[Surgical revascularization of the myocardium in patients with chronic coronary disease and depressed left ventricular function: 1-year observation]

Many reports confirm the importance and benefit of the surgical revascularization (CABG) in patients with ischemic heart disease and severely depressed left ventricular (LV) systolic function. This mode of treatment is better than medical therapy in patients with very low LV ejection fraction (LVEF) and can prolong the life. However, the effect of CABG on LV hemodynamics is still unclear. The aim of the study was: 1) to assess the effect of CABG on LV hemodynamics in patients with low LVEF and 2) to examine the influence of two types of cardioplegia-crystalloid (CC) and blood (BC) cardioplegia--on LV function during 1 year follow-up. 122 patients with stable angina pectoris qualified for CABG were included in the study. Patients were divided into two groups: group I-47 pts with LVEF < or = 40% and group II--75 pts with LVEF > 40% and then patients were randomized for two types of antegrade-retrograde cardioplegia (CC--subgroups Ia, IIa and BC--subgroups Ib, IIb). Before operation and 4 times after CABG (after 2-6 weeks, 3 months, 6 months and 1 year) echocardiographic examination was performed. Diameters of left atrium and ventricle, LVEF and wall motion score index (WMSI) were calculated. During 1 year 8 patients died (5 of them during perioperative period and 3 patients during follow-up). Patients in group I before operation were in higher NYHA and CCS class and had more often myocardial infarction. During each of the five echocardiographic examination the values of LVEF and WMSI did not differ between subgroups Ia vs Ib and IIa vs IIb. In group I, especially in patients with very low LVEF < or = 30%, the values of LVEF and WMSI improved significantly (p < 0.001) during 1 year of follow-up. But in group II a transient deterioration of LVEF (p < 0.05) 2-6 weeks after CABG was noted. We conclude that surgical revascularization in patients with severe depressed hemodynamics improves LV systolic function during 1 year follow-up. The use of CC or BC did not seem to make any difference to the early and long-term hemodynamic effect of the revascularization.

Value of heart rate variability parameters for prediction of serious arrhythmic events in patients with malignant ventricular arrhythmias

Heart rate variability (HRV) assesses the electrical stability of the heart and can identify patients at risk of sudden cardiac death (SCD). The value of 10 HRV parameters from 24 hour ECG (in both time and frequency domain) to predict serious arrhythmic events (SAE) in a group of 56 patients with ventricular tachycardia and/or ventricular fibrillation of different etiologies not due to acute myocardial infarction was explored. Eighteen patients had low left ventricular ejection fractions (LVEF). During follow-up (6-46 months, mean = 24) 8 SCD and 12 recurrences of malignant ventricular arrhythmias or ICD discharges were recorded. Proportional hazard analysis (Cox model) for SAE revealed that the mean of all 5 minute standard deviation of RR intervals (SD) and the amplitude of low frequency spectrum (L) were independent risk factors of SAE (P < 0.05). The best models were: SD+EF and L+EF where predictive values were high (sensitivity approximately 60%, specificity over 95%, positive predictive value over 90% and negative predictive value approximately 80%). Event-free survival curves revealed a significantly shorter survival in patients with EF < 40%: 47% vs. 92%, SD < 43 ms; 56% vs. 92% and L < 16 ms; 56% vs. 89% (all P < 0.001) after 2 years. The subgroup with low EF and SD < 43 ms revealed a significantly shortened survival (27% vs 83% at 2 years, P < 0.01). Some HRV parameters, SD from the time and L from the frequency domain, were predictive of a fatal outcome in VT/VF patients. Combined SD+EF and L+EF values are powerful predictors of serious arrhythmic events.

