Management of Persistent SARS-CoV-2 Infection in Patients with Follicular Lymphoma

INTRODUCTION

There is no consensus on the management of the coronavirus disease (COVID-19) in patients with secondary immunosuppression due to either an underlying hematological disease or to the effects of immunochemotherapy (ICT). Some of them may present persistent infection with multiple relapses of COVID-19, requiring several admissions. This study evaluated the clinical characteristics and outcomes after treatment of 5 patients with follicular lymphoma (FL), previously treated with ICT, who developed several episodes of COVID-19.

METHODS

We analyzed the clinical evolution and response to treatment with antiviral agent, steroids, and convalescent plasma in 5 patients with FL and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) persistent infection. Reverse transcriptase polymerase chain reaction tests and peripheral blood immunophenotype were performed for all patients.

RESULTS

All patients required hospitalization due to pneumonia with severity criteria and were re-admitted after a median of 22 days (13-42) from the previous discharge. They all showed B-cell depletion by immunophenotyping, and no traces of immunoglobulin antibodies against SARS-CoV-2 were detected in any of the cases. The survival rate was 80%.

CONCLUSION

The combination therapy evidenced clinical benefits, demonstrating its capacity to control infection in immunosuppressed FL patients treated with ICT.

Study of three families with Hb Agrinio [α29(B10)Leu→Pro, CTG>CCG (α2)] in the Spanish population: three homozygous cases

Most α-thalassemia (α-thal) mechanisms are deletions of one or both α-globin genes and less than 5.0-10.0% are point mutations. Hb Agrinio [α29(B10)Leu→Pro, CTG>CCG (α2)] is a hyperunstable α chain structural variant in which the thalassemic phenotype is determined by a post translational precipitation of the structurally anomalous chain in erythroid precursors. This study involved 14 cases with Hb Agrinio from three families. Selective sequencing of the α2 gene showed a CTG(Leu)>CCG(Pro) mutation at codon 29. The mutation was found in a heterozygous state in 11 cases and in a homozygous state in three cases. These are the first cases with Hb Agrinio described in Spain. In all cases where a leucine is exchanged for a proline, an unstable hemoglobin (Hb) will occur both in the α and the β chain. Some of these are as unstable as Hb Agrinio and their presence is difficult to detect except by DNA sequencing.

Magnetic navigation and voltage mapping guided implantation of a pacemaker atrial lead in a previously unpaceable patient

We report successful implantation of the atrial pacing lead in a patient in whom such operation had previously failed with the manual approach. Right atrial (RA) electro-anatomical voltage mapping was used to identify an area suitable for pacing and magnetic navigation to allow exhaustive RA exploration leading to successful RA lead screwing.

[Arrhythmia and sport]

Sports arrhythmia has gained wide attention with the mediatization of the death of famous sports stars. Sport strongly modifies the structure of the heart with the development of left ventricular hypertrophy which may be difficult to differentiate from that due to doping. Intense training modifies also the resting electrocardiogram with appearance of signs of left ventricular hypertrophy whereas resting sinus bradycardia and atrioventricular conduction disturbances usually reverts upon exertion. Accordingly, arrhythmia may develop ranging from extrasystoles to atrial fibrillation and even sudden death. Recent data suggest that if benign arrhythmia may be the result of the sole intense training and are reversible, malignant ventricular arrhythmia and sudden death mostly occur in unknown structural heart disease. Hypertrophic cardiomyopathy is amongst the most frequent post mortem diagnosis in this situation. Doping is now present in many sports and further threatens the athlete in the safe practice of sport.

[New concepts in the diagnosis and treatment of atrial flutter]

Atrial flutter may now be very frequently and definitely cured in a single session of radiofrequency ablation. However, the very name of atrial flutter gives rise to a certain confusion. Clinical experience from everyday activity in ablation laboratories, especially since the introduction of new mapping techniques, has shown that this entity is in fact multiple. Flutters may be classified by their electrocardiographic appearance and/or their electrophysiological mechanism with as many prognostic as therapeutic implications. This article reviews diagnostic features of typical and atypical flutter and the different treatments which may be proposed in different clinical situations.

[Ventricular tachycardia "in salvoes"]

The term of ventricular tachycardia "in salvoes" describes electrophysiographic appearances of several consecutive ectopic ventricular beats without interposition of sinus rhythm. This is an intermediate arrhythmic state between isolated ventricular extrasystoles and sustained ventricular tachycardia. The generally accepted definition of the term "sustained" implies a duration of over 30 seconds or poor haemodynamic tolerance. Strictly speaking, the term "salvoe" has no precise definition in cardiology. In the 1996 edition of the Petit Robert French dictionary, the term is defined as the simultaneous discharge of guns or successive blasts of canons. The Delaware medical dictionary does not provide a French definition of the term "salvoe". In practice, we use the term tachycardia in salvoes in the same meaning as ventricular tachycardia. Schematically, in clinical practice, two situations may be encountered. In the first case, salvoes of VT are recorded in apparently normal hearts; they are not life-threatening and, though often nearly asymptomatic, they may pose therapeutic problems. In the second case, the arrhythmia occurs in a diseased heart, with a low ejection fraction, in which the essential problem is the vital prognosis.

Atypical atrial flutters

Typical atrial flutter is due to a counterclockwise macro-re-entry circuit localized in the right atrium with a surface ECG pattern showing predominantly negative F waves in the inferior leads and positive F waves in V1. Recently it has been proposed to classify atrial flutter on the basis of its cavo-tricuspid isthmus dependence rather than on the ECG pattern. Therefore some atrial flutters are considered typical even if the ECG does not exhibit a typical pattern. This is the case for reverse typical atrial flutter, lower loop re-entry and partial-isthmus-dependent short circuit flutter. The term atypical flutter refers to a non-isthmus dependent flutter. Usually these patients have had previous cardiac surgery with a right or left atriotomy. Flutter involving a spontaneous right atrial scar is not uncommon.

