The evolution of mapping and ablation techniques in the treatment of atrial tachycardias occurring after atrial fibrillation ablation.

PURPOSE: A possible consequence of atrial fibrillation (AF) ablation is the occurrence of organized atrial tachycardias (ATs). ATs after AF ablation (ATAAF) may be more symptomatic than AF itself, thus necessitating catheter ablation. We evaluated the prognostic significance of clinical and invasive characteristics for long-term sinus rhythm (SR) maintenance following ATAAF ablation and assessed the effect of technological developments on these results. METHODS AND RESULTS: Fifty-six consecutive patients with symptomatic ATAAF participated in the study and 114 ATAAF were revealed (2.04 ± 0.93 per patient). Sixty-eight ATAAF (60%) were macroreentrant and 33 (29%) were microreentrant circuits, while 13 (11%) were focal automatic tachycardias. The mean follow-up was 40 ± 18 months with 34 (61%) patients maintaining SR. Treatment with contact force (CF) catheters and EnSite AutoMap module (n = 11) showed significantly better AT/AF free rates at 1-year follow-up (10/11, 91%) compared with treatment using CF catheters but not AutoMap module (n = 13) (8/13, 62%) and treatment with use of neither of these modalities (n = 32) (16/32, 50%). Among patients with macroreentrant circuits around the mitral annulus or left atrial roof (n = 38), the group treated with complete linear lesions in anatomical isthmuses (n = 25) showed significantly better SR maintenance (19/25, 76%) compared with patients (n = 13) treated by empirical ablation in critical functional areas (6/13, 46%). CONCLUSIONS: Technology advancement contributes substantially to long-term success in SR maintenance, by achieving detailed mapping and more effective ablation of ATAAF. The targeting of macroreentrant circuits by creating anatomical linear lesions appears to provide better results.

Plasma atrial natriuretic peptide levels in essential hypertension after treatment with verapamil.

The aim of this study was to evaluate the long term effects of the selective Ca2+-blocker verapamil on atrial natriuretic peptide (ANP) levels in patients with moderate essential hypertension. The drug was given orally in a daily dose of 300 mg for 30 days. At the end of this clinical trial, plasma ANP levels increased by 16.14% despite the drop in blood pressure while left atrial and ventricular diameters remained unchanged. These findings indicate that the increase of ANP plasma levels is not the result of a mechanical load on the left cardiac chambers but the result of a pharmacological action. These observations also indicate that verapamil exerts part of its antihypertensive action by increasing ANP plasma levels.

Clonidine and vasomotion physiology.

It is known that clonidine exerts a hyperpolarizing action and alpha 2-adrenergic activity. The experimental work investigates the conditions under which each action of clonidine is developed on vascular smooth muscle. Two parameters were studied in vitro on bovine aortic media, Ca2+ uptake and vascular tone. The Ca2+ uptake measurement was performed by incubating in Krebs' solution small slices of the preparation in the presence of 45Ca. Studies on vascular tone were performed on deendothelialized bovine aortic rings suspended in Krebs' solution. Low concentrations of clonidine (1 nM-1 microM) decrease Ca2+ uptake and relax the preparation, indicating dominance of the inhibiting action of clonidine may be due to an hyperpolarization. Clonidine 10 microM results in equalization of the opposing actions of Ca2+ uptake and vascular tone. When the preparation is stimulated by alpha 1-adrenergic against phenylephrine 1 microM, clonidine 1 nM-10 microM potentates the Ca2+ uptake and vascular contraction in a monophasic way, indicating that the depolarizing mechanisms connected with the alpha 1-adrenergic stimulation totally inhibit the relaxing action of clonidine possibly due to hyperpolarization. This action is restricted in the presence of yohimbine (alpha 2-adrenergic blocker).

ANP concentrations during interchanging DDD-VVI pacing modes in patients with retrograde ventriculoatrial conduction.

The main reason for the pacemaker syndrome during VVI pacing is the existence of ventriculoatrial conduction (V-AC). Twenty-five patients with a permanent DDD pacemaker and ventriculoatrial conduction were included in the study. IN those patients the hemodynamic changes were evaluated in relation to ANP plasma concentration changes during different modes of pacing. After a resting period of 30 minutes in the supine position ANP plasma concentration and blood pressure were evaluated: a) under DDD atrioventricular pacing at 90/min and for 30 minutes and b) under VVI pacing at 90/min and for 30 minutes. A decrease of systolic blood pressure by 12.77% (P < 0.0001) and diastolic blood pressure by 10.50% (P < 0.0001) was noticed during VVI pacing. ANP was increased during VVI pacing by 215.95% (P < 0.0001). It was observed that the acute transition from DDD to VVI pacing leads to a 3-fold increase in the levels of plasma ANP; this may be partially responsible for the pathogenesis of the haemodynamic changes during VVI pacing mediated through the direct hypotensive effect in addition to the coincidence of atrial and ventricular contraction. This study also proves the role of the increased systolic stress of atrial myocardium for the increased ANP secretion.

The effect of trimetazidine on reperfusion arrhythmias in acute myocardial infarction.

