Admission Cardiac Diagnostic Testing with Electrocardiography and Troponin Measurement Prognosticates Increased 30-Day Mortality in COVID-19.

Background Cardiovascular involvement in coronavirus disease 2019 (COVID-19) is common and leads to worsened mortality. Diagnostic cardiovascular studies may be helpful for resource appropriation and identifying patients at increased risk for death. Methods and Results We analyzed 887 patients (aged 64±17 years) admitted with COVID-19 from March 1 to April 3, 2020 in New York City with 12 lead electrocardiography within 2 days of diagnosis. Demographics, comorbidities, and laboratory testing, including high sensitivity cardiac troponin T (hs-cTnT), were abstracted. At 30 days follow-up, 556 patients (63%) were living without requiring mechanical ventilation, 123 (14%) were living and required mechanical ventilation, and 203 (23%) had expired. Electrocardiography findings included atrial fibrillation or atrial flutter (AF/AFL) in 46 (5%) and ST-T wave changes in 306 (38%). 27 (59%) patients with AF/AFL expired as compared to 181 (21%) of 841 with other non-life-threatening rhythms (P<0.001). Multivariable analysis incorporating age, comorbidities, AF/AFL, QRS abnormalities, and ST-T wave changes, and initial hs-cTnT ≥20 ng/L showed that increased age (HR 1.04/year), elevated hs-cTnT (HR 4.57), AF/AFL (HR 2.07), and a history of coronary artery disease (HR 1.56) and active cancer (HR 1.87) were associated with increased mortality. Conclusions Myocardial injury with hs-cTnT ≥20 ng/L, in addition to cardiac conduction perturbations, especially AF/AFL, upon hospital admission for COVID-19 infection is associated with markedly increased risk for mortality than either diagnostic abnormality alone.

Twelve hours of sustained ventricular fibrillation supported by a continuous-flow left ventricular assist device.

Left ventricular assist device (LVAD) therapy improves survival and quality of life by mechanically unloading the left ventricle and maintaining hemodynamics in patients with end-stage heart failure. LVADs can also be lifesaving by maintaining hemodynamics during ventricular arrhythmia. Continuous-flow LVADs have become the preferred LVAD technology. As presented here, a continuous-flow LVAD successfully provided hemodynamic support to a patient in sustained ventricular fibrillation for over 12 hours when the internal defibrillator was unable to terminate the arrhythmia. This case demonstrates that continuous-flow LVADs can be lifesaving in the setting of otherwise certain hemodynamic collapse from sustained ventricular fibrillation.

Rate responsive pacing using cardiac resynchronization therapy in patients with chronotropic incompetence and chronic heart failure.

AIMS: Chronotropic incompetence (CI) is a common finding in patients with advanced chronic heart failure (CHF) and is associated with a worse functional capacity. Whether rate responsive pacing with cardiac resynchronization therapy (CRT) would acutely improve exercise performance in patients with advanced CHF and severe CI (<70% age-predicted maximum heart rate) is unknown. METHODS AND RESULTS: Patients (n = 13) with CHF, a CRT device, and severe CI were randomized in a double-blind crossover pilot study to either DDD (control) or DDDR (rate responsive) pacing. Six minutes walk test (6MWT) distance, oxygen consumption at anaerobic threshold (VO(2) @ AT), and maximal oxygen consumption (VO(2) max) were measured. One week later, testing was repeated in the alternate pacing mode. Rate responsive pacing commenced with standard settings in only 9 of 13 (69%) patients. In these 9 subjects, 6MWT distance improved acutely from 358.5 ± 40.7 to 376.8 ± 24.5 m with DDDR pacing (P< 0.05). VO(2) max did not improve with DDDR pacing (14.0 ± 3.2 mL/kg/min) compared with DDD pacing (13.9 ± 3.0 mL/kg/min; P= 0.69). VO(2) @ AT tended towards improvement with DDDR pacing (10.8 ± 2.9 mL/kg/min) compared with DDD pacing (9.6 ± 1.8 mL/kg/min; P= 0.29). There was a linear relationship between the increase in heart rate at minute 3 during rate responsive pacing and improvement in VO(2) @ AT (r = 0.83, P< 0.05). CONCLUSION: When rate responsive pacing using a CRT device is achieved in patients with advanced CHF and severe CI, parameters of aerobic exercise performance improve acutely. Routine exercise testing to ensure successful restoration of heart rate response may be beneficial to optimize CRT settings in this patient population.

Dexmedetomidine related cardiac arrest in a patient with permanent pacemaker; a cautionary tale.

Dexmedetomidine (Precedex), an alpha-2 adrenergic receptor agonist is frequently and safely used as sedative agent during surgical procedures. We report a case of a 76-year-old woman who developed cardiac arrest from the use of dexmedetomidine during pacemaker lead extraction procedure.

Pacing in obstructive hypertrophic cardiomyopathy: a therapeutic option?

Hypertrophic cardiomyopathy (HCM) is a heterogeneous disease of cardiac muscle which can present with myriad functional and clinical manifestations. When symptoms and left ventricular outflow gradients are present, it is primarily treated with pharmacologic agents. For refractory patients, dual chamber pacing has been proposed; by altering timing and site of cardiac electrical activation, the hemodynamic abnormalities in HCM may be modified. Results of non-randomized and randomized trials have shown an average gradient reduction of 50%. However, pressure gradient reduction within the left ventricular outflow tract (LVOT) has not translated into improved objective functional measurements, even though subjective parameters may improve. Dual chamber pacing cannot be recommended as primary treatment for obstruction except in a subset of patients who are elderly or have significant comorbidities that preclude surgery. However, many patients will now receive implantable cardioverter-defibrillators (ICD) which will include both right atrial and right ventricular leads. This will allow DDD pacing which may be utilized for symptom palliation. Future investigations will determine if alternate forms of pacing, including left atrial or left ventricular pacing, may improve objective measures in these patients.