Randomized crossover comparison of right atrial appendage pacing versus interatrial septum pacing for prevention of paroxysmal atrial fibrillation in patients with sinus bradycardia.

BACKGROUND: New atrial pacing techniques and overdrive pacing algorithms have been introduced to prevent atrial fibrillation. This study was designed to test the hypotheses that (1) interatrial septum pacing (IASP) at the triangle of Koch would be more effective than right atrial appendage pacing (RAAP) in preventing paroxysmal atrial fibrillation (PAF) in patients with sinus bradycardia and (2) an algorithm (CAP) designed to achieve constant atrial capture would increase the efficacy of rate-responsive atrial pacing. METHODS: We studied 46 patients with PAF and sinus bradycardia implanted with a DDD(R) (Medtronic Thera) pacemaker. Twenty-four patients (6.0 +/- 10.1 PAF episodes/month within 3 months before study) were randomized to RAAP and 22 patients (5.4 +/- 7.1, not significant) to IASP. Within each arm 2 randomized crossover periods of CAP-OFF and CAP-ON function were programed. RESULTS: The PAF episodes per month significantly decreased in the RAAP (CAP-OFF: 2.1 +/- 4.2, P <.05; CAP-ON: 1.9 +/- 3.8, P <.05) and in the IASP group (CAP-OFF: 0.2 +/- 0.5, P <.05; CAP-ON: 0.2 +/- 0.5, P <.05). Values were significantly lower in the IASP group than in the RAAP group in both CAP-OFF (0.2 +/- 0.5 vs 2.1 +/- 4.2, P <.05) and CAP-ON (0.2 +/- 0.5 vs 1.9 +/- 3.8, P <.05) conditions. PAF burden was significantly lower in the IASP than in the RAAP group in CAP-OFF (47 +/- 84 min/d vs 140 +/- 217, P <.05) and in CAP-ON (41 +/- 72 vs 193 +/- 266, P <.05) conditions. No differences were observed within each arm in PAF burden between the 2 crossover CAP programing periods. CONCLUSIONS: Rate-adaptive IASP at the triangle of Koch is more effective than RAAP in preventing PAF in patients with sinus bradycardia. In our sample of patients no additional clinical benefit is furnished by the CAP algorithm.

Impact of consistent atrial pacing algorithm on premature atrial complexe number and paroxysmal atrial fibrillation recurrences in brady-tachy syndrome: a randomized prospective cross over study.

AIM OF THE STUDY: The Consistent Atrial Pacing (CAP) algorithm has been designed to achieve a high percentage of atrial pacing to suppress paroxysmal atrial fibrillation. The aim of our study was to compare the impact of DDDR+CAP versus DDDR pacing on paroxysmal atrial fibrillation recurrences and triggers in patients with Brady-Tachy Syndrome. METHODS: 61 patients, 23 M and 38 F, mean age 75+/-9 y, affected by Brady-Tachy Syndrome, implanted with a DDDR pacemaker, were randomized to DDDR or DDDR+CAP pacing with cross over of pacing modality after 1 month. RESULTS: 78 % of patients in DDDR pacing and 73 % in DDDR + CAP pacing (p=n.s.) were free from symptomatic paroxysmal atrial fibrillation recurrences. During DDDR+CAP pacing, the atrial pacing percentage increased from 77+/-29 % to 96+/-7 % (p<0.0001). Automatic mode switch episodes/day were 0.73+/-1.09 in DDDR and 0.79+/-1.14 (p=n.s.) in DDDR+CAP. In patients with less than 50 % of atrial pacing during DDDR, automaticmode switch episodes/day decreased during DDDR+CAP from 1.13+/-1.59 to 0.23+/-0.32 (p<0.05) and in patients with less than 90 % from 1.23+/-1.27 to 0.75+/-1.10 (p<0.001). The number of premature atrial complexes per day decreased during DDDR + CAP from 2665+/-4468 to 556+/-704 (p<0.02). CONCLUSION: CAP algorithm allowed continuous overdrive atrial pacing without major side effects. Triggers of paroxysmal atrial fibrillation induction, such as premature atrial complexes, were critically decreased. Paroxysmal atrial fibrillation episodes were reduced in patients with atrial pacing percentage lower than 90 % during DDDR pacing.

