Juan Benezet-Mazuecos

Long‐Term Outcomes of Ivabradine in Inappropriate Sinus Tachycardia Patients: Appropriate Efficacy or Inappropriate Patients

Inappropriate sinus tachycardia (IST) is characterized by persistent and disproportional elevation of heart rate (HR). Ivabradine has been successfully used in some patients.

Silent ischaemic brain lesions related to atrial high rate episodes in patients with cardiac implantable electronic devices

AIMSnMonitoring capabilities of cardiac implantable electronic devices have revealed that a large proportion of patients present silent atrial fibrillation (AF) detected as atrial high rate episodes (AHREs). Atrial high rate episodes >5 min have been linked to increased risk of clinical stroke, but a high proportion of ischaemic brain lesions (IBLs) could be subclinical.nnnMETHODS AND RESULTSnWe prospectively analysed the incidence of AHRE > 5 min in 109 patients (56% men, aged 74 ± 9 years) and the presence of silent IBL on computed tomography (CT) scan. Mean CHADS2 and CHA2DS2VASc scores were 2.3 ± 1.3 and 3.9 ± 1.6, respectively. Seventy-five patients (69%) had no history of AF or stroke/transient ischaemic attack (TIA). After 12 months, 28 patients (25.7%) showed at least one AHRE. Patients with AHREs were more likely to have history of AF. Computed tomography scan showed silent IBL in 28 (25.7%). The presence of IBL was significantly related to older patients, prior history of AF or stroke/TIA, higher CHADS2 or CHA2DS2VASc scores, and the presence of AHRE. Multivariable analysis demonstrated that AHRE was an independent predictor for silent IBL in overall population [hazard ratio (HR) 3.05 (1.06-8.81; P < 0.05)] but also in patients without prior history of AF or stroke/TIA [HR 9.76 (1.76-54.07; P < 0.05)].nnnCONCLUSIONnCardiac implantable electronic devices can accurately detect AF as AHRE. Atrial high rate episodes were associated to a higher incidence of silent IBL on CT scan. Atrial high rate episodes represent a kind of silent AF where management recommendations are lacking despite the fact that a higher embolic risk is present.

Early Differential Resolution of Right and Left Ventricular Obliteration in Löffler Endocarditis After Chemotherapy and Anticoagulation

A 27-year-old woman diagnosed of T-cell non-Hodgkin lymphoma was referred to our hospital for allogenic hemopoietic stem cell transplantation. In childhood, the patient was diagnosed with hypereosinophilic syndrome. One week before admission, the patient started to develop progressive dyspnea. On chest x-ray, there were signs consistent with congestive heart failure. Her white cell count was 5990/mm3 with 59% eosinophils. A transthoracic echocardiogram disclosed a complete obliteration of the apexes of both ventricles, which were filled with a mildly echogenic material consistent with fibrosis or thrombosis. The right and left atria were enlarged, and pulsed wave Doppler examination showed a restrictive left ventricular (LV) filling pattern (Figure 1A through 1C). All of these findings were compatible with the diagnosis of Loffler endocarditis. The patient was anticoagulated and received conventional treatment for heart failure, resulting in clinical improvement. One week after admission, chemotherapy with fludarabine and melphalan was started, and a nonmyeloablative transplantation was carried out using hematopoietic progenitors from a human leukocyte antigen–compatible brother. Four weeks after chemotherapy, a repeat echocardiogram showed the total disappearance of the LV obliteration and a normal filling …

Long-term prognosis of patients with life-threatening ventricular arrhythmias induced by coronary artery spasm

AimsnCoronary artery spasm (CAS) is associated with ventricular arrhythmias (VA). Much controversy remains regarding the best therapeutic interventions for this specific patient subset. We aimed to evaluate the clinical outcomes of patients with a history of life-threatening VA due to CAS with various medical interventions, as well as the need for ICD placement in the setting of optimal medical therapy.nnnMethods and resultsnA multicentre European retrospective survey of patients with VA in the setting of CAS was aggregated and relevant clinical and demographic data was analysed. Forty-nine appropriate patients were identified: 43 (87.8%) presented with VF and 6 (12.2%) with rapid VT. ICD implantation was performed in 44 (89.8%). During follow-up [59 (17-117) months], appropriate ICD shocks were documented in 12. In 8/12 (66.6%) no more ICD therapies were recorded after optimizing calcium channel blocker (CCB) therapy. SCD occurred in one patient without ICD. Treatment with beta-blockers was predictive of appropriate device discharge. Conversely, non-dihydropyridine CCB therapy was significantly protective against VAs.nnnConclusionnPatients with life-threatening VAs secondary to CAS are at particularly high-risk for recurrence, especially when insufficient medical therapy is administered. Non-dihydropyridine CCBs are capable of suppressing episodes, whereas beta-blocker treatment is predictive of VAs. Ultimately, in spite of medical intervention, some patients exhibited arrhythmogenic events in the long-term, suggesting that ICD implantation may still be indicated for all.