Dispersion of the QT interval as a predictor of cardiac death in patients with coronary heart disease

Abnormal dispersion of the QT interval (QTd), measured as interlead variability of QT, may reflect a regional variation in duration of ventricular action potential and, hence, of cardiac electrical instability. In this retrospective study, we analyzed the effect of QTd on survival and its relation to other known predictors of subsequent cardiac death (CD) and sudden cardiac death (SCD) in 162 patients with coronary heart disease (CHD). QTd was calculated as the difference between the highest and lowest values measured in each of the 12 ECG leads (Qtmax - QTmin). Seventeen CDs occurred, including nine SCDs, during a 25 +/- 11 month follow-up. There were significant differences in CD (P < 0.001 in log-rank test) and in SCD (P < 0.01). The 1- and 3-year survivals were 87.5% and 76.5% in patients with QTd > 0.060 seconds versus 98% and 93.5% in patients with QTd < 0.060 seconds, respectively. Additionally, a stepwise Cox regression analysis revealed that increased QTd was an independent risk factor of CD and SCD. A cut-off value of 60 ms for QTd had a 53% sensitivity and 79% specificity in discriminating patients who are at risk of CD. The positive and negative prognostic values were 23% and 93%, respectively. Our findings support the hypothesis that increased QTd has a prognostic value in the stratification of patients with CHD independent of other known risk factors.

Heart rate variability: its association with hemodynamic function of the left ventricle in patients with coronary heart disease

Patients with heart failure secondary to coronary heart disease (CHD) are characterized by an imbalance of the autonomic nervous system, which can be assessed by analysis of the heart rate variability (HRV). However it is still unclear whether all patients with CHD reveal suppression of HRV and if it is related to hemodynamic function and contractile disturbances of the left ventricle. To answer these questions data from 105 consecutive patients were analyzed and compared with 17 healthy subjects. All study participants underwent 24-hour ambulatory ECG recordings with calculation of HRV parameters and angiographic examination after collection of clinical data and other noninvasive evaluations. Time- (SDRR, SDANN, SD, pNN50) and frequency- (LF, HF) domain parameters of HRV were assessed. All ventriculographic and hemodynamic measurements were used in the analysis. Highly significant correlations were found between all HRV parameters, and left ventricular ejection fraction (LVEF) and left ventricular end-diastolic pressure (P < 0.001). Patients with LVEF < 40% were characterized by significantly lower values of HRV and impairment or lack (LVEF < 20%) of diurnal variation of frequency-domain measurements of HRV. Patients with segmental akinesis or dyskinesis also had lower values of HRV. The group with dyskinesis was characterized by significantly lower diurnal rhythms of LF and HF, independent of LVEF.

[Sick sinus syndrome (extrinsic and intrinsic form) during long term observation]

The aim of the study has to be find, on basis of long term follow-up, an independent factors determining of pacemaker implantation in patients with intrinsic and extrinsic form of sick sinus syndrome. The second point was to find an independent risk factors of stroke and another serious complication in this group of patients (specially in paced group). The study group consisted 169 pts with sick sinus syndrome (in all pts abnormal electrophysiological tests--transoesophageal atrial stimulation). The form of sinus node dysfunction (extrinsic or intrinsic) was determined on basis of electrophysiological study after pharmacological denervation of the heart (propranolol and atropine i.v. in doses 0.2 and 0.04 mg/kg body weight respectively). The statistical analysis was performed on all pts (97 men and 72 women 48 +/- 16 yrs old) using Cox's model of proportional hazardous analysing. The follow-up period ranging from 14 to 84 months (mean 49.9 +/- 19). Pacemaker was implanted in 88 pts during observation period. Stroke signs were found in 7 pts including 6 pts after pacemaker implantation. There was 13 death (7 sudden or primary neurological death).

CONCLUSIONS

1) independent factors of pacemaker implantation were syncope, age and persistent bradycardia, 2) form of sinus node dysfunction was not an independent factor of this decision, 3) age (older), persistent after pacemaker implantation syncope and registered in transesophageal ecg ventriculo-atrial condition were independent risk factors of stroke in pts with VVI stimulation, 4) despite of pacemaker implantation (VVI mode) many patients have presyncopal or syncope attacks but life comfort in this group was much better then before implantation.

