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Biomedical subjects

F Aina

Publications and source records attributed to F Aina.

18 recordsLinked to original sources
PubMed1997

Detection of moderate and severe coronary artery stenosis with technetium-99m tetrofosmin myocardial single-photon emission tomography.

The aim of this study was to determine the diagnostic accuracy of technetium-99m tetrofosmin myocardial imaging for the localization of coronary artery stenoses of different degrees of severity. Stress-rest single-photon emission tomography (SPET) was performed on separate days in 80 patients (64 males, 16 females; mean age 61 years; 43 patients with previous myocardial infarction; 18 patients with pharmacological stress), within 6 months of coronary angiography. Scintigraphic images were blindly and independently evaluated by three observers. Coronary stenosis was defined as a >50% narrowing in luminal diameter; severe stenosis was defined as a proximal stenosis of >75% or a peripheral stenosis of >90%. Coronary angiography revealed normal coronary arteries or insignificant coronary stenosis in 13 patients and significant coronary stenoses in 67 patients. The sensitivity and specificity of 99mTc-tetrofosmin SPET in respect of severely stenosed vessels were, respectively, 80% and 65% for the left anterior descending artery (LAD), 100% and 46% for the right coronary artery (RCA) and 58 and 78% for the left circumflex artery (LCx) territories. Considering all the significantly stenosed vessels, a significant decrease in sensitivity was observed for LAD territories (to 59%, P=0.05), and a nonsignificant decrease for RCA (88%) and LCx (47%) territories while specificity values remained essentially unchanged. No significant changes in sensitivity or specificity were observed when regions with previous myocardial infarction were excluded. In conclusion, the sensitivity of 99mTc-tetrofosmin SPET for the localization of individual stenosed vessels is only moderate when all significant stenoses are considered, but the ability of this technique to predict the location of severe coronary artery stenoses seems satisfactory, with the exception of the low specificity in respect of RCA territories.

Coronary Angiography↗
PubMed1996

[Short and intermediate term clinical outcome in patients with cardiogenic shock treated with aortic counterpulsation].

BACKGROUND: Despite improvements in coronary care, cardiogenic shock (CS) remains the leading cause of death in patients with dramatic cardiac diseases of which acute myocardial infarction (AMI) is the most frequent event. Conventional therapy for CS with coronary care unit (CCU) monitoring and vasopressor agents to support blood pressure has historically been associated with an 80% to 90% mortality rate in large series. Intra-aortic balloon pump (IABP) therapy for shock results in initial favourable clinical and haemodynamic responses, but ultimately, in most patients, death is merely delayed and hospital mortality still exceeds 80%. In several recent non-randomised series, coronary revascularisation performed early in the course of CS with the use of coronary artery by-pass grafting (CABG) or coronary angioplasty (PTCA) resulted in an apparent reduction in the hospital mortality rate to less than 50% in selected patients with shock. OBJECTIVES: This study reviews our experience of cardiogenic shock treatment at a time when standard care included aggressive use of the intra-aortic balloon pump counterpulsation, cardiac catheterisation, coronary angioplasty and/or coronary artery by-pass grafting, ventricular septal defect and mitral incompetence repair. METHODS: We retrospectively analysed 20 patients (13 M and 7 F, with an average age of 62 years and a half) affected by cardiogenic shock consecutively admitted to our CCU between October 1, 1992 and April 1, 1995. Fifteen patients (pts) were hospitalised for AMI, shock and pump failure (2 of them with pulmonary oedema), all with admittance delay less than 24 hours. Five patients were hospitalised for AMI with shock and mechanical defects, of which 3 pts with AMI and ventricular septal rupture and 2 pts with AMI and mitral regurgitation. All patients underwent IABP, coronary angiography (CA) and then were treated with PTCA, CABG and cardiac surgery or medical treatment. RESULTS: On the whole, 7 pts died (35%): 4 of shock, 1 of haemorrhagic complications, 1 of septic shock in the CCU, and 1 of heart failure after CABG in cardiosurgery. One more patient died of heart failure two months after discharge (late mortality 5%). Out of the 15 patients hospitalised with AMI, shock and pump failure, 13 patients with AMI and CS less than 24 hrs were treated as follows: 1 patient was successfully submitted to emergency CABG and 12 patients to PTCA of the infarct related artery (IRA). Eight patients enjoyed a good outcome, but 1 patient died of haemorrhagic complications and 4 with a persistently occluded IRA also died (3 in the CCU and 1 after CABG). Of the 2 remaining pts with AMI, shock and pulmonary oedema, 1 patient underwent CABG with success and 1 patient with the 3-vessel disease was submitted to PTCA with reperfusion of the IRA, but he died from reocclusion three days later. Out of the 5 patients with AMI, shock and mechanical defects, 3 patients with AMI and septal ventricular rupture underwent cardiac surgery and CABG with early and late success. One of the 2 patients with AMI, shock and mitral regurgitation underwent cardiac surgery with valve repair and CABG and had a good outcome, the other died from septic complications in the CCU. CONCLUSIONS: IABP is an useful device for stabilising patients in cardiogenic shock and safely performing angiography as well as PTCA, CABG or surgical correction of all mechanical complications with a more stable haemodynamic balance. Therefore, IABP is an useful tool to improve successful coronary revascularisation after direct PTCA or direct CABG. These data also suggest that the combination of successful coronary revascularisation and intra-aortic balloon pumping can improve survival in pts with cardiogenic shock complicating AMI with early pump failure.