Limitations of the AutoCapture™ Pacing System in patients with cardiac stimulation devices

AIMSnAutoCapture (St Jude Medical) is a technological development that confirms ventricular capture analysing the evoked response after a pacing impulse and adjusts the energy output to changes in the stimulation threshold. Although this algorithm is aimed to assure capture minimizing energy consumption, some patients might not benefit from it. The objective of this study is to identify them.nnnMETHODS AND RESULTSnLong-term AutoCapture efficiency was assessed using the data recorded in the programmer reports of patients undergoing scheduled pacemaker check-ups during 2012 in our institution. We have evaluated 160 consecutive patients (58% men) aged 78 ± 9 years. Pacemaker stimulation mode was DDD in 116 patients (72.5%) and VVI in 44 patients (27.5%). During the scheduled visits for pacemaker check-up, 73 patients (45.6%) showed abnormalities in the long-term AutoCapture function report (high variability in the AutoCapture stimulation threshold and/or out-of-range values). After multivariate analysis, abnormal AutoCapture pattern was associated to the presence of atrial fibrillation [odds ratio (OR) 3.96 (1.59-9.82; P < 0.05)]; and a ventricular pacing ≤25% of the time [OR 4.80 (2.09-11.05; P < 0.05)]. AutoCapture abnormalities were also described in three (1.8%) patients with very low stimulation threshold.nnnCONCLUSIONnAlthough AutoCapture algorithm has shown both efficacy and safety, our findings suggest that some patients with atrial fibrillation or those requiring ventricular pacing ≤25% of the time may not benefit from it. Activation of the algorithm should be individualized according to the patients characteristics and long-term AutoCapture pattern checked in the routine follow-up.

Anodal Stimulation in Biventricular Pacing: Unrecognized and Misinterpreted Phenomenon

An 84-year-old patient with history of nonischemic dilated cardiomyopathy with severe systolic dysfunction (left ventricular ejection fraction [LVEF] 30%), heart failure symptoms (New York Heart Association [NYHA] class III), sinus rhythm, and left bundle branch block (LBBB; QRS duration 140 ms) with a cardiac resynchronization therapy (CRT) pacemaker AnthemTM (St. Jude Medical, St. Paul, MN, USA) attended to scheduled device check-up (Fig. 1). Since CRT implantation 1 year before, the patient’s clinical situation had mildly improved to NYHA classes II-III, and LVEF was 35%. Device interrogation showed a biventricular pacing >99%. Right atrial and right ventricular (RV) stimulation threshold tests were performed normally (0.75 V at 0.4 ms and 0.75 V at 0.5 ms, respectively). Automatic left ventricular (LV) stimulation threshold was 3.0 V at 0.5 ms in bipolar configuration (tip LV—proximal ring RV). In order to optimize LV output, stimulation threshold for both configurations (bipolar and unipolar) were assessed using simultaneous electrocardiogram recording. LV stimulation threshold test in unipolar configuration showed a threshold of 2.75 V at 0.5 ms. LV threshold test in bipolar configuration (tip LV—proximal ring RV) showed an interesting phenomenon: at the beginning of the test, LV stimulation produced narrow biventricular stimulation QRS morphology; with the decreasing output energy it changed to RV stimulation QRS morphology and finally it showed lost capture (Fig. 2).

Inappropriate automatic mode switching episodes: What's the mechanism?

We present a case series of five patients reporting abnormal automatic mode switching (AMS) episodes during routinary cardiac defibrillator (ICD) and pacemaker (PM) follow-up. This non-previously described phenomenon was reported to St. Jude Medical (Abbott) Technical Support that confirmed the inappropriate automatic mode switching.

