Ancient remedies revisited: does Allium sativum (garlic) palliate the hepatopulmonary syndrome?

Hypoxia in the setting of liver disease is often multifactorial. Obstructive or restrictive lung disease, pleural effusions, and tense ascites are common underlying disorders. Less often observed and frequently unrecognized is hypoxia related to diffuse intrapulmonary shunting--the hepatopulmonary syndrome. Its etiology is unknown but may result from disordered gut peptide metabolism. Symptoms may be ameliorated by somatostatin and reversed by successful liver transplantation. Here we report a patient with severe hepatopulmonary syndrome who failed somatostatin therapy and declined liver transplantation. On her own the patient took large daily doses of powdered garlic (Allium sativum). She has experienced partial palliation of her symptoms and some objective signs of improvement over 18 months of continuous self-medication. The possible effects of garlic's main physiologically active compound, allicin, on gut peptide metabolism and pulmonary vasculature are unknown. This innocuous compound may deserve further investigation given the limited therapeutic options for this disorder.

Laser catheter-induced atrioventricular nodal delays and atrioventricular block in dogs: acute and chronic observations.

Selective modification of atrioventricular (AV) nodal conduction, that is, induction of varying degrees of AV nodal delays or block (second or third degree), or both, was achieved with a pervenous laser catheter technique. In six adult mongrel dogs anesthetized with pentobarbital (Nembutal), 5F leads were placed through femoral and external jugular veins and placed into the right atrium and His bundle region. Through another femoral vein, a 200 micron optical fiber was inserted by way of a 7F catheter with a preformed curved tip. Guided by fluoroscopy and His bundle electrograms, the fiber's tip was positioned in the AV nodal region. After autonomic blockade was achieved with intravenous propranolol (5 mg) and atropine (1 mg), AV conduction was analyzed. An argon laser delivered 3 to 4 watts into the fiber in bursts of 10 seconds' duration until the desired degree of AV nodal delay or block (second or third degree) was manifested. Monitoring of His bundle electrograms was continued for 2 hours. Four weekly serial electrocardiograms were recorded, after which electrophysiologic studies were repeated. Acute post-lasing studies showed that: in all six dogs, the mean PR interval was prolonged from 116 ms (range 100 to 135) to 153 ms (range 120 to 185), with the prolongation being caused exclusively by AH lengthening from 68 ms (range 50 to 90) to 105 ms (range 65 to 140); the mean effective refractory period of the AV node increased from less than 185 ms (range less than 150 to less than 200) to 215 ms (range 190 to 280); and the mean atrial pacing cycle length, at which second degree AV nodal block was manifested, increased from 210 ms (range 160 to 260) to 261 ms (range 205 to 320).(ABSTRACT TRUNCATED AT 250 WORDS)

Microtransection of the His bundle with laser radiation through a pervenous catheter: correlation of histologic and electrophysiologic data.

This study describes microtransection of the His bundle with a pervenous laser catheter in a live dog. In an adult mongrel dog anesthetized with Nembutol , administered intravenously, electrode catheters (No. 5Fr and 6Fr ) were inserted through a femoral vein and positioned in the high right atrium for atrial pacing and in the His bundle region for recording of His bundle electrograms. The AH and HV intervals were measured during normal sinus rhythm and atrial pacing. Through another femoral vein, a laser fiber was inserted through a lumen catheter (No. 7Fr ) with a preformed curved tip. Under fluoroscopic control, the laser fiber tip was positioned immediately next to the His bundle electrode catheter. During continuous His bundle recordings and fluoroscopic monitoring, short bursts (10 to 60 seconds) of argon laser were delivered (2.5 W) in order to produce His bundle interruption and complete heart block. Escape of a His bundle rhythm (cycle length = 1,100 ms) with QRS morphologic characteristics and duration similar to that of normal sinus rhythm was noted. "Split" His bundle potentials were recorded with an unchanged AH (50 ms) and an H'V interval of 20 ms. After the dog was killed, serial sections of the conduction system of the heart were analyzed. Histologic findings showed excellent correlation with electrophysiologic observations and validated "split" His bundle potentials. The laser radiation produced microtransection of the His bundle with a channel of tissue dissolution 0.2 to 0.3 mm wide in diameter. The latter passed through the His bundle at the junction of penetrating and branching segments, dividing it into superior and inferior portions that retained continuity with proximal and distal His bundle.(ABSTRACT TRUNCATED AT 250 WORDS)

