In patients with chronic atrial fibrillation and congestive heart failure presenting with narrow QRS complex the direct His-bundle pacing the use of dual chamber implantable cardioverter-defibrillator can be a definite treatment option meeting all therapeutic goals. This approach enables heart rate regularization, appropriate increase of beta-blocker dose with additional benefit in terms of arrhythmic death prophylaxis. The proper functioning of implantable cardioverter-defibrillator demands appropriate atrial channel/His-bundle signal sensing. The low His-bundle electrogram amplitude usually does not interfere with the device function and the DDI or DVI programming modes are reasonable. The authors present a case of unusually high His-bundle signal amplitude sensed by atrial channel of implantable cardioverter-defibrillator, which could potentially contribute to some particular programming considerations. The attending physician should be aware of some arrhythmia discriminators which may delay or even withhold the appropriate shock.
Despite its widely-understood physiological mode, artificial atrial pacing can negatively influence heart performance in many respects. We present the case of an 80-year-old woman with the signs and symptoms of diastolic heart failure which had originated, according to the patient herself, due to the implantation of a dual chamber pacemaker inserted for the treatment of sinus node disease. The atrial electrode was located in the right atrial appendage. Electrocardiographic and echocardiographic assessment indicated the possibility of a deleterious relationship between the atrial and ventricular contraction, which could be responsible for patient's symptoms. Some changes in device programming could contribute to a clinical improvement. Yet the question remains: should pacing of the Bachmann's bundle be implemented in our patient?
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In patients with sick sinus syndrome, and previously implanted dual-chamber pacemaker, the occurrence of atrial fibrillation finally assessed as permanent is most commonly regarded as a natural course of the disease. The inappropriate heart rate control and right ventricular pacing can both negatively influence left ventricle mechanical performance leading to cardiomyopathy and heart failure.It was presented the case of a 72-year-old woman with permanent atrial fibrillation with narrow QRS complex, after dual-chamber pacemaker implantation, admitted to our department with signs and symptoms of acute decompensated congestive heart failure. The modification of pharmacotherapy allowed to compensate heart failure, however with only small influence on structural remodelling and patient's symptoms. The successful upgrade of the pacing system to the direct His-bundle pacing enabled the restoration of proper function of the heart and full symptoms relief. The direct His-bundle pacing is an approach of choice in such a group of patients.
The current treatment of patients with heart failure and concomitant atrioventricular conduction delay is difficult. Recommendations indicate the possibility to use the classic resynchronization but in the presence of narrow QRS-complex such approach could be even harmful. Without a sufficient LBBB morphology as indication for classical CRT, those patients would lose their narrow QRS complex with negative consequences for the hearts functional status.
A new therapeutic option for those patients to re-establish the physiological atrioventricular mechanical sequence is the permanent His-bundle pacing (pHBP). Advantages like physiological activation sequence of the ventricular myocardium, less affected by AF compared to classical CRT and reversal of mitral regurgitation should be enumerated to show it's beneficial effect. Additionally the use of Bachmann's-bundle pacing can correct the prolonged interatrial conduction thus further contribute to the echocardiographic and clinical improvement.
The aim of the study is to assess the influence of Bachmann's-bundle pacing and His-bundle pacing on the reversed remodeling of the heart in patients with heart failure and atrioventricular block.
The study group included 21 patients (7 women and 14 men) undergoing cardiac resynchronization using Bachmann's-bundle pacing and permanent His-bundle pacing from LV channel for atrioventricular conduction delay. All the patients had narrow QRS-complex which prevented us to use classic resynchronization. 13 CRT-D and 8 CRT-P devices were implanted according to the ejection fraction and ventricular arrhythmia risk assessment. In all patients the direct His-bundle pacing was successfully achieved, selective in 17 and non-selective in 4 patients. The mean follow-up (FU) period was 8.8 months (1–26 months). The echocardiographic, clinical and ECG results are presented in the table 1.
Conclusions
1. The correction of atrioventricular and interatrial conduction delay resulting in improvement of atrioventricular mechanical coupling can contribute to the reversed remodeling of the heart.
2. This also improves the patient's functional status.
3. In some patients this approach could lead to the normalization of echocardiographic parameters of the left ventricle.
Funding Acknowledgement
Type of funding source: None
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