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Biomedical subjects

J L Delcan

Publications and source records attributed to J L Delcan.

At least 19 recordsLinked to original sources
PubMed1999

Randomized comparison of coronary stent implantation and balloon angioplasty in the treatment of de novo coronary artery lesions (START): a four-year follow-up.

OBJECTIVE: The purpose of this study was to test the hypothesis that stent implantation in de novo coronary artery lesions would result in lower restenosis rates and better long-term clinical outcomes than balloon angioplasty. BACKGROUND: Placement of an intracoronary stent, as compared with balloon angioplasty, has proven to reduce the rate of restenosis. However, the long-term clinical benefit of stenting over angioplasty has not been assessed in large randomized trials. METHODS: We randomly assigned 452 patients with either stable (129 patients) or unstable (323 patients) angina pectoris to elective stent implantation (229 patients) or standard balloon angioplasty (223 patients). Coronary angiography was performed at baseline, immediately after the procedure and six months later. End points were the rate of restenosis at six months and a composite of death, myocardial infarction (MI) and target vessel revascularization over four years of follow-up. RESULTS: Procedural success rate was achieved in 84% and 95% (balloon angioplasty vs. stent, respectively). The increase in the minimal luminal diameter was greater in the stent group both after the intervention (2.02 +/- 0.6 mm vs. 1.43 +/- 0.6 mm in the angioplasty group; p < 0.0001), and at six-month follow-up (1.98 +/- 0.7 mm vs. 1.63 +/- 0.7 mm; p < 0.001). The corresponding restenosis rates were 22% and 37%, respectively (p < 0.002). After four years, no differences in mortality (2.7% vs. 2.4%) and nonfatal MI (2.2% vs. 2.8%) were found between the stent and the angioplasty groups, respectively. However, the requirement for further revascularization procedures of the target lesions was significantly reduced in the stent group (12% vs. 25% in the angioplasty group; relative risk 0.49, 95% confidence interval 0.32 to 0.75, p = 0.0006); most of the repeat procedures (84%) were carried out within six months of entry into the study. CONCLUSIONS: Patients who received an intracoronary stent showed a lower rate of restenosis than those treated with conventional balloon angioplasty. The benefit of stenting was maintained four years after implantation, as manifested by a significant reduction in the need for repeat revascularization.

Aged↗
PubMed1998

First postpacing interval variability during right ventricular stimulation: a single algorithm for the differential diagnosis of regular tachycardias.

BACKGROUND: Failure to differentiate supraventricular from ventricular arrhythmias is the most frequent cause of inappropriate implantable cardioverter-defibrillator therapies. Although a sudden-onset criterion is available to differentiate sustained monomorphic ventricular tachycardias (SMVTs) and sinus tachycardias (STs), SMVTs arising during ST and SMVTs gradually accelerating above the cutoff rate can remain undetected. Regular paroxysmal atrial tachycardias (ATs) also can be undetected by onset and stability algorithms. We hypothesized that the first postpacing interval (FPPI) variability after overdrive right ventricular pacing may differentiate SMVTs from STs and ATs. METHODS AND RESULTS: FPPI variability was measured in 23 SMVTs (cycle length [CL] 366+/-50 ms [VT group]), 27 supraventricular tachycardias, 15 episodes of induced or simulated ATs (CL 376+/-29 ms [AT group]), and 12 exercise-related STs (CL 381+/-24 [ST group]). Sequences of trains of 5, 10, and 15 beats were delivered with a CL 40 ms shorter than the tachycardia CL. An FPPI absolute mean difference between consecutive trains of 5 and 10 beats (deltaFPPI) < or =25 ms identified all VTs (mean difference 5+/-7 ms). In the AT group, the deltaFPPI was >25 ms in all sequences (mean difference 129+/-60 ms, P<0.01). In the ST group, the deltaFPPI was >50 ms in all STs (mean difference 118+/-47 ms, P<0.01). CONCLUSIONS: FPPI variability may differentiate SMVT from AT and ST. This criterion is potentially useful in implantable devices that use a single ventricular lead.