[Cardioversion by external electric shock for atrial fibrillation: does patient age affect immediate results?]

The restoration of sinus rhythm by external electric shock in patients with persistent atrial fibrillation is a well established treatment. However, in current practice this treatment is generally indicated less in the elderly subject although this attitude is not factual. The objective of this work was to evaluate the immediate results of cardioversion by external electric shock, comparing the success rates in four age groups: under 60 years, between 60 and 69 years, between 70 and 79 years, and over 80 years. This study was performed on 182 consecutive patients aged from 25 to 89 years: 35 patients aged less than 60 years, 52 patients aged from 60 to 69 years, 65 patients aged from 70 to 79 years, and 30 patients aged 80 years or over. The success rates were 91.4% before 60 years, 90.4% between 60 and 69 years, 90.8% between 70 and 79 years, and 83.3% after 80 years. There was no significant difference between the success rates in the four age groups (p = 0.68). Among the other factors analysed, only the duration of atrial fibrillation and the body mass index significantly influenced the results of external electric shock in this series. This work suggests that age does not significantly influence the immediate results of external electric shock. According to these data it does not appear justified to contra-indicate cardioversion by external electric shock on the sole criterion of age.

Catheter ablation using very high frequency current: effects on the atrioventricular junction and ventricular myocardium in sheep

BACKGROUND

Radiofrequency ablation is currently used in the treatment of various cardiac arrhythmias. However, this technique is limited by impedance rise, leading to coagulum formation and desiccation of tissue. We developed a new generator, providing very high frequency (27 MHz) current, which is in the intermediate range between radiofrequency and microwave energy. The aim of this study was to evaluate the results for catheter ablation of the atrioventricular junction and characteristics of the lesions obtained at ventricular sites.

METHODS AND RESULTS

The generator was coupled to a specially designed 7-French coaxial catheter. The study included experiments performed on 10 sheep (Wt. 31- 42 kg). In seven sheep, the catheter was introduced into the femoral vein and advanced across the tricuspid annulus to record the largest possible His electrogram. VHF current was applied for 25 s, with increasing energies. The energy needed to obtain complete atrioventricular (AV) block ranged from 60 to 100 Watts. Six animals were observed for 6 to 21 days. Complete AV block was found to be persistent. In those seven sheep in whom AV junction was ablated and in three additional sheep, the ablation catheter was positioned toward the right ventricular apex using the same approach and into the left ventricle via the femoral artery, and 20 to 90 Watts energy was delivered in order to assess the size of the induced lesions. Side effects included ventricular tachycardia degenerating into ventricular fibrillation in six cases, but the same effect was observed in this animal model with radiofrequency energy. No cardiac perforation was noted. No thrombus was observed at the catheter tip. The size of the lesion ranged from 3 to 45 mm in width and 1 to 15 mm in depth.

CONCLUSIONS

Catheter ablation using VHF current is feasible and appears effective in producing stable AV block when applied at the AV junction and results in substantial myocardial lesions. Further studies are needed to define its clinical interest and side effects.

External cardioversion of atrial fibrillation: comparison of biphasic vs monophasic waveform shocks

AIMS

It is well established in transthoracic ventricular defibrillation that biphasic truncated waveform shocks are associated with superior defibrillation efficacy when compared with damped sine wave monophasic waveform shocks. The aim of this study was to explore whether biphasic waveform shocks were superior to monophasic waveform shocks for external cardioversion of atrial fibrillation (AF).

METHODS AND RESULTS

Fifty-seven patients in whom cardioversion of AF was indicated were randomized in this prospective study, to transthoracic cardioversion with either monophasic damped sine waveform shocks or biphasic impedance compensating waveform shocks. In the group randomized to monophasic waveform shocks (27 patients), a first shock of 150 J was delivered, followed (if necessary) by a 360 J shock. In the biphasic waveform group (30 patients), the first shock had an energy of 150 J and (if necessary) a second 150 J was delivered. All shocks were delivered in the anterolateral chest pad position. Sinus rhythm was restored in 16 patients (51%) with the first monophasic shock and in 27 patients (86%) with the first biphasic shock. The difference was statistically significant (P=0.02). After the second shock, sinus rhythm was obtained in a total of 24 patients (88%) with monophasic shocks and in 28 patients (93%) with biphasic shocks. No complication was observed in either group and cardiac enzymes (CK, CKmb, troponin I, myoglobin) did not show any significant changes.

CONCLUSION

This study suggests that at the same energy level of 150 J, biphasic impedance compensating waveform shocks are superior to monophasic damped sine waveform shocks cardioversion of atrial fibrillation.

Inhibition of Na,K-ATPase by external electrical cardioversion in a sheep model of atrial fibrillation

INTRODUCTION

Electrical external cardioversion commonly used to treat atrial fibrillation (AF) is associated with myocardial membrane damage and disturbances in ionic homeostasis (hemodynamically unstable). The present study was designed to investigate whether alterations in ionic homeostasis observed were due in part to changes in the myocardial activity of Na,K-ATPase.

METHODS AND RESULTS

AF was induced by pacing in ten anesthetized sheep divided into two groups. Group I (n = 4) received a single external countershock of 360 J after three episodes of AF lasting 10 minutes. Group II (n = 6) served as controls. Activity, responsiveness to ouabain, and membrane expression of catalytic alpha and beta subunits of Na,K-ATPase in sarcolemmal myocardial membrane fractions were investigated. Membrane fluidity and fatty acid composition, and plasma levels of atrial natriuretic factor (ANF) also were measured. One shock after episodes of AF significantly decreased ventricular Na,K-ATPase activity up to 50% (P < 0.001) without modification of atrial activity at the membrane level. Sites with low affinity to ouabain showed a fivefold lower affinity for ouabain in the cardioversion group than in the control group (IC50 = 7.9 micromol/L vs 40 micromol/L ouabain, P < 0.05). Plasma levels of ANF were significantly increased in the cardioversion group compared with the control group. These changes were independent of membrane modulation in terms of expression of Na,K-ATPase, membrane fluidity, and fatty acid composition.

