days). All three peptides proved to be powerful predictors of cardiovascular mortality by univariate Cox proportional hazards regression analyses (ANP: P < .0001; N-ANP: P = .0002; BNP: P < .0001). In a multivariate model, plasma BNP (P = .021) but not ANP (P = .638) or N-ANP (P = .782) provided additional prognostic information beyond left ventricular ejection fraction. Logistic regression analysis showed that ANP (P = .003) and N-ANP (P = .027) but not BNP (P = .14) were significantly associated with a left ventricular ejection fraction < or = 45%. CONCLUSIONS: These results suggest that plasma BNP determination provides important, independent prognostic information after AMI. Although plasma ANP appears to be a better predictor of left ventricular dysfunction, plasma BNP may have greater potential to complement standard prognostic indicators used in risk stratification after AMI because of its strong, independent association with long-term survival, enhanced in vitro stability, and simplicity of analysis.

Aged↗
PubMed2004

Sympathetic overactivity in patients with rheumatic mitral stenosis.

BACKGROUND: Mitral stenosis may increase sympathetic nervous activity by increasing left atrial pressure and reducing cardiac output. And elevated sympathetic nerve activity may be a risk factor for the development of clinical manifestations of mitral stenosis. In this study, we assessed the autonomic nervous system activity in patients with mitral stenosis by heart rate variability analysis and defined factors affecting autonomic functions. METHODS AND RESULTS: Fifty-four patients with rheumatic mitral stenosis were compared with an age- and gender-matched control group composed of 42 healthy individuals. SDNN, RMSSD, PNN50, and HF were lower; mean heart rate (HR), LF and LF/HF ratio were higher in the patients with mitral stenosis compared to the control group. SDNN was correlated positively with left ventricle ejection fraction (LVEF), negatively with mitral valve area, left atrial (LA) diameter, and duration of symptoms. RMSSD was correlated positively with mean transmitral gradient, negatively correlated with age; PNN50 was correlated negatively with mitral valve area and positively correlated with transmitral gradient. LF was positively and HF was negatively correlated with LA diameter; LF was correlated positively, and HF was negatively correlated with duration of symptoms. LF/HF ratio was positively correlated with LA diameter and duration of symptoms, negatively with LVEF and mean valve area. CONCLUSION: As a result, sympathetic nervous system activity is increased in patients with mitral stenosis and sympathetic overactivity worsens their symptoms. Most significant factors that affect autonomic functions in these patients are left atrial dilatation and mitral valve area.

Adult↗
PubMed2003

Atrial pacing lead location alters the hemodynamic effects of atrial-ventricular delay in dogs with pacing induced cardiomyopathy.

The role of atrial lead location in cardiovascular function in the presence of impaired ventricular dysfunction is unknown. We tested the hypothesis that left atrial (LA) and left ventricular (LV) hemodynamics are affected by alterations in AV delay and are influenced by atrial pacing site in dogs with dilated cardiomyopathy. Dogs (n = 7) were chronically paced at 220 beats/min for 3 weeks to produce cardiomyopathy and then instrumented for measurement of LA, LV end diastolic pressure (LVEDP) and mean arterial pressure (MAP), LA volume, LV short-axis diameter, and aortic and pulmonary venous blood flow. Hemodynamics were measured after instrumentation and during atrial overdrive pacing from the right atrial appendage (RAA), coronary sinus ostium (CSO) and lower LA lateral wall (LAW). The AV node was then ablated, and hemodynamics were compared during dual chamber AV pacing (right ventricular apex) from each atrial lead location at several AV delays between 20 and 350 ms. Atrial overdrive pacing from different sites did not alter hemodynamics. Cardiac output (CO), stroke volume, LVEDP, MAP and +dLVP/dt demonstrated significant (P < 0.05) variation with AV delay during dual chamber pacing. CO was higher during LAW pacing than RAA and CSO pacing (2.3 +/- 0.4 vs 2.1 +/- 0.3 vs 2.0 +/- 0.3 l/min, respectively) at an AV delay of 120 ms. Also, MAP was higher in the LAW than RAA and CSO (65 +/- 9 vs 59 +/- 9 vs 54 +/- 11 mmHg, respectively) at an AV delay of 350 ms. Atrial lead location affects indices of LV performance independent of AV delay during dual chamber pacing in dogs with cardiomyopathy.

