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Biomedical subjects

D D'Este

Publications and source records attributed to D D'Este.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Treatment of malignant ventricular tachyarrhythmia with amiodarone: comparison of empirical administration and administration guided by Holter or ventricular stimulation. Results of the parallel test].

To assess the most appropriate method of administering amiodarone and predicting its efficacy (empiric vs guided by Holter or by ventricular stimulation), 19 patients with sustained ventricular tachycardia or ventricular fibrillation underwent a "parallel study". Fifteen patients were men and 4 women, with a mean age of 65 years. A coronary artery disease with previous myocardial infarction was present in 15 patients, dilated cardiomyopathy in 3 and arrhythmogenic right ventricular dysplasia in 1 (mean left ventricular ejection fraction = 35%). All 19 patients had, as inclusion criteria, 1) frequent (greater than or equal to 30/hour) and/or repetitive (greater than or equal to 10/24 hours) ventricular premature beats during 24-hour Holter monitoring and 2) inducible sustained (greater than 30/sec) ventricular arrhythmias during programmed ventricular stimulation (1-3 extrastimuli from 2 right ventricular sites). Amiodarone was given at an initial dosage of 15 mg/kg/day for 2 weeks and then at a dosage of 5 mg/kg/day. After 15 days 24-hour Holter monitoring and programmed ventricular stimulation were repeated. The data of these tests, however, were not used to guide the therapy that remained empiric, but served only to assess retrospectively the predictive value of Holter monitoring and ventricular stimulation. The following main results were obtained: The mean duration of follow-up was 25 +/- 13 months. During this period 6 patients (32%) died, 3 from sudden and 3 from non-sudden cardiac death. Two other patients had recurrence of sustained ventricular arrhythmias. After 15 days of therapy amiodarone was effective at Holter monitoring in 15 patients (79%) and not effective in 4 (21%). Two of the 15 patients considered responders died suddenly during the follow-up and 2 had arrhythmic recurrence, vs 1 of the 4 non-responder patients who died suddenly (negative predictive value of Holter monitoring: 73%; positive predictive value: 25%; predictive accuracy: 63%). After 15 days of therapy amiodarone was effective at ventricular stimulation in 10 patients (53%) and not effective in 9 (47%). None of the 10 patients considered responders had arrhythmic events during the follow-up, vs 5 of the 9 non-responders, 3 of whom died suddenly and 2 of whom had arrhythmic recurrences (negative predictive value of ventricular stimulation: 100%; positive predictive value: 56%; predictive accuracy: 79%). Only 1 patient discontinued amiodarone after 25 months of follow-up because of development of an important blue-grey skin discoloration.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Electrogenesis of the S1S2S3 electrocardiographic pattern. A study in humans based on body surface potential and right ventricular endocardial mapping.

To study the electrogenesis of the S1S2S3 pattern, seven patients had body surface potential mapping and endocardial mapping of inflow tract, outflow tract, and apex of the right ventricle. QRS duration was longer in S1S2S3 versus controls (94 +/- 14 vs. 84 +/- 14 msec). Surface mapping was similar in S1S2S3 patients and in controls during the first 30-40 msec of QRS, but S1S2S3 patients subsequently presented the following differences: (1) earlier time of onset (34 +/- 3 vs. 44 +/- 6 msec) and a lower voltage (1,242 +/- 468 vs. 1,649 +/- 31 mV) of peak positive anterior maximum; (2) earlier dorsal migration (45 +/- 3 vs. 55 +/- 7 msec) of the maximum; (3) a second peak positive maximum at 58 +/- 3 msec, located on the dorsal spine; (4) the appearance of a right subclavicular positive area at 51 +/- 6 msec, which in controls was absent or appeared later (66 +/- 7 msec). At the end of QRS, the maximum was located in all but two S1S2S3 cases on the upper sternum. Right ventricular endocardial mapping showed a similar activation time of the apex in S1S2S3 patients and controls, but in the former a significant inflow (56 +/- 21 vs. 36 +/- 9 msec) and outflow tract (79 +/- 13 vs. 39 +/- 8 msec) activation delay was documented. The data obtained using body surface potential mapping suggest that an anomalous wavefront rightward and superiorly oriented is present in the S1S2S3 pattern, which is able to oppose the electrical forces of ventricular free walls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Empiric treatment with amiodarone in patients with sustained ventricular tachyarrhythmia. Results of a long-term follow-up].

