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PubMed1998

"Stunning" of the left atrium after spontaneous conversion of atrial fibrillation to sinus rhythm: demonstration by transesophageal Doppler techniques in a canine model.

OBJECTIVES: This study compared left atrial and left atrial appendage contraction velocities in sinus rhythm before and after a brief period of atrial fibrillation in a canine model. BACKGROUND: In patients, left atrial appendage contraction velocities measured during sinus rhythm after cardioversion from atrial fibrillation are depressed relative to left atrial appendage emptying velocities measured during atrial fibrillation, suggesting that the left atrial appendage is mechanically "stunned." METHODS: This phenomenon was studied in a canine model of acute (60 min) pacing-induced atrial fibrillation followed by spontaneous reversion to sinus rhythm using epicardial and transesophageal pulsed wave Doppler. Unique features of the model include: 1) comparison of left atrial function postconversion to baseline sinus rhythm rather than to measurements during atrial fibrillation, 2) control of the duration of atrial fibrillation and 3) elimination of the extraneous influences of direct current shock and antiarrhythmic agents, which may independently depress left atrial function. RESULTS: Hemodynamic conditions (heart rate, mean arterial pressure, cardiac output, mean pulmonary artery pressure, mean right atrial pressure and mean left atrial pressure) at baseline, during 60 min of atrial fibrillation and after reversion to sinus rhythm were constant throughout the study period. Peak left atrial contraction velocities (measured from the transmitral flow velocity profile) were significantly (p < 0.02) reduced to 64+/-22% of baseline values upon spontaneous conversion of atrial fibrillation to sinus rhythm and recovered to basal values by 20 min after resumption of sinus rhythm. Peak left atrial appendage contraction velocities were significantly (p < 0.001) reduced to 49+/-24% of baseline values upon spontaneous conversion of atrial fibrillation to sinus rhythm and recovered to basal values by 40 min after reversion to sinus rhythm. CONCLUSIONS: Even brief (60 min) periods of atrial fibrillation in normal canine hearts result in marked depression of global left atrial systolic function and regional left atrial (left atrial appendage) systolic function upon resumption of sinus rhythm. This "mechanical stunning" of left atrial systolic function appears to be more profound and of longer duration for the left atrial appendage compared with the left atrium as a whole, which may predispose the appendage to blood stasis and thrombus formation. Chronic models of atrial fibrillation need to be developed to examine the impact of longer periods of atrial fibrillation upon the magnitude and duration of postconversion left atrial "stunning."

Animals↗
PubMed2000

Sonographic appearances of preauricular sinus.

AIM: Preauricular sinuses are a common congenital abnormality. This study was performed to determine their sonographic features. MATERIALS AND METHODS: Fifteen preauricular sinuses (in 13 patients) were examined using a 5-10 MHz transducer to evaluate the nature of the sinus. Surgical correlation was obtained in 11 cases. RESULTS: Sonography detected the sinus in all cases. The maximum width of the sinus tract was 3 mm; it showed a branching pattern in four (27%) patients. Nine sinuses (60%) led to a cystic component, and the remaining six (40%) showed terminal ramification. Gas was identified within the sinus in nine (60%) cases. In the patients that underwent surgery, the diagnosis and the relationship of the sinus/ cystic component to the superficial temporal artery (STA), anterior crus of the helix and the tragus was confirmed and correlated well with the sonographic findings. However, the branching pattern of the sinus tract was difficult to confirm. CONCLUSION: Sonography readily detects preauricular sinuses and demonstrates their relationship to the STA, anterior crus of the helix, and the tragus, and can therefore be helpful in pre-operative assessment. Ahuja, A. T. (2000). Clinical Radiology 55, 528-532.

Adolescent↗
PubMed1998

Venous reconstruction in surgery of meningiomas invading the sagittal and transverse sinuses.

