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Biomedical subjects

M Brignole

Publications and source records attributed to M Brignole.

At least 73 records · Page 4Linked to original sources
PubMed1998

Effects of long-term vasodilator therapy in patients with carotid sinus hypersensitivity.

BACKGROUND: In patients affected by carotid sinus hypersensitivity, long-term vasodilator therapy might increase the risk of syncopal episodes by reducing systolic blood pressure and venous return to the heart. METHODS AND RESULTS: Thirty-two patients (mean age 73 +/- 9 years; 20 men) who met all the following criteria were included: (1) one or more episodes of syncope occurring during long-term (>6 months) treatment with angiotensin-converting enzyme inhibitors, long-acting nitrates, calcium antagonists, or a combination of these; (2) a positive response to carotid sinus massage, defined as the reproduction of spontaneous syncope in the presence of ventricular asystole > or =3 seconds or a fall in systolic blood pressure > or =50 mm Hg; (3) negative workup for other causes of syncope. The patients were randomly assigned to continue or to discontinue use of vasodilators; carotid sinus massage was repeated 2 weeks after randomization. By the end of the study period, the baseline values of systolic blood pressure were significantly different between the 2 groups of patients both in supine (P=.01) and upright (P=.03) positions. Syncope had been induced by carotid sinus massage in 81% of patients in the "on-vasodilator" group and in 62% of patients in the "off-vasodilator" group (P=.21). The cardioinhibitory reflex was of similar magnitude in the 2 groups, being found in 50% of the patients in each group, with a maximum ventricular pause of 7.1 +/- 2.7 and 6.7 +/- 1.8 seconds, respectively. The percentage decrease of blood pressure did not differ between the 2 groups, even if, in absolute values, the baseline difference of blood pressure roughly persisted for the duration of the test. In consequence of that, the rise of blood pressure to similar values was delayed approximately 30 seconds in the "on-vasodilator" group and took more than 2 minutes to return to baseline values. CONCLUSIONS: In patients affected by carotid sinus hypersensitivity, chronic vasodilator therapy does not have a direct effect on carotid sinus reflexivity, although the delayed recovery of pretest blood pressure values could indirectly potentiate the severity of the clinical manifestations of the syndrome. The persistence of hypotension for a longer time after the end of the massage suggests that vasodilators cause an impairment of compensatory mechanisms.

Aged↗
PubMed1997

Adenosine-induced atrioventricular block in patients with unexplained syncope: the diagnostic value of ATP testing.

BACKGROUND: ATP and its related nucleoside, adenosine, are ubiquitous biological compounds with potent depressant activity on the atrioventricular node. We hypothesized that an increased susceptibility of the atrioventricular node to adenosine may, in some cases, play a role in the genesis of syncope. METHODS AND RESULTS: The study was performed in two parts. In part 1, we evaluated the effects of a bolus injection of 20 mg ATP in a group of 60 patients (57+/-19 years, 31 men) with syncope of unexplained origin and in 90 control subjects without syncope (55+/-17 years, 46 men). In control subjects, the upper 95th percentile of the maximum RR interval distribution, during ATP-induced atrioventricular block (AVB), was 6000 ms. In the syncope group, 28% of patients had a maximum RR interval above this limit (P=.000). The distribution of the maximum RR interval below the 95th percentile was similar in the two groups. In part 2, we validated the ATP test in 24 patients who had the fortuitous ECG recording of a spontaneous syncope caused by a transient asystolic pause (AVB in 15 and sinus arrest in 9). The ATP test caused AVB with an asystolic pause of > or = 6000 ms in 53% of the patients with documented AVB but in none (0%) of the patients with documented sinus arrest (P=.01). Among the patients with spontaneous AVB, the ATP test was abnormal in 6 of the 7 patients (86%) in whom all conventional investigations for syncope had been negative and in 2 of the 8 patients (25%) who had shown positivity (P=.03). CONCLUSIONS: An increased susceptibility to ATP testing is present in patients with SUO and patients with syncope due to paroxysmal AVB. Thus, a logical inference is that ATP testing can be used to identify patients with syncope due to paroxysmal AVB. The results of this study form the necessary background for future prospective studies with an aim to validate this assumption.