[Intravenous ablation of the atrio-ventricular junction in patients with supraventricular tachyarrhythmias]

Since the first successful therapeutic DC ablation of the AV junction in 1986, we have treated 20 symptomatic patients with drug-refractory supraventricular tachyarrhythmias (average of 6 antiarrhythmic drugs prior to the ablation attempt). The primary rhythm disturbances necessitating ablation were: AV nodal reentrant tachycardia (50% of pts), atrial flutter or fibrillation, with an uncontrolled rapid ventricular response (40%), atrioventricular reentrant tachycardia using an accessory pathway (20%), atrial tachycardia (10%), and junctional reciprocating tachycardia (5%). Percutaneous catheter ablation of the AV junction was made by Gallagher's method. The USCI 4-polar catheter (7F) was used in 40% of pts, and bipolar Cordis catheter (5F) in the remaining 60%. 70% of pts received either one or two shocks, usually of 200 or 300 J during one session. Another 25% received stored cumulative energy from 800 to 1200 J (in two sessions), and one patient--1800 J (during three sessions). In 85% of pts, the immediate post-ablation conduction was third-degree AV block with the escape pacemaker, ranging from 20 to 50 beats/min., which was infra-His in 57%, and supra-His in 43% of pts. In 15% of pts were either first-degree AV block (10%) or normal AV conduction (5%). A His bundle deflection more than 0.2 mV was predictive of successful production of third-degree AV block. Except a mild and transient increase of indicating enzymes (CPK and CPK-MB) we did not observe any other serious complications directly related to the ablalation procedure. Follow-up study included 19 pts (time range from 2 to 56 months, mean 28).(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term antiarrhythmic pharmaco-therapy guided by Holter monitoring in patients with malignant ventricular arrhythmias and ischemic heart disease

In 126 patients with clinical ventricular tachycardia and/or fibrillation, ischemic heart disease and repetitive and/or frequent ventricular ectopic beats long-term therapy guided by Holter ecg was assessed. Criteria for efficacy of antiarrhythmic drugs were following: 1) > 75% decrease in ectopic beats, 2) elimination of salvos, 3) > 90% reduction of couples and R/T and 4) reduction of multiformity up to 2 forms. They were fulfilled in 71% of patients (responders). During follow-up 1-49 months, mean 20, rate of sudden death was lower in responders as compared with nonresponders (p < 0.05). However, suppression of ventricular ectopic beats was not predictive for a favorable outcome, because the incidence of arrhythmic events and total cardiac death was similar in the two groups.

Electrophysiologic properties of transplanted human heart with and without rejection

Twelve male heart transplant recipients underwent routine electrophysiologic evaluation. None were taking cardioactive drugs, and only two had symptoms of arrhythmia. Two patients had endocardial VVI pacemakers because of previous early sinus node dysfunction. With simultaneous endomyocardial biopsy, we found seven patients with no evidence of rejection (group 1) and five patients with mild rejection (group 2; three initial or mild; two definite rejection). In two group 1 patients with presyncope, corrected sinus node recovery time was prolonged, and pacemakers were implanted into the endocardium. In all patients atrioventricular conduction was normal. One patient had evidence of functional duality of anterograde atrioventricular nodal conduction. In group 2 patients prolongation of effective refractory period of the donor atrium, functional refractory period of the atrioventricular node, and effective refractory period of the right ventricle were observed. This prolongation of refractoriness may be one of the earliest markers of rejection.