Aged↗
PubMed1993

[The functional and hemodynamic benefits of automatic atrioventricular interval delay in permanent atrial synchronized pacing].

OBJECTIVES: In order to assess possible functional and hemodynamic benefits of different programming of atrioventricular (AV) delay--156 ms fixed vs 156 to 63 adaptive--two maximal exercise tests (cyclette) were performed in 8 patients (6 males, 2 females; 69 +/- 6 years) implanted with Chorus 6003 (Ela Medical, France) DDD pacemakers for complete AV block with normal sinus node function. METHODS: The measured parameters were: pacing rate, cardiac output (thermodilution method), oxygen consumption (2001 gas-exchange analyser), arterial-venous difference (derived from pulmonary oxygen saturation, through an optical-fibers Swan-Ganz catheter coupled to an Oximetric3-Abbott oximeter), human atrial natriuretic factor and lactate plasmatic levels, anaerobic threshold. RESULTS: A better cardiac output (11.4 +/- 1.7 vs 10.1 +/- 1.8 l/min) and oxygen consumption (1521 +/- 425 vs 1408 +/- 465 ml/min) were observed at maximal exercise with adaptive rather than with fixed AV delay programming (p < 0.05); moreover anaerobic threshold point was reached later during exercise test with adaptive AV delay (242 +/- 92 vs 216 +/- 109 sec, p = 0.05). On the contrary, with adaptive and fixed AV delay, there were not statistically different values of maximal heart rate (139 +/- 9 vs 139 +/- 9), levels at maximal exercise of arterial-venous difference (12.5 +/- 2 vs 12.8 +/- 1.4 Vol%O2), human atrial natriuretic factor (63 +/- 17 vs 78 +/- 48 pg/ml), lactate (29 +/- 15 vs 29 +/- 18 mg/dl), and oxygen consumption at anaerobic threshold point (772 +/- 164 vs 786 +/- 229 ml/min). CONCLUSIONS: In DDD pacing adaptive AV delay causes aerobic and hemodynamic benefits.

Aged↗
PubMed1990

Mechanisms accounting for lymphocytic alveolitis in hypersensitivity pneumonitis.

Hypersensitivity pneumonitis (HP) is a lung disorder characterized by an exaggerated accumulation of CD8+ T lymphocytes in the pulmonary parenchyma. To investigate the mechanisms accounting for the T cell alveolitis taking place in the lung of HP patients and their pattern of growth, cells recovered from the bronchoalveolar lavage (BAL) of seven patients were evaluated for: 1) the expression of activation markers, including IL-2R (p55 and p75 subunits), HLA-DR and VLA-1 Ag; 2) the ability of IL-2 and IL-4 to induce in vitro proliferation; 3) the capability to synthesize and release IL-2 by determining the levels of IL-2 in BAL cell-free supernatants and by evaluating the presence of mRNA transcripts for IL-2; and 4) the molecular configuration of the beta- and gamma-genes of the TCR. This study demonstrates that a high number of BAL lymphocytes recovered from the lungs of HP patients express activation markers including the p75 chain of IL-2R, VLA-1, and HLA-DR Ag. These cells express the CD3+,CD8+,CD16-,CD56+ phenotype and proliferate in vitro in the presence of IL-2 but do not release this cytokine. Furthermore, IL-2 transcripts could not be detected in BAL resting T lymphocytes. No proliferation was observed in the presence of IL-4. The analysis of the configuration of the TCR beta- and gamma-genes showed a polyclonal pattern, with the exception of one case in which extra bands were observed following digestion with BamHI and EcoRI restriction enzymes. Taken together, our data suggest that the IL-2 system may play a central role in the mechanisms accounting for lymphocytic alveolitis in HP patients. Although the pattern of growth is usually polyclonal, such polyclonal recruitment seems to be biased toward cells that have rearranged and possibly expressed particular V beta or V gamma genes, thus leading to the hypothesis that the events that take place in the lung of these patients may occasionally elicit an oligoclonal expansion of the cells proliferating in lung parenchyma.