SURGERY OF MENINGIOMAS INVOLVING MAJOR DURAL SINUSES LEAVES THE SURGEON CONFRONTED WITH A DIFFICULT DILEMMA: leave the fragment invading the sinus in place and have a higher risk of recurrence, or attempt a total removal with or without venous reconstruction and expose the patient to a potentially greater operative danger. The authors report a series of 47 meningiomas (41 of the sagittal sinus, 4 of the transverse sinus and 2 of the torcular) in whom gross total removal was achieved in all cases, and venous reconstruction (of various types) attempted in a majority. Thirty-nine patients had a good outcome and resumed their previous activities. There was a permanent neurological deficit in five due to infarction secondary to injury of central veins (all in the sagittal sinus midthird). Three patients died from brain swelling; all with meningioma totally occluding the sinus and in whom resection was achieved without sinus reconstruction. There were two recurrences in this series which has a mean follow-up of 7.5 years.The authors' surgical experience led them to favor whenever possible, total removal with sinus reconstruction, using a patch for meningiomas with partial sinus invasion and a venous bypass for those with total sinus occlusion.

Journal Article↗
PubMed2000

Evaluation of fluid collection in the pericardial sinuses and recesses: noncontrast-enhanced electron beam tomography.

RATIONALE AND OBJECTIVES: To evaluate the attenuation, size, and volume of the pericardial sinuses and recesses by using electrocardiographically triggered, noncontrast-enhanced electron beam tomography (EBT) and to consider its relation with sex, age, and heart volume. METHODS: Findings in 213 consecutive patients without known pericardial disease were studied. The patients underwent EBT scanning of the heart to evaluate coronary artery calcification. Incremental electrocardiographically triggered noncontrast images were obtained with a 100-ms exposure time and a 3-mm slice thickness. The appearance, density, and volume of the pericardial sinuses and recesses were calculated. RESULTS: Among the 213 patients, 97.2% had at least one of the sinuses or recesses visible on EBT. The sinuses or recesses were seen with the following frequency: transverse sinus (93.9%), oblique sinus (71.8%), and superior aortic recess (51.2%). The mean attenuation and volume were 9.9 +/- 7.3 Hounsfield units (HU), 12.6 +/- 8.1 HU, and 12.6 +/- 8.7 HU, and 1.9 +/- 1.3 mL, 1.3 +/- 1.0 mL, and 0.8 +/- 0.8 mL, respectively. The total volume of the pericardial sinuses (3.3 +/- 2.2 mL) had no significant relation with the total heart volume. CONCLUSIONS: Pericardial sinuses and recesses were frequently and well depicted on noncontrast EBT images. In patients without obvious pericardial effusion, physiological fluid collections were observed in the transverse and oblique sinuses or other recesses. Location, attenuation, and volume were helpful in the differentiation of normal pericardial sinuses from pericardial effusions and mediastinal lymph nodes.

Adult↗
PubMed1987

Coronary sinus interventions: from concept to clinics.

For almost 100 years the coronary venous system has attracted researchers as an access route to deprived myocardium. Different concepts have been tried and numerous experimental studies have been performed to evaluate whether coronary sinus occlusion, retroinfusion, and retroperfusion of arterial blood via the coronary sinus represent an effective treatment of myocardial ischemia. The early successful studies of Drs. Gregg, Eckstein, Beck and others led to the application of the Beck II procedure, a permanent retroperfusion technique used in the early 1950s to revascularize patients with diffuse atherosclerosis. The coronary sinus route was also used to retroperfuse blood intraoperatively during opening of the heart to keep the heart beating. Excessive mortality and severe side effects, such as myocardial edema and hemorrhage, and an insufficiently advanced technology resulted in the temporary demise of the coronary sinus approaches. Recently, however, the need to improve myocardial protection, despite enormous advances in coronary bypass surgery and interventional cardiology, has resulted in renewed interest in the coronary sinus as an access route to deprived myocardium. Advances in technology such as percutaneous catheter techniques have improved access to the coronary venous system and allowed for a physiological adaptation of coronary sinus retroperfusion techniques. Today the three major coronary sinus techniques, i.e., sychronized retroperfusion (SRP), retroinfusion of cardioplegia during cardiac arrest and retroinfusion of pharmaceutical agents in the normal working heart, and pressure-controlled intermittent coronary sinus occlusion (PICSO) have been documented as providing superior protection of jeopardized myocardium in selected subsets of patients. All of these techniques currently are under clinical consideration; the retroinfusion of cardioplegia has already found wide clinical acceptance, SRP and PICSO have only recently been tested in first clinical trials. Due to a vast resurgence in interest, it is desirable to survey the results obtained with each of these techniques, to discuss the pathophysiology and mode of action of coronary sinus interventions, and to assign them a place in the perspective of conventional therapies. Furthermore, an attempt will be made to weigh individual coronary sinus techniques against each other, discuss in which clinical settings each of them may be most effective, and define issues facing current development.