[PTCA and left ventricular systolic function (evaluation by exercise two-dimensional echocardiography)]

Successful transluminal coronary angioplasty (PTCA) should improve left ventricular systolic function. To assess the effect of this procedure 25 patients with coronary heart disease were examined before and 3-to 5 days after successful PTCA with electrocardiographic treadmill exercise test, and exercise two-dimensional echocardiography (modified Bruce protocol). Echocardiographic examination was obtained prior to and immediately following exercise. Left ventricular ejection fraction and segmental wall motion at the baseline and immediately after exercise were assessed. Electrocardiographic evidence of ischemia was found in 16 of 25 patients prior to PTCA and in 9 patients after PTCA. Following angioplasty, exercise duration was increased and the exercise-induced angina rate was significantly decreased. Ejection fraction did not change significantly in patients prior and after PTCA (52 +/- 10% versus 55 +/- 16%, p = NS). Following angioplasty, ejection fraction increased from 55 +/- 10% (rest) to 64 +/- 11% (exercise) (p less than 0.001). New exercise-induced echocardiographic segmental wall motion abnormalities were found in 16 of 25 patients prior to PTCA and in only one patient following PTCA. Significant improvement of ejection fraction and segmental wall motion were also observed in 11 patients with old myocardial infarction subjected to successful angioplasty of infarct-related coronary artery. Opposite to post-exercise results, the resting mean values of these echocardiographic parameters did not differ significantly between pre and post-PTCA examinations. These data demonstrate an improvement in systolic left ventricular function and better exercise tolerance following successful PTCA. This occurs also in patients with old myocardial infarction after angioplasty of infarct-related coronary artery. Two-dimensional exercise echocardiography may be helpful in assessing the early results of successful angioplasty.

[Does the appearance of pro-arrhythmic response to anti-arrhythmic drugs have prognostic significance?]

Study was undertaken to assess whether proarrhythmic response to antiarrhythmic drug is a risk factor for cardiac death in patients (pts) with ischaemic heart disease (IHD). In 782 pts with IHD and frequent and/or complex ventricular ectopic beats (VEB) 1041 drug tests guided by 24 hour Holter monitoring were conducted. The following drugs were assessed: propranolol, disopyramide, mexiletine, amiodarone. Pro-arrhythmia was defined according to Velebit: 1/greater than or equal to 4-fold increase in VEBs, 2/greater than or equal to 10-fold increase in repetitive forms of 3/new occurrence of ventricular tachycardia or ventricular fibrillation (VT/VF). Proarrhythmic effect was observed in 8.4% of pts and in 7.9% of drug tests. The frequency with individual drugs ranged from 5.7% to 9%. No drug was completely free of this type of reaction. Antiarrhythmic drugs inducing arrhythmogenic response were eliminated. Pts were followed-up for a mean of 22 months (range 1-49). Chronic antiarrhythmic treatment was conducted. Pts were discharged taking the agent deemed most effective for suppression of arrhythmia. Follow-up visits were made every 6-12 months. All cases of death were verified. In long-term observation cardiac death and sudden death occurred in 53 and 32 pts. With actuarial analysis (Kaplan-Meler method, log rank test) there was significant difference in cardiac death (p less than 0.05) of pro-arrhythmia (+) compared with ++pro-arrhythmia (-) pts at yr (11% v 4%, 7% v 3%) and 3 yr (24% x 11%, 16% v 7%). The relative importance of baseline clinical variables in predicting survival was assessed with a stepwise Cox regression.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of beta adrenergic blocking drugs on the prognostic value of ST-segment depression during exercise electrocardiogram testing]

Exercise testing has been shown to be predictive for future cardiac events in patients with established diagnosis of coronary heart disease. Exercise test parameters associated with poor prognosis may be unreliable if patient is receiving beta adrenergic agents. The purpose of this study was: 1) to compare the results of exercise testing performed before and during beta blocking therapy, and 2) to determine the role of beta blockers in the prognostic significance of the ST-segment response recorded during exercise testing. The study population consisted of 518 patients (mean age 52 +/- 7 years) with coronary heart disease. The diagnosis was based on the presence of one of the following three criteria: 1) typical history and significant ST-segment depression on resting or exercise electrocardiogram, 2) history of myocardial infarction, 3) significant coronary angiographic abnormalities. In all patients symptom-limited exercise test was performed before and two weeks after the onset of beta blocker therapy. The data from the first and second tests were estimated for significance of differences between the mean values with following results: maximal heart rate--135 +/- 21 and 123 +/- 19 bpm (p less than 0.001), maximal work load achieved--98 +/- 43 and 109 +/- 44 W (p less than 0.001), maximal systolic blood pressure--171 +/- 28 and 163 +/- 26 mmHg (p less than 0.001). Occurrence of characteristic ST-segment depression was more frequent during the first than during the second test (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Proarrhythmic response to antiarrhythmic drug as a risk factor for sudden cardiac death in patients with ischemic heart disease