Things are not always what they seem: pacemaker dysfunction or just a technical limitation?

A routinary electrocardiogram (ECG) performed in a 90-year-old patient with sinus node disease and a dual-chamber pacemaker (Endurity MRI, St. Jude Medical) programmed in DDDR mode showed atrial fibrillation (AF) with abnormal stimulation spikes: atrial pacing (AP) despite the presence of AF and ventricular pacing with too short R-R wave intervals or even on the T wave. What are we dealing with? The ECG shows three typical phenomena related to atrial undersensing during AF: atrial pacing (AP) over undetected atrial high-rate activity and ventricular pacing (VP) over the programmed high-rate limit due to ventricular undersensing during post-atrial pacing ventricular blanking interval (PAP VBi) and ventricular safety pacing interval (VSPi). ‘A’ shows AP, despite the presence of AF. We can appreciate

Novel electrocardiographic findings related to new cardiac electronic devices functions

An 81-year-old man was evaluated in the out-patient clinic after pacemaker generator replacement with an ECG performed in that moment that was described as “loss of capture in the stimulated beats” and “abnormal number of stimulation spikes” (Fig. 1). The patient was then referred to the ER for pacemaker interrogationwith the suspected diagnosis of pacemaker dysfunction. Seven years ago, the patient had received a dual-chamber pacemaker DDDR because of symptomatic sinus node dysfunction associated to first degree AV-block, left anterior hemiblock and right bundle brunch block. The patient underwent routinary pacemaker controls every year showing normal parameters but an increased right ventricle stimulation threshold (around 3 V at 0.50 ms). It was stable during the last 3 years, without changes in detection values or impedance. When the battery showed ERI (Elective Replacement Indicator), a new generator was implanted (St. Jude Accent ® DR, Minneapolis, USA). This pacemaker is equipped with the AutoCaptureTM Pacing System Technology. Many useful technological improvements have occurred since the first pacemaker implantation in 1958. This ECG illustrates howone of the most used automatic algorithms of the new generation pacemakers, the AutoCaptureTM, works. The AutoCaptureTM Pacing System is an algorithm designed to confirm a response (capture) to each of the pacemaker stimulations and to automatically adjust the energy output of the primary pacing pulse in response to changes in the threshold. This principle is based on the pacemakers ability to recognize the evoked response (the signal resulting from the electrical activation of the myocardium by a pacemaker stimulus) without beingmisled by residual polarization at the electrode–tissue interface [1]. This system monitors every beat for the presence of an evoked response signal and assures capture. After loss of capture, the device automatically searches the thresholds on a regular basis to determine the output energy level requirement. For this operation the AV interval is shortened to a programmable duration (usually 40–50 ms) during the test to avoid fusion with conducted beats. Loss of capture recovery triggers an automatic backup safety pulse to ensure capture in the absence of an evoked response. Automatic output regulation sets the output just above themeasured threshold (0.25 V over the threshold), ensuring the lowest energy level required for capture and thus optimizing device longevity (Fig. 2). The AutocaptureTM algorithm not only decreases energy consumption by keeping the stimulation output slightly above the actual threshold, but also increases patient safety by access to highoutput back-up pulses if there is loss of capture. It offers to the physicians an improved patient safety, a follow-up efficiency and longer device longevity by confirming beat-by-beat capture of each pacemaker stimulation [2].

Atypical left bundle branch block in dilative "burned-out" phase of hypertrophic cardiomyopathy.

We present the case of a 70‐year‐old man admitted in congestive heart failure. The patient was diagnosed 22 years ago of hypertrophic cardiomyopathy (HC). ECG showed a very peculiar and pathological form of left bundle branch block (LBBB). 2D‐echocardiogram revealed a dilated left ventricle (LV) and ejection fraction of 25%. LV remodeling represents an important component of the pathophysiology of HC and, paradoxically, some patients develop LV wall thinning, systolic dysfunction, and congestive heart failure (in the absence of coronary artery disease). This evolution is designated as “end‐stage” or “burned‐out” phase. We present this rare LBBB and his pathological evolution along the time as unique manifestation of this “burned‐out” phase. The mechanism of this wall thinning remains unclear but changes in ECG may alert us about it.