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P Blanch

Publications and source records attributed to P Blanch.

10 recordsLinked to original sources
PubMed1998

Comparison of patients with anterior wall healed myocardial infarction with and without exercise-induced ST-segment elevation.

To assess the extent of myocardial necrosis and ischemia in patients with anterior wall healed myocardial infarction depending on whether ST-segment elevation was present on precordial leads during exercise testing, 62 consecutive patients (49 men and 13 women, age [mean +/- SD] 56 +/- 11 years) with anterior wall infarcts were assessed with exercise technetium-99m (Tc-99m) methoxy-isobutyl-isonitrile single-photon emission computed tomography and quantification of the extent of necrosis and ischemia on polar maps: 22 patients had > or = 1 mm ST-segment elevation during exercise, and 40 did not. The extent of the necrosis in the anteroseptal (p = 0.001) and apical (p = 0.002) regions, the extent of ischemia in the lateral region (p = 0.003) on polar maps, and the frequency of ventricular aneurysm as shown by cardiac catheterization (p = 0.001) were significantly greater in patients with ST-segment elevation. In a multiple logistic regression model, both extent of necrosis in the anteroseptal region (odds ratio 10.8; 95% confidence interval 2.7 to 44.0) and extent of ischemia in the lateral region (odds ratio 7.25; 95% confidence interval 1.6 to 32.7) were associated with exercise-induced ST-segment elevation. These data suggest that ST-segment elevation in anterior infarctions is associated with wider necrosis in the anteroseptal and apical regions, with a wider extent of ischemia in the lateral region and a higher frequency of ventricular aneurysm. Consequently, it cannot be used as a marker of viability.

Cardiac Catheterization↗
PubMed1997

Acute ischemic ventricular arrhythmias in pigs with healed myocardial infarction: comparative effects of ischemia at a distance and ischemia at the infarct zone.

BACKGROUND: The myocardium bordering a healed infarction undergoes electrophysiological and autonomic neural derangements that may interact with a new ischemic episode to promote arrhythmias. Therefore, peri-infarction ischemia may be more arrhythmogenic than ischemia at a distance from the infarct zone, but this is not known. METHODS AND RESULTS: Forty-two anesthetized open-chest pigs with a 1-month-old myocardial infarction induced by permanent ligature of the distal left anterior descending coronary artery (LAD) underwent a coronary reocclusion at either the proximal LAD (group 1, peri-infarction ischemia, n=21) or at the circumflex coronary artery (group 2, ischemia at a distance, n=21). Ventricular arrhythmias were analyzed during 60 minutes of coronary reocclusion and during programmed electrical stimulation. Infarct size was measured, and underperfusion at the occluded area was estimated by recording 99mTc-tetrofosmin activity. Weights of acute ischemic (23+/-9 versus 21+/-9 g) and healed infarction (10+/-6 versus 10+/-3 g), baseline LV pressure and peak of LV dP/dt, and radiotracer activity at the occluded area (3+/-2% versus 5+/-2% of normal tissue) were comparable between the two groups. Compared with group 2, group 1 showed more ventricular premature beats (median, 136 versus 59; P=.008), a higher incidence of spontaneous sustained ventricular tachycardia (57% versus 19%, P=.02) and ventricular fibrillation (76% versus 47%, P=.05), and greater electrical inducibility of sustained ventricular tachycardia (65% versus 28%, P=.03) but comparable induction of ventricular fibrillation. CONCLUSIONS: Ischemia superimposed at the border of a 1-month-old myocardial infarction is more arrhythmogenic than ischemia at a distance from the infarct zone in swine. Data suggest the presence of electrophysiological instability at the peri-infarction zone.

Animals↗
PubMed1997

Local repolarization abnormalities induced by transcatheter radiofrequency ablation in pigs.