Adult↗
PubMed1988

Physiological sensitivity of respiratory-dependent cardiac pacing: four-year follow-up.

Clinical and physiological data on long-term follow-up of 143 patients with respiratory-dependent pacemakers (RDP3) are reported; 121 patients received ventricular (VVI-RD) and 22 patients atrial (AAI-RD) respiratory-dependent stimulation. Functional evaluation was based on the exercise testing (130 pts) with oxygen uptake VO2, ventilation, ECG and arterial pressure monitoring and the dynamic Holter electrocardiogram (95 pts). In each patient, the stimulation rate curve selected was that which produced the best work tolerance and moved the anaerobic threshold to the right. Respiratory levels were assessed by telemetry verifying proper sensing of tidal volume variations and absence of interference and artefacts. In patients with VVIR or AAIR stimulation, exercise tolerance, oxygen uptake and anaerobic threshold increased significantly in comparison with VVI or AAI pacing respectively. The physiological sensitivity of the stimulation system (i.e., a linear relationship of the pacing rate with metabolic requirements) was excellent (up to exhaustion) in 70%, very good (up to anaerobic threshold) in 20% and erratic (no relationship between pacing rate and VE/VO2) in 10% of patients. In dynamic electrocardiographic monitoring, the automatic pacing rate was always predominant during the night and during rest periods; the pacing rate increased properly with daily activity; myopotential inhibition (none longer than 3,500 ms) was observed in 38 patients, but without subjective complaints. The incidence of the RDP3 malfunction was less than 8%; it may have stemmed from the pacing system itself, or from other clinical conditions. Oversensing of impedance system pulses has not been recorded in the last 3 years. Partial respiration undersensing results from incorrect accessory lead position, pulmonary emphysema, marked obesity or other causes. Respiratory sensing becomes erratic at the anaerobic threshold point in such patients, but functions well at submaximum exercise levels. In patients with left ventricular failure, exercise tolerance was improved by setting a lower ratio between the pacing rate and respiration, which prevented the occurrence of excessive pacing rates.

Aged↗
PubMed1988

Respiratory-dependent atrial pacing, management of sinus node disease.

The effectiveness of respiratory-dependent atrial pacing (AAI-RD) was assessed in 23 patients (11 male, 12 female; 68 +/- 10 years) with symptomatic isolated sinus node disease (SND). Follow-up was performed at 3 month intervals and included history taking, physical examination, ECG recording and 24-hour Holter monitoring. An incremental treadmill exercise test was performed in 21/23 patients before pacemaker implantation, in 23/23 patients after implantation (at least two tests with different programmed settings of respiratory rate/paced rate ratio); 21/23 patients underwent treadmill tests during both fixed rate 70 bpm and AAI-RD pacing. Physiological sensitivity of AAI-RD pacing was found excellent in 34 tests (85%) and fair in six (15%). Spontaneous heart rate was significantly higher after pacemaker implantation (bpm 115 +/- 20 vs 98 +/- 24, P less than 0.001). In 10/21 patients paced rate was significantly higher during AAI-RD vs AAI pacing (131 +/- 9 vs 106 +/- 16, P less than 0.001) with better total work time (min 9.9 +/- 4 AAI-RD vs 6.8 +/- 2.6 AAI, P less than or equal to 0.002), higher oxygen consumption at anaerobic threshold (ml/min 1137 +/- 406 AAI-RD vs 882 +/- 268 AAI-RD vs 5.5 +/- 2.6 AAI, P = 0.001). No significant difference was found in 7/21 patients (overlap between spontaneous and paced rate during both AAI-RD and AAI programming); 4/21 patients did not reach anaerobic threshold owing to osteomuscular limitations. AV block was detected in 1/23 patients, Biorate circuital failure in 1/23, sporadic undersensing in 5/23, short and symptom-free myopotential inhibitions in 10/23.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

[Physiologic limitations of dual chamber stimulators during physical activity].