[Value of provocation tests in the evaluation of the treatment of ventricular tachycardias with amiodarone]. / Intérêt des tests de provocation dans l'appréciation du traitement des tachycardies ventriculaires par l'amiodarone.

The role of provocation tests for the assessment of amiodarone therapy in patients with ventricular tachycardia remains a subject of controversy: recent studies seem to show that the ability to initiate VT in patients on amiodarone is compatible with a good long-term result. Eighteen patients, 16 male and 2 female, average age 56 years, were treated with amiodarone (600 mg/day in 15 cases, and 400 mg/day in 3 cases) and submitted to provocative tests before and after treatment. The mean follow-up period was 14 +/- 4 months. In Group I (5 patients), VT could not be initiated after treatment and there were no relapses of the arrhythmia. In Group II (6 patients), non-sustained VT could be initiated and only one relapse was observed after a close reduction from 600 to 400 mg/day; Group III comprised 5 patients with spontaneous recurrences. An identical VT could be initiated during electrophysiological investigation which served as a basis for selection of an effective antiarrhythmic association. Two patients could not be studied after drug impregnation (1 sudden death, 1 exacerbation of VT). The results of this study show that provocative pacing can be useful in evaluating the efficacy of amiodarone, as in Groups I and II (61% of patients) a favourable prognosis could be predicted in 91% of cases. In cases of therapeutic failure with spontaneous recurrences of VT, the same provocation tests enabled a more effective drug combination to be selected.

[Evaluation of ventricular tachycardia by endocavitary stimulation. Apropos of 46 cases]. / Evaluation des tachycardies ventriculaires par la stimulation endocavitaire. A propos de 46 cas.

Thirty six patients (21 coronary artery disease, 8 cardiomyopathy, 3 mitral valve prolapse and 4 apparently normal) underwent endocavitary stimulation studies. The protocol consisted in delivering one or two right ventricular extrastimuli and twice the diastolic threshold either during spontaneous rhythm (S2 and S2-S3) or a paced ventricular rhythm (S1-S2 and S1-S2-S3). In 9 patients overdrive ventricular pacing at 150-200 bpm was required. Thirteen of the 15 documented sustained ventricular tachycardias could be induced by electrical stimulation (87%). In addition, 9 sustained ventricular tachycardias were induced in patients in whom the symptomatology corresponded to poorly tolerated tachycardia but in whom the documented arrhythmia was non-sustained ventricular tachycardia (4 cases), frequent ventricular extrasystoles with doublets (2 cases) or rare, isolated ventricular extrasystoles (3 cases). The method was less sensitive in non-sustained ventricular tachycardia in which the arrhythmia was induced in 10 of the 17 cases (59%). An antiarrhythmic drug was selected on the basis of these studies in 28 patients, 21 of whom had sustained ventricular tachycardia. There were 6 therapeutic failures with a follow-up of 6 to 24 months, three of which were observed in patients with coronary artery disease and a precarious haemodynamic state. This subgroup is not suitable for this type of evaluation. After reviewing other published series the authors emphasise the value of these investigations in chronic sustained ventricular tachycardia, in ventricular tachycardia with cardiovascular collapse and in the assessment of syncope of unknown origin. However, the systematic investigation of repetitive ventricular responses after ventricular stimulation in patients at high risk of sudden death remains controversial.

