Paroxysmal supraventricular tachycardia induced during exercise and ajmaline tests in the Wolff-Parkinson-White syndrome.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
S Laniado
Publications and source records attributed to S Laniado.
Anomalous origin of the right coronary artery from the ascending aorta. Diagnosis by digital subtraction angiography.
The anomalous origin of a coronary artery often poses diagnostic difficulties at angiography. The right coronary artery is more rarely affected than the left. A patient is presented in whom the right coronary artery arose from the ascending aorta. The diagnosis of this rare anomaly was facilitated by the use of digital subtraction aortography and allowed selective angiography of the artery with an appropriately shaped catheter.
Angiography↗
Percutaneous transluminal coronary angioplasty as a cause of isolated right ventricular infarction.
Acute myocardial infarction is a recognized major complication of percutaneous transluminal coronary angioplasty (PTCA). Isolated right ventricular infarction is rare. A 60-year-old patient underwent PTCA 24 h following clinically successful thrombolytic therapy for an acute occlusion of a dominant right coronary artery. Following successful PTCA of this artery, a right ventricular branch was noted to be occluded. This was associated with chest pain, elevated venous pressure, S-T segment elevation in ECG leads V1-3, and a transient rise in serum creatine kinase. The clinical course was uneventful and a week later the right ventricular ejection fraction had increased from 18 to 36%. The long-term effects of right ventricular infarction are benign and occlusion of a right ventricular branch during PTCA is rarely of clinical significance.
Angioplasty, Balloon↗
Idiopathic ventricular fibrillation: inducibility and beneficial effects of class I antiarrhythmic agents.
Ventricular fibrillation in patients without recognizable heart disease is uncommon and electrophysiologic data on such patients is limited. Over a 7 year period, five patients (three men and two women, ranging in age from 24 to 52 years) without demonstrable heart disease underwent electrophysiologic studies with pharmacologic drug testing because of single (four patients) or multiple (one patient) documented episodes of ventricular fibrillation. The arrhythmic event was unrelated to myocardial ischemia or infarction, metabolic or electrolyte disturbances, drug toxicity, preexcitation, or prolonged QT syndromes. In all three patients receiving no antiarrhythmic drugs and in two pretreated with amiodarone, a rapid poorly tolerated ventricular tachyarrhythmia requiring cardioversion was induced by programmed ventricular stimulation with up to two extrastimuli. In all instances, addition of either oral quinidine or oral disopyramide prevented the induction of sustained ventricular arrhythmias. All five patients were placed on antiarrhythmic drug regimens found effective during electrophysiologic studies and remained asymptomatic during follow-up periods ranging from 12 to 93 (mean 52) months. We conclude that in the patients with idiopathic ventricular fibrillation in our study: programmed ventricular stimulation reliably replicated the spontaneous arrhythmia, class I antiarrhythmic agents effectively prevented induction of the arrhythmia in the laboratory, and in contrast to the severity of the presenting arrhythmia, a benign clinical course was observed during long-term therapy with class I antiarrhythmic agents.
Adult↗
Effects of coronary occlusion on high-frequency content of the epicardial electrogram and body surface electrocardiogram.
The very high-frequency content (150 to 250 Hz) of epicardial electrogram waveforms was studied in 19 anesthetized dogs subjected to occlusion of left anterior descending coronary artery. Computer techniques of digital averaging and digital band-pass filtering were applied. Signals were obtained from epicardial electrodes placed in the ischemic left ventricular region and on the noninjured right ventricular surface, and from the body surface electrocardiogram. All recordings were made simultaneously before, during, and after coronary occlusion and subjected to the same analysis. The waveforms obtained from the ischemic left ventricular region showed a considerable decrease in high-frequency content, while those obtained from the noninjured right ventricular surface remained unchanged. The results correlated with the appearance of a zone of reduced amplitude in the body surface high-frequency QRS complex. Therefore, this macroscopic phenomenon measured noninvasively from the body surface is explained by local reduction of high-frequency activity in the ischemic region of the myocardium.
Animals↗
[Magnetic resonance imaging of the heart and the great vessels].
Explore the source record for details and available documents.
