Ajmaline Challenge To Unmask Infrahisian Disease In Patients With Recurrent And Unexplained Syncope, Preserved Ejection Fraction, With Or Without Conduction Abnormalities On Surface ECG

Background: Pharmacological challenge with class I antiarrhythmic drug is a recommended diagnostic test in patients with unexplained syncope only in the presence of bundle branch block, when non-invasive tests have failed to make the diagnosis. Its role in patients with minor or no conduction disturbances on 12-leads ECG has not been evaluated yet. It is also not clear which are the values of His-Ventricular interval to be considered diagnostic. We sought to evaluate the role of ajmaline challenge in unmasking the presence of an infrahisian disease in patients with recurrent and unexplained syncope, regardless of the existence of conduction disturbances on surface ECG. Materials And Methods: Patients with history of recurrent syncope, preserved EF and a negative first level workup were enrolled. Conduction disturbances on ECG were not considered as an exclusion criteria. During EPS, basal HV conduction was determined. In the presence of a HV >70 msec the study was interrupted and the patient was implanted with a pacemaker. If the HV was ≤ 70 msec, ajmaline was infused and HV was reassessed. The maximum value of HV was considered. A prolongation ≥ 100 msec was considered as diagnostic and indicative of conduction disease, and the patient underwent pacemaker implantation. Patients with an HV <100 msec were implanted with an ILR. Results: Sixteen consecutive patients were studied (age 76±5.2 years). Nine patients had conduction disturbances at baseline ECG (group ECG+). Among them, 5 had a basal diagnostic HV interval and 4 had a non-diagnostic HV interval. In the latter group, abnormal response to ajmaline was observed in 3 patients. In this group only one patient was implanted with an ILR, 8 patients were implanted with a pacemaker. Among the seven patients without conduction disturbances (group ECG-), no one had a diagnostic basal HV interval. After drug administration, 4 patients had a non-diagnostic response and were implanted with an ILR, while 3 patient had a pathological response and were implanted with a pacemaker. No difference was found in the values of maximum HV interval prolongation after ajmaline between the two groups (P = 0.89). During a mean follow up of 13±3 months, no patient has developed a syncopal episode. One patient in group ECG- and negative drug test was implanted after 3 months with a permanent pacemaker because of a two to one asymptomatic AV block at ILR interrogation. Conclusions: Ajmaline challenge is a useful tool to unmask the presence of a infrahisian disease in patients with preserved EF, unexplained syncope and negative workup, even in the absence of conduction disturbances on 12-leads ECG. It is a simple and safe test that may disclose the detection of the disease. In these patients, an earlier pacemaker implantation of a pacemaker, may avoid the consequences of a syncopal recurrence. Values of HV interval > 70 msec in basal conditions and ≥ 100 msec after ajmaline administration seem appropriate to unmask infrahisian disease. Larger population is required to validate this hypothesis.

[Complete atrioventricular block as the first clinical manifestation of a tick bite (Lyme disease)]

A 52-year-old male patient presented to the emergency department because of malaise and frequent dizziness. The ECG revealed high-grade atrioventricular block that required placement of a temporary pacemaker. There were no other abnormalities in physical and echocardiographic examination, and coronary angiography excluded the presence of coronary artery disease. IgM and IgG antibodies against Borrelia were positive, and antibiotic therapy with ceftriaxone at the dose of 2 g/die for 15 days resulted in rapid regression of atrioventricular block. Seven-day ECG recording immediately after discharge and 24h ECG monitoring at 40 days confirmed the total disappearance of atrioventricular block. This represents a case of atrioventricular block as the first manifestation of Borrelia infection (Lyme disease). A prompt diagnosis and antibiotic therapy usually result in complete resolution of atrioventricular block without the need for a permanent pacemaker.

[Dynamic phonocardiography in the study of mitral valve prolapse. Our experience]

The purpose of this paper is to check the usefulness of dynamic phonocardiography for mitral valve prolapse (MVP) diagnosis, especially in apparently silent cases, or with late-systolic click. In fact, possible MVP or mitral valve regurgitation can be shown. 148 patients (58 males, 90 females) have been examined by basal and dynamic phonocardiography and M-echocardiography. Patients were recruited for routine medical examination or during investigations for other causes or to explain evocative MVP troubles. Provocative tests by amyl nitrite, isoproterenol and methoxamine registered a late-systolic click in 17 normal cases and a late-systolic murmur in 22. M-echo demonstrated MVP in 142 cases (96%), with a slight prevalence of late-systolic MVP; tricuspid valve prolapse coexisted in 8 cases and aortic regurgitation in 12. Today echocardiography is the most important examination, but all our data point to the usefulness of dynamic phonocardiography for MVP diagnosis: in our opinion, the integration of both techniques represents the most correct approach.

[Evaluation of the cardiovascular effects of the beta-blockader atenolol]

The beta-blocking action of 100 mg per diem Atenol was evaluated in 8 patients with conditions requiring treatment with a beta-blocking drugs (ischaemic cardiopathy, arterial hypertension, hypertrophic myocardiopathy). Ergometer bicycle exertion tests were used to evaluate the extent of Atenol's beta-blocking action (in basal condition, 3 and 24 hours after administration of the drug) as well as Holter type dynamic ECG recordings (basal and under treatment). The drug significantly reduced cardiac frequency and arterial pressure both at rest and under exertion. It also significantly reduced average hourly and daily cardiac frequency as shown by dynamic ECG. No side effects of the drug were observed.