The long-term follow-up of 52 pts (36 M, 16 F, mean age: 62 years) with sustained ventricular tachyarrhythmias (SVT) was analyzed to assess the efficacy and feasibility of empiric amiodarone treatment. Forty-five pts had organic heart disease (mean EF: 38.3%) and 7 pts no overt heart disease. Twenty pts suffered from syncope or cardiac arrest secondary to sustained ventricular tachyarrhythmias (mean: 2.35 episodes) and 32 did not. All pts were given amiodarone empirically (mean dose: 390 mg) and followed-up for a mean period of 29.5 months (range 1-137). Two pts (3.8%) died of non cardiac causes, 5 (9.6%) of non sudden cardiac death and 7 (13.4%) of sudden death. Fifteen pts (28.8%) experienced non fatal arrhythmic recurrences. Four out of 7 pts who died suddenly experienced non fatal arrhythmic recurrence before death. The actuarial incidence of cardiac death was 10.8, 22.7, 31.5, 31.5% at 1, 2, 3 and 5 years; the actuarial incidence of sudden death was 8.9, 12, 22.1, 22.1% at 1, 2, 3 and 5 years; the actuarial incidence of non fatal arrhythmic recurrences was 17.4, 26.3, 26.3, 26.3, 44.7% at 1, 2, 3, 4 and 5 years. Univariate analysis identified recent myocardial infarction, NYHA functional class, detection of frequent and/or repetitive premature ventricular contractions on Holter monitoring and non fatal arrhythmic recurrences as predictors of cardiac death (p less than 0.05), while only non fatal arrhythmic recurrences were associated with sudden death (p less than 0.05). Twenty-two pts (42.3%) developed side effects. Nine (17.3%) discontinued amiodarone: 6 pts (11.5%) because of side effects and 3 inadvertently.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[The effects of enalapril on basal arterial pressure at rest and during exercise and on cardiac performance in hypertensive athletes].

A dose of 10 mg of enalapril was administered once a day to regularly trained hypertensive athletes (mean age 39 +/- 8.9 range 29-51) in order to evaluate the effect of the drug on ambulatory blood pressure and on blood pressure and physical performance during stress testing. STUDY DESIGN. This investigation was a randomized, double blind, cross-over versus placebo trial. At first, subjects whose blood pressure met the entry criteria (casual diastolic blood pressure greater than or equal to 95 mmHg), were subjected to 24-hour ambulatory blood pressure monitoring and maximal upright bicycle stress testing including measurement of O2 uptake. Then they were randomly assigned to treatment with placebo or enalapril. After one month they repeated stress testing and then they were crossed over. Stress testing was repeated in all subjects after two months. The 24-hour ambulatory blood pressure monitoring was repeated in all subjects during enalapril treatment only, by a non-blind investigator. RESULTS. Ambulatory blood pressure decreased significantly during enalapril and no changes in heart rate were observed during the monitoring. The results of bicycle stress testing, both in basal and during the placebo test were comparable as regards blood pressure response, maximal workload, effort duration, maximal heart rate and VO2 max. With enalapril systolic and diastolic blood pressure decreased significantly during stress testing both versus basal test and placebo test at each workload considered including maximal workload. No changes were observed during enalapril as regards maximal workload, effort duration, maximal heart rate and VO2 max. CONCLUSION. Our results suggest that enalapril could be effective in treating hypertensive athletes because it reduces blood pressure during physical effort without affecting physical performance. We conclude that enalapril could be considered a first-choice drug in hypertensive athletes doing aerobic sports.

