Effect of Biventricular Pacing on Left Ventricular Outflow Tract Pressure Gradient in a Patient with Hypertrophic Cardiomyopathy and Normal Interventricular Conduction
Abstract:We report a case of hypertrophic obstructive cardiomyopathy (HOCM) that was markedly improved by biventricular pacing. A 55-year-old woman with HOCM presented with palpitation and presyncope. Electrophysiologic study revealed an atrioventricular nodal reentrant tachycardia. After radiofrequency catheter ablation, a Mobitz type II atrioventricular block developed and a permanent pacemaker implantation was decided. Cardiac catheterization showed a left ventricular outflow tract (LVOT) gradient of 130 mmHg. Right… Show more
“…It has been previously suggested in some anecdotal case reports that implementation of left or biventricular pacing in symptomatic HOCM subjects may reduce the outflow tract gradient and alleviate symptoms 11–15 . Encouraged by these data, we implanted CRT‐D devices in consecutive symptomatic HOCM patients with a significant outflow gradient and indications for ICD.…”
These preliminary data suggest that CRT seems to be an effective method of reducing the outflow tract gradient and improving the functional status of symptomatic HOCM patients requiring ICD implantation. Our findings need to be confirmed by more extensive studies.
“…It has been previously suggested in some anecdotal case reports that implementation of left or biventricular pacing in symptomatic HOCM subjects may reduce the outflow tract gradient and alleviate symptoms 11–15 . Encouraged by these data, we implanted CRT‐D devices in consecutive symptomatic HOCM patients with a significant outflow gradient and indications for ICD.…”
These preliminary data suggest that CRT seems to be an effective method of reducing the outflow tract gradient and improving the functional status of symptomatic HOCM patients requiring ICD implantation. Our findings need to be confirmed by more extensive studies.
“…Dual chamber pacing is a therapeutic method for patients with HOCM. Although a reduction in the LVOT pressure gradient by dual chamber pacing has been demonstrated in previous studies, 11,12) some patients do not respond to dual chamber pacing. Achieving stronger dyssynchrony by dual chamber pacing is dependent in part on the pacing site, and it remains possible that the LVOT pressure gradient will be relieved to a greater degree by an appropriate pacing site.…”
SummaryAlthough hypertrophic cardiomyopathy (HCM) with an accessory pathway is encountered in clinical practice, there is little evidence of a coherent strategy for ablation of the accessory pathway in patients with HCM. We present the case of a 61-year-old man who had type B Wolff-Parkinson-White (WPW) syndrome with hypertrophic obstructive cardiomyopathy (HOCM). Due to paroxysmal atrial fibrillation, he underwent radiofrequency catheter ablation of the accessory pathway located in the right postero-lateral wall to prevent secondary symptomatic events. His LV dyssynchrony improved after the procedure, but the degree of the LV outflow tract (LVOT) pressure gradient was increased. To stabilize the LVOT pressure gradient, he needed additional medications. This case shows that patients with HOCM should be carefully evaluated before making a decision concerning ablation of the accessory pathway. ( 1,2) Radiofrequency catheter ablation (RFA) of the accessory pathway is acceptable first-time therapy for symptomatic WPW syndrome. On the other hand, hypertrophic obstructive cardiomyopathy (HOCM), which is characterized by LV outflow obstruction due to hypertrophy, predisposes the patients to hemodynamic collapse and thereby to a severe LV outflow tract (LVOT) pressure gradient.3) Although a previous report showed that 5% of patients with hypertrophic cardiomyopathy (HCM) had ventricular pre-excitation, the comorbidity of WPW syndrome and HOCM is rarely encountered in clinical practice.4) Patients with HOCM, generally, should be controlled with relative bradycardia, because the LV diastolic volume will be relatively increased and, accordingly, the LVOT pressure gradient will be relieved. In this regard, if they have an accessory pathway and experience AF, RFA is recommended for suppression of tachyarrhythmia. However, while deletion of the accessory pathway improves LV dyssynchrony, it may adversely affect the LVOT pressure gradient. There are some reports showing that the pressure gradient of HOCM is ameliorated by dual chamber pacing with short atrioventricular delay, which leads to LV dyssynchronous contraction. 5,6) In this regard, LV dyssynchrony might be required to relieve the LVOT pressure gradient of HOCM. We present a patient with both WPW syndrome and HOCM in whom the LVOT pressure gradient was affected by RFA.
Case ReportA 61-year-old man with no remarkable past medical history was brought to our hospital because of a pre-syncopal episode. He had felt chest discomfort and faintness about 30 minutes after lunch. His vital signs were stable and the symptoms had disappeared at the time of consultation. On physical examination, a systolic murmur was maximally audible from the middle left sternal border. There was no pitting edema in the lower extremities, and no abnormality in the neurological findings. Although most of his laboratory data were normal, his blood level of B-type natriuretic peptide (BNP) was high (325 pg/mL). A 12-lead electrocardiogram (ECG) showed a profound high-voltage of R wave (S wave in V1 ...
“…Decreased LV inotropy may also contribute to the reduction in obstruction ( 6 ). Optimization of the atrioventricular delay using a combination of echocardiography and the surface electrocardiogram (to ensure that there is no fusion between intrinsic and paced QRS complexes and therefore full pre-excitation from the apical pacing site) is crucial to ensure an optimal result ( 8 , 10 ). Figure 2 Suggested Mechanism of Action of RV Pacing to Reduce LVOTO (A) After transcatheter aortic valve replacement, the sudden reduction in left ventricular pressures reducing cross-sectional area of the left ventricular outflow tract and increasing flow across the aortic valve causes a Venturi-like effect on the mitral valve, with resultant dynamic left ventricular outflow tract obstruction (LVOTO).…”
We describe the first case of successful management of left ventricular outflow tract obstruction developing late after transcatheter aortic valve replacement with right ventricular apical pacing. The possible mechanisms of obstruction resolution are described. (
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