Evaluation of atrial function after surgical ablation of atrial fibrillation: a Speckle tracking study

AIM

AIM of our study was to assess atrial function in patients who underwent atrial fibrillation (AF) surgical ablation by a novel echocardiographic technique (speckle tracking).

METHODS

From February 2006 to April 2008, in 11 consecutive pts with paroxysmal or persistent AF (6 males, mean age 69.6±9.7 years) undergoing cardiac surgery, concomitant AF surgical ablation was performed with bipolar radiofrequency clamp (Cobra_Bipolar® system). These pts, all in stable sinus rhythm (SR), were echoed after a mean follow-up of 14.6±9.3 months from surgery. Speckle tracking was used to estimate global LA strain, peak strain and the standard deviation of the time-to-peak (% of R-R' interval) of the deformation of 6 segments identified along the septum, the roof and the lateral wall of LA in a 4-chamber view.

RESULTS

These patients showed a mild LA enlargement (mean volume 43.4±11.6 mL/sqm). In 5 of them (45.4%) no A waves were detected on MPWD and pulmonary venous flow, but speckle tracking showed preserved atrial function with a mean global strain of 5.5 ± 3.3 %, a mean peak strain of 10.4 ± 5.7 % and a TP-SD of 15.1±8.7 ms.

CONCLUSION

Our study seems to show that surgical AF ablation has a lower impact on atrial function in comparison with data from literature about percutaneous catheter ablation. This is probably related to an higher sensitivity of this type of echocardiography evaluation, but this finding must be confirmed by other trials.

The DDDR closed loop stimulation for the prevention of vasovagal syncope: results from the INVASY prospective feasibility registry

BACKGROUND

The contraction dynamics of the ventricular myocardium are affected before and during vasovagal fainting suggesting that the Closed Loop Stimulation (CLS) pacemaker could be useful for the treatment of these patients. CLS is a new concept of heart rate modulation in cardiac pacing. The pacemaker INOS(2) CLS (Biotronik, Germany) derives its information for heart rate optimization from myocardial contraction dynamics, by measuring right ventricular intracardiac impedance. The pacemaker becomes an integral part of the circulatory regulation and, therefore, reacts appropriately to different cardiovascular demands.

METHODS

In a prospective registry, 34 patients with a history of recurrent vasovagal syncopal events were implanted with INOS(2) DDDR CLS pacemakers. The aim of the study was to evaluate both long term clinical outcome, including the first recurrence of syncope, with DDDR-CLS pacing and acute precipitation of vasovagal fainting with DDDR-CLS mode compared with DDD during head up tilt testing.

RESULTS

During a follow up period of 12-50 months, 30 patients experienced no further syncopal events in daily life; 1 patient had no syncope but night palpitations, which were eliminated by pacemaker reprogramming; 2 patients had presyncopal episodes but not syncopes; 3 syncopal recurrences occurred in one patient in chronic atrial fibrillation, possibly not an ideal candidate for implantation.

CONCLUSIONS

Further studies for detailed understanding of the preventive mechanism of DDDR-CLS pacing in vasovagal syncope are warranted. A randomized multicentre prospective new study (INotropy controlled pacing in VAsovagal SYncope: INVASY) is now in progress to confirm the beneficial effect of DDDR-CLS pacing in a larger group of patients with recurrent vasovagal syncope.

[Myocardial revascularization may resolve arrhythmic warm-up in patients with implantable cardioverter-defibrillator: 2 case reports]

Patients with ventricular arrhythmias and coronary artery disease may have a poor clinical outcome because of an increased risk of sudden cardiac death. In these patients therapeutic approaches include two main strategies: automatic implantable cardioverter-defibrillator (ICD) and antiarrhythmic drugs (when left ventricular function is preserved). Patients with arrhythmic warm-up sustained by ischemic attacks may be stabilized after percutaneous or surgical revascularization. We report the cases of 2 ICD patients, in whom the correction of myocardial ischemia was successful in preventing further ICD discharges. In the first patient with known coronary artery disease (previous acute myocardial infarction and left ventricular ejection fraction 30%) a sudden arrhythmic warm-up was reported with 70 ICD discharges in 24 hours; the patient underwent coronary artery bypass surgery and only few isolated episodes of ventricular tachycardia were observed during the following 34 months. In the second patient with a history of dorsal acute myocardial infarction and two previous interventions of coronary artery bypass graft surgery, we observed a sudden and unexpected arrhythmic instabilization with several ICD discharges. After percutaneous transluminal angioplasty of a graft stenosis, the clinical situation was stabilized and no more ICD activations were observed during the follow-up. In selected patients arrhythmic warm-up can rely on an ischemic substrate, then a careful re-evaluation for ischemia is mandatory in order to resolve the situation.

Implantable cardioverter defibrillators and cellular telephones: is there any interference?