[Electrophysiological effects of encainide in man]. / Effets électrophysiologiques de l'encaïnide chez l'homme.

Encainide is an antiarrhythmic agent under evaluation; it is effective in ventricular and supraventricular arrhythmias. Its electrophysiological effects seem to differ according to the route of administration, oral or intravenous, probably because of the effects of active metabolites. Two electrophysiological studies were carried out in 20 patients, under basal conditions, and after 4 to 10 days oral administration at doses ranging from 75 to 300 mg/day. Encainide depressed intra-atrial conduction (prolongation of the P-A interval from 29,7 +/- 2,2 to 36 +/- 4,5 ms, p less than 0,01), slowed conduction in the atrioventricular mode (prolongation of the A-H interval from 74 +/- 14 to 98 +/- 15 ms, p less than 0,01) and the His-Purkinje system (lengthening of H-V from 50 +/- 3 to 70 +/- 6,2 ms, p less than 0,001). The sinus node function was depressed with lengthening of the corrected sinus node recovery time (297 +/- 64 to 387 +/- 71 ms, p less than 0,01) and of the sinoatrial conduction time (173 +/- 25 to 219 +/- 43, p less than 0,01). The atrial and ventricular refractory periods were significantly longer (245 +/- 16 ms to 273 +/- 10 ms, p less than 0,001, and 237 +/- 12 to 266 +/- 19 ms, p less than 0,01, respectively). This new antiarrhythmic agent therefore seems to act at all levels which suggests that it may have wide ranging antiarrhythmic effects.

[The functional dissociation of conduction within the human AV-node (author's transl)]. / Funktionelle Leitungsdissociation innerhalb des menschlichen AV-Knotens.

The functional dissociation (FD) of conduction within the AV-node is characterized by sudden prolongations and/or shortenings of the AH-time during stimulation. Examples for FD are presented during regular atrial stimulation and atrial extrastimulus technique. The appearance of FD is no proof for functional impairment of the AV-node. The blockade of the parasympathetic nervous system abolishes FD and leads to the well known continuous and regular adaptation of the AH-time with the various kinds of stimulation examined. It is recommended to replace the term "pathways" by the more comprehensive concept of functional dissociation with the AV-node.

Clinical electrophysiological effects of propranolol on normal sinus node function.

In 35 patients aged 18 to 69 years (mean 48) with clinical, electrocardiographic, or electrophysiological evidence of normal sinus node function, the effect of intravenous propranolol (0.1 mg/kg) was assessed on 3 indices of sinus node function. The drug significantly prolonged sinus node cycle length (12%), slightly prolonged the corrected sinus node recovery time (15%), and slightly but insignificantly lengthened sinuatrial conduction time. Propranolol may be administered safely in patients with normal sinus node function without the fear of producing severe sinus bradycardia, sinuatrial block, sinuatrial pauses, or prolonged sinus asystole, after spontaneous or stimulation-induced conversion of a tachycardia.

A new method for measurement of sinoatrial conduction time.

This study describes a new method (NM) for estimation of sinoatrial conduction time (SACT), which utilizes constant atrial pacing (AP) instead of the premature atrial beats (PABs) used in the method reported in 1973 by Strauss et al. The SACTs were obtained by both methods in 20 patients. The SACT by the Strauss method (SM) was calculated as A2A3 minus A1A1. The NM consists of high right AP for a train of eight consecutive beats at rates less than or equal to 10 beats/min faster than the sinus rhythm. The interval between the last paced atrial electrogram (Ap) and the first escape atrial electrogram (A) of sinus origin (Ap-A) was measured along with several post pacing sinus cycles. The SACT by the NM was calculated as follows: SACT = Ap-A minus A1A1. The effect of AP at higher rates was also analyzed. In two patients, the SACT with the SM could not be defined, as all the A2A3 intervals were fully compensatory; with the NM the SACT was 217 and 320 msec. In the remaining 18 patients the SACT was obtainable by both methods. With SM, the SACT ranged 105--452 msec (mean 219 +/- 102 SD) and with the NM it was 85--492 msec (mean 201 +/- 112 SD), and the difference was statistically significant (P = 0.0162). The coefficient of correlation between the two methods was r = 0.97. During AP at faster rates, a rate related increment in Ap-A intervals and also post pacing sinus cycles was noted. This study describes a new and simple method for measurement of SACT in man.