Analysis of heart rate variability five minutes before the onset of paroxysmal atrial fibrillation.

BACKGROUND: Various experimental and clinical observations suggest changes in sympathetic and vagal neural regulatory mechanisms play a critical role in altering cardiac electrical properties and favor the occurrence of arrhythmic events. There is limited information about the influences of the autonomic tone on the development of episodes of paroxysmal atrial fibrillation in patients with no evidence of organic heart disease. The aim of this study was to investigate changes in sympatho-vagal balance 5 minutes before the onset of atrial fibrillation. METHODS: We evaluated 28 patients with no history of heart disease who were not undergoing pharmacological treatment and who had at least one episode of paroxysmal atrial fibrillation recorded during an 24-hour ECG Holter monitoring. We analyzed values of frequency domain heart rate variability parameters 5 minutes before the onset of atrial fibrillation (prefa period) compared to an equivalent period at least 1 hour after from atrial fibrillation (random period). RESULTS: Thirty-six episodes of atrial fibrillation were recorded and our results showed we had two types of episodes. Eighteen were classified as Type A, in which we had an increase of low frequency (LF) (79.15 +/- 10.76 in comparison with 62.64 +/- 19.55) (P = 0.004) and a decrease of high frequency (HF) (20.82 +/- 10.74 in comparison with 37.64 +/- 20.20) (P = 0.004) consistent with an increase of sympathetic tone; and 18 were classified as Type B in which there was a decrease of LF (62.82 +/- 15.38 in comparison with 85.97 +/- 8.48) (P < 0.001), and an increase of HF (36.79 +/- 14.72 compared with 14.01 +/- 8.48) (P < 0.001), consistent with an increase of parasympathetic tone. CONCLUSION: We observed abrupt changes in sympathovagal balance in the last 5 minutes preceding an episode of atrial fibrillation. This can be related to a double behavior in the neurogenic drive: in Type A episodes there is an increase of the LF spectrum, LF:HF ratio, and a decrease of the HF spectrum consistent with an increase of neurogenic sympathetic drive; in Type B episodes there is a reduction of the LF spectrum, LF/HF ratio, and an increase of HF spectrum consistent with an enhancement of the neurogenic parasympathetic drive. In some patients, we found that the two mechanisms operate during different hours of the day and that sometimes there is an increase of sympathetic tone, and in the same instances an increase of parasympathetic tone. Heart-rate variability measures fluctuation in autonomic inputs to the heart rather than the mean level of autonomic impulse; autonomic imbalance is probably more important than the vagal or sympathetic drive alone.

[The management of syncope in the hospital: the OESIL Study (Osservatorio Epidemiologico della Sincope nel Lazio)]. / Gestione della sincope in ospedale: lo Studio OESIL (Osservatorio Epidemiologico della Sincope nel Lazio).

BACKGROUND: While syncope is generally considered a frequent finding in clinical practice, no clear epidemiological evidence is available about the relevance of such an event in the general population of Italy. METHODS: The OESIL Study was designed and undertaken in 15 hospitals of the Italian region of Latium in order to assess the percentage of emergency-room visits and admissions due to syncope, as well as to analyze the in-hospital diagnostic work-up performed for this condition. RESULTS: During a two-month observation period, 781 (372 males and 409 females, mean age 55.2 (22.8 years) consecutive patients came to the emergency rooms of the 15 hospitals included in the investigation due to a syncope spell (0.9% of emergency room visits); 450/781 patients (57.6%) were subsequently hospitalized (1.3% of all admissions): 48.0% of the admissions were admitted to a general medical ward, 29.3% to an observation ward, 13.3% to a cardiology section, 1.6% to a neurology section and 7.8% to other clinical sections (neurosurgery, general surgery). The mean duration of in-hospital stay was 6.9 (5.8 days; range 1-40 days). During the hospitalization period, 93.1% of patients underwent an ECG, 51.0% an EEG, 44.3% a CT scan of the central nervous system, 40.2% an echocardiogram and 19.5% a tilt-test. The syncope spell was considered to have a cardiovascular origin in 33.8% of the cases and a non-cardiovascular in 11.6% of the cases, while the origin was unknown in 54.4% of the cases. CONCLUSIONS: Collected data support the idea that syncope represents a frequent event in the general population and is responsible for a significant percentage of emergency-room visits and hospital admissions. However, the performance of conventional diagnostic work-ups is far from being satisfactory.