The aim of our study was to consider cellular telephone interference using different cellular telephones and implantable cardioverter defibrillator (ICD) models. Thirty (26 men, 4 women) patients with ICDs were considered during follow-up. The ICD models were: Telectronics (7), CPI (7), Medtronic (7), Ventritex (5), and Ela Medical (4). All patients were monitored with surface ECG; permanent telemetric endo-ECG monitoring was activated. Then, the effect of two different European telephone systems were tested: TACS system (Sony CM-R111, 2W power) and GSM system (Motorola MG1-4A11, 2 W power). For both systems, the effect during call, reception, active conversation (dialogue), and passive conversation (listening) were observed. Cellular telephones were located first in contact with the programming head, then near the leads system, and lastly, in the hands of the patient. At the end of the evaluations, memories were interrogated again to check for false arrhythmia detections. In five of these patients during arrhythmia induction at device implant (first implant or ICD replacement), we also evaluated possible interference between cellular telephones in the reception phase and the ventricular fibrillation detection phase of the ICD. All evaluated models showed significant noise in the telemetric transmission when the cellular telephone (both TACS and GSM) was located near the ICD and the programming head; noise was particularly significant during call and reception, in most cases leading to loss of telemetry. No false arrhythmia detections have been observed during tests with cellular telephones located on the ICDs. During tests performed with cellular telephones located near the leads or in the hands of patients, no telemetric noises orfalse arrhythmia detections were observed. During induced ventricularfibrillation and cellular telephones in reception mode near the device, the arrhythmia recognition was always correct and not delayed. In conclusion, present ICD models seem to be well protected from electromagnetic interference caused by European cellular telephones (TACS and GSM), without under-/oversensing of ventricular arrhythmias. However, cellular telephones disturb telemetry when located near the programming head. ICD patients should not be advised against the use of cellular telephones, but it has to be avoided during ICD interrogation and programming.

[Intracardiac ectopic thyroid: a report of a clinical case with a long-term follow-up]

We describe the prolonged follow-up of a 64-year-old female patient, with an ectopic intracardiac thyroid gland. The mass was first detected 14 years ago, during a routine echocardiographic examination. The patient suffered from episodes of palpitation and cardiac auscultation revealed a systolic murmur. At cardiac surgery a right ventricular mass penetrating most of the interventricular septum was found. The mass was also prolapsing into the pulmonary infundibulum and could not be removed. On histopathology examination, the presence of a normal tissue was demonstrated. Two main clinical events characterized the prolonged follow-up: the gradual development of a massive tricuspid insufficiency, probably due to the strict anatomic relationship between the septal tricuspid papillary muscle and the mass itself; frequent supraventricular arrhythmias, partially refractory to different pharmacologic regimens, which could be ascribed to the chronic overload of the right atrium. The mass size has been stable over the years, and no thyroid hormone derangement was ever found.

[Dual-chamber DDD pacing in NYHA III-IV functional class dilated cardiomyopathy: short and middle-term evaluation]

Effectiveness of dual-chamber pacing in patients with dilated cardiomyopathy is still controversial. Our study was performed: to select the most favorable individual atrioventricular (AV) delay; to compare hemodynamic short-term effects in each patient after 2 periods of DDD pacing and sinus rhythm (AV spontaneous); to assess hemodynamic long-term (1 year) effects after DDD pacing at optimum AV delay. In 1996, 9 patients (7 men, 2 women; mean age 69 +/- 5 years) with dilated cardiomyopathy (5 idiopathic, 4 ischemic), NYHA functional class III-IV, ejection fraction < 30%, end-diastolic volume > 60 ml/m2, mitral regurgitation +2/+3, PR interval > or = 200 ms, were enrolled. All patients were implanted with DDD pacemakers and monitored for: ejection fraction and end-diastolic volume (measured by echocardiography and radionuclide angiography); clinical conditions; exercise tolerance and maximum oxygen consumption (by Weber exercise protocol); neurohormonal activity (plasma renin, aldosterone, atrial natriuretic factor). Data were recorded: before DDD implantation; after 2 randomized, single-blind periods of 3 months in VVI mode (at ventricular "sentinel" rate of 50 b/min) and in DDD mode with the optimum AV delay, corresponding for each patient to the minimum end-diastolic volume measured by radionuclide angiography and to the highest cardiac output recorded by echocardiography; after 6 months of DDD pacing with most favorable AV delay. Three more patients died 6 months after (between sixth and twelfth month of follow-up), due to refractory heart failure; 1 patient dropped out because his pacemaker was programmed in VVI mode at low rate, due to intolerance of DDD pacing. Among the other 4 patients no clinical and laboratory parameters were significantly different after 1 year of follow-up. In conclusion, DDD pacing in selected patients with dilated cardiomyopathy showed disappointing results, despite a strict and laboratory monitoring; DDD pacing could be of major benefit in larger populations, according to Doppler mitral flow pattern: those patients with a larger A-wave amplitude could be more sensitive to DDD pacing than those with evidence of poor atrial systole. Moreover, biatral and/or biventricular pacing could also play a significant role.