Two pacing spikes on the T wave in a single-chamber pacemaker: What is the mechanism?

We report a case of a 54-year-old female, known symptomatic sick sinus syndrome, who had undergone a single-chamber pacemaker (VVI, St. Jude Medical, VERITY ADxXL SC SN 2413520) implantation in 2011. Electrocardiography (ECG) performed on a recent visit to the pacemaker clinic showed intermittent double pacing spikes on top of the T wave (Fig. 1A). What is the mechanism?

A Novel pacing option in patients with endomyocardial fibrosis: A case series.

Endomyocardial fibrosis (EMF) is characterized by fibrous tissue deposition on the endocardial surface leading to impaired filling of one or both ventricles, resulting in either right or left heart failure or both. Although Sinus node dysfunction and tachyarrhythmia - atrial fibrillation, ventricular tachycardia, have been commonly reported, complete heart block (CHB) necessitating a pacemaker is rare in EMF. Transvenous pacing is technically limited by fibrotic obliteration of the affected ventricle that results in poor lead parameters, and alternative pacing strategy like epicardial pacing may be required in many. We report three cases of EMF, who were treated with an alternative pacing strategy.

Venous flow patterns after percutaneous atrial septal defect closure: Does the mechanical device decrease right atrial compliance?

INTRODUCTION: Systemic venous flow patterns become abnormal and restrictive after surgical closure of ostium secundum atrial septal defect (ASD) but rarely studied after percutaneous device closure. METHODS: From January 2017 to January 2018, systemic venous Doppler flow patterns were documented prospectively in 50 subjects who underwent percutaneous closure of ASD, prior to, after procedure, and at 6-month follow-up and correlated with defect size and device size. RESULTS: In hepatic veins and superior venacava post device-closure closure, the velocity time integral (VTI) of forward flow in both systole (S) and diastole (D) increased. Overall S was higher than D, and D/S ratio was <1. The D/S ratio increased after device closure significantly reflecting that the improvement in atrial filling increase in diastolic flow more than the increase in systolic flow. Increase in flow velocities was more prominent at 6 months with further increase in D/S VTI ratios. When correlated with the defect size, in those with defect size less than 15 mm/sq.m (mean device size 13.05 ± 3.21 mm), the changes in S- or D-wave, D/S ratio were less prominent and statistically not significant, while in subjects with defect size ≥ 15 mm/sq.m (mean device size 23.02 (±4.77 mm), these changes were greater and statistical significant. CONCLUSION: Residual filling defects with restriction of systolic venous flow were observed in subjects after device closure, correlating with larger device sizes, implying the compliance abnormality conferred by them which progresses at 6 months. Subjects with persistent abnormalities would need careful follow up for incomplete remodeling and increase in atrial size related arrhythmias.

A case of 'tachy-brady syndrome': What is the mechanism?

A young male presented with incessant narrow QRS tachycardia and left ventricular dysfunction. 24-Holter monitoring revealed multiple episodes of sustained and nonsustained episodes of tachycardia with prolonged sinus pauses at termination. The analysis of the electrocardiogram, followed by an invasive electrophysiological study, suggested an unusual mechanism for this tachy-brady syndrome.

Natural history of aortic valve disease following intervention for rheumatic mitral valve disease.

BACKGROUND AND AIM OF THE STUDY: A significant proportion of patients who require interventions for rheumatic mitral valve (MV) disease have coexisting aortic valve (AV) disease. To date, little is known of the natural history of AV disease in these patients. METHODS: The details of a cohort of 200 patients (146 females, 54 males; mean age at MV intervention 30.3 +/- 9.9 years) with rheumatic heart disease were retrospectively reviewed. The patients had undergone an index MV intervention (either closed or balloon mitral valvotomy) or MV replacement between 1994 and 1996, and received long-term regular follow up examinations. The clinical and echocardiographic data at entry and at follow up were noted. Patients were allocated to two groups, based on whether the AV disease was absent (group I, n=98) or present (group II, n=102) at baseline. The AV disease was categorized as thickening only (group IIA), isolated aortic regurgitation (AR) (group IIB), or combined aortic stenosis (AS) and AR (group IIC). No patient had isolated AS at baseline. RESULTS: The mean follow up period was 9.3 +/- 1.07 years; during which 10 patients in group I developed new AV disease, which included AV thickening only (n=2), trivial-mild AR (n=7) and mild AS with trivial AR (n=1). Of 16 patients in group IIA, 11 developed isolated AR, and one patient progressed to have mild AS and AR. Among 69 patients in group IIB, 22 (31.9%) developed AS, and all had either mild (n=8) or moderate (n=14) AR with mild AS. Group IIC included 17 patients with mild combined AV disease at baseline, except for moderate AS and moderate AR in one patient each. Among 16 patients with mild AS in group IIC, six progressed to moderate AS and two to severe AS. AR became moderate in 10 patients and severe in one patient. The two patients who progressed to severe AS requiring AV replacement had mild AS at baseline. No patient who developed new combined AV disease had lesions with severity more than mild AS or moderate AR. On logistic regression analysis of the variables predisposing to progression of AV disease, such as age, gender, history of rheumatic fever (RF) and recurrence, and interval from RF episode to symptom onset, only the initial AV gradient was identified as being statistically significant (beta coefficient 0.528, SE = 0.17, p < 0.0001). CONCLUSION: Patients with no or mild AV disease at the time of MV intervention rarely develop severe AV disease, and seldom require AV surgery over the long-term follow up. The presence of mild AS at baseline is predictive in the minority of cases where AV disease will progress relatively more rapidly.

Tako-tsubo cardiomyopathy in a patient with myasthenia gravis crisis: a rare clinical association.

Tako-tsubo cardiomyopathy (TTC) is increasingly being recognised as transient left ventricular dysfunction following various hyperadrenergic states such as emotional or physical stressors. The association of this rare clinical entity with myasthenia gravis (MG) has been reported only twice in the literature, both following plasmapheresis for MG crisis. Here we describe a unique case of TTC in a 40-year-old woman with MG admitted with MG crisis managed conservatively. This case suggests that plasmapheresis is unlikely to have a causative role in the development of TTC in these patients. Patients with MG crisis may be at potential risk of developing TTC and careful clinical and electrocardiographic monitoring is necessary while treating them. The possible role of stress as the common precipitating factor in both conditions is also discussed.