Why is the patient still symptomatic after myectomy for HCM!

We describe the case of a young female patient with hypertrophic cardiomyopathy (HCM) with a dual chamber implantable cardioverter defibrillator (ICD), and complete heart block from a prior septal ablation procedure. Due to persistent left ventricular outflow tract (LVOT) obstruction and symptoms, she underwent surgical myectomy. Her exertional symptoms continued despite improved LVOT flow parameters. A comprehensive evaluation, including ICD interrogation, helped arrive at the correct diagnosis and treatment plan.

Abdominal Emergency After Subcutaneous ICD Implantation.

We describe a previously unreported and potentially fatal complication of colonic perforation following the implantation of a subcutaneous implantable cardioverter-defibrillator in a young patient with nonischemic cardiomyopathy. We discuss the importance of technique and postprocedural evaluation for subdiaphragmatic complications. This description emphasizes presenting complaints, early recognition, and management strategies. (Level of Difficulty: Beginner.).

Device Pocket Challenges in Elderly and Thin Individuals.

Aging results in loss of subcutaneous body fat as well as lean body mass. Elderly patients are also more likely to require cardiac implantable electronic devices (CIED) due to rising cardiovascular disease prevalence. A majority of the currently available devices require placement in a pocket created in the subcutaneous space between the subcutaneous fat tissue and the underlying chest wall muscle. Deficient subcutaneous fat tissue can result in device protrusion and even erosion through the skin. This can lead to significant morbidity and mortality especially when associated with device infection and need for device system extraction. This article reviews the scope of the problem and some of the strategies that can be employed to address the lack of subcutaneous soft tissue at the time of device implant.

Predictors of ventricular pacing burden after permanent pacemaker implantation following transcatheter aortic valve replacement.

BACKGROUND: In the era of an expanding use of transcatheter aortic valve replacement (TAVR), conduction disturbances and the requirement for permanent pacemaker (PPM) implantation remains a clinical concern. HYPOTHESIS: Using a single-center experience, we sought to identify predictors of ventricular pacing burden after TAVR in patients who required PPM implantation. METHODS: We conducted a retrospective study of 359 consecutive patients with symptomatic severe aortic valve stenosis who underwent TAVR at our institution between September 2013 and July 2019. Thirty patients (8.4%) required a PPM within 30 days after TAVR. Pre and post-TAVR electrocardiograms, pre-TAVR echocardiograms and computed tomography (CT), TAVR procedural details and post-TAVR device interrogation records at 1, 3, and 6 months were reviewed. RESULTS: Mean percentage of ventricular pacing (VP%) at 1, 3, and 6 months was 58%, 59%, and 56% respectively. Using univariate logistic regression analysis, patients who had low VP% < 5% at 6 months were more likely to have a prosthesis/echocardiography-derived left ventricular outflow tract (LVOT) diameter ratio < 1.3 (OR 7.00, P-value .048), prosthesis/CT-derived aortic annulus diameter ratio < 1.02 (OR 7.11, P-value .047), post-TAVR new-onset LBBB (OR 16.80, P-value .019), time to PPM implantation greater than 2 days post-TAVR (OR 9.38, P-value .026) and pre-TAVR use of a beta blocker (OR 9.40, P-value .026). CONCLUSIONS: In patients who required a PPM implantation post-TAVR, a lower TAVR prosthesis/LVOT or aortic annulus diameter ratio, post-TAVR new-onset LBBB and later time of PPM implantation showed a trend toward predicting a low VP% at 6 months.

The QuantumCor device for treating mitral regurgitation: an animal study.

OBJECTIVES: The mitral annular contraction achieved could help reduce mitral regurgitation (MR), and with appropriate modifications, be applied to human subjects providing a potentially effective percutaneous method of valve repair. BACKGROUND: MR is an important source of morbidity and is an independent predictor of mortality. A variety of percutaneous approaches are being developed to address this issue. We introduce a novel potential method utilizing radiofrequency (RF) energy to heat and shrink the mitral valve annulus in an animal model. METHODS: In open-heart procedures in 16 healthy sheep (six with naturally occurring MR), we used a malleable probe (QuantumCor, Lake Forest, CA) that conforms to the annular shape to deliver RF energy via a standard generator to replicate a surgical mitral annular ring. Seven sheep were followed chronically and their mitral annulus dimensions measured serially. RESULTS: All sheep underwent intracardiac echocardiography or direct circumferential measurement of the mitral annulus before and after RF therapy. RF therapy was administered in less than 4 min in each case, and the mean anteroposterior (AP) annular distance was reduced by a mean of 23.8% (AP diameter reduction 5.75 +/- 0.86 mm, P < 0.001) acutely. In the six sheep with nonischemic MR, regurgitation was eliminated. Acute histopathology (HP) demonstrated no damage to the leaflets, coronary sinuses, or coronary arteries. At the end of the intended 6-month period of the chronic part of the study, four of the seven animals survived. The four treatment animals showed significant reductions in mitral A-P dimension, with a percent diameter reduction of 26.4% (AP diameter reduction 7 +/- 2.3 mm). CONCLUSION: The application of RF directly to heat the mitral annulus has resulted in sustained contraction of the annulus in this limited preclinical animal study. With further study and possible modifications, it holds promise for future application in human subjects with MR.

A Case of Right Bundle Branch Block With Changing Axis.

A man in his 80s presented with recurrent presyncope and bradycardia. An electrocardiogram showed atrial fibrillation with an irregular ventricular rate of around 60 beats per minute, right bundle branch block, and left posterior fascicular block. What would you do next?

Hypersensitivity Reactions to oxaliplatin: incidence and management.