Adult↗
PubMed1990

[Clinical and prognostic value of evaluation of atrial vulnerability in an electrophysiological endocavitary and transesophageal study].

UNLABELLED: Atrial fibrillation or flutter is frequently inducible during endocavitary or transesophageal electrophysiologic study. However, its clinic and prognostic significance has not yet been clarified. We studied 443 patients: 276 underwent endocavitary electrophysiologic study, 228 underwent transesophageal electrophysiologic study and 61 underwent both methods. In 343 of them a satisfactory echocardiogram was obtained. Patients were divided in three groups: gr. I, 93 patients with documented episodes of paroxysmal atrial fibrillation or flutter; gr. II, 257 patients with or without heart disease without clinical atrial fibrillation or flutter; gr. III, 93 symptomatic or asymptomatic Wolff-Parkinson-White patients without clinical atrial fibrillation or flutter. Gr. I included patients without overt heart disease (20), with WPW (11), mitral valve prolapse (4), and miscellaneous (58). Gr. II included patients without overt heart disease (49), with concealed Kent bundles (7), Mahaim (1) or James fibers (1) mitral valve prolapse (6), sick sinus syndrome (40), miscellaneous (91), or syncope of an unknown origin (62). Atrial vulnerability was evaluated both by endocavitary and transesophageal electrophysiologic study using two different protocols; the first protocol was moderately aggressive (prot. A), while the second was aggressive (prot. B). Endocavitary electrophysiologic study. Prot. A: single and double extrastimuli at the three heart rates (sinus, 100 and 150/m'), 10/m' incremental atrial pacing from 160 to 250/m; prot. B: prot. A + incremental atrial pacing from 260/m' up to 2:1 St-A block. Transesophageal electrophysiologic study. Prot. A: 10" atrial burst at 100-600/m' prot. B: prot. A + 6-9" increasing rate bursts from 200 to 800/m'. End point of all protocols: initiation of greater than 1' atrial fibrillation or atrial flutter. RESULTS: Endocavitary electrophysiologic study. A greater than 1' atrial fibrillation or atrial flutter was induced with the two protocols respectively in 67% (52/78) and 85% (51/60) of gr. I, in 17% (26/150) and 36% (38/105) of gr. II and in 35% (17/48) and 44% (21/48) of gr. III (gr. I vs gr. II p less than 0.001 for prot. A and p less than 0.01 for prot. B; gr. II vs gr. III p less than 0.001 for prot. A and NS for prot. B). Induced atrial fibrillation or atrial flutter using the two protocols had a greater than 5' duration respectively in 83 and 78% of gr. I, 62 and 42% of gr. II and in 41 and 38% of gr. III.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1990

[Evaluation of the efficacy and tolerability of sustained-release nifedipine in arterial hypertension. Continuous monitoring of arterial pressure].

UNLABELLED: The anti-hypertensive efficacy of slow-release nifedipine 20 mg twice a day was investigated in 20 consecutive patients (13 females and 7 males, mean age 50.3 +/- 9.9 years) with mild to moderate hypertension (mean casual BP 162.2 +/- 7.5/103.1 +/- 4.7 mmHg) continuous blood pressure monitoring and routine laboratory tests were performed before and after three months of continuous therapy, whereas casual blood pressure was assessed after one and three months of therapy. RESULTS: In 4 patients, all female, adverse effects (headache) led to discontinuation of therapy. In the other 16 patients casual blood pressure decreased to 149.8 +/- 12.7/95.3 +/- 6.6 after one month and to 148.7 +/- 11.7/91.4 +/- 7.1 after three months (p less than 0.05 and became normal after three months in 11 patients (68%). Continuous blood pressure monitoring showed a significant fall in systolic and diastolic day time blood pressure (from 132.8 +/- 6.0/87.9 +/- 5.1 - p less than 0.02) and in systolic night time blood pressure (from 117.1 +/- 6.6 to 107.1 +/- 5.1 - p less than 0.02) without changing the shape of the circadian profiles. No significant changes in systolic blood pressure variability were observed. There was no correlation between pretreatment blood pressure levels and the extent of blood pressure fall during therapy. Heart rate, body weight and all biochemical parameters remains unchanged. CONCLUSION: Our findings confirm the antihypertensive efficacy of slow release nifedipine. This study does not concord with other reports regarding the tolerability of this drug in women. However the small number of patients does not allow any firm conclusions to be drawn.