Adenosine↗
PubMed1997

Assessment of atrioventricular junction ablation and DDDR mode-switching pacemaker versus pharmacological treatment in patients with severely symptomatic paroxysmal atrial fibrillation: a randomized controlled study.

BACKGROUND: The purpose of the study was to evaluate the effect of AV junction ablation and pacemaker implantation on quality of life and specific symptoms in patients with paroxysmal atrial fibrillation (AF) not controlled by drugs. METHODS AND RESULTS: We performed a multicenter, randomized, 6-month evaluation of the clinical effects of AV junction ablation and DDDR mode-switching pacemaker (Abl+Pm) versus pharmacological treatment in 43 patients with intolerable, recurrent paroxysmal AF of three or more episodes in the previous 6 months not controlled with three or more antiarrhythmic drugs. Before completion of the study, 3 patients in the drug group withdrew because of the severity of their symptoms and 1 patient assigned to the Abl+Pm group in whom the ablation procedure failed. At the end of the 6 months, the 21 patients of the Abl+Pm group who completed the study showed, in comparison with the 18 of the drug group, lower scores in the Living with Heart Failure Questionnaire (-51%, P=.0006), palpitations (-71%, P=.0000), effort dyspnea (-36%, P=.04), exercise intolerance score (-46%, P=.001), and easy fatigue (-51%, P=.02). The scores for rest dyspnea, chest discomfort, and NYHA functional classification were also lower (-56%, -50%, and -17%, respectively) in the Abl+Pm group, although not significantly. At the end of the study, palpitations were no longer present in 81% of the Abl+Pm group and in 11% of the drug group (P=.0000). AF was documented in 31 of 122 visits (25%) in the Abl+Pm group and in 9 of 107 examinations (8%) in the drug group (P=.0005); chronic AF developed in 5 (24%) and 0 (0%) in the two groups, respectively (P=.04). CONCLUSIONS: In patients with paroxysmal AF not controlled by pharmacological therapy, Abl+Pm treatment is highly effective and superior to drug therapy in controlling symptoms and improving quality of life. The discontinuation of drug therapy exposes patients to further recurrences of paroxysmal AF and the risk of developing permanent AF.

Aged↗
PubMed1997

Effects of permanent pacemaker and oral theophylline in sick sinus syndrome the THEOPACE study: a randomized controlled trial.

BACKGROUND: Pacemakers and theophylline are currently being used to relieve symptoms in patients with sick sinus syndrome (SSS). However, the impact of either therapy on the natural course of the disease is unknown. We conducted a randomized controlled trial to prospectively assess the effects of pacemakers and theophylline in patients with SSS. METHODS AND RESULTS: One hundred seven patients with symptomatic SSS (age, 73 +/- 11 years) were randomized to no treatment (control group, n = 35), oral theophylline (n = 36), or dual-chamber rate-responsive pacemaker therapy (n = 36). They were followed for up to 48 months (mean, 19 +/- 14 months). During follow-up, the occurrence of syncope was lower in the pacemaker group than in the control group (P = .02) and tended to be lower than in the theophylline group (P = .07). Heart failure occurred less often in patients assigned to pacemaker therapy and theophylline than in control patients (both, P = .05), whereas the incidence of sustained paroxysmal tachyarrhythmias, permanent atrial fibrillation, and thromboembolic events did not show any apparent difference among the three groups. Heart rate was higher in the theophylline group than in the control group. Both pacemaker therapy and theophylline improved symptom scores after 3 months of treatment; however, a similar improvement was observed in the control group. CONCLUSIONS: In patients with symptomatic SSS, therapy with theophylline or dual-chamber pacemaker is associated with a lower incidence of heart failure; pacemaker therapy is also associated with a lower incidence of syncope. The therapeutic benefits of pacemakers and theophylline on symptoms are partly a result of spontaneous improvement of the disease.

Administration, Oral↗
PubMed1997

Clinical usefulness of slow pathway ablation in patients with both paroxysmal atrioventricular nodal reentrant tachycardia and atrial fibrillation.

