Impact of Heart Rate and Left Ventricular Mass on Survival Following Heart Transplantation

Abstract

Purpose Small studies suggest increased left ventricular (LV) mass and resting heart rate (HR)are associated with increased mortality following heart transplantation. We aimed to validate these prior findings and determine if resting HR is correlated with increased LV mass. Methods Retrospective chart review was conducted on 326 consecutive patients following heart transplantation at a single transplant center. Spearman correlation coefficient was used to evaluate correlation between HR and LV mass. Transplant free survival was estimated using the Kaplan-Meier method and survival was compared between groups using the log rank test. Results A total of 326 consecutive heart transplant patients between September 2005 and July 2018 were identified. The average age was 53.6 (± 14.3) years old, 238 patients (73%) were male, and the median follow-up time was 3.7 years. The average HR was 93 (12) beats per minute (BPM) at 1 month and 95 (12) BPM at 1 year. The average LV mass index was 87.1 g/m2 (21.8) at 1 month and 79.2 g/m2 (17.6) at 1 year. No correlation was present between HR and LV mass at 1 month (r=-0.25) or 1 year (r=-0.07). Stratification by resting HR at 1 year (HR ≥ 90 vs < 90) did reveal a trend toward reduced transplant-free survival in patients with an elevated HR (p=0.08) (Figure). Low LV mass index (<80g/m2) at 1-month post-transplant was associated with significantly reduced transplant-free survival (p=0.024) although this relationship was not present at 1 year. Conclusion Resting HR and LV mass following heart transplant were not correlated in our patient cohort. While a trend toward reduced survival in patients with a HR ≥ 90 bpm at 1 year was present, further research is needed to determine whether treatment targeting HR reduction would result in improved survival. Small studies suggest increased left ventricular (LV) mass and resting heart rate (HR)are associated with increased mortality following heart transplantation. We aimed to validate these prior findings and determine if resting HR is correlated with increased LV mass. Retrospective chart review was conducted on 326 consecutive patients following heart transplantation at a single transplant center. Spearman correlation coefficient was used to evaluate correlation between HR and LV mass. Transplant free survival was estimated using the Kaplan-Meier method and survival was compared between groups using the log rank test. A total of 326 consecutive heart transplant patients between September 2005 and July 2018 were identified. The average age was 53.6 (± 14.3) years old, 238 patients (73%) were male, and the median follow-up time was 3.7 years. The average HR was 93 (12) beats per minute (BPM) at 1 month and 95 (12) BPM at 1 year. The average LV mass index was 87.1 g/m2 (21.8) at 1 month and 79.2 g/m2 (17.6) at 1 year. No correlation was present between HR and LV mass at 1 month (r=-0.25) or 1 year (r=-0.07). Stratification by resting HR at 1 year (HR ≥ 90 vs < 90) did reveal a trend toward reduced transplant-free survival in patients with an elevated HR (p=0.08) (Figure). Low LV mass index (<80g/m2) at 1-month post-transplant was associated with significantly reduced transplant-free survival (p=0.024) although this relationship was not present at 1 year. Resting HR and LV mass following heart transplant were not correlated in our patient cohort. While a trend toward reduced survival in patients with a HR ≥ 90 bpm at 1 year was present, further research is needed to determine whether treatment targeting HR reduction would result in improved survival.