Algorithms↗
PubMed1996

Alcohol concentration determines the type of atrial arrhythmia induced in a porcine model of acute alcoholic intoxication.

Alcohol abuse has long been suspected clinically to cause paroxysmal atrial tachyarrhythmias. However, such a relationship has never been conclusively proven, partly due to the lack of experimental evidence. Although atrial fibrillation (AF) is the most common atrial arrhythmia attributed to acute alcoholic ingestion, atrial flutter has occasionally been noted. We analyzed the possible role of alcohol in initiation and/or maintenance of a variety of atrial tachyarrhythmias in a closed-chest porcine model. Nine pigs underwent nine endocardial right atrial stimulation protocols (RASP) at baseline and 17 RASPs after increasing doses of ethanol (first infusion 1,230 mg/kg, second infusion 870 mg/kg) by means of one multipolar catheter advanced under heavy sedation from the femoral vein. Each RASP included 1, 2, and 3 extrastimuli, and rapid pacing at 5 times diastolic threshold. Venous ethanol concentrations were measured (HPGC method) every 10 minutes and at the time of arrhythmia induction. Atrial tachyarrhythmias were induced in 4 of 9 baseline RASPs, and lasted for a mean of 21 seconds, and in 16 of 17 RASPs after alcohol lasting for a mean of 357 seconds. Only fibrillation was observed at the baseline RASP. The atrial tachyarrhythmias induced after alcohol were AF in 11 RASPs and atrial flutter in 5 RASPs (in 5 animals). The mean venous ethanol concentration at the time of the longest arrhythmia induced for each RASP were 200 +/- 89 mg/dL for RASP inducing fibrillation and 292 +/- 40 mg/dL for RASP inducing flutter (P < 0.05). Flutter tended to be sustained (> 1 minute in duration) more often than fibrillation (4 of 5 flutter vs 2 of 11 fibrillation P < 0.05). In three experiments, atrial flutter persisted for > 10 minutes and was terminated by overdrive atrial pacing. We concluded: (1) in this closed-chest porcine model, an ethanol infusion facilitates a variety of atrial arrhythmias related to the ethanol concentration; (2) flutter tended to be sustained, and its termination by overdrive pacing suggests the possibility of an alcohol induced reentrant mechanism; and (3) the higher concentration required for atrial flutter, exceeding that usually seen in humans, may help to explain the rarity of atrial flutter in clinical alcohol intoxication.

Alcoholic Intoxication↗
PubMed1995

Evidence favoring the hypothesis that ventricular arrhythmias have prognostic significance in left ventricular hypertrophy secondary to systemic hypertension.

In the present review 6 lines of evidence will be discussed that suggest a prognostic significance for ventricular arrhythmias in patients with systemic hypertension and left ventricular hypertrophy: (1) in patients with systemic hypertension there is a statistical relation between asymptomatic ventricular arrhythmias and left ventricular hypertrophy; (2) in nonhypertensive left ventricular hypertrophy the prognostic value of ventricular arrhythmias is well known; (3) left ventricular hypertrophy is related to sudden death in patients with systemic hypertension; (4) it is generally acknowledged that ventricular arrhythmias are a frequent cause of sudden death; (5) there is experimental evidence to support the arrhythmic risk of left ventricular hypertrophy; and (6) it has been recently demonstrated that ventricular arrhythmias influence mortality in patients with left ventricular hypertrophy secondary to systemic hypertension. However, whether asymptomatic ventricular arrhythmias are specific markers for more severe sustained arrhythmias, or just markers for a more severe stage of the disease, remains to be determined.

Arrhythmias, Cardiac↗
PubMed1994

[Multiplanar transesophageal echocardiography: technique, methodology, and applications].