The prognostic significance of arrhythmogenic response to an antiarrhythmic drug was studied. In 782 patients with ischemic heart disease (IHD) and frequent and/or complex ventricular premature beats (VPBs), 1,041 drug tests guided by 24-hour Holter monitoring were conducted. The following drugs were assessed: beta blockers, disopyramide, mexiletine, amiodarone. Proarrhythmia was defined as: (1) greater than 4-fold increase in VPBs, (2) greater than 10-fold increase in repetitive forms, or (3) new occurrence of ventricular tachycardia or ventricular fibrillation (VT/VF). During a follow-up of 1-49 months (mean 22) patients were treated with antiarrhythmic drugs found to be safe in control Holter monitoring. Proarrhythmic effects were observed in 8.4% of patients. No drug was completely free of this type of reaction. In long-term observation, cardiac death and sudden death occurred in 53 and 32 patients, respectively. With actuarial analysis (Kaplan-Meier method, log-rank test) there was a significant difference in cardiac death (P less than 0.01) and sudden death rate (P less than 0.05) of proarrhythmia (+) compared with proarrhythmia (-) patients at 1 year (11% vs 4%, 7% vs 3%) and 3 years (24% vs 11%, 16% vs 7%). Proarrhythmic response was an independent risk factor apart from myocardial infarction, VT/VF, ejection fraction less than 40% and QTc greater than 440 msec. Arrhythmogenic response to antiarrhythmic drugs seems to be an additional predictor of sudden death in IHD.

Predictors of ventricular tachycardia inducibility in programmed electrical stimulation and the effectiveness of serial drug testing: Polish multicenter study

In 100 patients with IHD and complex ventricular arrhythmias, programmed electrical stimulation was performed using up to three extrastimuli at sinus rhythm, and paced 100, 120 and 140 beats/min delivered from the RV apex, outflow tract or the LV with ventricular mapping to evaluate late potentials (LP) in 41 patients. Sustained monomorphic VT (SMVT) was provoked in 91% of 42 patients with a history of VT/VF, P less than 0.001, all five patients had SMVT in 24-hour ECG, P less than 0.005, and 91% of 21 patients with LV dyskinesis, P less than 0.01. After depolarizations were found in 62% of 21 patients with a history of VT, in 58% of 31 patients with inducible VT, P less than 0.01 and in five of six patients with LV dyskinesis. In patients with inducible VT, LP had a higher amplitude (105 +/- 35 vs 60 +/- 47 microV) and were more delayed (202 +/- 96 vs 133 +/- 75 msec) than in noninducible patients. In 17 patients, serial drug testing was performed after oral administration using mexilitene, disopyramide, chinidine, propafenone, sotalol, and amiodarone. If one drug was tested, the therapy efficacy was 25%, if two drugs-60%, and if three drugs-75%. In eight patients, VT was inducible in all tests, but in only one of these patients chronic antiarrhythmic therapy was not effective. We conclude that the most important predictors of VT inducibility are a history of VT or 24-hour ECG, and LV dyskinesis. Serial drug testing is efficient only when many drugs are tested, but even if VT is inducible, it does not exclude the possibility of a good clinical outcome in chronic therapy.