Junctional pacemakers in man. Response to overdrive suppression with and without parasympathetic blockade.

This study analyzes the response to overdrive suppression of junctional pacemakers (JP) and correlates it with symptoms in 21 patients. Junctional rhythm (JR) was seen in 5 patients with intact A-V conduction, and in 16 with complete heart block, the JPs were located proximal to or within the His bundle (BH). Junctional recovery time (JRT) was measured following atrial or ventricular pacing during control and after atropine (2-2.5 mg). Control cycle length of the JR ranged from 835-2100 msec (mean 1402) and the corrected JRT (CJRT) ranged from 75 to greater than or equal to 7510 msec (mean 2966). Following atropine, the cycle length ranged from 660 to 2000 msec (mean 1115) and the CJRT ranged from 90 to greater than 6000 msec (mean 2050). All symptomatic patients were treated with permanent ventricular demand pacemakers and followed clinically from 6-72 months (mean = 35). Symptomatic patients could not be differentiated from asymptomatic patients on the basis of control heart rates, chronotropic response to atropine, and/or the site of origin of the JP as determined with BH recordings. However, presence or absence of symptoms of syncope and dizziness were well correlated with a CJRT greater than or less than 200 msec, respectively, either following atropine or during control. The determination of CJRT both before and after parasympathetic blockade provides a simpler and more reliable method for the therapeutic evaluation of patients.

[Clinical physiology and physiopathology of the atrioventricular node]. / Klinische Physiologic und Pathophysiologie des AV-Knotens.

The functional behaviour of the healthy and sick human AV-node under various clinical-experimental conditions is described with special reference to (1) AV-nodal conduction, (2) AV-nodel refractoriness, (3) influence of autonomic tone and (4) role of the AV-node in the initiation of rhythm disturbances.

[The influence of frequency and blockade of the autonomic nervous system on the functional behaviour of the human conduction system. Part B: Refractory periods (author's transl)]. / Die Beeinflussung der funktionellen Eigenschaften des menschlichen Erregungsleitungssystems durch Frequenzbelastung, elektroinduzierte Vorhofextrasystolen und Blockade des autonomen Nervensystems. Teil B: Refraktätsverhalten

32 patients were studied by His-bundle-electrocardiogram and programmed atrial stimulation to examine to which extent frequency and autonomic tone participate in influencing the effective (ERP) and functional (FRP) refractory periods of the atrium and AV-node. The measurements were performed during three electrically induced atrial frequencies before and after intravenous injection of 1 mg Atropine (15 patients) and 0.4 mg Visken (17 patients). For the atrium, frequency dominates the blockade of both components of the autonomic nervous system in influencing both refractory periods. Increase in frequency shortens both ERP and FRP of the atriu. The blockade of parasympathicus and sympathicus does not significantly influence the changes in atrial ERP and FRP induced by atrial pacing. The AV-node responses most sensitive to both pacing induced cycle length shortening and blockade of the autonomic tone. Cycle length shortening prolongs the nodal ERP. the FRP is either shortened or prolonged. Blockade of the parasympathicus shortens both nodal ERP and FRP. Blockade of the sympathicus lengthens both parameters. This behaviour of both refractory periods in response to atrial pacing and blockade of the autonomic tone are discussed with respect to the "gate mechanism" in the conduction system. In the majority of patients blockade of the parasympathicus shifts the "gate" from the AV-node to the atrium. Blockade of the sympathicus has the opposite effect in some cases.