OBJECTIVE: To present the experience of transesophageal echocardiography with a multiplane probe, its methodology, the advantages, disadvantages and diagnostic improvements of this type of probe. SETTING: Laboratory of Echocardiography of the General Hospital Gregorio Marañon. MATERIAL AND METHODS: Analysis of the first 1000 examinations performed on hospitalized patients and outpatients, in most cases to study either native valvular heart disease and valvular prosthesis or to search for embolic sources. We evaluate the advantages, disadvantages, initial difficulties and complications of this type of probe. RESULTS: Multiplane probe provides continuous imaging from 0 degree to 180 degrees without need of intraesophagic movements. This type of probe increases the diagnostic capability of transesophagic echocardiography because it performs as a scanning of anatomy and pathological features of cardiac chambers and great vessels. Pulmonary artery and its branches, right heart chambers and tricuspid valve, inferior and superior vena cava, outflow tract of both ventricles, aortic root, pulmonary veins and segmental views of both ventricles are well analyzed. Also in native and prosthetic regurgitants jets, cardiac tumors and other masses, diagnosis and complications of endocarditis, aortic dissection and in anomalous return of pulmonary veins, multiplane probe proves to be more informative. There was no difficulties in the intubation despite the bigger size of the transducer. No severe complications occurred. The higher price and the initial more difficult understanding of the images are the only disadvantages we have found. CONCLUSIONS: Multiplane probe contributes to increase diagnostic capability of transesophageal echocardiography without significant risk and it is an important and promising refinement of the transesophageal technique.

Echocardiography, Transesophageal↗
PubMed1993

The importance of antitachycardia pacing for patients presenting with ventricular tachycardia.

The initial experience from electrophysiological studies showed that pacing induced termination of ventricular tachycardias is usually possible but requires a critical pacing sequence. Studies on the resetting phenomenon showed, in most instances of failure of termination, that the "limiting factor" to produce ventricular tachycardia termination is usually failure to produce block within the circuit rather than failure to access or interact with the ventricular tachycardia origin. The resetting response is related to tachycardia termination in a number of ways. Of note is that a steeply increasing resetting pattern usually predicts tachycardia termination. Between 50% and 90% of induced ventricular tachycardias will be terminated by trains of rapid ventricular pacing. The analysis of the pacing rate necessary for termination shows that it varies widely. Paced cycle lengths of < 80% of tachycardia cycle length are necessary in at least 20% of tachycardias. In contrast, the incidence of acceleration is closely related to the paced cycle length: it is negligible with paced cycle lengths over 80% of tachycardia cycle length and increases to 36% with paced cycle lengths below 76% of tachycardia cycle length. Present information about efficacy of antitachycardia pacing in spontaneous tachycardias suggests that it is extremely effective, with over 90% success. However, it is likely that these data correspond to a selected group of tachycardias.

Cardiac Pacing, Artificial↗
PubMed1993

Treatment of ventricular arrhythmias in patients with hypertrophic cardiomyopathy.

In patients with hypertrophic cardiomyopathy, asymptomatic episodes of non-sustained ventricular tachycardia are frequent and of prognostic significance for sudden cardiac death in adults, particularly in those whose consciousness is impaired. Low-dose amiodarone, found to be beneficial in mildly symptomatic non-sustained ventricular tachycardia, but detrimental in a subgroup with prominent non-arrhythmic symptoms, could be an alternative to an electrophysiological approach in patients with syncope but preserved functional capacity. In cardiac arrest survivors, an electrophysiological approach seems preferable to empiric amiodarone, together with implantation of a defibrillator, at least in those in whom inducible arrhythmias cannot be suppressed.

Amiodarone↗
PubMed1993

[A pulsed Doppler transesophageal echocardiographic study of pulmonary venous flow in mitral regurgitation jets in the parietal direction].