Animals↗
PubMed1993

Sinus node dysfunction during long-term lithium treatment.

BACKGROUND AND OBJECTIVE: Lithium has occasionally been reported to cause symptomatic sinus node bradyarrhythmias. The prevalence and mechanism of these arrhythmias during long-term treatment are unknown. The aims of this study were (a) to evaluate the systemic effects of lithium treatment on cardiac conduction in individuals who were free from cardiovascular disorders; (b) to assess the prevalence of lithium treatment in a group of patients with pacemakers; and (c) to evaluate the interaction between the parasympathetic limb of the autonomous nervous system and the sinus node cells during long-term lithium treatment. PATIENTS AND METHODS: 45 patients who had been treated with lithium for > 12 months were investigated in a long-term electrocardiography study. Only patients without cardiovascular disease, or concomitant chronotropic medication, or metabolic disorders known to cause rhythm disturbances were included. An age-stratified population was used as a reference group. 21 patients also underwent analysis of carotid sinus pressure and sinus cycle length before and after atropine to clarify whether neural mechanisms were involved. The prevalence of lithium treated patients was determined in 650 patients with pacemakers. RESULTS: (a) Signs of moderate sinus node dysfunction (sinus arrest > 1.5 s, minimum heart rate < 50 beats/min) were found in 56% and 78% respectively in the lithium-treated group compared with 30% and 30% respectively in the reference group (p < 0.01). Severe sinus node dysfunction was equally common in both groups. (b) The prevalence of chronic lithium treatment in the pacemaker population was 0.46%. (c) Sinus cycle variations were abnormal in the basal state in three (14%) patients and in 11 (52%) patients after atropine despite signs of intact and normal parasympathetic innervation. CONCLUSIONS: Depressed sinus node function was significantly more common in a lithium-treated population than in an age-stratified reference group. Clinically significant dysfunction, however, was uncommon. The effect of lithium on the sinus node seemed to be intrinsic and was not caused by increased parasympathetic tone.

Aged↗
PubMed1982

The renal sinus during allograft rejection: sonographic and histopathologic findings.

In fourteen renal allografts, the sonographic appearance of the renal sinus was correlated with the histopathologic findings. In each allograft specimen, the histologic changes in the renal sinus were compared with those in the renal cortex. Except for one case (hyperacute rejection), the histologic rejection changes were of similar severity within the cortex and renal sinus. When the renal sinus histologic changes of rejection were considered to be minimal (three patients), the sonographic appearance of the renal sinus was classified as normal. With moderate histologic changes in the renal sinus (five patients), the sonographic findings in four patients were considered moderate, with a change in spatial distribution resulting in a coarse and uneven distribution of renal sinus echoes. When the renal sinus histologic changes of rejection were interpreted as severe (six patients), the sonographic findings were similarly more advanced. Except for a very few intense echoes distributed in an irregular pattern, the area of the renal sinus blended with the adjacent parenchyma. The study demonstrated a good correlation between histology and sonography of the renal sinus during allograft rejection, and promises reliable prediction of the severity of the rejection process using a noninvasive, rapid, and relatively simple approach.