CONCLUSION

This study suggests that left ventricular perturbation of ionic homeostasis subsequent to transthoracic cardioversion could result from inactivation of Na,K-ATPase activity.

[Implantable ventricular defibrillator. Systematic induction of ventricular arrhythmia is not useful except for implantation]

Checking the efficacy of a defibrillator after its implantation is current practice. This control usually entails induction of ventricular fibrillation (VF). The aim of this study was to assess the utility of this practice in patients with an endovascular system of electrodes. Implantation was acquired when a margin of security of 10 days or more had been obtained. During the postoperative test, the choice of energy was that which reduced VF at implantation. Of the 84 patients included in this study, 59 were implanted with an endovascular electrode system alone and the other 25 patients had endovascular electrodes associated with a subcutaneous patch electrode. The average time from implantation to the postoperative test was 31 +/- 12 days. Arrhythmia sensing was normal and reduction by the defibrillator was observed in all patients. The average energy of the electric shocks was not significantly different to that observed at implantation (18.6 +/- 3.6 J and 19.3 +/- 4.7 J). Fifty patients had antiarrhythmic drugs (amiodarone = 43) at implantation, and 32 at the time of the postoperative test (amiodarone = 17). This study showed that the postoperative test with induction of VF was normal in all patients. Therefore, the authors propose that follow-up should consist of consultation including interrogation of the defibrillator and a chest X-ray to check the position of the electrodes. If one of these tests is abnormal or if the perioperative threshold of defibrillation does not provide an adequate margin of safety, induction of a ventricular arrhythmia is necessary to check the function of the system.

Interelectrode (Accufix) lead fracture

An interelectrode fracture was diagnosed 7 years after the implantation of an Accufix lead. The lead body separated from the tip with the helix screwed into the atrial wall. The retention wire was intact and may have contributed to the lead rupture.

Internal low-energy cardioversion: a therapeutic option for restoring sinus rhythm in chronic atrial fibrillation after failure of external cardioversion

AIMS

Conventional external cardioversion remains the technique of choice for restoration of sinus rhythm in patients with chronic atrial fibrillation (AF). Recent reports have suggested that internal low-energy cardioversion is efficient and safe in terminating AF in patients with failed external cardioversion.

METHODS AND RESULTS

In 20 of 118 consecutive patients with spontaneous chronic AF (>7/days), who underwent low-energy cardioversion, one or more attempts at restoring sinus rhythm with external cardioversion had failed. Low-energy internal cardioversion was performed under light sedation. Shocks were delivered (using an external custom defibrillator) between two nonapolar catheters positioned in the right atrium (cathode) and in the coronary sinus (anode). Heart disease was present in 12 and absent in eight patients ('lone' atrial fibrillation). Atrial fibrillation was established for a period ranging from 12 days to 53 months. Low-energy internal cardioversion restored sinus rhythm in 15 of the 20 patients (75%) with a mean energy of 4.5+/-1.2 J, a mean conversion voltage of 355+/-53 V and a mean impedance of 63+/-8 ohms. No complications were observed. With a mean follow-up of 6+/-7 months, 11 patients (73%) were in stable sinus rhythm.

CONCLUSIONS

This study provides evidence in support of low-energy internal cardioversion as a valuable therapeutic option in patients in whom conventional external cardioversion failed. This technique is safe and does not require general anaesthesia.

[Hereditary resistance to vitamin K antagonists. Apropos of a case]

Resistance to vitamin K antagonists is a rare phenomenon. In general, it is the result of poor patient compliance, malabsorption, a diet rich in vitamin K, or the use of enzyme inducers. Occasionally, the diagnosis of resistance is made when plasma levels are high. The authors report a case of hereditary resistance to vitamin K antagonists in a 43 year old man admitted for atrial fibrillation. The precise prevalence of this anomaly is unknown. However, the existence should be known to clinicians who often use this important family of drugs.

[Heart perforation following transvenous implantation of a cardiac pacemaker]

OBJECTIVES

We studied the incidence, clinical signs and severity of heart perforations occurring after transvenous pacemaker implantation.

PATIENTS AND METHODS

A series of 16 consecutive cases of heart perforation observed in one cardiac pacing unit from 1989 to 1998 were reviewed.

RESULTS

Heart perforation occurred after implantation in 9 cases; the verall incidence for all lead implantation was 0.57%. The ventricle was perforated in 6 cases, the atrium in 1, and an undetermined site in 2 cases. Active fixation was involved in 5 cases, passive fixation in 4. A bipolar lead was used in 7 cases and a unipolar lead in 2. Heart perforation occurred after prior external stimulation in 7 cases, including one case with tamponnade requiring emergency pericardial drainage after implantation. Repositioning the lead in the ventricle was sufficient in 6 cases and a thoracotomy for an atrial wound was performed in 1 case. Difficulties in right ventricular catheterism due to kyphoscoliosis in elderly subjects was found to be a risk factor.

CONCLUSION

Heart perforation following transvenous pacemaker implantation is an exceptional complication with currently used material. Tamponnade is extremely rare. Besides verifying the mechanical performance of the leads, prevention requires a rigorous protocol for catheterism and wall fixation.

A role for the renin-angiotensin system in the evolution of cardiac memory

INTRODUCTION

We studied the role of the cardiac renin-angiotensin II system in the genesis of cardiac memory, in which T wave changes induced by ventricular pacing (VP) accumulate and persist during subsequent sinus rhythm.

METHODS AND RESULTS

Anesthetized dogs were instrumented via a thoracotomy and three 20-minute runs of VP were interspersed with periods of normal sinus rhythm sufficient to permit T wave recovery to 90% of control. Memory was quantified as the change (delta) in T wave vector angle showing accumulation over the three monitoring periods. In five control dogs T wave vector = -27 +/- 49 degrees, and this shifted by 104 degrees (P < 0.05) over the three postpacing recovery periods. In seven dogs infused with the receptor blocker saralasin, five infused with the angiotensin-converting enzyme inhibitor captopril, and four infused with the tissue protease inhibitor chymostatin, there were significant reductions in the incidence and the accumulation of memory. In four other experiments, we used isolated, blood-perfused canine hearts to demonstrate that VP used to induce memory alters the contractile pattern of the left ventricle.