Blood Vessels↗
Comparison of exercise and ajmaline tests with electrophysiologic study in the Wolff-Parkinson-White syndrome.
Ajmaline test (50 mg intravenously over 1 minute) and ergometric exercise test were performed in 24 patients with the Wolff-Parkinson-White syndrome. The effects of both tests on the conduction in the accessory pathway (AP) were correlated with the anterograde effective refractory period (ERP) of the AP. Ajmaline caused transient anterograde block in the AP in 15 patients, 14 with an ERP of more than 250 ms and 1 with an ERP of 250 ms. Ajmaline failed to abolish preexcitation in 9 patients, all with ERP of the AP of 250 ms or less. Exercise testing caused anterograde block in the AP in 5 patients, in 2 during exercise (ERP of 340 and 360 ms) and in the remaining 3 patients during the recovery phase (ERP of 600, 520 and 460 ms). Of the 10 patients with an ERP of 250 ms or less, ajmaline did not abolish preexcitation in 9 and exercise did not abolish it in any of them. Of the 7 patients with an ERP of 330 ms or more, ajmaline abolished preexcitation in 7 and exercise abolished it in 5 patients. Of the 7 patients with ERP of the AP more than 250 ms but less than 330 ms, ajmaline but not exercise abolished preexcitation in all. Thus, ajmaline and exercise testing can detect patients with short and long ERPs of the AP, respectively, and the effects of ajmaline and exercise tests combined may be useful in the noninvasive assessment of various ranges of ERP of the AP.
Adult↗
Paroxysmal atrioventricular block triggered by orthostatic hypotension.
Explore the source record for details and available documents.
Electrocardiography↗
Dynamics of mitral regurgitation during nitroglycerin therapy: a Doppler echocardiographic study.
Seven patients with decompensated chronic heart failure and functional mitral regurgitation were studied before and during administration of nitroglycerin at a mean dose of 42 micrograms/min (range 20 to 90 micrograms/min). Forward aortic flow obtained by pulsed Doppler increased significantly from 35 +/- 8 to 45 +/- 9 ml/beat (p less than 0.001) and correlated well with the cardiac output measured by thermodilution technique (r = 0.8). Whereas regurgitant mitral volume calculated from the difference between echocardiographic total stroke volume and forward aortic flow decreased significantly from 19 +/- 9 to 3 +/- 3 ml/beat (p less than 0.001), peak velocity of mitral regurgitant flow increased from 4.1 +/- 0.9 to 4.4 +/- 1.0 m/sec (p less than 0.05). The decrease in effective mitral regurgitation area derived from a modified Gorlin formula average 80%. Accordingly, in patients with decompensated chronic heart failure and functional mitral regurgitation, nitroglycerin decreases mitral regurgitant area substantially, and thus almost abolishes mitral regurgitation despite an increase in systolic pressure gradient between left ventricle and atrium. Moreover, the increase in forward flow can be entirely accounted for by the reduction in mitral regurgitant flow.
Aged↗
Mechanisms of syncope in glossopharyngeal neuralgia.
Syncope is a rare presentation of glossopharyngeal neuralgia (GN). The mechanisms of the syncope were studied in a patient with recurrent episodes comprising prolonged cardiac standstill and arterial hypotension. During attacks, no supraventricular or ventricular potentials were recorded in the ECG. Atropine prevented the cardiac arrest without affecting the pain, indicating the vagus as the efferent limb of the reflex asystole. Following atropine blood pressure continued to fall during GN attacks, suggesting abolition of sympathetic tone. Indeed, serum norepinephrine levels fell during these attacks. Infiltration of either vagus above the clavicle with local anesthetics did not abolish the cardiac asystole. Carbamazepine and a dual chamber pacemaker were effective in controlling the symptoms of the patient. The results suggest that, during a neuralgic attack, the stimulation excites both vagi, causing asystole and simultaneously abolishes sympathetic tone.
Biomechanical Phenomena↗
High frequency electrocardiography using an advanced method of signal averaging for non-invasive detection of coronary artery disease in patients with normal conventional electrocardiogram.