Radiofrequency (RF) ablation alters action potential repolarization of myocardial cells and, theoretically, this should induce ST-T segment changes in the ECG. Since these ECG abnormalities have been rarely reported in patients submitted to RF ablation we assess the ability of the procedure to cause ST-T segment changes in local electrograms. Epicardial ECG mapping was performed in 17 anesthetized open chest pigs submitted to endocardial (n = 9) or to epicardial (n = 8) unipolar radiofrequency ablation (500 kHz, 20 W for 5-10 s). To characterize the cellular electrophysiological alterations induced by RF ablation transmembrane action potentials were recorded at various distances from the ablation lesion; these were compared with seven control pigs. Endocardial RF ablation induced a transient (< 5 min) change of 6.1 +/- 2.4 mV in T wave amplitude (baseline: 12.8 +/- 5.6 mV, P < 0.001) in 141 out of 269 epicardial electrodes. T wave changes were associated with shortening in local activation time (20.1 +/- 2.3 ms at baseline vs 18.5 +/- 2.5 ms at 60 s after ablation, P = 0.03). RF current caused persistent St segment elevation at the center of the ablation lesion with no transmural expansion. Intracellular potentials along a 2-6 mm wide myocardial band bordering the RF lesion lower amplitude (101 +/- 7.0 mV vs 71 +/- 23 mV, P < 0.01) and shorter duration (254 +/- 44 ms vs 156 +/- 29 ms, P < 0.01) than control hearts. The center of the ablation lesion was electrically unexcitable. We concluded that RF ablation alters cellular electrophysiology in small areas surrounding the ablation lesion and this causes short-lasting transmural changes in T 3 wave amplitude and nontransmural ST segment elevation.

Action Potentials↗
PubMed1996

Neurally mediated negative inotropic effect impairs myocardial function during cholinergic coronary vasoconstriction in pigs.

BACKGROUND: Myocardial dysfunction elicited during cholinergic coronary vasospasm is generally ascribed to myocardial ischemia. However, when pericoronary nerves extend to the ventricles, efferent vagal discharges that elicit coronary vasoconstriction may, at the same time, depress myocardial contractility by releasing acetylcholine into the myocardium. We analyzed whether a neurally mediated effect contributes to impairment of ventricular function during cholinergic coronary vasoconstriction. METHODS AND RESULTS: Left ventricular (LV) function, ECG mapping, and coronary angiography were analyzed during pericoronary application of methacholine (MCh) to the left anteriors. descending coronary artery in 53 chloralose-anesthetized openchest pigs. MCh induced local coronary vasoconstriction and depressed coronary blood flow (13.3 +/- 3.7 to 6.0 +/- 4.6 mL/min [54%]; ANOVA, P < .001), systolic LV pressure (105 +/- 10 to 91 +/- 10 mm Hg [13%], P < .001), peak LV (+)dP/dt (2890 +/- 524 to 2270 +/- 447 mm Hg/s [21%], P < .001), peak LV (-)dP/dt (1446 +/- 484 to 1048 +/- 276 mm Hg/s [27%], P < .001), and regional systolic segment shortening (0.32 +/- 0.09% to 0.18 +/- 0.14% [43%], P = .02) and caused local ST-segment elevation (0.9 +/- 0.8 to 8.4 +/- 3.9 mV, P < .001). These changes were not preceded by heart rate variations, were reproducible, and were inhibited by atropine. MCh during perfusion of nitroglycerin (2 micrograms.kg-1.min-1 IV) continued to depress LV pressure (9%, P = .002), LV (+)dP/dt (16%, P < .01), LV (-)dP/dt (20%, P < .01), and segment shortening (18%, P = .03) even though coronary blood flow drop was markedly attenuated (7% versus 54%; ANOVA, P < .01). Disruption of pericoronary nerves with phenol attenuated MCh-induced LV pressure fall (P < .05). Histological data show that cholinergic and adrenergic pericoronary nerves extend into the ventricular myocardium. CONCLUSIONS: A neurally mediated effect, in addition to ischemia, impairs LV function during cholinergic coronary constriction in a model with pericoronary nerves extending into the ventricles.

Animals↗
PubMed1996

Predisposing factors and prognostic value of sustained monomorphic ventricular tachycardia in the early phase of acute myocardial infarction.

OBJECTIVES: The purpose of the study was to analyze the factors that favor the occurrence of sustained monomorphic ventricular tachycardia in the early phase (< 48 h) of acute myocardial infarction and to establish its prognostic implications. BACKGROUND: Sustained monomorphic ventricular tachycardia early in the course of an acute myocardial infarction is an uncommon arrhythmia, and its significance has not been specifically studied. METHODS: The clinical characteristics and prognosis of sustained monomorphic ventricular tachycardia were studied in 21 (1.9%) of 1,120 consecutive patients admitted to the coronary care unit with a diagnosis of myocardial infarction. RESULTS: Patients with sustained monomorphic ventricular tachycardia had a larger infarct on the basis of peak creatine kinase, MB fraction (CK-MB) isoenzyme activity (435 +/- 253 IU/liter vs. 168 +/- 145 IU/liter, p < 0.001) and higher mortality rate (43% vs. 11%, p < 0.001). By logistic regression analysis, independent predictors of sustained monomorphic ventricular tachycardia were CK-MB (odds ratio [OR] 11.8), Killip class (OR 4.0) and bifascicular bundle branch block (OR 3.1). Moreover, sustained monomorphic ventricular tachycardia was itself an independent predictor of mortality (OR 5.0). Compared with patients with ventricular fibrillation, those with sustained monomorphic ventricular tachycardia had a worse Killip class (Killip class > I: 63% vs. 30%, p < 0.05), higher CK-MB activity (430 +/- 260 IU/liter vs. 242 +/- 176 IU/liter, p < 0.01) and higher arrhythmia recurrence rate (31% vs. 4%, p < 0.01). During the follow-up period, 5 (42%) of 12 survivors in the sustained monomorphic ventricular tachycardia group died of cardiac-related causes. Recurrence of ventricular tachycardia was seen in two patients (17%). CONCLUSIONS: Sustained monomorphic ventricular tachycardia during the first 48 h of myocardial infarction is a sign of extensive myocardial damage and an independent predictor of in-hospital mortality.