CONCLUSIONS

We propose that the alteration in myocardial stretch induced by pacing activates angiotensin II synthesis by cardiac cells. We propose, further that the endogenous cardiac renin-angiotensin II system (blocked by saralasin, captopril and by chymostatin) is an important contributor to the induction of memory.

[Utilization of transcutaneous anesthetics during heart catheterization]

OBJECTIVES

Assess the efficacy of an anesthetic cream for cardiac catheterization.

PATIENTS AND METHODS

Percutaneous anesthesia was studied in a series of 100 consecutive patients undergoing cardiac catheterization. The anesthesia was composed with an eutetic mixture of local anesthetics and applied precisely over the puncture area in a randomized controlled study. After admission, patients were randomized into two groups: 50 patients received lidocaine infiltration and 50 patients received associated cream and infiltration. Percutaneous anesthesia was to be applied 2 hours before entering the operating room.

RESULTS

No complication developed with this cream combined with lidocaine infiltration. Serum concentration indicated very low levels which were very well tolerated. Patient comfort improved with the anesthetic cream-lidocaine infiltration association.

CONCLUSION

The use of an anesthetic cream is safe and effective, especially combined with lidocaine infiltration during cardiac catheterization. Cost is high and the association might be reserved for special indications (obesity, children).

[Atrial defibrillators or implantable atrioverters. Initial results]

The atrial defibrillator is a new non-pharmacological treatment of atrial fibrillation (AF) for restoration of sinus rhythm. This device has two programmable modes: automatic or activated by the physician or patient. In the automatic mode, the device delivers a shock synchronous with the R wave to restore sinus rhythm when AF is detected. Two patients with paroxysmal AF resistant to pharmacological therapy were included in a study to assess the efficacy and safety of the atrial defibrillator in the mode activated by the physician. The device implanted in the pectoral region is connected to 3 electrodes, two for atrial defibrillation and sensing positioned in the coronary sinus and right atrium respectively and a sensing and pacing electrode in the right ventricle. The right ventricle is paced if a post-shock pause is detected. It is possible to interrogate the device with a programmer using its Holter function and so determine the number of episodes of AF sensed and treated. The number, intensity and energy of the shocks and the parameters of ventricular stimulation are programmable. In these two patients, the atrial defibrillator effectively reduced prolonged episodes of AF with a follow-up of 12 and 7 months. No pro-arrhythmic effects were observed. Further clinical evaluation is under way to assess this new mode of treatment, including the mode activated by the patient, safety and tolerance of the shocks. In our two patients, the treatment of prolonged episodes of AF was followed by reduction of many short or asymptomatic episodes.

[Cardioversion of atrial fibrillation with low energy internal electric shock]

The efficacy and safety of low internal cardioversion for the reduction of atrial fibrillation was assessed prospectively in 104 consecutive patients. Sixty-two patients had chronic atrial fibrillation (Group I). 16 patients had paroxysmal atrial fibrillation (Group II) and 26 patients had induced atrial fibrillation (Group III). The average duration of the current episode of atrial fibrillation was 9 +/- 19 months in Group I, 4 +/- 2 days in Group II and 18 +/- 7 minutes in Group III. Two intracardiac defibrillation catheters were used, one (the cathode) in the right atrium and the other in the coronary sinus or left branch of the pulmonary artery (anode). These catheters were connected to an external defibrillator delivering biphasic 3/3 ms shocks with a voltage which could be programmed from 10 to 400 volts. The shocks were synchronised on the R wave. Sinus rhythm was restored in 44 of the 62 patients in Group I (70%), 12 of the 16 patients in Group II (75%) and 20 of the 26 patients in Group III (77%). The average voltages and energies restoring sinus rhythm were 300 +/- 68 volts and 3.5 +/- 1.5 joules respectively in Group I, 245 +/- 72 volts and 2.0 +/- 2.9 joules in Group II, and 270 +/- 67 volts and 2.6 +/- 1.2 joules in Group III. These results show that the energy required to restore sinus rhythm is significantly greater in patients with chronic atrial fibrillation than in patients with paroxysmal or induced atrial fibrillation. There were no ventricular proarrhythmic effects in the 686 shocks synchronised on the R wave. This study shows that internal cardioversion of atrial fibrillation is feasible with low energies under simple sedation. These results support the concept of an implantable atrial defibrillator.

Transvenous cardioversion of atrial fibrillation using low-energy shocks

Recent reports have suggested that transvenous cardioversion of atrial fibrillation is feasible using low-energy shocks and a right atrium coronary sinus electrode configuration. We evaluated in a prospective study the efficacy and safety of low-energy internal cardioversion of atrial fibrillation in 104 consecutive patients. Sixty-two patients presented with chronic atrial fibrillation (group I), 16 had paroxysmal atrial fibrillation (group II), and 26 had an induced atrial fibrillation episode (group III). The mean duration of the presenting episode of atrial fibrillation was 9 +/- 19 months for group I, 4 +/- 2 days for group II, and 18 +/- 7 minutes for group III. Atrial defibrillation was performed using two intracardiac catheters: one was placed in the right atrium (cathode) and the other in the coronary sinus or in the left branch of the pulmonary artery (anode). The catheters were connected to a customized external defibrillator capable of delivering 3/3-ms biphasic waveform shocks with a voltage programmable between 10 and 400 volts. The shocks were synchronized to the R wave. Sinus rhythm was restored in 44 of the 62 patients in group I (70%), in 12 of the 16 patients in group II (75%), and in 20 of 26 patients in group III (77%). The mean voltage and energy required for cardioversion were respectively 300 +/- 68 V and 3.5 +/- 1.5 J, for group I, 245 +/- 72 V and 2.0 +/- 0.9 J for group II, and 270 +/- 67 V and 2.6 +/- 1.2 J for group III. The leading-edge voltage required for sinus rhythm restoration was significantly higher (p < 0.05) in the chronic atrial fibrillation group than in the paroxysmal or induced groups. No proarrhythmic effects occurred for the delivered 686 R-wave synchronized shocks. This study of a large group of patients confirms and extends the results of previous reports. Such findings may have clinical implications for elective cardioversion of atrial fibrillation and the development of an implantable atrial defibrillator.