Adult↗
PubMed1989

[Usefulness of transesophageal electrophysiological study during the ergometric test in the evaluation of supraventricular paroxysmal tachycardia occurring during exertion].

Transesophageal electrophysiologic study has recently been proposed for the evaluation of supraventricular arrhythmias. In this report we present 13 cases, with palpitations occurring only during effort, due to a suspected supraventricular tachycardia, in which the usefulness of the transesophageal electrophysiologic study performed during stress test was evaluated. Of these 13 patients, nine were male and four were female, mean age was 29 yrs. Twelve cases had no heart disease, one had a moderate mitral valve insufficiency. Nine cases had a normal ECG, four had a WPW pattern. In 9/13 cases no significant arrhythmia was ever documented, in 1/13 ventricular premature beats were present in the basal ECG, in 1/13 a atrial fibrillation and in 2/13 a supraventricular reciprocating tachycardia was recorded. In all cases a maximal exercise test and a 24-hour Holter monitoring were performed. In all pts a transesophageal electrophysiologic study was performed both at rest and during extra-stimuli and incremental atrial pacing. The end point of transesophageal study was the induction of a sustained (greater than 30") supraventricular tachycardia. RESULTS. Maximal exercise test was negative in 11/13 cases; it showed ventricular premature beats in one case and initiated a supraventricular tachycardia in one. The 24 hour Holter monitoring was negative in 12/13 cases while it showed frequent ventricular premature beats in one. Resting transesophageal electrophysiologic study revealed dual A-V nodal pathways in six pts: in one of them a junctional re-entry was induced; in two a single echo beat was observed, while in three no reentry was observed. In three cases a supraventricular tachycardia was induced which was sustained in one and unsustained (7" and 24") in two cases. In 4 cases transesophageal electrophysiologic study gave no information. Transesophageal stimulation during exercise induced a greater than 30" reciprocating tachycardia in all patients, at work loads of 30-180 watts. Six pts had an intranodal tachycardia (V-A less than 70 msec) a further six pts had a atrioventricular tachycardia involving a Kent bundle (V-A greater than or equal to 70 msec), which was concealed in two, and one had a atrial tachycardia. In four cases (3 with intranodal and 1 with atrioventricular tachycardia), exercise transesophageal study was repeated after chronic therapy with betablockers (sotalol 240 mg/die or metoprolol 200 mg/die). In all cases, after therapy, the induced tachycardia had a longer cycle and in two cases it was induced at a higher work load. In a further two cases flecainide (200 mg/die) was tested. In one case (with atrial tachycardia), the arrhythmia was no longer inducible after therapy, in another case (with intranodal tachycardia) the drug had no effect. CONCLUSIONS. In patients with paroxysmal supraventricular tachyarrhythmias occurring during effort the basal ECG is normal or shows a WPW pattern. The maximal exercise test and 24 hour Holter monitoring give no information in over 90% of cases.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1988

Atrial electrophysiologic properties of patients with asymptomatic Wolff-Parkinson-White syndrome.