Dual chamber DDD pacing is fully physiologic when chronotropic response of sinus node to exercise is normal and when retrograde ventriculo-atrial conduction is absent. Comparison of results from exercise test with increasing work load showed that atrial-triggered ventricular pacing provides a significant functional benefit (delta VO2 15%) P less than 0.01, if compared with fixed rate ventricular pacing. The benefit is closely related with the amount of sinus rate increase during exercise. In patients with sinus node syndrome the atrial triggered ventricular pacing rate did not show significant increase during exercise and exercise capability was similar to that observed with fixed ventricular pacing. Retrograde ventriculo-atrial conduction was observed in 56% of patients with sick sinus syndrome and 28% of patients with complete AV block and was the reason for endless loop tachycardias (ELTs). ELTs can be eliminated by lengthening atrial refractory period (ARP). In patients with ARP greater than or equal to 250 ms (47%), mild (8:7, 4:3) or important (2:1) AV block appeared during exercise test, with sudden drop of pacing rate and cardiac output at highest work load. Among other "physiologic" pacing modes, respiration traced ventricular stimulation showed high physiologic sensitivity (90%) and haemodynamic benefit comparable to that obtained during dual chamber pacing and without the related disadvantages.

Aged↗
PubMed1986

[Ventricular repolarization abnormalities and arrhythmia in the athlete. A long-term follow-up clinical case].

Clinical and prognostic significance of ventricular repolarization anomalies in sportsmen is still uncertain, even if they are most commonly regarded as benign. We studied a patient in whom those manifestations didn't show any progression within 30 years even after interruption of athletics and were related to idiopathic hypertrophic cardiomyopathy. Anatomical findings were combined with cardiac rhythm and conduction disturbances (paroxysmal atrial flutter, premature contractions, 2nd degree AV block). In our patient ventricular repolarization anomalies, even though without a negative prognosis, can't be related to "athlete's heart" but rather to organic cardiomyopathy.

Atrial Flutter↗
PubMed1985

Respiration-dependent ventricular pacing compared with fixed ventricular and atrial-ventricular synchronous pacing: aerobic and hemodynamic variables.

A pacemaker that adapts heart rate in response to the patient's metabolic requirements has been developed. The pacemaker uses breathing frequency and tidal volume as the indicators of physiologic demand. Maximal physical work capacity, anaerobic threshold, oxygen uptake (16 patients) and hemodynamic variables (9 patients) were assessed with fixed rate (VVI), atrial synchronous (VDT/I) and respiration-dependent ventricular (VVI-RD) pacing. All subjects attained their anaerobic threshold in stress tests with VVI pacing. The maximal physical capacity (p less than 0.001), work time to attain the anaerobic threshold (p less than 0.01) and oxygen uptake (p less than 0.001) were significantly greater with VVI-RD than with VVI pacing. The transition from the supine to the standing position was characterized by a significant increase of cardiac index at rest with both VDT/I and VVI-RD pacing as compared with VVI pacing. Progressive increments in the cardiac index and average left ventricular stroke work index were significantly different at submaximal and maximal exercise when VVI and VVI-RD were compared. At maximal exercise, mean cardiac output was also significantly different: 10.21 +/- 2.5 (SD) liters/min with VVI, 11.2 +/- 0.8 liters/min with VDT/I (p less than 0.05) and 12.65 +/- 3.1 liters/min with VVI-RD (p less than 0.05) pacing. Maximal oxygen extraction values were greater with VVI and VVI-RD pacing than with VDT/I pacing. Pulmonary artery end-diastolic pressures at maximal exercise were within the normal range with the three different modes of pacing. In conclusion, there is a significant (25%) improvement in exercise performance with VVI-RD pacing as compared with VVI pacing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Increasing cardiac rate by tracking the respiratory rate.

The rate responsive pacemaker using respiratory rate as a sensor was implanted in 22 patients, 19 patients for ventricular pacing and three for atrial pacing. The level of exercise achieved with this system was consistently higher than with a fixed ventricular pacing rate. In addition, no special chemical or mechanical sensors are required; the sensor itself is simple, long-lasting, and energy efficient. Thus, this system adapts easily to the individual patient.

Adolescent↗
PubMed1984

Respiration as a reliable physiological sensor for controlling cardiac pacing rate.

A study was carried out to determine whether variations in the respiration rate during physical exercise could be used as a physiological variable in controlling the rate of an implanted pacemaker. The relation between respiration rate and heart rate was significantly correlated in 73 patients (19 with normal lung function, four with restrictive pulmonary disease, and 50 with obstructive airways disease) during repeated calibrated ergometric tests; no significant differences were found between the subgroups. An external computerised programmable system with algorithm control activated by a radio frequency system was used to vary the cardiac stimulation rate in relation to respiration rate in 11 patients implanted with ventricular inhibited pacemakers. In addition, a prototype programmable pacemaker dependent on respiration rate was implanted in two patients. Maximum values of oxygen uptake, minute ventilation, and work time were increased during the exercise stress tests when the variable cardiac pacing rate was used. Thus respiration rate appears to be a valid and stable physiological variable for controlling the cardiac stimulation rate in order to improve cardiac output in patients dependent on pacemakers.