Some patients with atrioventricular (AV) node reentrant tachycardia (AVN RT) also presented with atrial fibrillation (AF). In this study we demonstrate that slow pathway ablation is able to suppress both AVN RT and AF in subjects without structural heart abnormalities, whereas in patients with structural heart abnormalities after ablation AF frequently recurs.

Adult↗
PubMed1997

Multiple mechanisms of successful slow-pathway catheter ablation of common atrioventricular nodal re-entrant tachycardia.

BACKGROUND: In patients with atrioventricular nodal re-entrant tachycardia, modifications of the antegrade atrioventricular nodal function curve caused by catheter ablation of the so-called slow pathway are heterogeneous, but have not yet been systematically evaluated. AIM: To test the hypothesis that successful treatment is independent of specific electrophysiological modifications of atrioventricular nodal conducting properties. METHOD: Standard electrophysiological parameters and comparable antegrade atrioventricular nodal function curves were obtained, before and after successful ablation, in 104 patients (mean age 52 +/- 16 years: 69 women) affected by the common form of atrioventricular nodal re-entrant tachycardia. RESULTS: Three different major patterns of antegrade atrioventricular nodal function curve were caused by ablation: downward shift of the curve with disappearance of atrioventricular nodal duality, suggesting the elimination of the slow pathway in 54 (52%) patients (type 1): absence of clear modifications of the curve (and of slow pathway ablation) in 33 (32%) patients (type 2); upward shift of the curve, suggesting a further slowing of conduction velocity through the slow pathway in 17 (16%) patients (type 3). Type-1 pattern was more frequent in patients < or = 45 years, whereas type-2 pattern was more frequent in those > 45 years. CONCLUSION: Successful ablation of atrioventricular nodal re-entrant tachycardia is independent of specific modifications of antegrade atrioventricular conduction and probably depends on critical nodal and perinodal tissue damage at different sites on the re-entrant circuit. The effects of ablation are influenced by patient age.

Adolescent↗
PubMed1997

Methods other than tilt testing for diagnosing neurocardiogenic (neurally mediated) syncope.

The recording of spontaneous episodes of bradycardiac neurocardiogenic syncope (NCS) has shown that: a prolonged ventricular asystole seems necessary to cause syncope; asystole is preceded by other bradyarrhythmias in the vast majority of cases; some warning symptoms precede the loss of consciousness in most cases; conventional dual-chamber pacing is efficacious both in patients with a positive response to carotid sinus massage (CSM) and eyeball compression test (EBC) and in those with a positive response to tilt-testing (TT). CSM, EBC, and TT are established tools for diagnosing NCS, when the recording of spontaneous syncope is lacking. When combined together, they are probably able to correctly identify most patients affected by NCS. Nevertheless, whether the type of reflex induced by the cardiovascular reflexivity maneuvers correlates with that of the spontaneous syncope is largely unknown. Our knowledge suggests that the correlation may be unsatisfactory, owing to the following: the variability of the mechanism of spontaneous syncope from patient to patient and also, in the same patient, from one episode to another; the discordance of the type of response when 2 or 3 tests are positive in the same patient, the response being more frequently asystolic with CSM and EBC and more frequently vasodepressor with TT: the different timing between hypotension induced by CSM (in which it follows the bradycardia) and that induced by TT (in which it usually precedes the bradycardia) and the uncertainty about the timing of hypotension during the spontaneous syncope; the good reproducibility of the spontaneous event by CSM and EBC, but not by TT, when cardiac asystole is the manifestation of NCS; and the fairly high rate of false-positive results of cardiovascular reflexivity maneuvers. Hypotension is the main reason for the failure of pacemaker therapy in all the forms of neurocardiogenic syncope (NCS), whether diagnosed by CSM, EBC, or TT. Thus, the need arises to correctly identify the magnitude of the hypotensive reflexes of spontaneous events.

Adult↗
PubMed1997

Detecting incipient vasovagal syncope: intraventricular acceleration.