To evaluate the existence of a peculiar atrial electrophysiologic substrate, we studied 18 patients with asymptomatic Wolff-Parkinson-White (WPW) syndrome. These patients were compared with 10 age-matched normal subjects (N). Effective and functional refractory periods were determined at two right atrial sites (high and low in the lateral wall), during atrial pacing (100 min-1) and at twice diastolic threshold. Disperson (D) of effective (ERP) and functional (FRP) refractoriness was evaluated as the difference between refractory periods at the two atrial sites. WPW patients showed significantly lower mean values of effective and functional refractoriness at both atrial sites and significantly higher mean values of D-ERP and D-FRP. Moreover, in calculating the highest normal values of D-ERP and D-FRP (as mean values of N plus 2SD) it was observed that WPW with abnormal values of D showed a statistically (chi 2 test) higher incidence (100%) of induced atrial fibrillation (AF). These findings indicate the existence of both an abnormal atrial electrophysiologic substrate and of a higher vulnerability in WPW. Finally, AF was induced generally at the site with the lower refractoriness (i.e. low lateral site). This should be taken into account when considering how atrial fibrillation can be induced more easily.

Adolescent↗
PubMed1988

[Distributions, mean values and correlations of various coronary risk factors in a population of Veneto].

During the National Research Council (CNR) program called Atherosclerosis-Risk Factors 2 (ATS-RF2) a random sample of 1903 subjects (50.1% male) aged 20-59 years was examined in the general population of Mirano-Venice. Mean values of serum total cholesterol and triglycerides, body mass index, as well as systolic and diastolic blood pressure were assessed. On the whole these turned out to be higher in men and increased with age. The continuously distributed variables showed an approximately normal distribution and a close correlation. Comparing our results with those obtained by other Italian units co-operating in the same CNR program, different levels of serum total cholesterol and systolic blood pressure were observed. The overall risk factor pattern in northern Italian regions is closer to that reported in the literature for central European countries than to that of southern Italian regions. These findings might explain why mortality due to ischaemic heart disease is higher in northern Italy and becomes progressively smaller in central and southern Italy.

Adult↗
PubMed1987

[Different degrees of risk of high-frequency atrial fibrillation in symptomatic and asymptomatic WPW syndrome. Electrophysiologic evaluation].

Sudden death in WPW pattern can occur when atrial fibrillation (a.f.) with rapid ventricular response develops. This event seems to be the final result of three concomitant conditions: the appearance of an orthodromic atrio-ventricular reciprocating tachycardia, the most common form of tachycardia in these patients; a high atrial vulnerability, which makes possible that reciprocating tachycardia degenerates into atrial fibrillation and a short anterograde refractory period of the Kent bundle. With the purpose of evaluating the risk to develop high frequency a.f., 36 WPW subjects were electrophysiologically studied. 22 were symptomatic for palpitations (Group I) and 14 were totally asymptomatic (Group II). 3/22 patients of Group I had experienced clinical atrial fibrillation (Subgroup I A), which was never documented in the remaining 19/22 (Subgroup I B). In all cases the following parameters were analyzed: the presence or absence of the retrograde conduction of the anomalous pathway, essential for the occurrence of orthodromic reciprocating atrio-ventricular tachycardia; the presence or absence of a high atrial vulnerability and the presence of RR intervals between pre-excited complexes during induced a.f. less than 250 msec. As an index of atrial vulnerability were considered the spontaneous degeneration into atrial fibrillation of an electrophysiologically induced reciprocating tachycardia and/or the induction of a sustained a.f. by programmed right atrial stimulation during sinus rhythm and/or during 600 and 400 ms atrial driving and/or by 160-250/m' atrial bursts. Results--Retrograde conduction of Kent bundle was documented in 100% of Gr. I vs 22% of Gr. II (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

[Value of serial electropharmacologic tests in the treatment of sustained ventricular arrhythmias].