Aged↗
PubMed1984

Permanent physiological pacing.

Ideal physiological form of pacing responds to body's needs for varying cardiac output indipendent of the requirement to synchronize with atrial activity. The atrial synchronous pacemakers are superior to the ventricular inhibited fixed rate pacing mode. Alternative methods of sensing physiological demands with single chamber ventricular pacing that produce a physiological rate response to exercise are described. System based on QT sensing and pacing system responsive to changes in respiratory rate have undergone successful clinical trials. Hemodynamics of rate responsive pacing are described. The highest cardiac performance during stress test in rate responsive pacing was achieved with the respiratory dependent pacemaker.

Cardiac Output↗
PubMed1983

Respiratory rate as a determinant of optimal pacing rate.

Efforts have been made to utilize biologic parameters for determining optimal cardiac pacing rates. In this study of 67 patients, a significant relationship between heart rate and respiratory rate was observed during dynamic exercise. A system using a radiofrequency activator to modify pacing rate is described. Eleven patients have received VVI pacemakers with a similar implanted radio receiver coil. In two patients the fully automatic system has been successfully implanted. The experience with respiratory rate as a determinant of pacing rate is encouraging.

Aged↗
PubMed1983

[Intracoronary thrombolysis].

Intracoronary Urokinase administration was attempted in 42 patients with acute myocardial infarction. One patient died before Urokinase infusion could be started, two patients during treatment. 34 patients (83%) had total occlusion of a coronary vessel, 7 patients (17%) had a subtotal occlusion. Urokinase was administered at a rate of 10.000 IU/min in 11 consecutive patients (Group I), 6000 IU/min in 11 patients (Group II), 4000 IU/min in 11 patients (Group III), 2000 IU/min in 8 patients (Group IV). Recanalization of the occluded vessel or amelioration of the subocclusion was obtained in 36 patients (88%). 35 patients were controlled 12 days after the procedure, with coronary-angiography and left ventriculography. Patency persisted in 31 patients and successful thrombolysis was associated with significant improvement of left ventricular ejection fraction in those patients with depressed ventricular function before Urokinase treatment.

Coronary Vessels↗
PubMed1980

[Digitalis therapy used according to the "rational" method. Techniques of application and clinical advantages (author's transl)].

Digitalis therapy in cardiac failure is used by physicians according to conventional dosages; we call this type of digitalization "empiric". With this method digitalis intoxication in hospitalized patients is likely to occur in 8 to 20% of the cases. Another method of digitalization which we call "rational" is based upon an initial dosage of 0.015 mg per Kilo of digoxin, followed by a maintenance dosage determined by the relationship between initial dosage and daily rate of elimination. The latter depends upon the individual value of endogenous creatinine clearance (determined by age, weight and sex). Blood level of digoxin during steady state was measured in 454 patients divided randomly in four groups, each of whom following a different protocol of digitalization: 31 patients were treated with the rapid "empiric" digitalization (group I), 249 patients with the slow "empiric" digitalization (group II), 81 patients with the "rational" digitalization (group III), and 93 patients after a initial "empiric" dosage were treated with a maintenance dosage calculated by the "rational" method. An excessive initial dosage (blood level of digoxin > 2 ng/ml) was observed in 47.9% of patients of group I, in 15.9% of patients in group II, in 9.8% of patients of group III and in 14.7% of patients of group IV. manifestations of digitalis intoxication occurred in 30% patients of group I, in 10% of patients of group II, in 4.9% of patients of group III, and in 2.1% of group IV. Blood value of digoxin below therapeutic levels (under 0.5 ng/ml) was observed in only 13.1% of patients of group II, in 8.6% of patients of group III, and in 8% of patients of group IV. The lower percentage of digitalis intoxication observed in patients treated with "rational" method of digitalization is highly significant if compared with that observed in patients treated with empiric digitalization. The use of the "Lanoxin-rulex" makes the rational digitalization easier to handle, and gives the physicians the habit of considering the more important determinants of digoxin blood level. Conditions more likely to determine a wrong digitalis dosage are discussed in detail.

Digitalis Glycosides↗