[Complex ventricular arrhythmias in ischemic heart disease]

The purpose of the study was to describe the clinical picture in patients with ischemic heart disease (IHD) and verifying severity of ventricular arrhythmias. The study included 856 patients with IHD aged 23-88 years (mean = 55.3), including 659 men and 197 women. Holter monitoring was performed in all patients. Ventricular arrhythmias were graded according to Lown. The patients were divided into five groups: group 1-349 patients with Lown's grade 1 and 2; group 2-95 patients with grade 3; group 3-152 patients with grade 4a and 4b; group 4-11 patients with grade 5; group 5-507 patients (selected from groups 2, 3 and 4) with Lown's grade 3 and 4 or 5. Arterial hypertension was found in 17.1%, myocardial infraction in 66%, and syncope in 12.3% of the patients. The patients with complex ventricular arrhythmias versus Lown's grade 1 and 2 show significant differences especially in respect to: the frequency of previous anterior myocardial infraction, the incidence of pain at rest, loss consciousness, the frequency of ventricular tachycardia and fibrillation, anginal pain and exercise-related arrhythmias. The patients with Lown's ventricular arrhythmia grade 3-5 do not differ significantly in their clinical manifestations of IHD from the patients with ventricular arrhythmias grade from 3 to 5. The development of silent myocardial ischemia during exercise stress testing is typical also for the patients with complex ventricular arrhythmias. A decreased contractility index, ejection fraction and dyskinesis are significantly more frequent in the patients with complex ventricular arrhythmias.

[Atrio-ventricular conduction in patients with permanent right-ventricular stimulation. I. Possibilities of evaluation by the method of trans-esophageal electrocardiogram]

We analyzed 214 patients with permanent, VVI mode stimulation divided in 5 groups. Group I 89 patients (pts) with sick sinus syndrome (sss) (mean age 60 +/- 14 yrs), group II 21 pts with sss and atrioventricular (a-v) conduction disturbances (mean age 54 +/- 19 yrs), group III 72 pts with a-v block, but without intraventricular conduction disturbances (mean age 68 +/- 11 yrs), group IV 20 pts with a-v block and registered bundle branch block (mean age 67 +/- 7) and group V 12 pts after His bundle ablation (mean age 51 +/- 20 yrs). In all pts we recorded leads I, II, III, V1, V6 and oesophageal (oe) on Mingophon 7 (Siemens-Elema) with paper speed 50 mm/s. All recordings were performed during basic and magnetic rate of the pulse generator. We could analyzed ventriculo-atrial (v-a) conduction in group I-IV respectively in 89.9%, 95.3%, 84.7%, 100%, 83.3% and in all population in 89.2% cases. In 23 pts (10.8%) we could not analyzed v-a conduction due to atrial flutter or fibrillation. V-a conduction was present in groups I-IV in 61.2%, 35%, 21.4%, 45% and 10% cases respectively.

CONCLUSIONS

1. In group patients with sick sinus syndrome and VVI stimulation ventriculo-atrial conduction was recorded in most cases. 2. Ventriculo-atrial conduction was recorded in part of the population with atrio-ventricular block. 3. Frequency of ventriculo-atrial conduction phenomenon is dependent on degree of a-v block. 4. Transesophageal recording of ventriculo-atrial conduction phenomenon in patients with implantable VVI pacemaker is simple, noninvasive and useful method for clinical practice.

[Atrio-ventricular conduction in patients with permanent right- ventricular stimulation. II. Atrio-ventricular conduction time in patients with normal and impaired atrio-ventricular conduction]

We analyzed transesophageal ECG recordings of 79 patients (42 men and women aged 17-85 mean 61 +/- 16 yrs) with present ventriculo-atrial conduction phenomenon during permanent VVI stimulation. All measurements we performed on basic and magnetic rate of the pulse generator. V-a conduction time was defined as mean (from 5 measurements) time from spike of the pulse generator to the first deflection of P wave recorded from esophagus and expressed in miliseconds. We compared v-a conduction time (v-act) on basic and magnetic rates of a stimulator and between groups with normal (group A, 49 pts) and prolonged a-v conduction time (group B, 30 pts). Group B was divided on group B-1 (19 pts without bundle branch blocks) and B-2 (11 pts with bundle branch blocks during observations). V-act during magnetic rate (cycle 596 +/- 70 ms) was significantly longer than during basic rate (cycle 834 +/- 66 ms) (191 +/- 48 ms vs 185 +/- 44 ms, p 0.05). V-act in patients with a-v block (group B) was significantly longer than in patients with normal a-v conduction (group B) (219 +/- 45 ms vs 190 +/- 47 ms, p 0.02). The longest v-act was observed in group B-2 (236 +/- 32 ms).