Steroid-eluting electrodes prevent chronic pacing threshold rise in the atrial chamber after oral propafenone administration.

The aim of the study was to evaluate chronic atrial pacing threshold increase after oral propafenone therapy. Fifty patients affected by advanced AV block and sick sinus syndrome were studied at least 6 months after pacemaker implantation, before and after oral propafenone therapy (450-900 mg/day based on body weight). The patients were subdivided into three groups as to the type of electrode implanted, all three unipolar: group I (20 patients) Medtronic CapSure 4003, group II (13 patients) Medtronic Target Tip 4011, group III (17 patients) Medtronic 4057 screw-in leads. In all cases, Medtronic unipolar pacemakers were implanted with the same noninvasive autothreshold measurement method. Propafenone and 5-OH-propafenone blood levels were measured 3-5 hours after drug administration. The packing autothreshold was measured at 0.8, 1.6, and 2.5 V by reducing the pulse width. After propafenone, groups II and III showed a statistically significant threshold rise (P ranging from < 0.01 to 0.05), whereas no significant difference was found in group I. Propafenone and 5-OH-propafenone blood vessels did not show any significant difference among the three groups. Strength-duration curves were drawn for the three groups before and after propafenone: at baseline the curves shifted to the left with the steep part above the knee, clearly favoring CapSure over the other two groups. After propafenone, the curves shifted to the right, with the flat par progressively more evident in groups II and III. In the atrial chamber, steroid-eluting leads prevented threshold increase after propafenone therapy, in contrast with a significant threshold rise with conventional porous and screw-in leads.

Reliability of a new algorithm for automatic mode switching from DDDR to DDIR pacing mode in sinus node disease patients with chronotropic incompetence and recurrent paroxysmal atrial fibrillation.

To evaluate the safety and efficacy of a new algorithm for automatic mode switching (AMS) from DDD-DDDR to DDIR, 26 patients, 16 females and 10 males, mean age 73 +/- 6 years of age, affected by sinus node disease, chronotropic incompetence, and recurrent paroxysmal atrial fibrillation (PAF) received the Medtronic Thera DR pacemaker. The device continuously calculates, in ms, the running average of the intrinsic atrial rate (MAR) and compares the current atrial interval (CAI) with the stored MAR. When the CAI is greater than the MAR it increases by 8 ms, and when the CAI is less than the MAR, it decreases by 23 ms. When MAR < or = 330 ms (182 beats/min), tachycardia is detected and AMS is activated. All patients had clinical evaluation, 12-lead ECG, Holter monitoring, and exercise testing after implantation and every 3 months for 1 year. The results were compared with the data stored in the pacemaker memory: AMS episodes number; the histogram of the last 14 episodes; and atrial electrogram recording. Twenty-two Holter recordings in 13 patients showed PAF and in all of them AMS occurred simultaneously. AMS lasted between 10 seconds and 20 hours, and MAR ranged from 195-400 beats/min. No episode of PAF and no AMS were recorded in 39 Holter recordings in 22 patients. Appropriate AMS was confirmed in five patients by stored atrial electrogram and in nine by 12-lead ECG and pacemaker event markers. Mean atrial sensing was 2.13 +/- 1.04 mV during PAF and 3.18 +/- 1.46 mV during sinus rhythm. No PAF episode and no AMS were recorded during exercise testing. In conclusion, this new algorithm was very reliable, sensitive, and specific.

[Postoperative ischemic ileocolitis in the elderly. Suggested therapy with intraluminal administration of oxygen and glutamine]. / Ileocolite ischemica post-operatoria nell'anziano. Proposta di terapia con somministrazione endoluminale di ossigeno e glutamina.

