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Effect of verapamil studied by programmed electrical stimulation of the heart in patients with paroxysmal re-entrant supraventricular tachycardia.

Atrioventricular (AV) conduction, ventriculoatrial (VA) conduction, and the mechanism of tachycardia, were studied by programmed electrical stimulation before and after the administration of verapamil, in 10 patients with paroxysmal re-entrant supraventricular tachycardia. In 7 patients the tachycardia circuit was confined to the AV node. In 3 patients an accessory pathway conducting only in the ventriculoatrial direction was used during tachycardia. When administered intravenously during tachycardia, verapamil terminated the arrhythmia in 9 patients. Verapamil lengthened the effective and the

[A study of atrio-ventricular conduction in subjects with the Lown-Ganong-Levine syndrome (author's transl)].

Eight subjects with the Lown-Ganong-Levine syndrome were studied by means of His bundle recordings during sinus rhythm and during atrial pacing. During sinus rhythm in all cases, the A-H interval was lesser than the mean value observed in 10 control subjects. Atrial pacing at rates up to 190/min produced three types of responses. Four patients showed an initial increment in A-H interval, followed by a plateau response at higher rates. One patient showed an initial increment and a plateau response in A-H interval at low and intermediate rates, followed by a sudden and conspicuous increment at h

Electrocardiographic features of atrial depolarization during pacing of right atrial appendage.

Identification of atrial capture during pacing from right atrial appendage is frequently difficult. Electrocardiograms of forty five patients implanted with AAI/DDD pacemakers (thirty unipolar, fifteen bipolar) were analysed to characterize the specific morphology of paced P waves. Compared to sinus P waves, atrial pacing resulted in atrial depolarization of lower amplitude (0.16 +/- 0.05 mv vs 0.11 +/- 0.032 mv, P less than 0.005) but increased duration (0.07 +/- 0.009 sec vs 0.08 +/- 0.017 sec, P less than 0.005). P wave morphology was similar in unipolar and bipolar pacing units. It was pos

Calcium channel blockers.

Calcium (Ca(++)) plays an essential role in many cardiovascular physiologic processes. Electrophysiologic properties of the sinus and atrioventricular nodes greatly depend on Ca(++) ion influx. Also, Ca(++) is the main link for excitation-contraction coupling of the myocardium. Ca(++) channel blockers are a group of heterogeneous compounds that block the ionic influx of Ca(++) into the myocardial and vascular smooth muscle cells. Because Ca(++) plays a central role, it is not surprising that Ca(++) channel blockers can produce profound alterations in cardiovascular functions. Recently several …

Extra AV nodal Wenckebach periodicity.

Extra AV nodal Wenckebach periodicity was diagnosed in seven patients. The most frequent form of this conduction abnormality was an exit block. The underlying block was localized in the sinoatrial junction and in the atria in two patients; the AV junction and the ventricle were the site of the Wenckebach periodicity in one case each. In extra AV nodal exit block, the actual conduction delay is not seen on the ECG and the diagnosis is based on the progressive shortening of the P-P or R-R intervals followed by a pause which is less than twice the shortest P-P (R-R) interval depending on the leve

The anatomic substrate for preexcitation in corrected transposition.

We report three cases of corrected transposition (CT), all with Ebstein's disease, ventricular septal defect (VSD) and ventricular preexcitation. In cases 1 and 2, the ECG revealed sinus rhythm, with type A fusion preexcitation QRS complexes, suggesting left-sided Kent bundles and intact conduction system (CS). Complete serial section (SS) of the CS in both cases revealed an anterior CS and a Kent bundle in the posteroseptal wall of the morphologic right ventricle (MRV). Case 3 had intermittent preexcitation, with periods of complete atrioventricular (AV) block with narrow QRS escape rhythm. T

Functional characteristics of retrograde conduction in a pacing model of "endless loop tachycardia".

A pacing model was designed that stimulated "endless loop tachycardia," a complication found in the new generation of DDD (atrioventricular [AV] universal) pacemakers. The functional characteristics of the train of ventricular impulses simulating endless loop tachycardia were studied during both AV sequential pacing and basic ventricular drive. AV sequential pacing, by causing a decrease in ventriculoatrial (VA) conduction time of the first beat of the endless loop tachycardia, was associated with a decrease in the cycle length at which VA block occurred in 9 of 12 patients. The site of block

Simultaneous "traumatic Gerbode" and aortic rupture due to blunt chest trauma.

The Gerbode defect is characterized by a perimembranous ventricular septal defect between the left ventricle and the right atrium. This intracardiac shunt is a congenital defect but may be iatrogenic after valve surgery or atrioventricular node ablation, may be the result of endocarditis or may be traumatic. It is really rarely encountered as sequelae of non-penetrating heart trauma, and their clinical manifestations may often be unrecognized in the multi-injured patient. However, they are serious complications, and their diagnostic approach is not always feasible. We hereby present a case of …

Cytomorphology of anaplastic ependymoma in a pleural effusion. A case report.

In a 42-year-old women a recurrent anaplastic ependymoma of the frontal lobe developed intracerebral metastases and, after implantation of an atrioventricular shunt, also metastasized to the lung, pleural cavity and mediastinal lymph nodes. In routinely stained smear preparations of the pleural effusion sediment, the typical cytologic features of an anaplastic ependymoma were found--papilliform cell clusters with acellular axes ("pseudorosettes"), incomplete true ependymal rosettes, and epithelioid and tanycytoid tumor cells with signs of anaplasia. A peculiar matrix material was a characteris

When Sleep Mode Becomes a Nightmare.