Adult↗
PubMed1995

[The follow-up of transposition of the great arteries corrected by Senning's technic].

INTRODUCTION AND OBJECTIVES: The incidence of late complications after a physiological correction of the patients with transposition of the great arteries (D-TGA) is very significant, due to the alternative operation of the arterial switch. METHODS: We studied 125 patients with D-TGA, treated with Senning surgical correction between december of 1978 and november of 1990. Surgery was performed at a mean age of 11.7 months (from 7 days to 11.2 years), and the postoperative mean follow-up was 7.3 years (from 1.4 to 14.3 years). We analyzed their evolutive clinical condition, ECG, Holter and echocardiogram-Doppler. Four groups were defined: A) Simple, 48.8%. B) Associated with ventricular septal defect, 22.4%. C) With pulmonary stenosis, 15.2%. D) Both anomalies, 13.6%. RESULTS: Sixteen children died (12.8%), 11 of them on the postoperative period. The remaining 5 patients died, at a mean time of 34.3 months after surgery, because they were in cardiac failure. All of patients had enlargement of right ventricle and tricuspid regurgitation was observed in 39 children. There were 3 reoperations. Atrioventricular block was observed in 5.7% of the patients, 33.3% were not in sinus rhythm, 6.6% had atrial flutter-fibrillation, sinus node dysfunction was observed in 24.7%, and five permanent pacemakers were implanted (4.7%). CONCLUSIONS: The later mortality is not high, and the clinical outcome is good, but the frequent rhythm disturbances and enlargement of the right ventricle could let us conclude the hypothesis that anatomical correction is an optimal alternative procedure.

Analysis of Variance↗
PubMed1994

Evaluation of a fiberoptic system for airway pressure monitoring.

OBJECTIVE: Our objective was to evaluate the accuracy of a novel fiberoptic system for airway pressure measurement at the carinal end of the endotracheal tube in an in vitro pediatric lung model. METHODS: A fiberoptic pressure measuring system was compared to the conventional method of measuring airway pressure with a pneumatic transducer using a test lung model. Pressure measurements were obtained using four endotracheal tubes of various internal diameters (ID) (3 to 6 mm) during simulated spontaneous and mechanical ventilation. Airway pressure was measured using both methods simultaneously and the results were compared by statistical analysis. RESULTS: Airway pressure measured by the fiberoptic system was not significantly different from measurements obtained by the pneumatic transducer except when using the 3-mm and 4-mm ID endotracheal tubes during mechanical ventilation. CONCLUSIONS: We conclude that the fiberoptic system provides accurate and precise measurement of airway pressure during spontaneous and mechanical ventilation. Additionally, the statistically significant differences obtained for 3- and 4-mm tubes are not large enough to be clinically significant. The fiberoptic system offers advantages over the pneumatic system for measuring the airway pressure. These advantages include decreased chance of false pressure measurement secondary to occlusion with water or mucous, less chance of kinking, and possibly, more rapid response to pressure changes due to the mechanical ventilator.

Airway Resistance↗
PubMed1994

[Extrinsic compression of the pulmonary artery by a mediastinal lymphoma. Diagnosis by Doppler echocardiography].

A patient with an anterior mediastinal tumor and cardiomegaly observed by plain chest roentgenogram is presented. The echocardiographic-Doppler examination showed massive pericardial efussion with hemodynamic compromise, and external compression of the right atrium and pulmonary artery. A pericardiocentesis was performed, and a mediastinoscopy with biopsy was diagnostic of lymphoblastic lymphoma.

Adolescent↗