OBJECTIVE: Transesophageal echocardiographic analysis of the degree of severity of mitral regurgitation eccentric wall jets by color Doppler and pulsed Doppler interrogation of the pulmonary venous flow. DESIGN: Transesophageal echocardiographic prospective study. SETTING: consecutive out and in patients referred to the Echocardiographic Laboratory of Gregorio Marañon General Hospital, Madrid, Spain. MATERIAL AND METHODS: We studied 90 consecutive patients with the clinical and echocardiographic diagnosis of valvular mitral regurgitation. In each patient through pulsed Doppler transesophageal echocardiographic technique, we measured the peak velocities and areas of systolic forward flow and systolic reversed flow of the left superior pulmonary vein. By pulsed color Doppler transesophageal echocardiographic technique, we calculated total area, severity and spatial direction of the mitral regurgitant jet. MAIN RESULTS: There were 80% (72/90) of patients included in the JC group and 20% (18/90) in the JP group. The color Doppler maximal area in the JC group was 484 +/- 118 mm2 and 445 +/- 79 mm2 (p = NS) in the JP group. Mild mitral regurgitation was present in 32% (23/72) and 55% (10/18) of the patients in the JC and JP groups (p < 0.01) respectively. Severe mitral regurgitation was present in 29% (21/72) and 0% (0/18) of the same groups (p < 0.0001). Peak velocity of pulsed Doppler pulmonary venous systolic forward flow in JC and JP groups was 47 +/- 7 cm/sec and 29 +/- 8 cm/sec respectively (p < 0.01). Maximal area of pulmonary venous flow wave in JC and JP groups was 1215 +/- 140 mm2 and 568 +/- 176 mm2 (p < 0.001) respectively. Peak velocity of reversed systolic pulmonary venous flow in JC and JP groups was 28 +/- 10 cm/sec and 46 +/- 8 cm/sec (p < 0.01) respectively. Maximal area of reversed pulmonary venous flow of JC and JP groups was 124 +/- 30 mm2 and 389 +/- 40 mm2 (p < 0.001) respectively. CONCLUSIONS: Color Doppler echocardiographic evaluation of mitral regurgitation wall jets, is not an exact method to quantify their degree of severity. In the assessment of extreme eccentric mitral regurgitation jets that interact with the atrial wall, the color Doppler quantification criteria is not sufficient. In these cases of mitral regurgitation wall jets, pulmonary venous pulsed Doppler flow criteria can be useful.

Adult↗
PubMed1993

[Meaning of mosaic color area in mitral regurgitation. Echocardiographic transesophageal study].

OBJECTIVE: The purpose of our study was to analyse the meaning of total and mosaic color Doppler area of the mitral regurgitation jet, in terms of the degree of mitral regurgitation severity. PATIENTS: In and out patients referred to the Echocardiographic Laboratory of Gregorio Marañon General Hospital, Madrid. SETTING: Transesophageal echocardiographic prospective study MATERIAL AND METHODS: By pulsed and color Doppler transesophageal approach we studied 94 consecutive patients with mitral regurgitation diagnosis. We divided the entire population in three groups according to the degree of transthoracic mitral regurgitation severity and mitral regurgitation color area index (Groups I, II and III). In each patient we systematically measured the regurgitant maximal area (AT) and of the aliasing color area, as well as maximal peak velocity (VIS) and area (AIS) of the reversed pulmonary venous pulsed Doppler flow obtained at the level of the left upper pulmonary vein. RESULTS: For the group I, color Doppler AT was 411 +/- 315 mm2 and AN was 204 +/- 123 mm2 (R = 0.25), pulmonary venous pulsed Doppler VIS was 4 +/- 8 cm/sec (R = NS for AT and 0.79 for AN) and AIS was 9 +/- 6 mm2 (R = NS for AT and 0.82 for AN). In the group II, color Doppler AT was 802 +/- 447 mm2, AN was 671 +/- 307 mm2 (R = 0.42). the pulmonary venous pulsed Doppler VIS was 22 +/- 12 cm/sec (R = NS for AT and 0.66 for AN). In the group III we obtained an AT value of 1174 +/- 462 mm2 and an AN value of 1092 +/- 417 mm2 (R = 0.62). In this group the pulmonary venous pulsed Doppler VIS was 50 +/- 13 cm/sec (R = 0.57 for AT and 0.76 for AN) and the correspondent AIS was 671 +/- 570 mm2 (R = 0.38 for AT and 0.91 for AN). CONCLUSIONS: Mosaic transesophageal echocardiographic color Doppler area of mitral regurgitant jets has a direct relationship with the reversal criteria of pulsed Doppler pulmonary venous flow. This relationship is greater than the total color Doppler area of the same regurgitant jet. The mosaic color Doppler area of mitral regurgitant jets is a more correct estimation of the systolic variation of left atrial pressure, when compared with the total color area of mitral regurgitation.