The ability to detect coronary artery disease (CAD) in patients with normal, conventional electrocardiograms (ECG) was studied using high frequency electrocardiography and an advanced method of signal averaging in three groups of subjects. Group A consisted of ten healthy subjects under the age of 30; Group B of 15 patients with chest pains and normal coronary arteries; and Group C of 20 patients with chest pains and CAD. Four hundred ECG waveforms from leads V3, V4 and V5 were recorded, and the recorded analog data were digitized. The digitized waveforms were averaged using a cross-correlation function which operates in the frequency domain (fast-Fourier transform algorithm). The signals were filtered with a digital band pass filter with 150 and 250 Hz low and high cut-off frequencies, respectively. Zones of reduced amplitude in the envelope of the filtered QRS complex of at least two precordial leads were found more significantly in patients with CAD (75%) than in patients without CAD (12% for Groups A and B, p less than 0.00003). However, no significant difference was found between the voltage over the high frequency QRS complex and that of its envelope between the three groups. It is concluded that the morphology of the high frequency QRS complex as determined by this advanced method of analysis of the signal averaged ECG may be a useful indicator for the presence of CAD in patients with normal conventional ECG's.
Adult↗
Transcatheter electrical shock ablation of ventricular tachycardia.
Transcatheter shock ablation of ventricular tachycardia was attempted in seven patients who had drug-resistant ventricular tachycardia and in one patient in whom ventricular tachycardia was electrophysiologically induced during therapy with multiple antiarrhythmic drugs. Seven patients had previous myocardial infarction and five of them were high risk candidates for surgical therapy. One patient without organic heart disease had repetitive ventricular tachycardia manifesting two different patterns of left bundle branch block. After endocardial mapping, synchronized unipolar 250 to 300 J shocks (one to six) were delivered between the pole recording the earliest endocardial activity during ventricular tachycardia (40 to 200 ms before the onset of the QRS complex) and a body surface electrode. Immediate complications included severe but reversible cardiogenic shock (one patient), nonclinical ventricular tachycardia (two patients, requiring cardioversion in one), transient atrioventricular and intraventricular conduction disturbances (three patients) and permanent left bundle branch block (one patient). A late complication in one patient, left heart failure, occurred 3 days after delivery of five intracardiac shocks. In two patients, left ventricular ejection fraction markedly decreased and in one of them new ventricular contraction abnormalities appeared. Clinical ventricular tachycardia did not recur in five of the seven post-myocardial infarction patients after 7 to 17 months, and it was not inducible in the four patients undergoing late electrophysiologic study. In the patient with idiopathic ventricular tachycardia, one of the configurational types of ventricular tachycardia recurred.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Antiarrhythmic and haemodynamic effects of tiapamil, a new calcium antagonist, during coronary artery occlusion and reperfusion in dogs.
The antiarrhythmic and haemodynamic effects of tiapamil, a new calcium antagonist, were studied in 28 anaesthetised open chest dogs. Tiapamil (2 mg X kg-1 intravenously over 5 min) was infused 15 min before a 20 min ligature of the left anterior descending coronary artery in 11 dogs. In 17 dogs physiological solution was given instead of tiapamil. In this control group, ventricular fibrillation developed during coronary occlusion in 14 (82%) dogs and after coronary reperfusion in seven of 9 (77%) dogs, which reached this stage. In contrast, in the dogs pretreated with tiapamil, ventricular fibrillation did not develop during coronary occlusion in any of the 11 dogs and did develop after coronary reperfusion in only one (9%). In addition, tiapamil appreciably decreased heart rate and blood pressure and increased cardiac output and stroke volume. These antiarrhythmic and haemodynamic effects of tiapamil suggest that this drug would be useful in the management of patients with coronary artery disease.
Animals↗
Recurrent preexcited reciprocating tachycardia, concealed ventricular preexcitation and conduction disturbances in the normal atrioventricular pathway in a newborn.
We describe a newborn infant with concealed ventricular preexcitation in sinus rhythm on the early ECGs, and who developed recurrent episodes of preexcited reciprocating tachycardia. Manifestation of the ventricular preexcitation and initiation of the tachycardias were dependent on the presence of severe conduction disturbances in the normal atrioventricular pathway, probably in the atrioventricular node.