The peak endocardial acceleration (PEA) caused by ventricular isometric contraction can be measured with an implantable microaccelerometer located inside the tip of a normal unipolar pacing lead. It has been shown that PEA correlates with myocardial contractility and the maximum rate of rise of ventricular pressure (peak dP/dt) of the left ventricle. A PEA measuring system was temporarily inserted into the apex of the right ventricle in seven patients affected by syncope of uncertain origin. Each patient subsequently underwent 60 degrees tilt testing with three different protocols: without pharmacological challenge (baseline); potentiated with sublingual trinitroglycerin (at a dose of 0.3 mg); and with isoproterenol infusion (at a dose of 3 micrograms/min). Each phase lasted 20 minutes. Syncope was induced in 1 patient during the baseline phase, in 3 patients during the trinitrin phase, and in 4 patients during the isoproterenol phase. Six patients had a negative response during the baseline phase and served as a control group. From the beginning of upright posture to the time of maximum heart rate, PEA increased by about the same amount in both positive and negative patients, but absolute values were from two- to three fold higher with isoproterenol (from 1.2 +/- 0.5 G to 1.6 +/- 0.8 G, from 0.8 +/- 0.2 G to 1.2 +/- 0.4 G, and from 2.8 +/- 1.8 G to 3.6 +/- 1.8 G, respectively, for negative, positive baseline or trinitrin, and positive isoproterenol tests). At the time of syncope, PEA values fell to baseline values. PEA changes were inversely correlated with blood pressure changes and directly correlated with heart rate changes. Thus, tilt induced syncope occurred both at low and high levels of left ventricular contractility. Whether spontaneous syncopes occur at low or high PEA behavior remains to be established. Since heart rate correlates well with changes in PEA and is far easier to measure, it is unlikely that a PEA measurement system or, in general, a contractility-based system, might become an ideal sensing parameter for the introduction of devices to combat vasovagal syncope.

Acceleration↗
PubMed1996

A patient with syncopal ventricular tachycardia (noninducible on electrophysiologic study) and coronary artery disease.

The case of a 63-year-old patient with coronary artery disease presenting with syncopal sustained ventricular tachycardia is reported. He had very poor ventricular function, an extensive myocardial scar, and limited area of reversible ischemia. Coronary angiographic examination showed a left main equivalent coronary artery disease with critical stenosis. Although this patient should theoretically benefit from revascularization, we decided against this due to the high estimated perioperative mortality rate for coronary artery bypass grafting in such a patient. Therefore, we intensively treated myocardial ischemia and pump failure with digoxon, furosemide, dihydralazine, nitrates, and warfarin and prescribed a back-up defibrillator implant.

Cardiac Pacing, Artificial↗
PubMed1995

Value of head-up tilt testing potentiated with sublingual nitroglycerin to assess the origin of unexplained syncope.

This study was undertaken to assess the value of sublingual nitroglycerin administration during upright tilt as a simple practical test for the diagnosis of vasovagal syncope. To this purpose, 235 patients with syncope of unknown origin and no evidence of organic heart disease (110 men, mean age 52 +/- 20 years) and 35 asymptomatic control subjects underwent head-up tilt testing with nitroglycerin challenge. Patients and subjects were tilted at 60 degrees for 45 + 20 minutes; the initial 45 minutes were without medication and the final 20 minutes after 300 micrograms of sublingual nitroglycerin. During the drug-free phase of the test, 59 patients (25%) and no controls had a positive response. After drug administration, a positive response (syncope in association with sudden hypotension and bradycardia) occurred in 60 patients (26%) and in 2 controls (6%), whereas an exaggerated or false-positive response (minor or different symptoms in association with slowly increasing hypotension alone) was observed in 33 patients (14%) and in 5 controls (14%). We conclude that the sublingual nitroglycerin head-up tilt test is a useful tool to unmask the vasovagal origin of unexplained syncope in patients without organic heart disease. The addition of nitroglycerin to upright tilt allows the positive rate of passive tilting to be doubled (51% vs 25%) while maintaining a high specificity (94% vs 100%).

Administration, Sublingual↗
PubMed1995

Mechanisms of syncope caused by transient bradycardia and the diagnostic value of electrophysiologic testing and cardiovascular reflexivity maneuvers.