The study aims to evaluate the effect of trimetazidine in reducing reperfusion arrhythmias in patients with acute myocardial infarction after successful thrombolysis. A total of 169 patients were included in the study, 83 of whom received trimetazidine orally at an initial dose of 60 mg followed by 20 mg tid for 5 days. These patients formed the study group (group T) while the remaining 86, the control group (group C). Successful thrombolysis by clinical and electrocardiographic criteria was observed in 53 patients of group T and in 55 patients of group C. Reperfusion arrhythmias were observed in 16 patients in group T (30.1%) and in 31 in group C (56.3%). This difference was statistically significant. Serious ventricular arrhythmias (sustained ventricular tachycardia, ventricular fibrillation) were observed in 1 patient of group T (1.8%) and in 6 patients of group C (10.9%). This difference was also statistically significant. It is concluded that trimetazidine administration can reduce the rate of reperfusion arrhythmias. This conclusion should be confirmed by larger clinical trials in order to give to the clinical results a stronger statistical power.

Increased lung uptake during myocardial scintigraphy improves the detection and localization of coronary artery disease.

Increased lung uptake during exercise thallium 201 scanning denotes severe ventricular hypofunction. To assess whether there is any relationship between this finding and the stenosis of a single coronary artery, the authors studied 140 patients (age 57.5 +/- 12 years) with both exercise thallium and coronary angiography within three months. A planar view was acquired for two hundred forty seconds immediately postexercise and prior to the single photon emission computed tomography acquisition. Two identical regions of interest outlining the left ventricle and the right lung in the planar view were used for calculation of the lung uptake, expressed as a lung-to-heart counts ratio. The patients were divided into four angiographic groups: (I) lesions at the left anterior descending (LAD), n = 35; (II) stenosis at the circumflex (CRX), n = 35; (III) stenosis at the right coronary artery (RCA), n = 35; and (IV) another group of 35 normal subjects serving as controls. No patient had a previous myocardial infraction (MI) or any cardiac operation. Patients in groups I (0.53 +/- 0.094) and II (0.44 +/- 0.072) had higher lung uptake than those in groups III (0.43 +/- 0.061) or IV (0.42 +/- 0.050). There was no difference between groups III and IV, or II and IV, but the difference between I and IV was of statistical significance (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of a low-dose fish oil concentrate on angina, exercise tolerance time, serum triglycerides, and platelet function.

Fish oils have shown beneficial effects on various parameters in patients with coronary artery disease (CAD). The purpose of this study was to investigate whether the same effects can be demonstrated with a low dose of fish oil concentrate (FOC). Thirty-nine patients were studied and divided into two groups. Twenty were given 10 g fish oil (group A) and 19 were given 10 g placebo Italian olive oil (group B). Weekly anginal attacks (AA), weekly glyceryl trinitrate consumption (GTN), exercise tolerance time (ETT), serum triglycerides (ST), platelet aggregation ratio (PAR), and beta-thromboglobulin were measured at eight and twelve weeks after start of treatment. 1. The number of anginal attacks recorded by both groups decreased by 41% in group A reaching statistical significance (P < 0.05). No change was observed in group B. 2. GTN consumption decreased in group A (P < 0.05) with no significant change in group B (P:ns). 3. ETT increased significantly in group A eight and twelve weeks after start of treatment (20.6% P < 0.01, 22.6% P < 0.01). A smaller but insignificant increase was observed in group B (P: ns). 4. ST decreased significantly in group A by 22% eight weeks after start of treatment (P < 0.01) and to a lesser degree (11%) twelve weeks after start of treatment (P: ns). In group B, ST slightly increased (P: ns). 5. No statistically significant change was observed in either group in regard to PAR and beta-thromboglobulin (P: ns). These observations suggest that dietary supplementation with a low dose of FOC may have beneficial effects on the clinical status of patients with CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of Q with non-Q myocardial infarction using signal averaged ECG.

Forty consecutive patients (pts) with acute myocardial infarction (MI) who survived to be discharged from the hospital were studied with high gain signal averaged electrocardiography (SAECG). 28% of the pts with non-Q MI had an abnormal SAECG as compared to 15% in the Q MI group. It was also found that SAECG showed a significantly longer filtering QRS duration in the non-Q MI group. The results above were considered as indicative of more delayed activation in pts with non-Q MI providing probably a substrate for more frequent reentrant arrhythmias.

Mechanographic assessment of disopyramide in postinfarction patients.

The inotropic effect of a per os single dose of 200 mg disopyramide phosphate was studied in 25 patients during the second week after acute myocardial infarction with no signs of heart failure. Systolic time intervals and the indices derived from the uncalibrated differentiated carotidogram and apexcardiogram were used to assess changes in cardiac performance. The results were as follows: a) Reduction by 3.2% of the haemodynamic ratio LVET/PEP. b) Reduction by 20.1% of the maximal relative upstroke velocity in the differentiated carotidogram (B/S2) p less than 0.05). c) Decrease by 13.1% of the ratio, total amplitude/dicrotic deflection (T/S2) in the same tracing (p less than 0.05). d) Decrease by 2.8% of the ratio, early systolic wave/early diastolic complex wave (b/ef) in the differentiated apexcardiogram. e) Increase by 3.2% of the ratio early diastolic complex total amplitude (ef/ZN) in the previous tracing. The above changes were indicative of a slight negative inotropic effect of the drug.