Adipose Tissue↗
PubMed1983

Effects of gamma-aminobutyric acid on neural regulation of the canine sinus node.

The direct effects of gamma-aminobutyric acid (GABA) on the sinus node and its neural regulation were studied by selective perfusion of the sinus node artery (SNA) in 26 open-chest pentobarbital-anesthetized dogs. GABA (1-1,000 micrograms/ml, 2 ml, SNA) produced no direct effect on intrinsic sinus rate, but in several experiments (at 1 microgram/ml) it produced an inconsistent augmentation of the sinus tachycardia due to right stellate stimulation. At all other concentrations tested (10-1,000 micrograms/ml), GABA did not significantly alter the sinus node response to stellate stimulation. Local alpha-receptor blockade with phentolamine or muscarinic receptor blockade with atropine through the SNA prior to the perfusion of GABA did not change the sinus node responses. GABA (10-1,000 micrograms/ml, 2 ml, SNA) significantly attenuated (by 45-80% of control) the sinus bradycardia due to stimulation of the right vagosympathetic trunk. The sinus node response to selective perfusion of norepinephrine or acetylcholine (0.01 micrograms/ml, 2 ml, SNA) was not affected by GABA. The stellate augmentation (when present) and vagal attenuation were both antagonized by perfusion of picrotoxin (1,000 micrograms/ml, 2 ml, SNA). It is concluded that GABA does not exert any direct effect on the sinus node but may indirectly influence sinus rate by an effect on local nerves or ganglia.

Animals↗
PubMed1988

Short- and long-term effects of transcatheter ablation of the coronary sinus by radiofrequency energy.

Catheter ablation of left-sided atrioventricular accessory pathways through the coronary sinus by direct-current shock may be complicated by rupture and thrombosis of the coronary sinus and injury to the coronary arteries. This study examined short and long-term effects of radiofrequency catheter ablation of the coronary sinus in 20 closed-chest dogs to determine whether this technique is feasible for potential interruption of left-sided accessory pathways. Single-pulsed radiofrequency energy (750 kHz, 85-293 J) was delivered to three sites in the distal and middle coronary sinus between the distal (1) or the proximal electrodes (2 or 3) of a standard 6 French quadripolar catheter and a chest-wall patch electrode. Single-pulsed radiofrequency energy (78-293 J) was also applied to two sites near the ostium of the coronary sinus with the proximal (4) or the distal (1) electrode of the same catheter. Coronary artery and levophase coronary sinus angiograms obtained before and immediately after ablation, as well as before killing, showed intact vascular structures in all dogs. Right atrial, pulmonary arterial, and aortic pressures measured in three dogs did not change significantly at the time of energy delivery. No significant changes were found in atrioventricular nodal refractoriness and conduction. None of the dogs had significant rhythm disturbances during and after ablation as evaluated by ambulatory electrocardiographic monitoring and periodic rhythm strips at follow-up. Ten dogs were killed 1-7 days after ablation, three dogs were killed at 4 weeks, three dogs at 6 weeks, two dogs at 8 weeks, and two dogs at 12 weeks. Discrete lesions ranging in size from 3 x 3 to 8 x 10 mm2 in surface area and 0.5-4.5 mm in depth were found in the coronary sinus with most of the lesions extending to the left atrial and left ventricular myocardium. There was neither rupture of the coronary sinus nor occlusion of the coronary arteries. Mural thrombus was found in the coronary sinus on five acute lesions in two dogs, but none was noted on the chronic lesions, which was characterized by chronic granulation tissue and fibrosis. Two dogs in the study during chronic conditions had damage to branches of the underlying coronary artery that showed necrotizing arteritis and arterial sclerosis. Conduction system studies in four dogs showed some chronic inflammatory and fibrotic changes. Similar discrete lesions were found in situ in the coronary sinus of four postmortem human hearts with radiofrequency catheter ablation.(ABSTRACT TRUNCATED AT 400 WORDS)

Angiography↗
PubMed1982

Effects of ouabain and vagal stimulation on sinus nodal function in conscious dogs.