Analysis of Variance↗
PubMed1985

Echocardiographic evaluation of left ventricular function, mass and wall stress in children with isolated ventricular septal defect.

M-Mode echocardiography was performed in 22 normal children and 22 children with ventricular septal defects. Left ventricular and left atrial chamber dimensions and wall thicknesses were measured in all patients. Utilizing these data, indices of left ventricular function were derived: shortening fraction, velocity of fiber shortening, peak diastolic fiber lengthening, end-systolic wall stress, radius thickness ratio, and ventricular mass. The results showed that ventricular septal defect was associated with enlarged left ventricular and atrial dimensions and increased shortening fraction, but that velocity of shortening and early diastolic lengthening remained normal. Left ventricular mass was increased, thus maintaining normal wall stress and radius/thickness ratio. Cardiac failure complicating ventricular septal defect was associated with enlarged left ventricular and atrial dimensions (indexed for weight). Ventricular mass, wall stress and function, however, were similar in subjects with ventricular septal defect, with or without cardiac failure. Since left ventricular mass was adequate to maintain wall stress and function in subjects with heart failure, other factors were presumably responsible for heart failure complicating ventricular septal defect.

Journal Article↗
PubMed2005

Atrial function after surgical and percutaneous closure of atrial septal defect: a strain rate imaging study.

The effect of operation and the effect of the imposition of an occluding device on atrial function for patients with an atrial septal defect (ASD) has never been studied. Thus, the aim of this study was to evaluate for the first time both left atrial (LA) and right atrial (RA) function of children after transcatheter ASD closure with that of sex- and age-matched patients with surgically treated ASD, and sex- and age-matched control subjects using strain (epsilon) and epsilon rate imaging (SR). In all, 45 participants formed our studied sample: 15 patients after successful ASD device closure (ASD-D [atrial septal defect device closure] group, mean age: 9 +/- 3 years) and 15 age- and sex-matched patients after successful ASD surgical closure (ASD-S [atrial septal defect surgical closure] group, mean age: 9 +/- 3 years). All patients underwent ASD correction at least 6 months before the study. As a control group we selected 15 age- and sex-matched control subjects. In the ASD-S group the peak systolic epsilon and SR values were significantly reduced in both RA and LA when compared with control and ASD-D groups (P < .01). In the ASD-D group there was no significant difference in both LA and RA deformation properties when compared with control subjects. SR imaging indexes could provide new, noninvasive, clinically relevant insight on regional changes in atrial function for patients with ASD. ASD percutaneous closure is useful not only because it is less expensive and invasive than open-heart operation but also for its conservation of both LA and RA regional myocardial properties.

Atrial Function↗
PubMed2005

Does atrial fibrillation in elderly patients with chronic heart failure limit the efficacy of carvedilol? Suggestions from an observational study.

BACKGROUND: No clinical investigation provided any information about a possible influence of atrial fibrillation on the response to beta-blocker therapy in elderly patients with chronic heart failure (CHF). The aim of this study was to observe carvedilol effects in a cohort of patients > 70 years of age with CHF due to left ventricular dysfunction and with chronic atrial fibrillation. METHODS: An observational, 12-month prospective clinical and echocardiographic study was carried out on 240 patients > 70 years of age with heart failure due to systolic dysfunction, 64 of whom with atrial fibrillation. RESULTS: After 1 year of beta-blocker treatment, patients with atrial fibrillation and those in sinus rhythm showed similar benefits, in terms of symptomatic improvement (deltaNYHA -0.44 if atrial fibrillation vs -0.57 if sinus rhythm, p = NS), reduction of events (death + hospitalizations -38 vs -15%), recovery of cardiac function (left ventricular ejection fraction delta +8.8 vs +9.4%, p = NS; left ventricular end-diastolic volume delta -17.2 vs -12.5 ml, p = NS), and reduction in mitral regurgitation (delta -042 vs -0.57, p = NS). No difference was found between the two study groups regarding left ventricular end-diastolic volume reduction (12% in atrial fibrillation patients and 18% in sinus rhythm patients, p = NS) and prevalence of the "reverse remodeling" phenomenon (22 and 21%, respectively, p = NS). CONCLUSIONS: In CHF patients > 70 years of age, beta-adrenergic blockade was shown to be equally effective in improving symptoms and left ventricular geometry and function in patients with atrial fibrillation or in sinus rhythm, without any adjunctive sign of long-term clinical deterioration.

Adrenergic beta-Antagonists↗