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Little information is available regarding cardiac automatism and conduction disturbances in patients affected by congestive (CCM) or hypertrophic (HCM) cardiomyopathies. For this reason 29 patients with HCM (10 cases) and CCM (19 cases) and disturbances of sinus node automaticity or AV conduction underwent an electrophysiologic study. Eight patients affected by HCM were also submitted to cardiac catheterization. Sinus node function was normal in each of the HCM patients, and impaired in 6 of the 19 CCM patients. The intra-atrial conduction was prolonged in only one CCM case. One HCM and 2 CCM patients showed an impaired intranodal AV conduction. Thirteen patients (44%) showed a prolonged HV interval (3 HCM and 10 CCM patients). No calcific deposits on the aortic valve were discovered by X ray stratigraphic examination in any of the patients. In 6 cases a progression of the conduction disturbances was observed. Ventricular pre-excitation was present in 4 patients (13%).

This study was undertaken to assess the risk of developing complete heart block during general anesthesia in patients with bundle branch block. His bundle electrograms were recorded during sinus rhythm and after atrail pacing in 11 patients (5 LBBB, 2 RBBB, 3 RBBB and LAH, 1 RBBB and LBH) before and after administration of Pentothal 0.20 g e.v., Succinylcholine 1 mg/kg e.v., and breathing of fluothane 1%or Ethrane. Minimal effects on sinus functions and A-V node conduction was observed during anesthesia; Fluothane only increased slightly AH intervals (+11%). Both Fluothane and Ethrane effects on HV conduction was insignificant. In 9 patients HV intervals increased of 5% after Succinylcholine; 2 patients developed a complete heart block distal to his after the drug. Possible causes of the complete heart block are discussed and a direct effect of Succinylcholine is hypothesized.

On the basis of personal experience of 22 patients, 11 with sick sinus node syndrome (SSNS) and 11 without, it was concluded that the seat and length of atrial stimulation has little importance for the determination of recovery time for corrected sinus node (RTCSN). The frequency of optimal stimulation seems to be 110 impulses per minute for 2 minutes, by which it generally reaches the maximum value of RTCSN. Using this method, the falsely normal RTCSN in SSNS subjects can be verified; in these cases the test should be repeated within a larger frequency scope.

The experience of the Cardiac Electrostimulation Center of S. Camillo Hospital in Rome on 1503 patients treated with permanent pacemakers for an 11 year period is referred. The Authors analyze the increase of the activity of the Center during these years and some events that caused it. 94.5% of the patients were more than 50 years old; the dominant pathology has been ischemic and idiopathic cardiopathy, which together include 94.7% of the totality. The indication to the implant has been A-V block in 70% of the patients; intraventricular block in 20%; sick sinus syndrome in 10%. In the last years the prophylactic indication has increased (from 0.4% to 4.4%). 2459 pacemakers have been used, of which 79.5% was QRS-inhibit. The mercury prosthesis have been progressively substituted with the lithium ones. 1642 catheters (implant and reimplant) have been used; principally endocardic (95%) and monopolar (85%). The substitution of the catheter has been necessary in 9% of the totality; in 2.6% of the endocardic and in 15.9% of the epimyocardic. Among 50 electrodes, after a period of observation of about 7.7 years, 36 are still in function. The percentage of the complications has been 17.1%; the most important complications have been: dislocation (6%), microdislocation (1.5%), late high threshold (2.1%), failure of catheter (1.2%), generator malfunction (2.3%). The total mortality has been 15.4%; 0.2% caused by deficit of the implant; 2% sudden deaths and 13.2% not depending from the implant; 243 patients (16%) are not to be found. The frequency of out-patients controls has decreased in the last 2 years (from 3.8 controls per years to 1.8).

First there is a description of present methods available for controlling the functioning of pacemakers, most of which are already being used in traditional clinic-electronic control. There follows a presentation of telephone monitoring (ECG + Pacing Rate) and its limits so far as photoanalysis is concerned. Mention is made of the new italian system of telephone monitoring which also includes measurement of amplitude and width of the pulse. Personal experience of the diagnostic value of photoanalysis is given. This concords with others as to its necessity to detect any failure from circuitry defects or from breakage or insulation of electrode. In conclusion the hope is expressed of actuating a completely trustworthy control system which includes a high degree of foreseeing failure (telephone monitoring) and diagnostic value (Rx + photoanalysis). At last the advantages of an automatic follow-up system in a pacemaker patient clinic are discussed.