Ischaemic ileocolitis in postoperative course of major abdominal surgery is a great challenge for the surgeon: the mortality rate is very high, and therapeutic choices are poor. In the elderly patients ischaemic bleeding ileocolitis is often determined by low flow: sepsis and cytologic damage are primed by activation of endotoxins and chemical mediators, and bacterial translocation could develop across intestinal wall. In our case the patient (male, caucasian, 68 years old) underwent bilio-hepatic resection for hilar cholangiocarcinoma. In the postoperative period continuous enteric haemorrhage was determined by an ischaemic ileocolitis demonstrated by colonoscopy. Abdominal angiography did not show stenosis or occlusion of mesenteric vessels. We administered dopamine and dobutamine as vasodilator drugs for splanchnic circulation without any positive response. Surgical removal of the colon was unsuccessful to stop bleeding. ileostomy and sigmostomy were performed. Histologic samples of the specimen showed ischaemic ileocolitis. After a few days the patient bled again. As last therapeutic choice, we bubbled oxygen in a solution of L-glutamin 500 mml (3 liters/min for 5 min). We administered 500 mml of this solution three times a day by enteral sond, and 100 mml twice a day by sigmoidostomy and endoluminal oxygenation was performed twice a day (1l/min for 1-2 minutes) under continuous control. Bleeding was reducing during the next five days, until stopping. If glutamine and O2 can be considered the fuel of enterocytes, we hypothesized endoluminal oxygenation and glutamine enteral supply of the small intestine could feeding enterocytes, until a complete restoration of enteral mucosa and stopping of the haemorrhage.

[The prognostic value of the ejection fraction at rest and under stress assessed by nuclear angiography in myocardial infarct patients]. / Valore prognostico della frazione di eiezione a riposo e da sforzo valutata mediante angiografia nucleare in pazienti con infarto del miocardio.

BACKGROUND: The aim of this study was to assess the utility of ejection fraction at rest (rEF) and its change during stress (delta EF) as a predictor of cardiac events during the follow-up of patients (pts) with myocardial infarction. METHODS: 74 pts (44 treated with thrombolytic therapy (TR), and 30 not (noTR)), were studied with 99mTcPYP angiography within 2 +/- 1 months, after AMI. By 20 +/- 10 months, 41 pts had no events (Group A) while 33 pts experienced cardiac events (3 deaths, 16 angina, 12 CABG, and 2 PTCA). RESULTS: rEF was similar in both Groups A and B (A 47 +/- 8 vs B 45 +/- 10 p. ns), 44 +/- 15 vs B-noTR 46 +/- 12 p. ns). delta EF was different between Groups A and B. Group A showed a positive delta EF (3.2 +/- 6), and this result was more evident in thrombolyzed AMI (A-TR 4.4 +/- 4.5 vs A-noTR 1.16 +/- 3.9 p. < 0.01). Group B showed a negative delta EF (-4.4 +/- 5.3), and this result was more evident in non thrombolyzed AMI (B-TR -2 +/- 6.4 vs B-noTR -5.8 +/- 8 p. < 0.01). CONCLUSIONS: A decrease in EF during exercise radionuclide angiography is useful in identifying pts with high risk of cardiac events after AMI. Thrombolytic therapy improves stress EF in both Groups A and B.

Ventricular cross stimulation in a dual chamber pacing system: phenomenon analysis.

Seven cases of ventricular cross stimulation from a group of 23 patients implanted with DDD devices are presented. In two patients the phenomenon was observed at the moment of DDD programming at nominal values, and in five other patients it was reproduced by increasing the atrial output voltage up to ten volts. In all 23 patients cross stimulation disappeared permanently within 24 hours after implantation. From the onset of cross stimulation to its end, atrial and ventricular threshold voltages were unchanged, while the atrial and ventricular impedances significantly decreased. These results suggest that an important role in the phenomenon occurs by impedance variation at the interface between the pulse generator and body tissue.

[Extension of necrosis and left ventricular function in recent myocardial infarct. Correlation between a QRS scoring system and various echocardiographic indexes]. / Estensione della necrosi e funzione ventricolare sinistra nell'infarto miocardico recente. Correlazione fra un sistema di punteggio del QRS e alcuni indici ecocardiografici.