Low-energy cardioversion of spontaneous atrial fibrillation. Immediate and long-term results

BACKGROUND

Recent studies have suggested that induced atrial fibrillation (AF) could be successfully terminated by using a two-catheter electrode system and low energy (< 400 V). This study evaluated the efficacy and safety of low-energy cardioversion in spontaneous chronic and paroxysmal AF.

METHODS AND RESULTS

Forty-two consecutive patients with spontaneous AF underwent low-energy electrical cardioversion. AF was chronic (> or = 1 month) with a mean duration of 9 +/- 19 months in 28 patients (group I) or paroxysmal with a history of recurrent attacks and a mean duration of the present episode of 7 +/- 16 days in 14 patients (group II). An underlying heart disease was present in 28 patients. A 3/3-ms biphasic shock was delivered between catheters positioned in the right atrium and the coronary sinus in 32 patients. In 10 patients, the left pulmonary artery branch was used. The catheters were connected to a custom external defibrillator. The shocks were synchronized to the R wave. Following a test shock of 60 V, the energy was increased in 40-V steps until a maximum of 400 V or restoration of sinus rhythm. Sinus rhythm was restored in 22 of the 28 patients (78%) of group I by using a mean leading-edge voltage of 297 +/- 57 V (mean energy 3.3 +/- 1.3 J) and in 11 of 14 patients (78%) of group II by using a mean leading-edge voltage of 223 +/- 41 V (mean energy, 1.8 +/- 0.7 J). The energy required for terminating chronic AF was significantly (P < .001) higher than that required for terminating paroxysmal AF. Among the other variables studied, the duration of AF significantly affected the successful voltage. Ventricular proarrhythmia occurred in 1 patient with atrial flutter due to an unsynchronized shock. Of the 22 patients of group I in whom sinus rhythm was restored, 14 (63%) remained in sinus rhythm with a mean follow-up of 9 +/- 3 months. Pain level showed a good correlation with increasing voltage. However, a marked inter-individual variation was noted.

CONCLUSIONS

Atrial defibrillation using low energy between two intracardiac catheters with an electrical field between the right and left atria and the protocol used is feasible in patients with persistent spontaneous AF. The technique is safe provided synchronization to the R wave is achieved. A low recurrence rate of AF was seen in patients in whom sinus rhythm was restored.

[Identification of 5 variants of the hemoglobin beta chain using DNA analysis (amplification, sequencing and restriction enzymes)]

PURPOSE

To confirm the conventional techniques for studying structural haemoglobinopathies and to show off the simplicity and efficacy of new methods based on the study of DNA.

PATIENTS AND METHODS

Peripheral blood samples of 17 patients with 5 haemoglobin variants detected by conventional and shown off by means of sequencing according to Sanger's method, plus PCR-RFLP, were studied.

RESULTS

Five structural haemoglobin variants were found, which distributed as follows: 7 cases of Hb Complutense (beta 127 Gln-->Glu), 1 Hb D-Punjab (beta 121 Glu-->Gln), 3 Hb Hofu (beta 126 Val-->Glu), 3 Hb J-Baltimore (beta 16 Gly-->Asp) and 3 Hb San Diego (beta 109 Val-->Met).

CONCLUSIONS

These results allow us to stress the simplicity and usefulness of DNA analysis (sequencing , amplification and enzymatic digestion) to identify haemoglobin variants as opposed to laborious analysis of the primary structure by means of HPLC peptide separation.

Using the right drug: a treatment algorithm for regular supraventricular tachycardias

Despite the recent advent of and the successful results from catheter ablation, pharmacological therapy is still used by most clinicians as the first line therapy in patients with regular supraventricular tachycardias. Before prescribing an antiarrhythmic agent, documentation of the arrhythmia using a 12-lead electrocardiogram (ECG) is necessary to identify the type of tachycardia. The ECG diagnosis is based on the presence and polarity of the P wave, the P to QRS relationship, the presence of QRS alternation and the effect of bundle branch block on tachycardia rate. Most regular supraventricular tachycardias use the atrioventricular node either passively, as in atrial tachycardias or flutter, or actively, as paroxysmal junctional tachycardias. The Sicilian Gambit approach attempted to introduce some rationale in the choice of an antiarrhythmic agent, taking into account tachycardia mechanism, by defining the critical components of the tachycardia and the vulnerable parameter, i.e. the component that may readily be affected by an appropriate antiarrhythmic agent. For this approach, an electrophysiological study is particularly useful. The most common regular paroxysmal supraventricular tachycardias include atrioventricular nodal re-entrant tachycardias and atrioventricular re-entrant tachycardias which use an overt or concealed accessory atrioventricular connection (Kent bundle) or atriofascicular connection (Mahaim). For acute termination of paroxysmal junctional tachycardia, intravenous adenosine is the drug of choice. For the prevention of the tachycardia attacks in atrioventricular nodal re-entrant tachycardia, the agents with a depressive effect on the antegrade slow pathway, such as calcium channel blockers or beta-blockers, are likely to be effective. If they fail, sodium channel blockers (propafenone or flecainide) may be indicated. In tachycardias involving accessory connections, agents that affect fast channel dependent tissue (propafenone, flecainide, cibenzoline, disopyramide or hydroquinidine) are effective. Potassium current blockers, such as sotalol or amiodarone, represent an alternative therapy. In atrial tachycardias, the use of propafenone, flecainide or sotalol constitute a logical choice. In drug-resistant cases, amiodarone is the most potent agent. Radiofrequency ablation of the slow atrioventricular nodal pathway, of an accessory connection or of an atrial focus, is indicated in drug-resistant or drug-intolerant patients and is increasingly offered as an alternative therapy.