In order to assess the risk of complete AV block in patients with intraventricular conduction disturbances who undergo general anesthesia, 20 patients with various conduction defects (7 LBBB, 1 RBBB and 1st degree AV block, 1 incomplete RBBB, 9 RBBB + LAH and 2 RBBB + LPH) were studied by means of His bundle recording and corrected sinus node recovery time (CSNRT) before and after the subministration of thiopental (0.2 g I.V.), succinylcholine (1 mg/kg I.V.), Fluothane (1%) and Ethrane (1.6%). Nineteen patients displayed signs of dizziness or syncope; both the sinus rate and the CSNRT, did not undergo significant variations. A slight and not significant variation of intranodal conduction during sinus rhythm was observed after Fluothane administration (AH was prolonged by 8%). A less evident negative dromotropic action of thiopental and Ethrane was only revealed by atrial pacing. No significant variations were demonstrated in His-ventricular conduction after administration of the various drugs. The maximum average increase (1.5%) of the H-V interval was observed after administration of succinylcholine. Acute AV block distal to the His bundle appeared in three patients after succinylcholine administration.

Measurements of threshold of electrical stimulation were performed in thirty patients with A-V block, at the time of implantation of the pacemaker, after 10 days, 1-2 months and 1 year. The Vario-pacemaker was used for the measurements. An increase in the stimulation threshold of about 260% was noted after 10 days and 1-2 months. One year after the implantation of the pacemaker, the myocardial threshold was about 200% of the initial value. The method is easy to perform. It is very useful to follow the myocardial threshold changes for a long period after the implantation.

The prognostic value of induction of ventricular tachycardia (VT) by programmed electrical stimulation (PES) was analyzed in 123 patients: 64 (Group I) with spontaneous recurrent VT and 59 (Group II) without a history of serious arrhythmias. Thirty-three patients with spontaneous VT underwent coronary and left ventricular angiography to compare electrical instability with the presence of ventricular disfunction and/or the extent of coronary artery disease (CAD). PES reproducibly induced VT in 49/64 patients with spontaneous VT (sensitivity = 77%) and in 6/59 patients without VT (specificity = 90%). Twenty-two patients (66%) had ventricular disfunction defined by an ejection fraction of less than or equal to 40% or regional wall motion abnormalities. Only 4 patients (33%) had proximal 3-vessel CAD. The mean follow-up period was 16 +/- 12 months. Eight of Group I patients died suddenly and 24 had recurrent symptomatic VT. Three of Group I patients died (1 cardiac failure, 2 non-cardiac deaths), all the survivors were free of serious arrhythmias. In Group I patients mortality was correlated with: recent anterior myocardial infarction, inducible sustained VT with PES, ejection fraction less than or equal to 0.40, ventricular ipoasynergy and or at least one coronary stenosis greater than or equal to 70%. This study suggests that inducible VT is a marker of the risk of sudden death. Electrical instability may occur independent from the etiology of cardiopathy, ventricular disfunction and extent of CAD, but these parameters are correlated to global and sudden mortality in the group of patients with spontaneous VT.

Disturbances in atrioventricular conduction were demonstrated in 17 out of 38 cases of sik sinus node syndrome (MNSA). 14 cases had BAV, in varying degrees, 9 had intraventricular conduction disturbances, 13 had pathological values of A-H, 6 pathological values of H-V, 4 contemporaneous lengthening of A-H and H-V. The ECG and hissian electrogram examinations enabled the identification of the seat and the extension of the conduction disturbance, which was schematized as nodal, nodal and truncular, intraventricular (mono-, bi-, and trifascicular) and diffused. It is possible that the damage to the conduction system associated with MNSA has the same etiology. The frequency of the association of MNSA with conduction disturbances suggests, in the case indicated, the use of a ventricular electrostimulation.

143 patients were examined for SNRT and thus divided: 1st group: 39 patients with indisputable clinical signs of MNS (bradycardia-tachycardia, synocopes); 2nd group: 18 patients with constant sinusal bradycardia, but without arrhythmias; 3rd group: 86 patients without any clinical signs of sisusal automatism deficit. The average SNRT results were: 2346 plus or minus 1404 msec in the 1st group; 1337 plus or minus 181 msec in the 2nd group and 1021 plus or minus 216 msec in the 3rd. Corrected SNRT gave an average result of 1315 plus or minus 1300 msec in the 1st group; 329 plus or minus 229 msec in the 2nd and 234 plus or minus 133msec in the 3rd group. The values between the average and standard deviation...