Beneficial Effect of Dual-Chamber Pacing for a Left Mid-Ventricular Obstruction With Apical Aneurysm.

Abstract

t has been well established that dual-chamber pacing reduces the pressure gradients in the left ventricular outflow tract (LVOT) and improves the symptoms of hypertrophic obstructive cardiomyopathy. [1][2][3][4][5] However, the effect of pacing therapy on a hypertrophic mid-ventricular obstruction (MVO) with an apical aneurysm has rarely been described 6 and we report such a case that was dramatically improved by dual-chamber pacing.This report is of special interest from 2 points of view. We demonstrate, on the basis of this case, that the pacing therapy was effective in not only reducing intraventricular pressure gradient, but also in preventing sustained ventricular tachycardia (VT). Secondly, we are the first to attempt to evaluate the intraventricular flow dynamics during pacing in such a case. Case ReportA 63-year-old woman suffered chest discomfort with a syncope attack and was admitted to hospital. Her past history and familial history were unremarkable. The 12-lead electrocardiogram (ECG) on admission showed sustained monomorphic VT (170 beats/min) with a right bundle branch block pattern in V1 and a QS pattern in leads I, II, III, aVF and V2-6, and an axis of -140°. These findings were Circulation Journal Vol.66, October 2002 similar to those seen with VT originating from the septoapical area of the left ventricle (Fig 1). 7 After spontaneous recovery to sinus rhythm 40 s later, the ECG showed negative T waves in leads I, II, III, aVF and V1-6 with slight ST elevation in III, aVF and V4 (Fig 1). Holter monitoring showed 2 episodes of sustained monomorphic VT (30-40 s), 1,220 episodes of nonsustained monomorphic VT and 355 episodes of couplet ventricular extrasystoles per day. Although a -blocking agent is the drug of choice, it did not completely suppress the VT. The 2-dimensional echocardiographic examination revealed left mid-ventricular hypertrophy at the papillary muscle level and a discrete Invasive assessment of intraventricular pressure showed a peak-to-peak gradient greater than 100 mmHg. Treatment with antiarrhythmic agents could not prevent the VT, but dual-chamber pacing reduced the intraventricular pressure gradient and suppressed the VT completely. Continuous wave Doppler showed that the early systolic ejection flow from the apex had disappeared, that there was isovolumetric relaxation flow toward the apex and that there was attenuation of the diastolic paradoxical jet flow toward the basal chamber. Such findings by continuous wave Doppler can be useful in pacing therapy for evaluating changes in the severity of mid-ventricular obstruction. (Circ J 2002; 66: 981 -984)

Phenotypic overlap in hypertrophic cardiomyopathy: Apical hypertrophy, midventricular obstruction, and apical aneurysm

“…Numerous previous case reports and studies have suggested the existence of overlap between APH, MVO, and APA [8,9,12,13,[16][17][18][19][20][21][22][23]. APH has often been complicated by MVO in previous case reports and studies [9,13,18,20,23].…”

“…A reduced capillary myocardial ratio, small vessel disease, and other factors may also cause regional apical ischemia and lead to the development of apical infarction and APA [27,28]. Previous case reports and studies have indicated that MVO is likely to complicate APA in patients with HCM [8,9,[16][17][18][20][21][22]. Figali and colleagues [29] reported that patients with the MVO variant of HCM are at a higher risk of developing left ventricular hypokinesia or APA formation.…”

“…APA is a rare variant of HCM, in which there is a thin-walled dyskinetic or akinetic segment at the most distal portion of the chamber that has relatively wide communication with the left ventricular cavity [8]. While numerous previous case reports and studies have suggested the existence of considerable overlap between APH, MVO, and APA [8,9,12,13,[16][17][18][19][20][21][22][23], the clinical courses of the above three forms of HCM seem to be heterogeneous. Our previous study and a report by Maron and colleagues have demonstrated a largely unfavorable clinical course for HCM patients with MVO and/or APA [8,9].…”

Mid-Ventricular Obstructive Hypertrophic Cardiomyopathy Associated with an Apical Aneurysm: Evaluation of Possible Causes of Aneurysm Formation

“…Generally, beta blockers are the first choice of treatment for patients with subaortic obstructive hypertrophic cardiomyopathy,12 but the optimal treatment for MVOHCM has not yet been established. Dual-chamber pacing13,14 and percutaneous myocardial ablation6,15 have been proposed as non-surgical treatments, but their long-term prognosis and procedural safety await further observation with a large patient population.…”

Percutaneous Myocardial Ablation for Left Mid-Ventricular Obstructive Hypertrophic Cardiomyopathy

“…Randomized trials have shown a limited hemodynamic and clinical improvement in severely symptomatic patients with hypertrophic obstructive cardiomyopathy [11,12]. Although there is single report of a therapeutic effect of DDD pacing in MVO [13], it cannot be recommended for routine application due to failure of reliable predictability of individual therapeutic success [11,12,14]. Recently, myocardial ablation for pressure gradient reduction in patients with MVO has been reported [15].…”