Oxaliplatin (Eloxatin) is a novel platinum compound that has activity in a wide variety of tumors. Several hypersensitivity reactions distinct from laryngopharyngeal dysesthesia have been described. We retrospectively analyzed 169 consecutive patients who received oxaliplatin for esophageal or colorectal cancer between 1/1/00 and 7/31/02 and reviewed any significant adverse reactions labeled as hypersensitivity reactions. Thirty-two patients (19%) reportedly experienced hypersensitivity. Skin rash was the most common event (22 patients), occurring after a median of three infusions. Fever was seen in five patients after a median of two infusions. Five patients experienced respiratory symptoms at median infusion number 6. Ocular symptoms of lacrimation and blurring of vision were seen in two patients. Five patients experienced more than one type of reaction. Treatments prescribed for hypersensitivity were antihistamines, steroids, and topical emollients. One patient developed grade 4 hypersensitivity during cycle 6, characterized by laryngeal edema, tongue swelling, and labored breathing. This patient underwent a desensitization procedure, adapted from guidelines for carboplatin (Paraplatin) allergy. Subsequently, three cycles were administered over 6 hours and were well tolerated. However, during the fourth infusion postdesensitization, the patient developed recurrent signs of hypersensitivity. In conclusion, hypersensitivity is frequently seen with oxaliplatin, but most reactions are mild.

Supraventricular and ventricular arrhythmias.

Cardiac arrhythmias comprise of a heterogeneous group of disorders which manifest in a wide range of clinical presentations. They can be associated with underlying cardiac disease and portend a grave prognosis, with some arrhythmias being rapidly fatal. Other arrhythmias, however are relatively benign and can be asymptomatic or may be a mere inconvenience for the patient. All primary care physicians can expect to encounter some forms of arrhythmias during the course of their practice. This review article provides a brief overview of the commonly seen tachyarrhythmias for the general practitioner and provides relevant updates on the recent developments in our understanding of their mechanisms and management.

Effect of head-up tilt-table testing on left ventricular longitudinal strain in patients with neurocardiogenic syncope.

Recent studies have shown conflicting data regarding left ventricular (LV) function in patients with neurocardiogenic syncope, with some investigators reporting a marked decrease in LV end-systolic wall stress and stress-corrected fractional shortening. We sought to determine the characteristics of resting LV deformation in patients with neurocardiogenic syncope by selective motion tracking of subendocardial and subepicardial regions using speckle tracking echocardiography. We assessed resting LV function in 82 patients undergoing head-up tilt-table (HUTT) testing. Patients were divided into 3 groups based on a positive HUTT test with associated co-morbid conditions (n = 30), no associated co-morbid conditions (n = 30), or negative HUTT results (n = 22). LV longitudinal, circumferential, and radial strains were obtained by speckle tracking echocardiography of subendocardial and subepicardial regions in each group and compared with resting LV deformation in 20 healthy control subjects. Compared with endocardial longitudinal strain in control subjects, that in patients with positive HUTT results was attenuated, irrespective of co-morbid conditions (p <0.05). Circumferential and radial strains did not differ among groups. On multivariate logistic regression analysis, endocardial longitudinal strain was an independent predictor (odds ratio, 1.16; p = 0.01) of positive HUTT test results. In conclusion, resting LV longitudinal strain is attenuated in patients with positive HUTT test results. Overall, these results may suggest that an increase in resting LV contractility is not a prerequisite for development of neurocardiogenic syncope.

Newer oral anticoagulant agents: a new era in medicine.

After a gap of almost 60 years following the development of warfarin, 2 new categories of oral anticoagulant agents have been approved for clinical use - the direct thrombin inhibitors and factor Xa inhibitors. These agents promise to be more convenient to administer with fixed dosing but still have equivalent efficacy and improved bleeding risk compared to warfarin. The clinical community is looking forward to the widespread usage of these agents but there is also some apprehension regarding bleeding risks, non-availability of specific reversal strategies and lack of specific monitoring parameters. This review article will attempt to educate the reader about three representative drugs from these classes: Dabigatran, Rivaroxaban and Apixaban. We will discuss the historical perspective to the development of these drugs, available research data and pharmacology of these agents. The best strategies for monitoring and reversal of these drugs in special situations will also be touched upon.

Pacing polarity and left ventricular mechanical activation sequence in cardiac resynchronization therapy.

OBJECTIVE: The aim of this study is to evaluate the relationship between polarity of left ventricular (LV) pacing and the resultant regional, global, and transmural mechanical sequence of contraction. BACKGROUND: Cardiac resynchronization therapy (CRT) is widely utilized in patients with drug refractory congestive heart failure with systolic dysfunction (EF <35 %) and intraventricular conduction delay (QRS duration >120 ms). However, little is known about polarity of pacing stimulation and the resultant differences in LV mechanics. METHODS: The polarity of pacing was altered sequentially in 20 patients (73 ± 13, 16 males) with preexisting biventricular devices with potential choice of multiple vectors for pacing stimulation. Initial unipolar or extended bipolar configurations were switched to bipolar configuration or vice versa, and echocardiographic images were acquired for off-line analysis. Regional and global LV longitudinal and radial mechanics were assessed selectively from the subendocardial and subepicardial regions with 2D speckle-tracking echocardiography. Left ventricular capture by each vector configuration was confirmed by local lead capture and appropriate QRS alteration. RESULTS: Unipolar pacing resulted in increased dispersion of LV regional endocardial strains with a higher base-to-apex gradients of longitudinal shortening strains (P < 0.05). LV longitudinal shortening strain magnitude was higher at LV base with bipolar stimulation in comparison with unipolar stimulation (-10.5 ± 10.5 vs. -4.2 ± 6.3, P = 0.02). CONCLUSION: There is a difference in the mechanical activation sequence of the LV between unipolar vs. bipolar pacing stimulation. This may have important implications for CRT.