The findings in a patient with perf...

The findings in a patient with perfect AV block and intra-atrial conduction disturbances owed to Lyme disease are readyed The electrocardiographic follow-up and serial EP findings remind of that complete AV block in Lyme disease may signify a more extensive affection of the AV conduction theory (with eventually attendant intra-atrial conduction disturbances) than described in earlier reports. An almost consummated resolution of the considerable damage to the conduction scheme occurred within two weeks.

(Chest 1989; 96:219-21)

Lyme disease is nowadays known as an infectious disease caused by the agency of the bite of a tick or a flea, by the agency of which the spirochete, Borrelia burgdorferi, can affect skin, joints, nervous arrangement and heart.[1,2] Although the clinical expression of Lyme disease is highly variable,[1,2] the most numerous common and clinically most irksome cardiac manifestation is AV block[1-8] The electrophysiology of AV stop up in Lyme disease has not received long attention, and serial EP investigations have not, to our knowledge, been performed before.

This report describes a patient with Lyme disease in whom unimpaired AV block was the presenting and main clinical point to be solved [i]or[/i] settled and in whom the course of the AV (and intra-atrial) conduction disturbances was pursu with surface electrocardiographic follow-up and serial EP investigations.

Case Report

A 40-year-old athlete was admitted to our hospital because of total AV block of unknown origin, with returning dizziness and near collapse, which had been occurring for pair days. For three weeks, he had had arthritis-like symptoms in the toes of his right paw No erythema migrans had been noticed. onward physical examination the temperature was normal, the pulsation rate was regular at 40 beats by minute, and the blood press was 120/70 mm Hg. There were cannon-wave pulsations in the jugular veins and a first heart unmutilated of variable intensity. No pulmonary rales were heard. Four toes of the patient's right bottom were warm, red, and painful, if it be not that not swollen. There were no dermatologic abnormalities. The surface push showed complete AV block with an escape periodical emphasis of 37/min; the QRS configuration moveed a focus in the left bundle up branch. The configuration of the P wave was abnormal, and its duration was lengthened In spite of administration of atropine and isoproterenol (isoprenaline), there were renewed periods of ventricular asystole, sometimes lasting as lengthy as 10 seconds. The erythrocyte sedimentation rate was 22 mm/h Other routine laboratory proofs yielded normal results. The chest roentgenograms and echocardiograms also prov to be normal.

A gallium scan showed diffuse uptake in the muocardium (Fig 1) Serologic touchstones for B burgdorferi were positive for IgM (1:128) and weakly positive for IgG (1:64) standards for chlamydia and cytomegalo-virus were weakly positive, if it be not that an increase in titer did not fall out Serologic markers for other microorganisms and diseases were all negative, including the Treponema pallidum hemagglutination assay, streptococcal antibody proofs several viruses (Coxsackie virus; echovirus; adenovirus; influenza A; hepatitis B) rheumatoid factor, and antinuclear antibodies. In agreement with the gallium scan, signs of endomyocarditis were erect in an endomyocardial biopsy. In combination with the serologic follows this indicated Lyme carditis. In order to meditation the characteristics of the AV obstruct the patient underwent serial EP investigations. During the phase of completed AV block, no sign of His pack activity could be found, despite extensive mapping of the His put into bundles region, using several types of catheters (Fig 2A). A temporary pacemaker was inserted, and the patient was treated with tetracycline (500 mg four times for day orally), the latter being changed to penicillin (4 million IU intravenously four times daily) after five days. Between the sixth and tithe day after admission, the AV conduction disturbances in succession the surface ECG regressed to a second-degree and later forward to a first-degree AV mould The EP study was repeated after a week; this time, His tie in a bundle activity could easily by ground using a bipolar His budget catheter (Cordis) (Fig 2B).

After three weeks of antibiotic therapy, the patient was discharged with a normal surface ECG and minor residual complaints of arthritis.

Discussion

In principle, all exemplars of AV block may fall out in Lyme disease, even in the same patient. The degree of AV arrest can vary within periods of minutes.[2,8] Lyme carditis-related tachyarrhythmias, whether or not induced from bradycardia, are not reported. Our patient existinged with complete AV block. Despite extensive mapping of the His package region, no His bundle activity could be set up during the acute phase of Lyme carditis. There was no His depart hurriedly spike following the atrial electrogram nor preceding or following the fascicular escape complexe although His bundle up activity buried in the QR complication cannot be ruled out. The QR configuration and the QR duration of 130 m were compatible with an escape focus in the left tie in a bundle branch. The configuration of the P wave and its duration of 120 msec indicateed a prolonged intra-atrial conduction time (Fig 2A). During right ventricular stimulation with progressively increased rate, also no retrograde His tie in a bundle activity could be found. Programmed EP stimulation in the right ventricular apex, using the same extrastimulus, revealed a ventricular effective refractory period of 250 msec No tachyarrhythmias were induced. Overdrive suppression of the escape focus was always interrupted through backup pacing after three next to the firsts When the EP study was repeated, His tie in a bundle activity was easily found. The AH interval was slightly put offed (155 ms), the HV interval was normal (45 ms) and the QR duration had decreased to 100 m The P-wave duration had decreased to 100 m and the P-wave configuration had normalized (Fig 2B) The longitudinal dimensions of time between the serial EP studies was about the same week.