Electrocardiography↗
Interrelationship of mid-diastolic mitral valve motion, pulmonary venous flow, and transmitral flow.
This study offers a unifying mechanism of left ventricular filling dynamics to link the unexplained mid-diastolic motion of the mitral valve with an associated increase in transmitral flow, with the phasic character of pulmonary vein flow, and with changes in the atrioventricular pressure difference. M mode echograms of mitral valve motion and Doppler echocardiograms of mitral and pulmonary vein flow velocities were recorded in 12 healthy volunteers (heart rate = 60 +/- 9 beats/min). All echocardiograms showed an undulation in the mitral valve (L motion) at a relatively constant delay from the peak of the diastolic phase of pulmonary vein flow (K phase). In six subjects, the L motion was also associated with a distinct wave of mitral flow (L wave). Measured from the onset of the QRS complex, Q-K was 577 +/- 39 msec; Q-L was 703 +/- 42 msec, and K-L was 125 +/- 16 msec. Multiple measurements within each subject during respiratory variations in RR interval indicated exceptionally small differences in the temporal relationships (mean coefficient of variation 2%). Early rapid flow deceleration is caused by a reversal of the atrioventricular pressure gradient, and the L wave arises from the subsequent reestablishment of a positive gradient due to left atrial filling via the pulmonary veins. The mitral valve moves passively in response to the flowing blood and the associated pressure difference. This interpretation is confirmed by (1) a computational model, and (2) a retrospective analysis of data from patients with mitral stenosis and from conscious dogs instrumented to measure transmitral pressure-flow relationships.
Adolescent↗
Haemodynamic effects of Ro 13-6438, a new inotropic agent with vasodilating properties.
The chemical class 1,5 dihydroimidazo (2,1-6) guinazolin-2(3H)ones has been shown to have positive inotropic activity, some of its members displaying a favourable ratio between positive inotropic and chronotropic activity. This study was designed to determine the cardiovascular properties of Ro 13-6483, a non-glycoside, non-catechol positive inotropic agent, in anaesthetized, open chest mongrel dogs. Ro 13-6483 (1 mg/kg) was administered intravenously over a 5-min period to 6 dogs. Haemodynamic changes were measured continuously over a period of 45 min. Ro 13-6438 increased stroke volume by 61.9% (p less than 0.001) and cardiac output by 53.3% (p less than 0.001). Systolic and diastolic blood pressure decreased significantly (p less than 0.01). Heart rate did not change. The lowering of the blood pressure, without a significant increase in heart rate, observed after Ro 13-6483 administration might prove to be of value in patients with congestive heart failure, since Ro 13-6483 would reduce afterload and improve the competency of the heart, in addition to the positive inotropic effects.
Animals↗
Catheter ablation of incessant ventricular tachycardia refractory to external cardioversions.
Explore the source record for details and available documents.
Adult↗
Comparative electrophysiologic effects of adenosine triphosphate and adenosine in the canine heart: influence of atropine, propranolol, vagotomy, dipyridamole and aminophylline.
The electrophysiologic effects of adenosine triphosphate (ATP) and adenosine and the modification of these effects by atropine, propranolol, vagotomy, dipyridamole and aminophylline were studied in a canine model. Both ATP and adenosine exerted transient, dose-dependent negative chronotropic and dromotropic effects on the sinoatrial and atrioventricular nodes, respectively. At all doses tested, the effects of ATP were more pronounced. Treatment with either atropine or propranolol plus bilateral cervical vagotomy attenuated the effects of ATP but not of adenosine. In the presence of propranolol plus vagotomy, both the negative chronotropic and dromotropic effects of ATP and adenosine were enhanced and attenuated in a similar manner by dipyridamole and aminophylline. Thus, when ATP and adenosine are injected rapidly into the right atrium of the intact canine heart, vagal involvement in the mechanism of action of ATP but not of adenosine is mainly responsible for the difference in the magnitude of the electrophysiologic effects of these 2 compounds, and only a small part of the electrophysiologic effects of ATP are the result of its degradation to adenosine.
Adenosine↗