The purpose of this study was to evaluate the extension of myocardial necrosis and the impairment of left ventricular function in patients with recent myocardial infarction by means of the standard 12-lead ECG. Then, we tried to correlate the QRS scoring system proposed by Wagner and coll. with some indexes obtained from a M-Mode and Two-Dimensional echocardiographic examination (echo-score, number of compromised areas, E-septum separation and left ventricular ejection fraction) in a group of 105 pts. (mean age 61.54 +/- 9.66 SD years). Patients were divided into three groups: 47 with anterior infarction, 45 with inferior infarction and 13 with anterior and inferior infarction. A statistically significant correlation was found between the QRS scoring system and (a) the infarct size (r between ECG-score and echo-score = 0.40, p less than 0.001; r between ECG-score and compromised areas = 0.47, p less than 0.001) and (b) left ventricular ejection fraction (r = -0.48, p less than 0.001), measured echocardiographically, particularly in pts. with anterior infarction. No correlation was found with the E-septum separation. In conclusion, the correlation between QRS scoring system and echo indexes appeared statistically significant, even if minimally applicable to single cases.

[Sickle cell anemia in surgical patients. Significance and problems]. / La falcemia nel paziente chirurgico. Significato e problemi.

Drepanocytosis, a disease notoriously widespread among blacks, is surprisingly frequent in certain Italian islands. Surgical aspects of the disease are discussed: erythrocyte sequestration attacks, pigmentary cholelithiasis, priapism, malleolar ulcers and vaso-occlusive attacks. A knowledge of such aspects is considered fundamental for the purposes of a reasoned differential diagnosis in the field of paediatric pathologies requiring surgery.

[New prospects offered by echography in the diagnosis of carcinoma of the gallbladder]. / Nuove prospettive offerte dall'ecografia nella diagnosi del carcinoma della colecisti.

Experience in diagnosing several cases of primary carcinoma of the cholecyst echographically in reported. The most important ultrasonic characteristics in relation to staging of the lesion are reviewed. It is seen that echographic features always correlate with surgical findings, confirming the diagnostic accuracy of the method which permits morphofunctional as well as structural evaluation. At this time echography seems to be the most rational tool for efficient diagnosis, a step forward in ensuring timely surgery and the improvement of long term prospects for the condition.

[Experimental intrauterine surgery. Morphological study of lung development in the sheep fetus with congenital diaphragmatic hernia]. / Chirurgia sperimentale endouterina. Studio morfologico dello sviluppo polmonare nel feto di pecora con ernia diaframmatica congenita.

Experimental comparison of the lungs of 7 sheep foetuses with surgically induced CDH and 7 controls permitted an assessment to be made of the changes that take place in lung growth, generally described as hypoplasia, through a study of their morphology and histology, and the lung: lamb weight ratio. Changes increased in gravity in function of the duration of hernia. They included: reduced alveolar expansion, fewer generations of bronchi and alveoli, and septal thickening. An increase in the smooth muscle component of 5th-6th generation arteries (i.e. resistance) may offer an explanation of the hypertension characteristic of CDH, and the non-reactivity of these vessels in response to vasodilators. It is also suggested that damage to the mesenchyma can be regarded as the sole cause of the changes in lung growth observed in CDH. Early treatment before these changes become irreversible is thus advisable.

[Morphologic and functional aspects of left ventricular hypertrophy evaluated by computerized echocardiography]. / Aspetti morfologici e funzionali dell'ipertrofia ventricolare sinistra, valutati attraverso la lettura computerizzata dei tracciati ecocardiografici.