The value of electropharmacological testing in patients (pts) with sustained ventricular tachyarrhythmias was studied in 46 consecutive pts (24 with sustained ventricular tachycardia (SVT) and 22 with cardiac arrest due to a ventricular tachyarrhythmia. Forty-two pts underwent a baseline electrophysiological study. The ventricular stimulation protocol included up to 3 extrastimuli during spontaneous rhythm and during paced ventricular rhythm at 100/min, 130/min, 160/min and brief bursts pacing at 2 ventricular sites. Ventricular tachycardia was induced in 37/42 pts (88%) (sustained in 32 pts and non sustained in 5 pts). Twenty nine pts underwent 79 trials of different drug regimens (mean 2.72 per pt, range 1-8). A totally successful drug regimen was found in 15/29 pts (51.7%) and a partially successful drug regimen in 11/29 pts (37.9%). Twenty-three pts were discharged on a drug regimen successful during serial electropharmacological testing (Group I) and 23 pts were discharged on an empiric drug regimen (Group II). Each pt was followed-up for a mean period of 15 months (range 1-74). Group I pts had fewer arrhythmia recurrence (SVT and/or sudden death) than Group II pts (2/23 vs 13/23 p less than 0.01). In conclusion electropharmacological testing is an useful tool in the therapy of pts with sustained ventricular tachyarrhythmias.

Adolescent↗
PubMed1985

[Idiopathic ventricular tachycardia responsive to verapamil. Presentation of 3 cases and review of the literature].

Recently a unique clinical entity has been suggested in subjects without apparent heart disease presenting with recurrent ventricular tachycardia (VT) characterized by RBBB + LAH electrocardiographic pattern, relatively slow rate, induction by atrial stimulation, and interruption by verapamil. According to these characteristics, three cases (2 M and 1 F, aged 18, 33 and 66 years) are presented in this study. They have had palpitations from one to twenty years, but not syncopal episodes. During VT the cycle length ranged from 300 to 480 msec. VT was terminated both by verapamil and by ajmaline. VT was inducible in 3/3 cases by incremental atrial pacing when cycle length of pacing became similar to that of spontaneous VT; in 2/3 cases VT was induced by programmed right atrial stimulation and in 2/3 cases by programmed ventricular stimulation. Serial electrophysiological studies for pharmacological and therapeutic evaluation applied to 1/3 cases showed: amiodarone given orally (200 mg/die) for two months prevented the induction of VT while verapamil, propranolol, mexiletine, and propafenone tested intravenously were ineffective. In the remaining two patients amiodarone, tested only intravenously, was not effective to prevent the induction of VT but lengthened its cycle length. All patients received amiodarone orally (200 mg/die) and were followed for 2,7 and 8 years respectively. Two of them had no more episodes of VT and one, while asymptomatic, continued to present with. The electrophysiological mechanism of this form of VT cannot be identified with certainty, but many data suggest a reentry in the posterior fascicle of left bundle branch as the most probable mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

[Predictive value of the ajmaline test in dysfunction of the sinus node. Prospective 4-year follow-up relative to 77 patients].