We studied the effects of intravenous ouabain administration (15 micrograms/kg) and vagal stimulation on instrumented conscious dogs. In these dogs, a special electrode was implanted on the epicardial surface over the sinus node and plaque electrodes were placed on the superior vena cava and left atrial appendage. Unipolar sinus electrograms were recorded through the terminals of the sinus electrode paired with the superior vena caval electrode. An electrode also was implanted around the desheathed cervical vagosympathetic trunk, and a coiled polyethylene tube with side holes was implanted cranial to it. Ouabain administration resulted in: (1) an increase in the sinus cycle lengths and sinoatrial intervals and increase in beat-to-beat variation of the sinus cycles and sinoatrial intervals, and (2) periods of sinus pacemaker shift, sinus arrest and sinoatrial block that occurred spontaneously or after atrial overdrive stimulation delivered through the electrode on the left atrial appendage. These effects of ouabain were abolished by intravenous administration of atropine (2 mg). Prior to vagal stimulation, intravenous propranolol (0.5 mg/kg) was administered to block sympathetic responses and 0.75% bupivacaine was injected through the polyethylene tube to block afferent transmission. Vagal stimulation in conscious dogs resulted in two types of responses: (1) slowing of sinus pacemaker rate accompanied by a decrease in diastolic slope and followed by sinus pacemaker shifts, and (2) gradual prolongation of the sinoatrial intervals followed by failure of sinoatrial conduction. An intravenous bolus of acetylcholine (0.1 mg) resulted in a response of type 2 in dogs in which vagal stimulation produced a response of type 1. The marked similarity between the effects of ouabain and vagal stimulation on sinus function and the abolition of the effects of ouabain by atropine suggest that the ouabain effects are vagally mediated.

Action Potentials↗
PubMed1989

Intermittent coronary sinus occlusion after coronary arterial ligation results in venous retroperfusion.

Coronary sinus occlusion retards necrosis of ischemic myocardium. To test the hypothesis that coronary sinus occlusion induces retrograde venoarterial flow, the coronary arteriovenous pressure gradient and the coronary arterial oxygen saturation were measured distal to a left anterior descending coronary artery ligature in dogs. In parallel, we constructed a mathematical model of known coronary physiology to characterize pressure and flow patterns during coronary sinus occlusion. In dogs, coronary sinus occlusion produced a systolic pressure gradient between the coronary artery and the coronary sinus of -20 +/- 9 mm Hg (higher venous pressure, p less than 0.0001) and a positive diastolic gradient of 3 +/- 5 mm Hg (lower venous pressure p less than 0.01). An average reduction in the oxygen saturation in the ligated coronary artery of 20 +/- 13% was also observed (p less than 0.005) consequent to admixture of venous (desaturated) blood. By graded inflation of the coronary sinus balloon, it was demonstrated that desaturation of arterial blood typically occurs above a coronary sinus systolic pressure of 40-50 mm Hg. The mathematical model indicates the possibility of venoarterial pressure gradients and reversal of flow at the microcirculatory level during coronary sinus occlusion. These studies provide evidence that retrograde flow into the ischemic zone occurs in association with intermittent coronary sinus occlusion. Thus, alternating flow over the ischemic territory may be the mechanism of myocardial salvage during intermittent coronary sinus occlusion.

Animals↗
PubMed1981

Effects of clonidine on sinus node function in man.