CONCLUSIONS

1. Ventriculo-atrial conduction time could be measured in patients with permanent VVI stimulation using esophageal ECG recording. 2. Shortening of the stimulation cycle prolonges ventriculo-atrial conduction time. 3. Ventriculo-atrial conduction time is longest in group with atrio-ventricular conduction disturbances, especially in group with registered bundle branch block.

[Comparative evaluation of the results of Holter monitoring and programmed ventricular stimulation in patients with ischemic heart disease]

24-hour ECG Holter monitoring and programmed ventricular stimulation were performed in 81 patients (64 males and 17 females aged 35-65). No ++anti-arrhythythmic agents nor beta-blockers were administrated. 58 patients suffered from myocardial infarction in the past, and 38 had a history of ventricular tachycardia. Right atrial and ventricular stimulation (in 7 patients also left ventricular stimulation) was performed using stimuli of a 2 ms pulse width. 24-hour ECG Holter monitoring was recorded on a magnetic tape from two bipolar precordial leads. Both examinations results were compared to assess correlation between ECG Holter monitoring parameters and inducibility of VT or VF by programmed stimulation. Significant correlation was stated among occurrence of: 1) spontaneous sustained ventricular tachycardia and induced by stimulation monomorphic sustained VT (p less than 0.005) as well as estimated both sustained and nonsustained VT (p less than 0.010) 2) spontaneous nonsustained VT and induced by stimulation sustained or nonsustained monomorphic VT (p less than 0.025). There was no correlation between spontaneous ventricular arrhythmias estimated by Lown and Wolf's classification and possibility to induce monomorphic VT as well as between any of ECG Holter monitoring parameters and polymorphic VT or ventricular fibrillation induced by stimulation. Aggressiveness extent of stimulation protocol necessary to induce monomorphic VT was similar in patients with or without VT recorded by Holter method.

Predictive value of various types of ventricular response to programmed ventricular stimulation: relation to Holter monitoring

The study was performed to determine the predictive value of programmed stimulation for identification of pts with ventricular arrhythmias: 75 patients were studied by means of 24-hour ambulatory ECG (24 ECG) and programmed right (in some patients also left) ventricle stimulation at sinus and two or three pacing rates using two (standard) and three extrastimuli or burst stimulation (extensive protocol). Lown classes 0, 1-3 and 4a-4b were observed in 24 ECG in 35, 14, and 26 patients, respectively. In programmed stimulation 1-6 repetitive ventricular responses (RVR) were found in 56 pts, nonsustained ventricular tachycardia in 11 and sustained ventricular tachycardia in 21 pts. High incidence of induced VT was found in pts with complex ventricular arrhythmia in 24 ECG, 81% of this group, in all but six pts only standard protocol was used. The 1-6 RVR were observed in almost 40% of pts without any arrhythmia.

CONCLUSION

Only VT induction is a useful index for high risk patients.

ADH and thermal sweating

Sweating responses to heat exposure were compared in healthy subjects pretreated with pitressin or alcohol and in the control group. Between the three groups, there were no consistent differences in the rate of sweating expressed both as a total body weight loss during 2-h heat exposure and in mg of sweat per skin area covered by a paper disc. Likewise, there were no differences in the sweat osmolality or electrolyte concentration. There was also no evidence of inverse correlation between plasma ADH level and rate of sweat secretion or its concentration when pooled data of all subjects were analyzed. It was concluded that ADH did not substantially affect thermal sweating in men.