Adult↗
PubMed1993

[Transesophageal echocardiography study with dynamic spontaneous contrast of the left atrial appendage, its relationship with the anatomy and thrombus formation].

OBJECTIVE: Transesophageal two-dimensional echocardiographic study of anatomical characteristics of the left atrial appendage and its relation to spontaneous dynamic echocardiographic contrast. DESIGN: Outpatients undergoing a prospective two-dimensional transesophageal echocardiographic study. SETTING: Consecutive outpatients studied at the Echocardiographic Laboratory of Gregorio Marañon General Hospital, Madrid. MATERIAL AND METHODS: In each patient at the level of the left atrial appendage we calculated the following transesophageal echocardiographic parameters: end-systolic and end-diastolic maximal longitudinal and transversal diameters, total systolic and diastolic areas, percentage of systolic fractional shortening, presence of left atrial appendage thrombus and spontaneous dynamic echo-contrast. MAIN RESULTS: Left atrial appendage spontaneous dynamic contrast was observed in 48% of the total population. In the group of patients with left atrial spontaneous echo-contrast we observed larger longitudinal systolic (44 +/- 14 mm vs 28 +/- 13 mm, p = 0.01) and diastolic (52 +/- 16 mm vs 38 +/- 12 mm, p = 0.005) diameters, larger transversal systolic (25 +/- 10 mm vs 19 +/- 6 mm, p = 0.03) and diastolic (28 +/- 8 mm vs 25 +/- 9 mm, p = NS) diameters and also larger systolic (601 +/- 204 mm2 vs 337 +/- 110 mm2, p < 0.0001) and diastolic (715 +/- 230 mm2 vs 507 +/- 184 mm2, p = 0.001) areas, compared to the group without this dynamic echocardiographic phenomena. Left atrial appendage percentage of fractional shortening was considerably reduced in patients with spontaneous dynamic echo-contrast (15 +/- 14% vs 39 +/- 18%, p = 0.001) and related to local thrombus formation (13% vs 1%, p < 0.001). CONCLUSIONS: Left atrial spontaneous dynamic echo-contrast is more common in patients with enlarged left atrial appendage systo-diastolic diameters and areas. In this group of patients the presence of left atrial spontaneous echo-contrast is related to a significant reduction in left atrial appendage contractile function and thrombus formation. Parameter analysis of left atrial appendage anatomy by two-dimensional transesophageal echocardiography may have clinical relevance in the assessment of patients with high risk for left atria thromboembolic phenomena.

Diastole↗
PubMed1992

Frequency and implications of resetting and entrainment with right atrial stimulation in atrial flutter.

Thirty-three patients (24 with typical and 9 with atypical flutter-wave morphology) were studied to evaluate the incidence and implications of resetting and entrainment of atrial flutter with right atrial stimulation. Resetting with single extrastimulus was present in 23 cases (group A) and absent in 10 (group B). Most cases of reset flutter were typical (20 of 23). Fixed fusion indicative of entrainment was observed in all 29 cases with pacing trains. Groups A and B did not differ significantly in flutter cycle length (230 +/- 20 vs 223 +/- 19 ms), atrial functional refractory period (165 +/- 18 vs 167 +/- 22 ms) or longest paced cycle length producing entrainment (213 +/- 19 vs 210 +/- 19 ms). In contrast, the return cycle after the longest paced cycle length producing entrainment was significantly shorter in group A (228 +/- 27 vs 284 +/- 56 ms; p = 0.001). The return cycle in group A was virtually identical to the flutter cycle length, whereas in group B it was greater (p = 0.002 compared with group A). Resetting was more frequent in typical than atypical flutter (20 of 24 vs 3 of 9; p = 0.01). Both typical and atypical flutter can be transiently entrained by right atrial pacing. Lack of resetting and longer return cycle, suggesting a longer conduction time between the reentrant circuit and the stimulation site, were mostly observed in atypical flutter. The data suggest a different location for both types of flutter, and may have implications for ablation techniques. A more cautious approach, with more extensive mapping, appears appropriate for ablation attempts of atypical flutter.

Adult↗