Drugs interfering with sympathetic tone may result in depression of the function of the sinus node, especially in patients with disease of the sinus node. In 11 patients presenting with palpitations, vertigo, or syncope, the heart rate, the recovery time of the sinus node, the carotid sinus pressure slowing, and the atrioventricular conduction capacity were assessed before and every five minutes up to 30 minutes after intravenous administration of 0.15 mg of clonidine. The following significant maximal mean effects were noted at about 15 minutes after the administration of clonidine: the heart rate decreased 12 percent (59 vs 52 beats per minute); and the atrioventricular conduction capacity (ie, paced heart rate at second-degree atrioventricular block) decreased by 9 percent (132 vs 121 beats per minute), while the maximal recovery time of the sinus node increased by a factor of two (1,704 vs 3,562 msec) when atrial overdrives of 120, 150, and 200 beats per minute were used for each five minute period. In analyzing maximal carotid sinus pressure slowing after administration of clonidine, three of 11 patients developed hypersensitive carotid sinus reflex de novo, and two patients showed a decrease and three patients an increase of carotid sinus pressure slowing, while three patients had no carotid sinus pressure slowing both before and after administration of clonidine. We conclude that caution should be taken in administering clonidine to patients with signs indicative of dysfunction of the sinus node.

Aged↗
PubMed2002

Hypoechoic normal renal sinus and renal pelvis tumors: sonographic differentiation.

OBJECTIVE: To evaluate the sonographic findings of an unusually hypoechoic renal sinus that mimics a tumor in the renal pelvis or renal sinus. METHODS: Sonographic scans of 7 patients with an unusually hypoechoic portion in the renal sinus were reviewed retrospectively. Computed tomography, excretory urography, or both confirmed all sinuses as normal. Five consecutive cases of renal pelvis tumors, which were detected on sonography initially in same period, were also reviewed to determine the differences between the 2 conditions. All cases were transitional cell carcinomas of the renal calyces. The images were analyzed for location, shape, margin, presence of posterior sonic attenuation, and associated findings such as caliectasis. RESULTS: Sonographic findings noted in patients with hypoechoic normal renal sinuses were irregular and poorly defined margins (n = 7), a central and symmetric location in the renal sinus (n = 6), the presence of posterior sonic attenuation with nonvisualization of the posterior border of the lesion (n = 7), an unaffected peripheral hyperechoic renal sinus (n = 7), and traversing hilar vessels in the lesion on color Doppler sonography (n = 7). In contrast, renal pelvis tumors had a relatively well-defined margin (n = 4), an eccentric location in the renal sinus (n = 2), a partially or completely obliterated hyperechoic renal sinus (n = 2), a visible posterior margin (n = 5), no posterior shadowing (n = 5), vessel displacement by the mass on color Doppler sonography (n = 5), and associated caliectasis (n = 1). CONCLUSIONS: By being familiar with the sonographic characteristics of a hypoechoic renal sinus, it can be differentiated from renal pelvis tumors, and unnecessary diagnostic workups can be avoided.

Adult↗
PubMed1995

Objective Pulse-Synchronous "Essential" Tinnitus due to Narrowing of the Transverse Dural Venous Sinus.

Subjective tinnitus is a common problem with many etiologies. Objective tinnitus, in which the sound is perceived by both the patient and the examiner, is less common. Objective tinnitus of the vascular type, in which a pulse synchronous bruit is heard by an independent observer, is frequently related to an underlying arterial or arteriovenous malformation, most commonly a dural arteriovenous fistula (DAVF) involving the transverse and sigmoid sinuses. The remaining cases are usually termed "essential" vascular tinnitus, and are presumed to have a venous etiology. In these cases, the audible noise is generally assumed to be produced within the sino-jugular connection, or within an enlarged jugular bulb. We present four documented cases of objective pulse synchronous tinnitus due to focal narrowing (acquired and developmental) of the mid-portion of the transverse dural sinus. In all cases, a bruit was audible directly over a focal constriction in the sinus, demonstrated by cerebral angiography or direct catheter venography. In one case, selective venography revealed a distensible sinus narrowing, associated with a jet of contrast marking fast flow within a developmental sinus segmentation. In another case, a loud pulse synchronous bruit was heard directly over a focal transverse sinus stenosis, which was detected by angiography at the site of a vascular surgical clip. In this case, magnetic resonance (MR) falsely predicted sinus occlusion. In two other cases, an audible bruit was also heard directly overlying a narrowed transverse sinus, seen in the venous phase of angiography. Transverse sinus stenosis is an unappreciated cause of objective pulsatile tinnitus, and we believe that this mechanism may underlie many cases of "essential" or venous etiology tinnitus not otherwise anatomically explained. Non-invasive testing, computed tomography (CT) and MR and non-directed angiography may overlook it. Conventional catheter arteriography or venography should be performed in such cases, with attention to the dural sinuses, if other tests fail to define the anatomic basis of the audible bruit.