BACKGROUND: Atrioventricular node (AVN) ablation preceded by pacemaker insertion is a safe procedure used for both rate and symptom control in symptomatic atrial fibrillation. CASE SUMMARY: This is a case of bradycardia-induced PMVT which occurred after AVN ablation, despite the presence of a VVI-R pacemaker inserted a few months prior. Lower pacing rates were allowed during the night due to 'sleep mode' being enabled. The nocturnal bradycardia resulted in ventricular escape rhythm with frequent ectopy, leading to 'R on T' mediated PMVT. Turning the sleep function off suppressed the ectopic a…

Fear of ventricular tachycardia in Syncope: Clinical reasoning versus reflex alarmism.

Despite widespread concern, ventricular tachycardia (VT) is rarely the actual cause of syncope, even in patients with structural heart disease. Indeed sustained VT occurs, it typically results in cardiac arrest rather than transient loss of consciousness, with the exception of torsades de pointes. On the other hand when syncope is arrhythmic, it is more commonly due to atrioventricular (AV) block or sinus node dysfunction, age-related conditions due to conduction system fibrosis. We argue that current guideline-based risk stratification may overestimate arrhythmic and sudden death risk in pati

An example of the deleterious effects of right ventricular apical pacing.

Pacemaker implantation remains the mainstay of treatment in patients with symptomatic sinus node disease or severe heart block. Despite the dramatic benefits of this therapy, a high burden of ventricular pacing is known to have its disadvantages. Reported is the case of an 85-year-old woman with a history of sick sinus syndrome who presented with congestive heart failure after her atrioventricular sequential pacemaker defaulted to ventricular pacing mode as a result of battery depletion. After replacement of her generator and reinstitution of atrial pacing, dramatic improvements in her symptom

Синус остановился в связи с кардитом Лайма.

Болезнь Лайма является наиболее распространенным заболеванием в Соединенных Штатах. Он вызван спирошетом Борелия Бурдорфери. Сердечное вмешательство наблюдается у 4-10% пациентов с болезнью Лайма. Основным проявлением кардиота Лайма является болезнь системы самокондукции, при этом доминирующее значение имеет атриовентурный узел. В редких случаях у пациентов с кардиотом Лайма возникают другие расстройства системы провода, такие, как ствол связки, интравентрикулярная задержка и надвентрикулярная или желудочно - желудочная тахикардия. Мы сообщаем необычный случай с 59-летним мужчиной, у которого

Совпадение в аннотации оригинала
Lyme disease is the most prevalent tick-borne disease in the United States. It is caused by the spirochete Borrelia burgdorferi. Cardiac involvement is seen in 4% to 10% of patients with Lyme disease. The principal manifestation of Lyme carditis is self-limited conduction system disease, with predominant involvement of the atrioventricular node. On rare occa…

Conversion of paroxysmal atrial fibrillation to sinus rhythm by intravenous pirmenol.

The acute effects of pirmenol on atrial fibrillation were investigated in 40 patients with paroxysm of atrial fibrillation. Patients were randomized to receive either pirmenol, 50 or 100 mg intravenously, or placebo. Patients with congestive heart failure or a history of sinus node disorder were excluded. Sinus rhythm was achieved in 12 of 20 patients in 2 to 16 minutes after pirmenol administration and in 3 of 20 patients in the control group within 1 hour. A nodal escape rhythm during sinus slowing was observed in 1 patient. No sinus arrest, atrioventricular conduction disturbance or hypoten

Role of calcium antagonists in cardiovascular therapy.

The development of drugs which selectively block the "slow" channels by which calcium enters the cell (calcium antagonists) has provided valuable information about the role of transmembrane calcium exchange in man and has offered new therapeutic approaches. The principal effect on the cardiovascular system is relaxation of vascular smooth muscle but some of these drugs also have electrophysiological effects, especially slowing of conduction in the atrioventricular node; verapamil is the agent of choice in supraventricular tachycardia. Significant myocardial depression does not usually occur wi…

A Clinical Score Model to Predict Lethal Events in Young Patients (≤19 Years) With the Brugada Syndrome.

Risk stratification in Brugada syndrome in young patients remains challenging. We investigated the clinical characteristics, prognosis, and risk in young patients with the Brugada syndrome. We studied 95 patients with the Brugada syndrome aged ≤19 years. The median age at diagnosis was 12.9 years. The clinical presentation was sudden cardiac death in 7% and syncope in 21%. The remaining 72% were asymptomatic at diagnosis. Electrical abnormalities were present in 36%, including spontaneous type I electrocardiogram (12%), sinus node dysfunction (9%), atrioventricular block (17%), intraventricula

Influence of Cheyne-Stokes respiration on ventricular response to atrial fibrillation in heart failure.

In subjects with sinus rhythm, respiration has a profound effect on heart rate variability (HRV) at high frequencies (HF). Because this HF respiratory arrhythmia is lost in atrial fibrillation (AF), it has been assumed that respiration does not influence the ventricular response. However, previous investigations have not considered the possibility that respiration might influence HRV at lower frequencies. We hypothesized that Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) would entrain HRV at very low frequency (VLF) in AF by modulating atrioventricular (AV) nodal refractory peri