To establish the usefulness of Ajmaline test for the evaluation of sinus node function, 77 pts (47 M, 30 F, mean age +/- SD = 61 +/- 15 yrs) first underwent an electrophysiologic study and then were followed-up for a mean period of 46.3 months. The following parameters were determined before and after i.v. administration of Ajmaline (1 mg/kg in 1 minute): sinus cycle length (SCL), corrected sinus node recovery time (CSNRT) and sino-atrial conduction time (SACT). The pts were divided into 3 groups: Group A: 10 pts without clinical or electrocardiographic signs of sinus node dysfunction (SND) and with normal control CSNRT and SACT (less than or equal to 500 and less than or equal to 120 msec, respectively); Group B: 46 pts with clinical-electrocardiographic signs of suspected or apparently not severe SND (sinus bradycardia greater than or equal to 40 beats/min and/or syncopes with positive vagal manoeuvres) and/or slightly abnormal control CSNRT (greater than 500 less than or equal to 600 msec) and/or SACT (greater than 120 less than or equal to 150 msec); Group C: 21 pts with clinical-electrocardiographic signs of apparently severe SND (sinus bradycardia less than or equal to 39 beats/min, sino-atrial block, sinus arrest) and/or definitely prolonged control CSNRT and/or SACT (greater than 600 and greater than 150 msec, respectively). The Ajmaline test was considered negative for the presence of a severe SND if SCL was not prolonged after the administration of the drug more than 20% and CSNRT and SACT were not prolonged more than 50% compared to the control values. Otherwise the Ajmaline test was considered positive. Twenty-seven out of the 77 pts studied underwent permanent pacemaker implantation (23 immediately after the electrophysiologic study and 4 during the follow-up). The following results were obtained: the Ajmaline test was negative in 100% of group A, 87% of group B and 48% of group C pts and positive in 0% of group A, 13% of group B and 52% of group C pts; during the follow-up a negative test resulted predictive in 56 out of 60 pts (92%) and a positive test in 16 out of 17 pts (94%). The predictive accuracy of the test was, therefore, 93.5%. These results indicate that Ajmaline test is an useful provocative test for disclosing, during electrophysiologic studies, pts who have severe SND and for selecting those who need pacemaker implantation.

Adolescent↗
PubMed1985

[Post-ischemic inversion of the T wave].

The significance of new T wave inversion (so called post-ischemic T wave inversion) in the basal electrocardiogram of patients suffering from unstable angina is still controversial. Some AA suggest that the patients who develop this ecg pattern represent a subgroup with poor prognosis, particularly when to deep negative T waves (greater than 3 mm) a long QT interval is associated (giant negative T waves). On the contrary other AA suggest that there is not a different prognosis between patients which develop and which do not develop post-ischemic T waves (post-I T waves). We studied 113 patients with unstable angina: 95 patients were reviewed retrospectively (group I), 18 patients were studied perspectively (group II). In group I 63/95 developed post-I T waves (49 in anterior, 9 in inferior and 5 in both anterior and inferior leads) while 32/95 did not develop post-ischemic T waves. In group II all 18 patients developed post-ischemic T waves according to the characteristics of giant negative T waves. Follow up periods were 62 +/- 36 months in group I and 11 +/- 7 months in group II. In 61 cases (45 of group I and 16 of group II) the electrocardiogram was registered during anginal pain. ST increase and/or pseudonormalization of T wave from negative to positive, indicating transmural ischemia, was observed in 59% of patients with post-ischemic T waves vs 30% of pts without post-ischemic T waves (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1984

[Intrinsic function of the sinus node in patients with syncope and positive vagal maneuvers].

This study was undertaken to establish the nature (intrinsic or extrinsic) of sinus node dysfunction in patients presenting with syncope and abnormal response (sinus pause greater than 3'') to vagal manoeuvres (carotid sinus massage and/or eye-ball compression). To this purpose 29 patients (20 males, 9 females, aged 18-79 yrs, mean = 60) underwent an electrophysiologic study. In all we measured before and after autonomic blockade with Propranolol (0.2 mg/kg) and Atropine sulfate (0.04 mg/kg) the following parameters: sinus rate, corrected sinus node recovery time and sino-atrial conduction time. According to the presence or absence of electrocardiographic signs of sinus node dysfunction the patients were divided into three groups: Group A: 11 patients without electrocardiographic signs of sinus node dysfunction; Group B: 13 patients with borderline electrocardiographic signs of sinus node dysfunction (sinus bradycardia between 40 and 60 beats/min); Group C: 5 patients with definite electrocardiographic signs of sinus node dysfunction (sinus bradycardia less than or equal to 39 beats/min and/or sinoatrial block and/or sinus arrest). Fifteen patients (52%) had signs of organic heart disease. The main results obtained were: At least one electrophysiological test (sinus rate, corrected sinus node recovery time or sino-atrial conduction time) was abnormal in 10 patients (34,5%) before autonomic blockade and in 8 patients (27%) after autonomic blockade. Two of these 8 patients belonged to Group A (18%), 1 to Group B (8%) and 5 to Group C (100%). Six of these 8 patients were suffering from an organic heart disease and 2 were not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Mid-diastolic intraventricular functional block. A new mechanism for intermittent intraventricular blocks?