Multicenter low energy transvenous atrial defibrillation (XAD) trial results in different subsets of atrial fibrillation

OBJECTIVES

This prospective, multicenter trial was aimed at defining efficacy and safety of low energy shocks during atrial fibrillation in a diverse cohort of patients.

BACKGROUND

Experimental studies in sheep and preliminary data in humans have suggested that low energy internal shocks delivered between right atrial and coronary sinus electrode catheters may terminate atrial fibrillation.

METHODS

Biphasic 3/3-ms R wave synchronous shocks were delivered between two electrode catheters in the right atrium and coronary sinus. The defibrillation protocol started with a test shock of 20 V, and shocks increased in 40-V steps until restoration of sinus rhythm or a maximum of 400 V. Shock delivery was withheld after short RR intervals. In 141 patients with atrial fibrillation, the protocol was carried out under sedation in case the shock was associated with discomfort. The atrial arrhythmia was paroxysmal (< or = 7 days) in 50 patients, chronic (> 30 days) in 53, intermediate (> 7 days, < or = 30 days) in 18 and induced in 20. Underlying heart disease was present in 88 patients (62%).

RESULTS

Paroxysmal atrial fibrillation was successfully terminated in 46 (92%) of 50 patients, chronic atrial fibrillation in 37 (70%) of 53, intermediate in 16 (89%) of 18 and induced in 16 (80%) of 20. Mean conversion threshold was 1.8 J (213 V) in the induced group, 2.0 J (229 V) in the paroxysmal group, 2.8 J (272 V) in the intermediate group and 3.6 J (311 V) in the chronic group. The conversion voltage was significantly (p < 0.001) higher in the chronic group than in the other groups of atrial fibrillation and increased significantly with the duration of atrial fibrillation and with left atrial size (p < 0.05). Of 1,779 R wave synchronized shocks delivered with a mean (+/-SD) preceding RR interval of 676 +/- 149 ms, no ventricular arrhythmia was induced. The latter may occur after unsynchronized shocks.

CONCLUSIONS

Low energy transvenous shocks in patients with atrial fibrillation are effective and safe, provided that shocks are properly synchronized to R waves with preceding RR intervals that meet appropriate cycle length criteria. This study provides data that may be useful in the development of an implanted atrial defibrillator.

Prospective assessment of the minimum energy needed for external electrical cardioversion of atrial fibrillation

This study demonstrates that shocks <200 J often are effective for transthoracic cardioversion of atrial fibrillation (AF). Lower energy shocks are more likely to be effective when the AF is <24 hours in duration or in patients with idiopathic AF.

[Radiofrequency ablation of resistant atrial flutter: a new anatomical approach]

Several reports have suggested that radiofrequency ablation could prevent atrial flutter resistant to antiarrhythmic therapy. The usual recommendation is to apply the radiofrequency current in a zone situated between the tricuspid valve and orifice of inferior vena cava. The aim of this study was to assess the efficacy of another site of ablation of flutter extending from the tricuspid valve to the orifice of the coronary sinus, either alone or associated with a site between the coronary sinus and the lateral wall of the right atrium. Twenty patients aged 42 to 78 years (mean : 6 +/- 11 years) were included. Atrial flutter was paroxysmal in 15 patients and chronic in 5 patients. Each patients had documented failure of 1 to 5 antiarrhythmic agents (average 3.1 +/- 1.6). The site of ablation was localised by anatomical criteria alone. During follow-up of 7 +/- 5 months (range 1 to 18 months), 13 patients had no recurrence of atrial flutter after ablation, 5 patients had recurrence and 2 patients had paroxysmal atrial fibrillation alone: the success rate was 15/20 (75%). This study suggests that the zone between the tricuspid valve and coronary sinus may be a site for radiofrequency ablation of atrial flutter. It is valuable alternative to the usually recommended technique.

[Antiarrhythmic drugs in paroxysmal atrial fibrillation. When and how?]

Atrial fibrillation (AF), carries a serious risk of systemic embolic complications, especially cerebral. Antiarrhythmic therapy is the most used method for restoring or maintaining sinus rhythm, and for preventing recurrences or of controlling the ventricular response. A clinical classification was recently suggested to define when to use antiarrhythmic drugs. In a first episode of symptomatic AF (Class I), it is not possible to assess the chances of recurrence and preventive antiarrhythmic therapy would not seem justified. In recurrent paroxysmal AF, the arrhythmias may be asymptomatic (Class IIa) and antiarrhythmic therapy may be questionned. When the attacks are infrequent (< 1 every 3 months, Class IIb), episodic pharmacological intervention to restore sinus rhythm or to slow the ventricular rate may be valuable, but the efficacy and safety of such treatment should be assessed. In Class IIc, appropriate antiarrhythmic treatment to prevent recurrence is often indicated. Atrial fibrillation resistant to one or more antiarrhythmic drugs (Class III) may also be subdivised into three subgroups as for Class II. In addition to the use of alternating of antiarrhythmic drugs not previously used, it is justifiable to consider investigations to determine the mechanism of resistant AF use only drugs of the which slow the ventricular rate. The choice of antiarrhythmic drug may be guided by the concepts of the Silician Gambit, taking into consideration the mechanism of AF and the therapeutic objective. In AF, the mechanism is reentry, the vulnerable parameter the atrial refractory period. To increase the refractory period, the target should be the sodium or potassium currents. The status of left ventricular function is an important parameter in the choice of an antiarrhythmic agent.