Journal Article↗
PubMed1975

[Sinus node syndrome].

Recently disorders of sinus node function have found increasing interest in clinical medicine thanks to new diagnostic and therapeutic developments. This paper represents a comprehensive review of these conditions, combined under the name "Sick Sinus Syndrome" (SSS). Besides a detailed analysis of 63 cases seen at our institution, the results of other groups are compared and extensively discussed. The clinical picture of the SSS is characterized by a wide variety of bradycardiac and tachycardic atrial arrhythmias, occurring separately or in combination. These can be classified in three subgroups: Patients with exclusive sinus bradycardia; patients with sinoatrial exit block or transient episodes of sinus arrest with or without AV escape rhythms; and finally patients with the bradycardia/tachycardia-syndrome, which are complicated by additional atrial tachyarrhythmias. The symptomatology of the SSS is multiform and extends from symptomless cases and those with only general signs of reduced cardiac function to patients with recurrent severe syncopal attacks which may lead to cerebral damage and even death. Besides the typical history, the diagnosis of the SSS primarily rests upon the ECG, especially the long term ECG recorded continuously on a 24 hrs. tape (Holter technique). Also the exercise ECG is of some value, characteristically showing an inadequate increase in the sinus rate, sometimes with AV escape systoles and -rhythms. In addition various provocative tests have been devised which are of help to differentiate between a pathologic and a normal sinus node function. Among these the determination of the sinus node recovery time following overdrive atrial pacing has gained wide acceptance. In most cases the exact etiology of the SSS is not known. In addition to coronary and inflammatory heart diseases a primarily degenerative lesion of the sinus node, comparable to cases with "primary heart block" are discussed. There is also a remarkably frequent past history diththeria. Rarer causes of the condition represent cases with cardiomyopathy, thyreotoxic heart disease, collagen and other disorders and also a familial manifestation of the SSS has been described. Therapeutically, pharmacologic treatment with vagolytic, beta-adrenergic or the common antiarrhythmic drugs is often unsuccessful, especially in the treatment of the Brady-Tachy-Syndrome. Digitalis glycosides, however, are frequently of some value, as they represent an effective prophylactic agent against atrial tachyarrhythmias without prolonging the sinus node recovery time or reducing significantly the sinus rate. While a few patients do not require any treatment, an artificial cardiac pacemaker has to be inserted in most cases. Atrial stimulation may be superior to ventricular on-demand pacing in some patients, and also a special system for the treatment of the SSS combined with significant AV block (binodal disease) has been designed, the bifocal sequential pacemaker.

Age Factors↗
PubMed2001

The pressure waveform of coronary sinus in human hearts.