Experimental and clinical studies have demonstrated the existence of phase 3 and phase 4 functional blocks. In this report six cases are presented in which the electrophysiological study demonstrated the existence of a functional intraventricular block different from phase 3 and phase 4 blocks. In these cases the occurrence of the block was related to the presence in mid-diastole of a zone of block preceded and followed by intervals of unimpaired conduction. In two of 6 cases the functional block (infrahisian block) was not present in the basal tracing; it occurred during programmed atrial stimulation in a range of critical H1H2 coupling intervals delivered late in diastole, and did not appear after earlier stimuli. In the remaining four cases the conduction disturbance (2 RBBB, 2 infrahisian blocks) was present in the basal tracing, but disappeared both during early and late supraventricular extrastimuli, the first having short H1H2 intervals, the latter having H1H2 intervals longer than H1H1 basal cycle length. The width of the mid-diastolic zone of block varied from a few msec to hundreds of sec, and increased as heart rate increased. Two hypotheses are put forward in order to explain the electrophysiological mechanism responsible for the phenomenon: 1) a longitudinal dissociation in the conducting system, generating two different ways, one having a long refractory period, the other having a phase 4 spontaneous depolarization; they would be responsible of phase 3 and phase 4 blocks respectively. The early and late zones of conduction could be explained by an alternate conduction in one of the two ways, while the mid-diastolic zone of block could be due to a simultaneous block in both ways; 2) the existence of a diastolic oscillatory potential (late after-depolarization). In the latter case we can suppose that the mid-diastolic block was due to the stimulation of the cells of the conducting system before the restoration of the normal diastolic potential. Our electrophysiological data offer a new contribution to the understanding of intermittent intraventricular blocks. However further experimental and clinical studies are needed to confirm our electrophysiological hypotheses.

Adult↗
PubMed1983

Possible role of a ventricular conduction disturbance in the electrogenesis of the ECG-VCG signs of myocardial infarction.

The typical QRS patterns of myocardial infarction (MI-QRS) are commonly attributed to myocardial cellular death. However, observation of a transient appearance of MI-QRS during coronary insufficiency, the disappearance of MI-QRS after coronary by-pass surgery and the appearance of MI-QRS after intracranial hemorrhage suggest that a different electrophysiological mechanism may be at work. There is a single convincing explanation for all these observations. It seems possible, at least theoretically, that a localized conduction disturbance can generate or contribute to the generation of the MI-QRS. The results obtained in nine out of 194 cases studied by means of premature right atrial stimulation (PRAS) in our laboratory seem to confirm this hypothesis. In five of them we observed typical MI-QRS in the aberrant beats which were absent in the basal tracings. In the other four cases, MI-QRS which were present in basal tracings disappeared in the aberrant beats. In three of these a reduction in the duration of QRS was also observed, while in the fourth the duration of QRS did not change. In no case could the alterations of QRS (induction or disappearance of MI-QRS) be explained by a classical conduction disturbance, preexcitation or by a premature ventricular beat. While the induction of MI-QRS was clearly due to an aberrant conduction in the supraventricular beats, the disappearance of basal MI-QRS changes in premature supraventricular beats is more difficult to explain. One possible electrophysiological mechanism could be a supernormal phase conduction. If this is the case, the basal MI-QRS could be due to a ventricular conduction disturbance. In conclusion, our results suggest that MI-QRS can be generated, at least in our cases, by a localized conduction disturbance.

Adult↗