We have investigated the possible echocardiographic progression of left ventricular (LV) hypertrophy, in different stages of primary hypertension. Both morphological (LV mass and ratio of interventricular septal thickness to posterior wall thickness-IVST/PWT-, in M-mode) and functional data (parietal stress, duration, degree and velocity of filling in the four phases of diastole, obtained through computerised interpretation of M-mode tracings), were examined. We also tried to assess the morphofunctional differences between LV hypertrophy secondary to primary hypertension and LV hypertrophy secondary to renovascular hypertension, hypertrophic obstructive cardiomyopathy and physical training. Patients with primary hypertension were further subdivided in three groups: A) 14 patients with hypertension of less than one year's duration, B) 28 patients with long-lasting hypertension, and C) 5 patients with cardiomegaly. There was a progressive increase from controls to Group C patients of left ventricular mass (controls 171 +/- 25; Group A 168 +/- 72; Group B 253 +/- 83; Group C 439 +/- 117) and septal hypertrophy (controls IVST/PVT 1 +/- 0.1; Group A 1.2 +/- 0.2; Group B 1.4 +/- 0.3; Group C 1.5 +/- 0.1). The isovolumic relaxation period was prolonged only in Group C (controls 8.6 +/- 3.5 per cent of the diastole; Group C 15 +/- 3.5%) LV dimensions during slow filling and atrial contraction as well as filling velocity during this latter phase of the cardiac cycle were increased in Group A (7.8 +/- 2.3 and 7.3 +/- 2%; 1.2 +/- 0.6 cm/cm X sec respectively) and B (10 +/- 6 and 10.8 +/- 4%; 1.2 +/- 0.6 cm/cm X sec) compared to the controls (5 +/- 2.8 and 3.7 +/- 2%; 0.7 +/- 0.2 cm/cm X sec). The Vcf max was not significantly different in the three groups. The patients with renovascular hypertension (N = 14) could be differentiated from those with primary hypertension of Group B for a greater increase in LV mass, with concentric hypertrophy (IVST/PWT = 1.2 +/- 0.2), for a greater prolongation of IRP (16 +/- 0.6% of diastole), with increased diameter changes in this phase (displacement ratio = 3.3 +/- 2.3%, in Group B; 4.7 +/- 3.8%, in renovascular hypertension), for a normal displacement and velocity of slow and atrial filling, despite the impairment of rapid filling found in this group, too (% displacement and velocity, respectively: 19 +/- 5% and 1.8 +/- 0.6 cm/cm X sec).

[Experimental intrauterine surgery: the creation of a congenital diaphragmatic hernia in a sheep fetus]. / Chirurgia sperimentale endouterina: la creazione di un'ernia diaframmatica congenita nel feto di pecora.

Up to 50% of the neonates operated during the first hours of life for a congenital diaphragmatic hernia die. The presence of a severe lung hypoplasia, which is at the origin of hypoxia, acidosis, increased pulmonary vascular resistance and right to left shunt, explains the poor clinical results, in spite of surgical success and intensive therapy. A modern approach to the problem includes treatment with pulmonary vasodilator drugs, whose effects are still discussed. Perhaps the prenatal recognition of the defect could improve prognosis. Lots of experience are needed to know more on the subject. This could be obtained with an experimental approach on newborn animals with a CDH. The article relates authors experience in the creation of a CDH in a foetus of sheep, by means of a surgical intervention during its intrauterine life.

[Hirschsprung's disease in adolescents and adults]. / Il morbo di Hirschsprung nell'adolescente e nell'adulto.

Megacolon must be considered as a diagnosis in any case of intractable constipation also in the adult. Besides the Hirschsprung's disease and the idiopathic megacolon, which have no apparent organic cause, many other pathologic conditions may produce a marked dilatation of the large bowel. The differential diagnosis depends, after a valuation of the clinical and radiologic features, also from enzymatic, histologic and functional tests. The Hirschsprung's disease can be observed after the infancy in: 1) Patients in whom diagnosis is made only in adult age; 2) Patients with a diagnosis made in infancy or childhood, with moderate symptoms, treated with a conservative methods, who are getting worse; 3) Adult relapsers after a previous inadequate operation. Group II also includes the patients who need an emergency operation, because of a perforation or a volvolus of a dilatated loop. We report three cases of adult Hirschsprung's disease and two adult "idiopathic megacolon". The patients with aganglionic megacolon were admitted to our Hospital respectively for an abdominal palpable mass, a volvolus and incontinence. The two patients with idiopathic megacolon showed the same clinical picture of those with Hirschsprung's disease. We choose a surgical therapy in all five patients, with good long-term results.