BACKGROUND: The pressure waveform of coronary sinus in human hearts has never been well described. Retrograde cardioplegia perfusion has become a popular method of myocardial protection in recent years, and identification of the pressure waveform of the coronary sinus might help intubate the coronary sinus in retrograde cardioplegia perfusion by differentiating it from that of the right atrium. The purpose of this study is to identify the pressure waveform of the coronary sinus. METHODS: We inserted a catheter into the coronary sinus under direct vision via a right atriotomy after completion of open heart operation in eight patients. The pressure waveforms of coronary sinus and central venous line, as well as the electrocardiogram (EKG), were recorded simultaneously after the patient was stable and weaned from the cardiopulmonary bypass. The recorded pressure waveforms of coronary sinus and central venous line were compared. RESULTS: The pressure waveform of coronary sinus was found to have three peaks, more prominent than those of the central venous line waveform. CONCLUSIONS: The pressure waveform of coronary sinus could be distinguished from that of the central venous line. The difference might help coronary sinus cannulation for retrograde cardioplegia perfusion.

Adolescent↗
PubMed2002

Perianal sinuses in neonates and infants.

OBJECTIVE: The aim of this study is to evaluate the etiology of perianal abscess or discharges in neonates and infants and some of them are perianal sinuses with blind inner end without connection to the anal canal, and some of these cases have a different histological pattern. Complete surgical excision and primary closure of their wounds can cure these patients. METHODS: Between January 1988 and December 2000, (81) neonates and infants (aged 2 weeks to 2 years) with perianal sinuses, fistula-in-ano abscess dealt in the Al-Zahrawi and Al-Khansa Teaching Hospitals, Mosul, Iraq, were studied. Fifty-one patients displayed an onset of symptoms during their first year of age, all cases had a gentle probing and proctoscopy under general anesthesia, and the discharge from abscess from the patients were sent for culture. Thirty patients with proper sinuses had excision of the sinus and primary closure; children with fistulae underwent fistulectomy; perianal abscesses drained. All the excised specimens were examined histopathologically. RESULTS: All children, except 3, were boys. Out of the 81 cases studied, 30 patients (37%) proved to have proper sinuses with blind inner end. Eight of these showed a different histological pattern, and in 2 cases, the histopathology was that of rectal duplication, the microbiology of the discharge from the proper sinuses was showing a predominance of non-gut derived organisms. All patients cured by excision of the sinuses and primary closure. CONCLUSION: Fistulae are the most common perianal discharging lesions in neonates and infants, blind sinuses are another cause in a considerable number. We propose a diagnostic strategy and treatment for those children presenting with discharging perianal lesions; for anticipation of these sinuses 3 points need to be considered before attempting surgery. 1) Blind sinus tract on gentle probing. 2) Normal anal and rectal mucosa on proctoscopy. 3) High bacterial yield of non-gut derived organisms on culture of the pus or discharge. Their treatment is by simple excision (coring) and primary closure; this method will shorten the healing and recovery time.

Abscess↗
PubMed1975

[The effect of drugs on "sino-atrial conduction time" and on sinus-node automaticity in man].

The effect of atropine, propafenone, and disopyramide on sinus node automaticity and "sino-atrial conduction" was tested in normal patients and patients with the sick sinus-syndrome. "Sino-atrial conduction time" was estimated indirectly by the extrastimulus technique. Atropine (n = 11) caused a significant increase in heart rate in all patients. The sinus node recovery time was shortened in 10 patients. "Sino-atrial conduction time" decreased on an average 35% (P less than 0.01). Three patients with a sick sinus-syndrome demonstrated a change of the pattern of the postextrasystolic pauses indicating great improvement in sino-atrial conduction. Propafenone (n = 10) led to a significant prolongation of the sinus node recovery time by 17% and of the "sino-atrial conduction time" by 27%. Disopyramide (n = 8) had no significant influence on heart rate and "sino-atrial conduction time". Sinus node recovery time was not changed in 6 patients. However, in two patients with a sick sinus-syndrome a dangerous prolongation of the sinus node recovery time after application of disopyramide occurred. The results indicate that atropine enhances sinus node function and sino-atrial conduction. On the other hand, propafenone and disopyramide exert either a depressant influence on sinus node automaticity or on sino-atrial conduction.

Atropine↗