A new electrocardiogram algorithm for diagnosing loss of ventricular capture during cardiac resynchronisation therapy.

AIMS: The prerequisite for cardiac resynchronization therapy (CRT) is ventricular capture, which may be verified by analysis of the surface electrocardiogram (ECG). Few algorithms exist to diagnose loss of ventricular capture. METHODS AND RESULTS: Electrocardiograms from 126 CRT patients were analysed during biventricular (BV), right ventricular (RV), and left ventricular (LV) pacing. An algorithm evaluating QRS narrowing in the limb leads and increasing negativity in lead I to diagnose changes in ventricular capture was devised, prospectively validated, and compared with two existing algorithms. Performance of the algorithm according to ventricular lead position was also assessed. RESULTS: Our algorithm had an accuracy of 88% to correctly identify the changes in ventricular capture (either loss or gain of RV or LV capture). The algorithm had a sensitivity of 94% and a specificity of 96% with an accuracy of 96% for identifying loss of LV capture (the most clinically relevant change), and compared favourably with the existing algorithms. Performance of the algorithms was not significantly affected by RV or LV lead position. CONCLUSION: A simple two-step algorithm evaluating QRS width in the limb leads and changes in negativity in lead I can accurately diagnose the lead responsible for intermittent loss of ventricular capture in CRT. This simple tool may be of particular use outside the setting of specialized device clinics.

Comparison of tools and techniques for implanting pacemaker leads on the ventricular mid-septum.

INTRODUCTION: Many physicians target the interventricular septum for pacemaker implantation, but the lead may inadvertently end up in an anterior position. AIMS: We sought to compare two stylet shapes to achieve mid-septal lead placement, as well as the utility of a novel right anterior oblique (RAO) fluoroscopic landmark. METHODS AND RESULTS: Patients undergoing pacemaker implantation were enrolled into four consecutive groups according to stylet shape: a standard curve [two-dimensional (2D) stylet] or with an additional distal posterior curve [three-dimensional (3D) stylet], and whether RAO fluoroscopy was used. Left oblique anterior (LAO) and postero-anterior (PA) fluoroscopic views were used in all cases. After implantation, validation of right ventricular lead position (septal vs. anterior) was performed by echocardiography. A total of 113 patients were included, of whom lead position could be validated in 106 patients. Septal position was achieved in only 10 of 22 (45%) patients in the 2D stylet group and in 17 of 23 (74%) patients in the 3D stylet group (P = 0.07) when only PA and LAO fluoroscopy were used. Results were significantly improved by additional use of RAO fluoroscopy, with successful septal placement in 25 of 28 (89%) patients in the 2D stylet + RAO group (P = 0.001) and 32 of 33 (97%) patients in the 3D stylet + RAO group (P = 0.015). CONCLUSIONS: A septal lead position was obtained in only about half of the patients when a 2D stylet was used with only LAO and PA fluoroscopic views. A 3D stylet was useful to attain the target position, and additional RAO fluoroscopy significantly improved success rate with both stylet shapes.

Inappropriate mode switch consecutive to P-wave double counting.

We report a case of multiple inappropriate mode switches in a patient with a dual-chamber pacemaker, resulting from P-wave double counting due to a double potential on the atrial electrogram. The differential diagnosis of this rarely reported phenomenon is discussed.

Biatrial pacing improves atrial haemodynamics and atrioventricular timing compared with pacing from the right atrial appendage.

AIMS: Patients with interatrial conduction delay may have suboptimal left atrioventricular (AV) timing due to delayed contraction of the left atrium with foreshortening of ventricular filling. This may be an issue in pacemaker patients, especially those requiring resychronization therapy. Pacing from the high interatrial septum (IAS) or the distal or proximal coronary sinus (CSD and CSP) may improve left AV synchrony compared with pacing from the right atrial appendage (RAA). Our aim was to compare haemodynamics of these pacing sites. METHODS AND RESULTS: A total of 24 patients undergoing radiofrequency ablation for paroxysmal atrial fibrillation were studied. Left atrial pressures were recorded in sinus rhythm, and during pacing from the RAA, IAS, CSD, CSP, and with biatrial (BiA) pacing from the IAS + CSD. Amplitudes, +dP/dT(max), and timing of the a-wave were compared between recordings. Left atrial contractility, measured by +dP/dT(max), was greatest during BiA pacing (P ≤ 0.03 for all comparisons). There was a marked reduction in delay to peak a-wave when pacing from all sites compared with the RAA, with BiA pacing yielding the shortest delay (P ≤ 0.001). However, AV conduction was shortened by all alternative pacing sites, which mitigated the anticipation of left atrial contraction with respect to ventricular activation, except for BiA pacing (P < 0.001). Pacing of the IAS did not result in any improvement in haemodynamics or AV synchrony. CONCLUSION: Multisite atrial pacing results in favourable acute atrial haemodynamics and left AV synchrony. This may be a solution in pacemaker patients with interatrial conduction delay.

Listeria brain abscess, Pneumocystis pneumonia and Kaposi's sarcoma after temozolomide.

BACKGROUND: A 55-year-old man with glioblastoma multiforme was treated with continuous, dose-dense temozolomide. This therapy was curtailed after three cycles because of nausea, asthenia, and neuropsychological deterioration. During a subsequent course of radiotherapy, the patient developed fever, headaches, and cutaneous lesions. INVESTIGATIONS: Physical examination, cerebral MRI, brain biopsy, skin biopsy, immunohistochemistry, bronchoscopy with bronchoalveolar lavage, and laboratory tests. DIAGNOSIS: Severe temozolomide-induced immunosuppression, exacerbated by corticosteroids, with profound T-cell lymphocytopenia and simultaneous opportunistic infections with Pneumocystis jiroveci pneumonia, brain abscess with Listeria monocytogenes, and cutaneous Kaposi's sarcoma. MANAGEMENT: Discontinuation of temozolomide, discontinuation of radiotherapy, antibiotic treatment with amoxicillin and gentamicin, and administration of atovaquone and pentamidine.

Dramatic beneficial effects of sildenafil in recurrent massive pulmonary embolism.

OBJECTIVE: Sildenafil has a well established pulmonary vasodilatory effect, but has seldom been used in critically ill patients. We report a case of severe recurrent pulmonary embolism in which sildenafil was used as a rescue therapy. RESULTS: After oral administration of 50 mg of sildenafil, cardiac index increased from 2.11/min/m(2) to 3.21/min/m(2); mean pulmonary artery pressure decreased from 56 mmHg to 46 mmHg, and pulmonary vascular resistance index decreased from 700 dynes/cm(-5)/m(2) to 425 dynes/cm(-5)/m(2), without reduction of arterial systemic pressure. Clinical condition also improved during the following days under treatment of 50 mg sildenafil three times daily. CONCLUSIONS: These observations should stimulate studies with sildenafil in the ICU setting. Sildenafil is easy to administer in every ICU and at any time. If its potential is confirmed, it may be a life-saving drug in some emergency situations caused by severe pulmonary hypertension.