Intravenous cibenzoline in the management of acute supraventricular tachyarrhythmias

Intravenous cibenzoline was evaluated in 37 patients with acute supraventricular tachyarrhythmias and a ventricular rate > 120 beats/min. The presenting arrhythmia was atrial fibrillation in 15 patients, atrial flutter in 5, ectopic atrial tachycardia in 11, and paroxysmal atrioventricular (AV) junctional reentrant tachycardia in 6 patients. Intravenous cibenzoline was administered as a bolus given over 2 minutes, at a dose of 1 mg/kg in the first 26 patients and 1.2 mg/kg in the subsequent 11 patients, 15 minutes following failure of placebo (isotonic glucose). The results were evaluated 15 minutes after the intravenous injection. Restoration of sinus rhythm was obtained in 3 out of 6 patients with paroxysmal AV junctional tachycardia (50%) and in 7 out of 31 patients (23%) with atrial tachyarrhythmias (5 out of 15 patients with atrial fibrillation and 2 out of 16 patients with ectopic atrial tachycardia or atrial flutter). Five additional patients with atrial tachyarrhythmias had slowing of ventricular rate below 100 beats/min. Therefore, a satisfactory result, that is, restoration of sinus rhythm or slowing of ventricular rate, occurred in 15 patients (40.5%). Side effects were transient, including visual disturbance (one patient), asymptomatic widening of QRS complex (three patients), incessant reciprocating tachycardia (one patient), and acceleration of ventricular rate (eight patients), resulting in 1:1 flutter, with poor tolerance in two patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Paroxysmal atrial fibrillation: a need for classification

Classification of Atrial Fibrillation.

INTRODUCTION

Clinical aspects of paroxysmal atrial fibrillation are heterogeneous. The attacks of atrial fibrillation may differ in their duration frequency and presence and severity of symptoms. Therefore, a proposal for a clinical classification of paroxysmal atrial fibrillation may be helpful. We tested a new classification system in a cohort of 51 consecutive hospitalized patients with paroxysmal atrial fibrillation.

METHODS AND RESULTS

Paroxysmal atrial fibrillation was subdivided into three classes. Class I included a first attack of symptomatic atrial fibrillation either with spontaneous termination (IA) or requiring cardioversion because of poor tolerance (IB). Class II included recurrent attacks in untreated patients within three subgroups: IIA with no symptoms, IIB with < 1 symptomatic attack per 3-month period, and IIC > with 1 symptomatic attack per 3-month period. Class III included recurrent atrial fibrillation unresponsive to one or more antiarrhythmic agents for prevention of recurrences. Class III also consisted of three subgroups: IIIA with no or mild symptoms, IIIB with < 1 symptomatic attack per 3-month period, and IIIC with > 1 symptomatic attack per 3-month period. The criteria for paroxysmal atrial fibrillation (episode > 2 minutes and < 7 days in duration) were fulfilled by 51 patients (29 men, 22 women; mean age 61 +/- 14 years). Structural heart disease was present in 31 patients; the atrial fibrillation was idiopathic in 18 (35%). All 51 patients could be classified within the three classes and their subgroups: 14 patients (27%) in Class I, 13 (25%) in Class II, and 24 (47%) in Class III. The incidences of idiopathic atrial fibrillation were 21%, 30%, and 45% of the patients in Classes I, II, and III, respectively.

CONCLUSIONS

Based on this new classification system, all hospitalized patients with paroxysmal atrial fibrillation could be classified. This classification may be useful to delineate better the clinical subgroups of patients with paroxysmal atrial fibrillation, to characterize better the patient population in future studies, and to improve treatment strategies.

Characterization of a new alpha-thalassemia-1 mutation in a Spanish family

A novel alpha-thalassemia-1 deletion of 14-15.4 kb that removes the alpha-2, alpha-1, theta-1 genes and pseudo-alpha-1 genes, has been detected in a father and 2 of his children from northern Spain.

[Pharmacological treatment of ventricular tachycardia]

Pharmacological antiarrhythmic therapy is the treatment of first intention for the prevention of ventricular tachycardia (VT). In sustained VT, electrophysiological investigations without treatment enable the induction of VT, the demonstration of its reproducibility, the confirmation of diagnosis (if necessary), the determination of its mechanism and the choice of treatment. In an effort to standardise the technique, a minimum acceptable protocol of stimulations was agreed upon: at least 2 cycles (600 milliseconds and 400 milliseconds) and 3 extrastimuli (S2, S3, S4). The percentage of inducibility (sensitivity) depends on the underlying heart disease and is of the order of 90-95% in coronary artery disease with a history of infarction. Serial electrophysiological studies show non-inducibility of VT with treatment in 20-60% of cases. This result is influenced by the ejection fraction, the type of ventricular arrhythmia (fibrillation or tachycardia) and the antiarrhythmic agent tested. A Class IA, then a Class IC antiarrhythmics or sotalol (if the ejection fraction is over 40%) are evaluated by this technique. Empiric therapy has no place in the management of malignant poorly tolerated arrhythmias. In recurrent, well tolerated arrhythmias which are non-inducible, treatment may be guided by the results of Holter monitoring, providing the patient has a sufficient number of extrasystoles. Exercise stress tests may be useful in effort or catecholamine-induced tachycardias. There is no consensus about the management of non-sustained VT. When these arrhythmias are associated with syncope or cardiac arrest, programmed ventricular stimulation seems indicated. The choice of antiarrhythmic drugs and their results are reviewed.