Transient bradycardia may be intrinsic because of sinus node or atrioventricular (AV) conduction abnormalities, or extrinsic because of abnormal vagal reflex. Twenty-five consecutive patients, referred to us for study of unexplained syncope, who, during electrocardiographic monitoring, had a documented episode of intermittent bradycardia that caused syncope, underwent a full electrophysiologic study, carotid sinus massage, and the head-up tilt test. A prolonged ventricular asystole (5 to 20 seconds) was documented during syncope in all patients: sinus arrest in 13, AV block in 7, sinus arrest plus AV block in 3, and asystolic pause during atrial fibrillation in 2. Abnormal electrophysiologic findings suggested the correct diagnosis in 6 patients (24%): block within the bundle of His in 5 and sick sinus syndrome in 1. An abnormal response to carotid sinus massage or to the head-up tilt test suggested a neurally mediated mechanism in 17 patients (68%). Overall, electrophysiologic study and vasovagal maneuvers were able to identify the mechanism of spontaneous syncope in 23 patients (92%). Thus, in patients affected by syncope due to transient bradycardia, the most likely mechanism of syncope is neurogenic, whereas it is cardiogenic only in a few instances. Electrophysiologic testing, carotid sinus massage, and the head-up tilt test can identify most of these patients. Conversely, when all these tests are negative, it is unlikely that transient bradycardia is the cause of syncope. Because of the different mechanisms involved, electrophysiologic study and vasovagal maneuvers are complementary diagnostic tools.

Adult↗
PubMed1995

[The re-evaluation of the vasodepressive component in the carotid sinus syndrome].

BACKGROUND: The evaluation of the vasodepressor (VD) reflex of the carotid sinus syndrome is usually inaccurate, due to the difficulty in blood pressure measurement. AIM: To study the VD reflex with a beat-to-beat not invasive technique. METHODS: We investigated 68 patients (49 males, 19 females; mean age 70 +/- 11 years) affected by carotid sinus syndrome: cardioinhibitory (CI) form was present in 47 patients, mixed (M) form in 10 patients and VD form in 11 patients. The control group consisted of 9 patients (6 male, mean age 71 +/- 8 years) affected by third degree atrioventricular block who had received the implant of a permanent pacemaker and were pacemaker-dependent with a prolonged asystole at time of temporary inhibition of the pacemaker itself. The study of the VD reflex was performed in the supine position; beat-to-beat arterial systolic pressure was monitored by a photoplethysmographic method using a finger cuff (Finapres technique). RESULTS: In all the patients the carotid sinus massage caused a marked fall in systolic blood pressure which was greatest at the end of the massage: from 143 +/- 25 mm Hg to 74 +/- 20 mm Hg in the patients with CI form, from 144 +/- 14 mm Hg to 76 +/- 18 mm Hg in those with M form and from 125 +/- 26 mm Hg to 65 +/- 13 mm Hg in those with VD form. A decrease in systolic blood pressure > or = 50 mm Hg occurred in 84% of cases. Afterwards, the patients with CI form had a progressive increase of systolic blood pressure that reached the initial value after a mean of 27 seconds. In the patients with VD form systolic blood pressure was significantly (p < or = 0.5) lower than that observed in all the other groups, beginning from the third second after the end of the massage; mean systolic blood pressure value remained significantly lower than the initial value for more than 27 seconds. The patients with M form showed an intermediate pattern. Also control group patients showed a fall in systolic blood pressure immediately after pacemaker inhibition (from 152 +/- 29 mm Hg to 87 +/- 25 mm Hg) that was of similar extent than that observed in carotid sinus syndrome patients, but pressure returned to initial value within 9 seconds. CONCLUSIONS: An important VD reflex is present in most patients with carotid sinus syndrome. It lasts more than the CI reflex and it persists for several seconds after the end of the massage. The initial fall of systolic blood pressure is of similar extent in all the forms of carotid sinus syndrome, but the patients with the VD form are characterized by a longer duration and greater entity of the decrease. These results point out the importance of the VD reflex in patients with the carotid sinus syndrome.

Aged↗