Cloning, functional expression, and regulation of two K+ channels in human T lymphocytes

Low stringency screening of a Jurkat cDNA library with a rat brain K+ channel (RCK1) probe has resulted in the isolation of HLK3, a voltage-gated K+ channel. In Xenopus oocytes, the HLK3 clone directs the expression of a rapidly activating transient outward K+ current similar to the type n K+ current recorded in Jurkat T cells. The HLK3 gene is located on the short arm of human chromosome 1 (p13.3). Polymerase chain reaction was used to clone HIsK from Jurkat cDNA. The HIsK clone shares the same sequence with a previously described genomic clone (Murai, T., Kazikuka, A., Takumi, T., Ohkubo, H., and Nakanishi, S. (1989) Biochem. Biophys. Res. Commun. 161, 176-181). In Xenopus oocytes, it encodes a slowly activating, noninactivating K+ channel which cannot be recorded in Jurkat cells by conventional patch-clamp techniques. Transcripts of both clones are present at a similar level before and after activation of purified human T lymphocytes and Jurkat cells, reflecting a constitutive expression of K+ channel messages. This finding is in good agreement with the electrophysiological results for type n K+ current density on the same cells. HLK3 current is very sensitive to the scorpion toxin charybdotoxin (IC50 = 0.8 nM). HIsK current is totally insensitive to this toxin but is blocked by the antiarrhythmic clofilium (IC50 = 80 microM). While charybdotoxin has no effect on interleukin 2 mRNA induction, clofilium potently inhibits interleukin 2 mRNA expression upon mitogen-induced T cell activation. It is concluded that the HLK3 channel is not an important component of the T cell mitogenic response. Other targets for K+ channel blockers, such as the HIsK protein, could be involved in the activation process.

Cloning, expression, pharmacology and regulation of a delayed rectifier K+ channel in mouse heart

Neonatal mouse cardiac poly(A)+ mRNA microinjection into Xenopus oocytes directed the expression of a delayed rectifier K+ current. A cDNA encoding this channel, called mIsK, was cloned from a neonatal mouse heart cDNA library whose properties were studied after expression of the complementary RNA in Xenopus oocytes. Among the different known K+ channel blockers, only the class III antiarrhythmic clofilium inhibited mIsK in the 10-100 microM range. The channel was completely insensitive to other antiarrhythmics such as quinine, quinidine, sotalol or amiodarone. mIsK was enhanced by increasing intracellular Ca2+ and by microinjected Ca(2+)-calmodulin dependent protein kinase II. These stimulations were reversed by the calmodulin antagonist W7. Conversely, the phorbol ester PMA, the diacylglycerol analog OAG and microinjected purified protein kinase C inhibited mIsK. This inhibitory effect could be prevented by the protein kinase C inhibitor staurosporine. These results were consistent with the presence of consensus sequences for kinase II and kinase C in the mIsK structure. Cultured newborn mouse ventricular cardiac cells exhibited a delayed rectifier K+ current which had biophysical properties similar to those of cloned mIsK and which was inhibited by clofilium and protein kinase C activators. In situ hybridization experiments revealed that mIsK mRNA was homogeneously distributed in the cardiac tissue. Neonatal mouse heart expressed the most mIsK mRNA compared with various other rat and mouse tissues. Since this K+ channel generates a current which appears to be involved in the control of both the action potential duration and the beating rate, these results suggest an important role for the mIsK channel in cardiac cell physiology and cardiac pathology.

[Hemolytic anemia caused by pyrimidine 5'-nucleotidase (P5N) deficiency 15 years later. Apropos of 2 new cases of hereditary deficit and another one of lead poisoning]

Congenital pyrimidin 5'nucleotidase deficiency manifests as hemolytic anemia with basophilic stippling. In lead poisoning, anemia, basophilic stippling and inhibition of erythrocyte pyrimidin 5' deficiency are also observed. In the present work, we report two cases of hemolytic anemia secondary to congenital deficiency of pyrimidin 5' nucleotidase and another case secondary to lead poisoning. Since 1974, when pyrimidin 5' nucleotidase deficiency was isolated, is known that hemolysis is related to the accumulation of pyrimidin nucleotides within the erythrocytes that behave as metabolic inhibitors. However, the precise metabolic process whose inhibition leads to the shortening of erythrocytes half life has not been elucidated yet.

Characterization of a new alpha-thalassemia-1 deletion in a Spanish family

A new type of alpha-thalassemia-1 was characterized in one Spanish patient with Hb H disease and in her mother. The restriction map of this deletion suggests that the deletion of 22 kb has occurred on a chromosome carrying a zeta-globin triplication. The resulting chromosome lacks the alpha 2- and alpha 1-globin genes, the psi alpha 2- and psi alpha 1-globin genes, and one of the three zeta-globin genes, while the other two zeta-globin genes and the theta 1-globin gene have been retained.

Protection of indwelling vascular catheters: incidence of bacterial contamination and catheter-related sepsis

We compared the incidence of catheter contamination and catheter-related sepsis in 200 noninfected patients admitted postoperatively to the surgical ICU. Four methods of catheter fixation were used: (a) povidone-iodine ointment (Betadine) with a sterile gauze and adhesive dressing (Elastoplast); (b) Op-Site film; (c) Op-Site spray followed by Op-Site film; and (d) Beta-dine and Op-Site film. Of 708 catheters used for 200 patients, 516 (72.8%) were cultured. There was no catheter-related septicemia but 13 (2.52%) catheters were contaminated. However, these were evenly distributed among the four groups. We, therefore, conclude that aseptic insertion of catheters, daily inspection of puncture site, and replacement of tubing are the determining factors in preventing catheter-related sepsis.

[Evaluation of dermatologic impairment in occupational health]

This paper presents a simple method for evaluating the extent of impairment in occupational dermatosis based on the portion (P) of the anatomic area involved (A) and the coefficient of physiologic disturbance (C). A percentage value is assigned to each anatomic area on the basis of its functional importance. The coefficient of physiologic disturbance is the average of four factors (stiffness, dehydration, thickening, and pruritus or pain). The formula (P X A). C gives the final percentage of impairment.

Therapy of infected dermatitis: comparative response to two corticosteroid antimicrobial creams

In a double-blind, parallel trial which lasted 1 week and comprised eighty-eight patients, a study of the response to topical therapy of the infected component of four common eczematous processes showed that the treatment outcome with corticosteroid antimicrobial creams was not influenced by the type of dermatitis. The cream with fluocinonide 0.05% was significantly better than the cream with triamcinolone 0.1%. Both creams were clinically superior to a cream containing only the antimicrobial agents but exerted a similar antimicrobial activity.